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Journal
Sustainable Design & Applied Research in Engineering and the Built Environment November 2014 Issue 4
The Journal of Applied Research in Innovative Engineering and the Built Environment
School of Multidisciplinary Technologies
Building Servicesnews
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Areas of research
Focus on applied research The School of Electrical and Electronic Engineering (SEEE) in the Dublin Institute of Technology focuses on applied research with a strong emphasis on producing useful and novel ideas to help Irish
U U U U U U U U U U U U U U
Biomedical Engineering Assistive Technology and Health Informatics Audio Engineering Wireless Comms Photonics Sensing for Structures RF Propagation Microelectronic Circuits and Systems Control Systems and Robotics Engineering Education and Teaching & Learning Pedagogy Information and Communications Security Sustainable Design Energy Management Lighting Renewable Technologies
industry compete globally.
Each year SEEE research produces patents and technologies to licence and most recently has resulted in a spin-out company in the area of mobile communications. SEEE research is recognised for its impact and quality, which in many cases is on a par with that of the very best groups internationally. Researchers in the school have also built strong collaborations with internationally-renowned groups in Europe, India, China and elsewhere, allowing the School’s researchers to access unique research knowledge and facilities. Contact Professor Michael Conlon Head of School Tel: +353 1 402 4617/4650/4575 Email: seee.admin@dit.ie
School Research Centres The Antenna & High Frequency Research Centre (AHFR) ahfr.dit.ie/ The Dublin Energy Lab (DEL) dublinenergylab.dit.ie/ dublinenergylab/ The Photonics Centre (PRC) prc.dit.ie/ The Electrical Power Research Centre (EPRC) dit.ie/eprc/ The Communications Network Research Institute (CNRI) cnri.dit.ie/
www.dit.ie/colleges/collegeofengineeringbuiltenvironment/collegeresearch/
Contents
Introduction
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Editor’s foreword
Welcome to the the fourth edition of the SDAR Journal which the Chartered
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A reader’s guide to this issue
Institute of Buildings Services Engineers (CIBSE) in Ireland is delighted to partner with the Dublin Institute of Technology (DIT) in producing this exciting publication.
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Implementation of ISO 50001 Energy Management System in Sports Stadia Aidan Byrne, Martin Barrett and Richard Kelly
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A new approach to interior lighting design: early stage research in Ireland James Duff and Kevin Kelly
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Leveraging Lean in construction: A case study of a BIM-based HVAC manufacturing process Colin Conway, Colin Keane, Sean McCarthy, Ciara Ahern and Avril Behan
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Retrofit electrochromic glazing in a UK office Ruth Kelly Waskett, Birgit Painter, John Mardaljevic and Katherine Irvine
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The partnership approach between CIBSE and DIT is an excellent example of industry and third-level colleges working together in response to the need for more research in the areas of sustainability and low-energy technology. Compiling the results of some of this research in a single journal makes for a valuable source of information to researchers, designers and all involved in the built environment. The recovery that we are experiencing in the construction sector at present is giving rise to an increased demand for engineering solutions that are innovative, and this only can be delivered by detailed investigation of new ideas and new technology. In Ireland we are fortunate to have highly-educated and capable engineers and scientists who can deliver on the demand for this detailed research. The various events that CIBSE Ireland organises in conjunction with the DIT, such as the Irish Lighter, Young Lighter and SDAR Awards, are potential sources for future research papers. Other CPD events including the annual CIBSE Ireland conference and the building services master class at the SEAI Energy Show are also ideal platforms to showcase papers that could eventually be published in the SDAR Journal. I would encourage third-level students, academic staff and also the industry as a whole to be actively involved in these events by providing papers, including case study information, that we can all learn from. Through the medium of the SDAR Journal we will then ensure that the benefits of this information are made freely available for all involved in the building services sector.
A Cost-optimal assessment of buildings in Ireland using Directive 2010/31/EU of the Energy Performance of Buildings Recast Christopher Pountney, David Ross and Sean Armstrong
The SDAR Journal is a sustainable design and applied research publication written by engineers and researchers for professionals in the built environment Editor: Dr Kevin Kelly, DIT & CIBSE Contact: kevin.kelly@dit.ie Deputy Editor: Dr Keith Sunderland; Head of Electrical Services Engineering, DIT Contact: keith.sunderland@dit.ie Support Editorial Team: Thomas Shannon, Yvonne Desmond, Pat Lehane The Reviewing Panel is: Dr Martin Barrett, Professor Michael Conlon, Professor Tim Dwyer, Dr Avril Behan, Sean Dowd, Kevin Gaughan, Michael McNerney, David Doherty, Dr Marek Rebow and Professor Gerald Farrell. Upload papers and access articles online: http://arrow.dit.ie/sdar/ Published by: CIBSE Ireland and the College of Engineering & Built Environment, DIT Produced by: Pressline Ltd, Carraig Court, George’s Avenue, Blackrock, Co Dublin. Tel: 01 - 288 5001/2/3 Fax: 01 - 288 6966 email: pat@pressline.ie
Sean Dowd Chairman, CIBSE Ireland
DIT is delighted to be co-publisher of the fourth edition of the SDAR Journal. The ongoing collaboration between DIT and CIBSE represented by this publication is of great importance to us as an academic research community. As Director and Dean of the College of Engineering and Built Environment at DIT, I am very aware how important it is for us to fulfil a core objective of our mission to build strong relationships with industry and to help disseminate new knowledge and ideas. This journal offers a means for authors from a variety of institutions and organisations to share significant research contributions with the wider world of engineering and the built environment. As result, it provides a direct high-quality pathway for this College to realise one of our core objectives. We place a strong focus on applied research in DIT which is recognised for its impact and quality, and in many cases is on a par with that of the very best groups internationally. As a College we have a strong emphasis on research in areas such as energy management, renewable energy technologies, electrical energy systems and sustainable design in the built environment. These research areas are of vital importance in a world which increasingly realises the very finite nature of our planet’s resources, and the need to protect and nurture our environment. I congratulate the editors of the journal and the authors on the high quality of their work and on their contributions to research in this area, in Ireland and further afield.
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Professor Gerald Farrell ISSN 2009-549X © SDAR Research Journal Additional copies can be purchased for €50
Director and Dean of the College of Engineering and Built Environment, DIT
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SDAR Journal 2014
Editor’s foreword Once again we bring you our annual issue of the SDAR Journal. This journal is intended to encourage innovative practice in low-energy design of the built environment, and to encourage applied research among professional practitioners and new researchers in academia. The papers published are intended to inform design practice in construction and to assist innovative engineers striving towards optimisation of building integrated renewable technologies. CIBSE and DIT came together four years ago to jointly publish this journal. The intention then was to disseminate insightful findings to the professional community involved in the built environment. This is still the case. We assume the reader to be a sceptic who will be convinced by evidence. We are not interested in green bling on buildings or unproven designs. We want instead to encourage post-occupancy evaluation of innovations that support more sustainable and energy-efficient practice leading to mainstreaming of good-quality leading-edge projects. While we want to hear what works well, we are conscious of the fact that the professional community can also be informed by what went wrong. Therefore we encourage critical reflection and objective evaluation of real-world projects. Moving forward we want to publish more papers from our architectural and construction colleagues. In this issue we feature a paper on Building Information Modelling (BIM). BIM is not just the application of software but a paradigm shift in construction projects that demands a new psyche for large contractors who wish to compete internationally for large projects. BIM facilitates collaborative working between all members of the design and construction team. BIM processes accelerate project design times, reduce costs, and are shown to improve the speed and quality of large projects. BIM also improves facilities management and cost control tasks. We would be delighted to receive your abstracts or ideas and can offer support in the writing up of papers. The industry is data rich but sometimes time poor. We encourage and support in practical terms synergies with academia. Academics are eager to support this applied research process and will provide time on task in exchange for access to useful data. A good example of this is the lead paper in this issue, where a working engineer collaborated with academics in the School of Electrical and Electronic Engineering to produce a paper that will be informative to those involved with stadia design and management throughout the world. We are also keen to publish papers about current issues such as the EPBD Recast paper in this issue. Would-be contributors are encouraged to submit abstracts for the annual SDAR Awards and Irish Lighter competitions. Both competitions are effectively feeders for this journal. We particularly encourage novice researchers and industry professionals to submit short abstracts of their work, either to the above competitions or directly to me. There are two papers in this issue from PhD candidates who are also working engineers, one is on lighting design and the other is about electrochromic glazing.
Dr Kevin T. Kelly C Eng FCIBSE FSLL FIEI Head of School of Multidisciplinary Technologies Dublin Institute of Technology
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A Reader’s Gude
A Reader’s Guide In this issue we bring you five varied and interesting papers that are briefly described below. The first paper by Byrne et al is a world’s first implementation of ISO 50001 Energy Management System in an international sports stadium. The changes implemented are explained and resulted in an impressive €1 million plus saving in three years. This is estimated as “costs avoided” to account for increased energy unit rates. Energy savings were in the order of 14,000 MWh over the same period. Identifying significant energy users (SEUs) and the parameters affecting variability in energy is seen as crucial to a successful outcome. The Aviva Stadium in Dublin invested in sub-metering to achieve the energy savings it did. The second paper is on lighting and the main author, James Duff, is an engineer/lighting designer and a part-time PhD student in DIT. Duff is at an advanced stage of his PhD and has some insights into the direction that interior lighting design practice is likely to take. It is widely accepted in the lighting community that present guidance and standards lead only to functional interiors with adequate illuminance on the working plane. Duff is striving for more with a robust examination of theories put forward by Cuttle in New Zealand. This leads Duff to examining whether the idea of brightness adequacy and room appearance can be legislated for in lighting standards. In this paper he explains, analyses and discusses the new methodology proposed and explains how research in DIT is progressing to overcome the barriers of implementation of this method within lighting standards. The third paper describes Building Information Modelling (BIM) and Lean construction methods, implemented by Mercury Engineering. This paper is written collaboratively between the company
engineers and academics in DIT who lead and teach BIM in DIT. The paper identifies some early results of implementing BIM processes that acted as drivers of Lean construction. It is also an example of exemplary collaboration between disciplines (building services, electrical, manufacturing and geomatics) facilitated by BIM processes and technologies, and the move away from the silos that traditionally defined this sector. The paper focuses on the business and personal benefits of implementing BIM and details the processes that have resulted in a significant increase in efficiency for the contractor. As more clients demand BIM preparedness and experience, this paper provides evidence of the benefits for contractors of BIMifying their processes and of leveraging Lean. This is a must read for any contractor who wishes to compete nationally or internationally for large projects. The fourth paper is the first UK case study that monitors closely occupants’ reaction to the use of electrochromic glazing in a building. The author is an engineer and daylight specialist who is completing her PhD in De Montfort University in the UK. Ruth Kelly shows the potential for this technology and how it can improve occupant comfort, provide greater access to daylight and a view to outside, while decreasing energy usage. The fifth and final paper assesses buildings in Ireland against the EPBD Recast. It is the first cost-optimal assessment of national energy performance standards for buildings in Ireland. The focus is on both residential and non-residential buildings and the new-build standards required under Part L. It evaluates the impact on primary energy demand associated with a range of energy efficiency measures and renewable technologies. Results show that new build residential standards are within or beyond the cost optimal range but that for non-residential buildings the current standards are outside the cost-optimal range. 3
Email: contact@cibseireland.org Web: www.cibseireland.org
We’re always on the lookout for you … CIBSE is the professional body that exists to “support the science, art and practice of building services engineering, by providing our members and the public with first class information and education services and promoting the spirit of fellowship which guides our work.” CIBSE promotes the career of building services engineers by accrediting courses of study in further and higher education. It also approves work-based training programmes and provides routes to full professional registration and membership, including Chartered Engineer, Incorporated Engineer and Engineering Technician. Once you are qualified, CIBSE offers you a range of services, all focussed on maintaining and enhancing professional excellence throughout your career. CIBSE members in Ireland are represented by an active Regional Committee which is involved in organising CPD events, technical evenings, training courses, social events and an annual conference. The committee welcomes new members, suggestions, and collaborations with other institutions in the built environment.
Providing best practice advice, information and education services The Chartered Institution of Building Services Engineers in Ireland
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Implementation of ISO 50001 Energy Management System in Sports Stadia
Aidan Byrne AVIVA STADIUM aidan.byrne@avivastadium.ie
Martin Barrett DUBLIN INSTITUTE OF TECHNOLOGY
Richard Kelly DUBLIN INSTITUTE OF TECHNOLOGY
School of Multidisciplinary Technologies
Building Servicesnews
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Abstract Many modern sports stadia around the world
1. Introduction
consume large amounts of energy during their day-
As the focus on energy continues to sharpen worldwide due to political, financial or environmentally driven factors, energy management systems such as the ISO 50001 Energy Management System aim to address these issues by enabling organisations to effectively manage their energy use, consumption, efficiency and performance. Many industries have already begun to adopt the ISO 50001 Standard. However, the sports stadia industry has been slow to adapt to this recent trend.
to-day operations. With the cost of this energy constantly on the rise, the challenge of managing this uncontrolled cost has become increasingly more important for the successful and sustainable operation of these facilities. It is essential that some form of energy management system be embraced by these sports stadia. This paper is a case study on Aviva Stadium’s recent implementation of the ISO 50001 Energy Management System. The authors identify the potential challenges and benefits of implementing the ISO 50001 Energy Management System in sports stadia. Final certification to the standard came on the 25th of September 2013 making Aviva Stadium the first stadium in the world to have achieved thirdparty certification to the ISO 50001 standard. This paper can act as a guide for other stadia wishing to adapt ISO 50001 to their venue, especially since it resulted in a €1 million energy cost avoidance over
The Aviva Stadium in Dublin, Ireland has led the way for stadia around the world by becoming the first stadium in the world to implement and achieve third-party certification to the ISO 50001 standard. By using their experience in implementing ISO 50001 this paper aims to identify the potential challenges and benefits of implementing this standard within a sports stadium, and act as a guide for other stadia who wish to implement ISO 50001 in the future.
1.1 Background Aviva Stadium was officially completed in May 2010. It was then handed over to a management company which was set-up by the two host organisations i.e. The Irish Rugby Football Union (IRFU) and the Football Association of Ireland (FAI). This management company is registered as New Stadium Ltd, or ‘NSL’ as its also known, but trades as Aviva Stadium and is responsible for the dayto-day operations of the stadium, all pitch events and concerts which are held within the stadium.
a three-year period.
Key Words: ISO 50001, Energy Management, Sports Stadia. Figure 1: Aviva Stadium, Dublin, Ireland.
Upon opening, it was quite apparent to the senior management of NSL that energy would be a major concern. Almost immediately it was clear that estimated energy costs foreseen were greatly underestimated by the designers. Despite the Aviva Stadium being a state-of-the-art facility, encompassing some of the best plant and equipment available at the time of construction, the designer’s main priority was to create a stadium which could cater for up to 50,000 people, up to 25 times a year, and not for the hosting of meetings, incentives, conferences and events (M.I.C.E). But M.I.C.E are the second most essential revenue stream for the stadium, and are much more frequent throughout the year. As a result, the stadium consumed over 19,000MWH of energy during its opening year. To address this issue the decision to implement the ISO 50001
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Implementation of ISO 50001 Energy Management System in Sports Stadia
of the energy management system’s complexity, degree of documentation used, and the amount of resources required /available.
25,000 20,000
MWh
15,000 10,000 5,000 2010
2011
2012
2013
Elec
9,370
7,724
6,203
6,425
Gas
10,088
8,718
6,505
8,724
Figure 2: Aviva Stadium's annual energy consumption (2010- 2013).
Energy Management System was made in August 2011. Final certification to the standard came on the 25th of September 2013 making Aviva Stadium the first stadium in the world to have achieved third-party certification to the ISO 50001 standard.
ISO 50001 outlines rules and requirements for its implementation, but does not impose any definitive quantitative requirements for energy performance. It simply states that an organisation should strive to achieve commitments outlined in its energy policy, nor does it enforce the obligations to which an organisation must comply in order to meet its legal and other requirements (International Organisation for Standardisation, 2011). The ISO 50001 standard uses the Plan-Do-Check-Act (PDCA) methodology to continuously improve energy use in an organisation by incorporating energy management practices into normal, everyday organisational practices (International Organisation for Standardisation, 2011). • Plan: conduct the energy review and establish the baseline, energy performance indicators (EnPIs), objectives, targets and action plans necessary to deliver results that will improve energy performance in accordance with the organisation’s energy policy.
Figure 2 outlines the stadium’s annual energy consumption over the four years 2010 – 2013. It is clear that 2010’s consumption was much greater than the subsequent years following the implementation of ISO 50001 in May of 2011. However, the rise in gas consumption in 2013 was a direct result of the record low temperatures in Jan – April of that year.
2.
• Do: implement the energy management action plans. • Check: monitor and measure processes and key characteristics of operations that determine energy performance against the energy policy and objectives, and report the results.
ISO 50001
The ISO 50001 Energy Management Standard was created by the International Organisation for Standardisation (ISO) and was developed by the ISO/TC 242 “Energy Management” technical committee. This committee was set up in 2008, and the final draft of ISO 50001 was released in June 2011. The committee consisted of 55 participating countries most notably the United States through the American National Standards Institute (ANSI) who were joint secretariat with Brazil’s Associação Brasileira de Normas Técnicas (ABNT) which translates as the Brazilian National Standards Organisation. Ireland participated through the National Standards Authority of Ireland (NSAI), and an additional 16 other countries observed the work of this standard. These countries, unlike their participating counterparts, followed the work but could not make any comments or vote during the development process (International Organisation for Standardisation, 2011). The standard outlines the requirements/specifications for any organisation in establishing, implementing, maintaining and improving an energy management system (EnMS) through a systematic approach which will achieve continuous improvement of the organisations energy performance. Included in this is the energy efficiency, consumption, energy use, and security of supply irrespective of the organisation’s geographical, cultural or social conditions. The continual nature of this energy reduction process also reduces the associated energy costs and greenhouse gas emissions, thereby reducing the environmental impact made by the organisation. The application of the standard can be tailored to suit the specific needs or requirements of any organisation, irrespective
• Act: take actions to continually improve energy performance and the EnMS. .
3.
Applying ISO 50001 to Sports Stadia
Even though the ISO 50001 Energy Management System was designed to suit almost any organisation irrespective of its type, size or complexity, applying the ISO 50001 Energy Management System to a Sports Stadium is quite a unique process.
Figure 3: Aviva Stadium's Energy Management Process.
Using Aviva Stadium’s implementation as a guide, this section will outline the various steps taken by the Aviva when implementing ISO 50001. Figure 3 shows the energy management process used by the Aviva Stadium’s energy management team. This flow chart is their interpretation of the PDCA cycle used by the ISO 50001
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standard. It is divided into five main steps which are described as follows.
3.1 Commit The most important step in any implementation is the commitment stage where the benefits of implementing ISO 50001 are identified and communicated to senior management. Should the standard be deemed appropriate and in line with other objectives and goals associated with the successful operation of the organisation, implementation may proceed. It is vital that top management, or in the case of a sports stadium that the Stadium Director/CEO, clearly understands the benefits of ISO 50001 and commits to it by creating an energy policy stating the organisation’s commitment to the continual improvement of energy performance. It must also comply with any legal and other requirements expected of the organisation. This policy must be regularly reviewed and updated, generally during the annual Management Review. A management representative then needs to be appointed who will have the appropriate skills and competency to carry out the required tasks in managing an energy management system. At the Aviva Stadium the electrical engineer, now Facilities Manager, was chosen to be the management representative, alongside the stadium’s maintenance officer who is also responsible for the operation of the EnMS. However, as both people have other responsibilities (primary roles), the implementation of the ISO 50001 standard was of a secondary focus compared to the ongoing maintenance of the facility and the hosting of large scale events. International matches dictated how much time could be allocated to the implementation process, thereby elongating the estimated time-frame required for final certification.
3.2 Identify Once the commitment to the EnMS has been established, a review of the activities which may affect the energy performance must be undertaken. This is known as “The Energy Review”. During this energy review several things need to be identified: current energy sources, past and present energy consumption, significant energy users (SEUs), their relevant variables and energy performance indicators (EnPIs) and opportunities for improving energy performance. By analysing the stadium’s energy consumption data, trends and patterns in energy use can be identified and a profile of energy use can be created for the stadium and from that, a baseline can be set. This baseline then becomes the benchmark for measuring changes in energy performance (UBMi, 2013). For example, the Aviva Stadium currently uses 2012’s energy consumption as its baseline as it is a more accurate depiction of the stadium’s current energy use. This is due to some major changes which were made since opening. Once this analysis of energy consumption has been completed, the areas of most significant energy usage can then be identified. This SEU identification process was found to be profoundly
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challenging. This was primarily related to the fact that Aviva Stadium’s original design did not include any sub-metering for thermal or electrical loads. Due to this fact, the ‘Bottom Up’ approach was applied during the initial SEU identification process. Tabulated information was gathered including plant schedules and equipment name plates, to quantify the energy consumption relating to each particular process or system. An example of this was an Excel spreadsheet created to tabulate the energy consumption of all HVAC plant within the stadium. However, the accuracy of this method proved relatively poor. As the purpose of identifying SEUs is to prioritise the allocation of resources when reducing the consumption of significant areas of energy use, should the identified areas of significant energy use be incorrect (due to inaccurate information) the allocation of resources may be wasted. Because of this fact the Aviva Stadium installed a very comprehensive sub-metering system which consists of over 150 electrical meters, 3 gas sub-meters, 6 thermal heat meters, and a web-based monitoring system. The initial cost of this installation is in the region of 5 – 10% of the stadium’s average annual energy spend. This system has allowed them to identify their most significant energy users more accurately, and easily. This has resulted in less time spent on identifying these SEUs, and a more efficient allocation of resources (i.e. money, time, skills etc.). Not every energy user identified by sub-metering should be deemed significant. Wooding, G and Oung, K 2013 believe the term significant energy use is a subjective determination by the organisation, so long as it meets at least one of the two following criteria: i. The energy consumption is large in proportion to other areas of energy use. ii. The energy use offers significant opportunities for energy performance improvement. For example in Figure 4, the HVAC system consumed significantly more energy than any other system in the stadium, therefore making it the top SEU. On the other hand the pitch “grow lights” consumed over 1,200,000 kWh of electricity, but were deemed not be an SEU as they did not offer any significant opportunity for energy performance improvement (unless even newer lighting rigs are purchased), but this is not feasible at this time. The Pareto 80/20 rule can also be utilised by organisations as a means of identifying their significant energy users (SEUs). By identifying 80 per cent of the energy consumed (beginning with the largest loads) as significant, the systems, plant or equipment which are responsible for this energy use can be identified as the site’s SEUs (see Aviva Stadium’s SEU Pareto chart in Figure 4). The Pareto chart shown was created using a mixture of metered and tabulated data, therefore its accuracy is not absolute. This is currently being corrected by staff at the Aviva, and the recent installation of heat meters will yield more specific data over the coming heating session (2014). Also, the baseload SEU is expected to be made redundant next year due to increased electrical metered data.
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MWh
Implementation of ISO 50001 Energy Management System in Sports Stadia
120%
4,000 3,500 3,000 2,500 2,000 1,500 1,000 500
100% 80% 60% 40% 20% 0% r g d n ts ing ing AC loa tin ate gh tio SEU r t HV ase Hea t W wli Ligh ate gera C B ch EU Ho Gro fri Re Pit
Figure 4: Aviva Stadium’s SEU Pareto chart 2013.
Relevant variables must then be identified for each SEU as it is of vital importance that all external factors that have a significant impact on their energy consumption be identified. This particular exercise proved to be almost impossible during the initial stages of the implementation at Aviva Stadium through a lack of submetering as they could not differentiate between the many separate loads which were amalgamated together. Therefore no one variable or driver could be identified as being a significant factor in the overall consumption of energy. Energy Performance Indicators (EnPIs) are crucial in the monitoring and measurement of the energy performance of each SEU, and they should be used as a means of identifying significant deviations in energy performance. They should be tightly related to the relevant variables which affect each SEU. EnPIs are essential in the design of measures which identify opportunities to reduce energy consumption and improve energy efficiency Eccleston (2012). This process of constructing effective EnPIs to monitor the energy performance of these SEUs still proves to be quite difficult and time consuming at the Aviva Stadium. One such example of an actual EnPI used by the Aviva Stadium, (which was alluded to previously in this paper) is the measure of external temperature versus the amount of energy consumed by the heating system: Where – kWh, is the energy consumption (i.e. gas); – HDD, are the heating degree days using 15°C as the base temperature; For example, in November 2013, 1,336,298 kWh of gas was consumed with 270 HDD. This equates to a ratio of 4949 kWh/ HDD. During the previous November only 879,712 kWh of gas was consumed despite having 272 HDD, and therefore a lower ratio of 3232 kWh/HDD. This then identified a significant deviation in gas consumption for that month. A similar EnPI can also be utilised for stadia which also have an under-pitch heating system. In this case the HDD base temperature used is around 10°C. This is because grass is expected to grow at, and above 10°C, and will help to identify if the heating system is under control. Once EnPIs are established and monitored opportunities for improvement in energy performance should be prioritised and recorded (UBMi, 2013). These opportunities for improvement
(OFIs) should be aimed towards energy technologies and source substitutions including material substitution, renewables, selective system component replacement, electronic control systems, and other logistical considerations. A register of OFIs should be maintained for further development later-on in the planning stages, Eccleston (2012). One of the most significant opportunities for improvement implemented by the Aviva Stadium was the re-programming of the Building Management System (BMS). This allowed them to change which items of plant came on with each space time-zone and only cost the Aviva €2000. As the designers primary design brief was large pitch events, this resulted in far too much plant being called to run by the BMS when each space was in use. In some cases it was found that air handling units and fans were running despite having no effect on certain event spaces. This new re-programmable matrix has allowed the technical staff at the Aviva Stadium to correct this issue. After making this change to the BMS a regression analysis was completed the following year which showed that R2 value greater than 0.9 was achieved for the heating system which showed a strong relationship between its gas consumption and external temperature (the heating degree days versus the gas consumed). Prior to this change in 2011 this was not the case as the R2 value was 0.7. This showed that the heating system was not adequately controlled.
3.3 Plan The true planning stage begins when an organisation establishes, implements, and maintains documented energy objectives and targets (International Organisation for Standardisation, 2011). The U.S Department of Energy (2012) describes these objectives and targets as instruments to meet the commitments made in the energy policy. Wooding & Oung (2013) urge that these objectives and targets be measurable, realistic and achievable within a set time frame, or as Welch 2011 referred to as SMART objectives: Specific, Measurable, Appropriate, Realistic, Time-Bound. It is important that these objectives and targets be approved by top management and communicated to those who may have an impact on them. They must also be reviewed on a regular basis and during the annual management review. Eccleston et al. (2012) also suggests that when establishing and reviewing these objectives and targets, the following should be considered: legal and other requirements, significant energy users, and opportunities for improvement which were identified during the energy review. It is critical that sports stadia management bear in mind their obligations to governing sporting bodies when reviewing their other requirements. For example, the Aviva Stadium is required to provide 2,500 Lux of vertical illuminance on the pitch for broadcasting purposes, therefore the sports (flood) lights may be required even during the middle of the day. This may seem like a waste of energy, but it is defined as a requirement for the event. In most cases objectives and targets may be set by top management. For example, reduce energy consumption by 10% in
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2014. However, it is critical that such an objective be set by top management so they can then allocate sufficient resources to achieve target. In other settings such as the Aviva Stadium, energy targets are established by the energy team which collates all of the opportunities for improvement (OFIs) selected for implementation that year. The total estimated energy reduction calculated by their implementation becomes the energy reduction target for that year. The final part in setting these objectives and targets is the establishment of an energy action plan which needs to be documented and maintained to show how these objectives and targets will be achieved. It should also state how any improvements in energy performance will be verified, and what method of result verification has been used (Campbell, 2012). This energy action plan will be the main charter for the energy management system, and great attention must be given to the allocation of resources when trying to successfully implement this energy action plan. An example from Aviva Stadium’s 2013 action plan was the objective to improve the energy performance of the kiosk areas by shutting/powering them down in between events. This was to be verified by the use of electrical meters, and was also externally verified by an external energy consultant who conducted a separate measurement and verification plan on behalf of the stadium’s electricity supplier. This was in order to claim credits for energy saving initiatives. This objective was achieved, and 306,124 kWh was saved in 2013.
3.4 Take action Not only is the “Take Action” stage about implementing the energy action plan, it is also about implementing what the NSAI (2012) refers to as the six elements of the implementation and operation section of the standard. These correspond directly with sub-section 4.5 and include: competence, communication, documentation, operational control, design, procurement of energy services, products, equipment and energy. Eccleston et al. (2012) describe competence in respect to energy management as ensuring that any person or persons working for or on behalf of an organisation, who are related to significant energy uses, are competent on the basis of appropriate education, training and skills, or experience. Following on from this, Wooding & Oung (2013) discuss the requirement as per the standard, that an organisation carry out a training needs analysis to ensure that the necessary skills and competencies are properly identified and recorded. Any gaps identified by this analysis should be filled with relevant training, work experience or education. During the implementation at the Aviva Stadium a training needs analysis was undertaken for all persons who have an effect on the stadium’s significant energy users. A list of the required training and competencies was compiled and a training register created. This register identified the training needs of each person, and which standard operating procedure (SOP) to be followed. Energy awareness plays a huge role in the success of any energy management system. Welch (2011) discusses the importance of
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awareness training with respect to the energy policy, role of employees, and the potential consequences of staff failing to follow procedures which may lead to significant deviations in energy performance. Awareness can be increased using several different communication methods including energy awareness campaigns, flyers, newsletters etc. It is advised that any awareness campaign be initiated by a direct communication from a stadium’s director, as this adds a significant weight to the topic being discussed. Staff are more likely to pay heed to their “boss” versus their colleague who may be the management representative/energy manager. This was then the approach taken by the Aviva Stadium during their energy awareness campaign where the stadium’s director introduced the topic of energy awareness, ISO 50001 to all full-time internal staff before handing over to the other speakers. The main author of this paper spoke about energy awareness in the home initially to help people understand the benefits of energy awareness. The management representative then spoke about energy awareness at work and the ISO 50001 system. Documentation is a key component of any EnMS. As (Wooding & Oung 2013) explain, it is the process of establishing, implementing and maintaining procedures to control the EnMS documentation. It must ensure that these documents are approved, reviewed, updated, and any changes or revisions be clearly identifiable. Controlled documents must be legible and readily available, and the unintended use of obsolete documents prevented. The energy team at the Aviva often found that the vast amounts of documentation required (due in part to third-party certification) often hampered any “actual” energy management progress during the initial implementation phase. In particular, keeping the document control register and the legal requirement register up to date required a significant investment of staff time. Operational control requires organisations to identify and plan their operation and maintenance activities which are related to their SEUs, and ensure that they are carried out under specific conditions (Campbell, 2012). Eccleston et al. 2012 suggests using the lean/six sigma implementation tools for the planning of these operations, as those methodologies are geared towards operational process improvement i.e. reducing energy costs, improving energy efficiency, and improving overall energy performance. Design requires that energy performance and improvements in energy performance be considered when designing new, modified, and renovated facilities, plant, equipment, systems, and processes which may have a significant impact on energy performance. Procurement of energy services, products, equipment and energy also requires an organisation to consider energy performance and efficiency when procuring these products or services. It is imperative that a controlled purchasing specification be developed and documented for these services (Wooding, 2013). It is suggested that reference be made to energy criteria during any requests for quotations, proposals, other communication with suppliers, and also in any procurement justifications made by the organisation. An example of this at the Aviva Stadium was when
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they were replacing the filters in their air handling unit (AHUs), they made it abundantly clear to the supplier that energy performance/efficiency was of critical importance. As a result, the supplier proposed the installation of an alternative fibre-glass bag filter to replace the existing synthetic bag and panel filters which were considerably more expensive but much more efficient. They also eliminated the need for the panel filter which reduced the pressure drop across the AHUs, therefore allowing the frequency of the variable speed drives (VSD) to be reduced, thus saving a considerable amount of electrical energy.
3.5 Review The Review stage of any EnMS can be divided into two separate parts i.e. Checking and the Management review which are both clearly defined in the ISO 50001 standard. The purpose of the checking section is to ensure that key characteristics which determine energy performance are monitored, measured and analysed at planned intervals which can be annual, bi-annual, quarterly, monthly etc. The ISO 50001 standard describes the term key characteristics as the following items to be reviewed by the energy measurement plan – the outputs from the energy review, relationship between SEUs and their relevant variables and EnPIs, and the effectiveness of the energy action plans in achieving the set objectives and targets. The measurement levels for each key characteristic should be appropriate to the size and complexity of the organisation. The accuracy and repeatability of the data used is vital, so calibration of all monitoring and measurement equipment must be undertaken. Wooding & Oung (2013) describe this process as being the use of energy monitoring, measurement and analysis to validate, correct and/or improve its energy planning process. As part of the Aviva Stadium’s EnMS, SEUs are reviewed on a monthly basis by inputting metered data for each energy user into a Pareto chart. This gives both the monthly SEU breakdown as well as the year-to-date status. The relationships between SEUs and their relevant variables are reviewed at different intervals depending on the SEU. For instance, the relationship between the previously-mentioned heating degree days and the HVAC system are constantly monitored using a weekly CUSUM and deviation spreadsheet. This spreadsheet identifies any deviations to the expected consumption levels (based on the heating degree days) and a separate monthly regression analysis is also completed to identify the actual relationship between gas consumption and the external weather. The US Department of Energy’s eGuide for ISO 50001 (2012) highlights the importance of monitoring and measurement data for the above key characteristics when identifying significant deviations in energy performance and defines these significant deviations as: A deviation may be identified by a specific level of variation or can be evaluated by knowledgeable personnel to determine if it is significant and if action is required.
These deviations should be recorded and maintained in a deviation log, and in Aviva Stadium’s case, any deviation either 20% above or below expected levels are recorded in its deviation log book, resulting in further investigation, corrective and preventative action. The next part of the checking section is to evaluate the compliance with both legal and other requirements as was previously mentioned in Section 3.3. The organisation must establish a process to evaluate its compliance with legal and other requirements. This process should enable management to monitor progress against planned milestones relating to these requirements, which may not only consist of the EnMS’s technical and economic performance, but may also avoid potential violations of laws and regulations, as well as lawsuits. One such milestone at the Aviva was the obligation to obtain a Display Energy Cert (DEC). This was identified through the Pegasus Legal Register which manages their compliance with all legislation relating to energy, health and safety, and corporate law by completing a series of questionnaires. It also tracks the progress of all outstanding requirements. Sub-section 4.6.3 Internal audit of the EnMS requires an organisation to “carry out and record internal audits at planned intervals” (Wooding, 2013), so as to ensure that the EnMS conforms to the ISO 50001 standard, and activities necessary to improve the EnMS are carried out at planned intervals and are effective in improving the EnMS’s ability to improve its energy performance. All internal audit conformance results must be recorded. The difference between compliance and conformance to the EnMS standard is that the internal audit shall evaluate the ability of an organisation’s EnMS to conform to the standard, while compliance is to meet the commitments made by the energy policy, and to achieve the objectives and targets set out during the energy action plan. The result of the internal audit will be a non-conformities, correction, corrective action and preventative action plan NSAI (2012) where the cause of all non-conformities, or potential nonconformities can be determined, and whether corrective or preventative action is required. Section 4.7 Management review requires that top management review and record the current status of the organisation’s EnMS to determine if it is suitable, adequate and effective in managing the organisations energy performance Wooding (2013). Eccleston et al. (2012) surmises this as a systematic review by top management of the organisation’s energy-related information, the evaluation of this information, the allocation of resources, and the direction of improvement actions where necessary. Welch (2011) believes that this management review should be held at least once a year and should include the current energy policy, energy review, internal audit report and the status of the NC, CAPA plan. This can be an intense process, but is vital in the successful completion of the EnMS cycle. It closes the loop, allowing the cycle to repeat with renewed commitment from top management to the energy management process.
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4.
Benefits
Table 2 – Actual Energy Consumptions and Costs
The following benefits were found to be associated with Aviva Stadium’s implementation of the ISO 50001 Energy Management System.
As outlined in Figure 2, the stadium’s annual energy consumption has steadily declined since implementation began back in early 2011. In the first year it was calculated that over 7,758 MWh of electricity and 6,317 MWh of gas was saved over this three-year period following the initial implementation of ISO 50001.
2011 7,724 8,718 1,646 1,370
2012 6,203 6,505 3,167 3,584
2013 6,425 8,724 2,945 1,364
2013 6,425 8,724 726,116
Gas Elec € / MWh Gas
286,947 91 28
306,354 89 35
305,510 101 47
456,722 113 52
MWh
7,759 6,317
€
€120
€1,1200,000
€100
€1,1000,000
€80 € / MWh
€800,000
€60
€600,000 €400,000
€40
€200,000
€20 €
€ 2010 Elec
2011
2012 Gas (AUP)
Table 3 – Estimated Costs Elec Gas
2011 834,900 354,490
2012 949,210 473,832
2013 1,059,004 528,115
Table 4 – Estimated Savings / Costs Avoided
€1,1400,000
2013 Elec (AUP)
Figure 5: Aviva Stadium’s annual energy costs.
Even though some savings were curbed by the constant rise in energy prices, had energy consumption at Aviva Stadium stayed at 2010 levels (through the lack of energy management), the potential energy costs encountered by Aviva Stadium would have been significantly higher. Therefore the potential savings (or costs avoided) as a result of implementing the ISO 50001 Energy Management System can be calculated by multiplying the average unit price of both gas and electricity for each year (2011 – 2013) by the energy consumption in 2010. As a result the energy costs avoided by Aviva Stadium over the course of their ISO 50001 implementation were calculated to be €1,088,244 thus far.
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2012 6,203 6,505 628,384
Total Savings (MWh)
Despite this steady decrease in energy consumption the constant upward trend in the market price, or Average Unit Price (AUP) of energy over the last number of years which can be seen in Figure 5, has offset much of the potential financial savings at Aviva Stadium.
Gas
2011 7,724 8,718 688,221
€
Table 1 – Aviva Stadium's Energy Savings 2010 9,370 10,088
2010 9,370 10,088 852,747
€
4.1 Energy Costs
MWh Elec Gas Elec saved Gas saved
Elec Gas Elec
Elec Gas
2011 146,679 48,136
2012 320,826 168,322
2013 332,888 71,393
Sub total €800,393 €287,851
Total €1,088,244
4.2 Operational Efficiency and Costs Other economic benefits related to the implementation of ISO 50001 at Aviva Stadium were in relation to operational efficiencies achieved through the elimination of costs associated with external auditor assistance which was required for their existing Sustainable Management System BS 8901 (now ISO 20121). By implementing ISO 50001 the internal auditing process of both management systems was improved by allowing the operators of each system to audit the other. This eliminated the need for external auditor’s assistance when conducting thorough and unbiased audits, thus avoiding costs. Additionally, this correlation between both management systems meant that the training required for the staff conducting internal audits could be packaged together by the chosen service provider, who could then deliver on-site training tailored specifically for the internal auditing of both the ISO 50001 and ISO 20121 management systems. This resulted in a significant reduction in the overall training cost as opposed to sending each system operator away separately to attend offsite training.
4.3 Reputation and Market Share Protection The reputation of Aviva Stadium is deemed second to none with regard to the implementation of ISO 50001 as it was the first stadium in the world to achieve third-party certification to the standard. This was confirmed by a Senior Scientific Officer on Environmental Management for the Federal Environment Agency in Germany (equivalent to the Environmental Protection Agency (EPA) in America). This official was also part of the ISO/TC 242 Energy Management technical committee which was set up to create the ISO 50001, who explained that there is no centralised database tracking third-party certifications around the world. However, an informal list of certifications is maintained on behalf of the
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German government. This list is the closest thing to a centralised database that could be found and based on that information, Aviva Stadium is the first stadium in the world to achieve third party certification to the standard. The implementation of ISO 50001 has improved Aviva Stadium’s status with its own key shareholders. The FAI and IRFU finance the stadium’s energy cost evenly between them. Certification to ISO 50001 exhibits to both organisations that the use of energy within the stadium is being managed to an internationally recognised standard. Achieving third-party certification to ISO 50001 standard is also currently deemed to be a competitive and market share advantage to Aviva Stadium, but the sporting sector is slowly shifting towards these certifications being prerequisites when tendering for major sporting events or tournaments. When the FAI and Dublin City Council bid to host a package of games during the EURO 2020 Football Championship, UEFA had a requirement that a minimum of 50% of energy used by the host stadium should come from renewable energy sources. Because the Aviva Stadium is certified to both the ISO 50001 and BS 8901 standards, this was a positive factor in the success of the bid.
5.
Discussion
The aim of this paper was to act as a guide for other stadia who wish to implement the ISO 50001 standard using Aviva Stadium’s recent implementation, whilst also identifying the potential challenges and benefits of implementing ISO 50001. These results and conclusions are summarised as follows; • When implementing ISO 50001 it is of vital importance that management give their full commitment to its implementation, and not just pay lip service to it. • One of the main challenges faced during the Aviva Stadium’s implementation was the balancing act the energy team had to play between implementing ISO 50001 and their other primary duties/roles i.e. the ongoing maintenance of the facility and the hosting of large scale events. This is a specific challenge facing any stadia that wishes to implement the standard using in-house resources.
implemented by the Aviva Stadium to date was the alteration to their BMS which gave them finer control over their HVAC system. • By shutting down levels 1 and 5 between events, over 300,000 kWh of electricity was saved in 2013. • It is estimated that the Aviva Stadium has avoided over €1,088,244 in potential energy costs since implementing the ISO 50001.
Acknowledgements The main author would like to acknowledge the contribution of his colleague Eamon Williams who co-implemented the ISO 50001 standard with him at the Aviva Stadium, and would like to thank his co-authors Dr Martin Barrett and Richard Kelly of DIT for their contribution and support.
References Campbell, C., (2012). Practical Guidance for ISO 50001 Implementation. Houston: LRQA. Eccleston, F. M. T. C., (2012). Inside Energy: Developing and Managing an ISO 50001 Energy Management System. s.l.:CRC Press. Wooding, K. O., (2013). Implementing and Improving an Energy Management System. London: BSI. International Organisation for Standardisation, (2011). ISO 50001:2011. s.l.:s.n. NSAI, (2012). ISO 50001 Energy Management System: Detailed Guide. [Online] Available at: http://www.nsai.ie/NSAI/files/bd/bd0f95ec-74d0-4c04-a99076f3343a6f7d.pdf U.S Department of Energy, (2012). DOE eGuide for ISO 50001. [Online] Available at: http://ecenter.ee.doe.gov/EM/SPM/ Pages/Step1.aspx UBMi, (2013). A Barbour Guide: Energy Management Systems BS ISO 50001:2011. s.l.:UBMi. Welch, T. E., (2011). Implementing ISO 50001: While integrating with your environmental management system. Florida: TriMark Press.
• Identifying significant energy users and their relevant variables is crucial, but it was the greatest difficulty encountered by the Aviva Stadium due to their initial lack of sub-metering. It is recommended that future stadia include a sub-metering system as part of the original construction, and for existing stadia that do not already have sub-metering, it is recommended that 5-10% of a year’s energy consumption be allocated to the installation of sub-metering. • Aviva Stadium’s current SEUs are the HVAC system, their electrical baseload, the under-pitch heating system, and their domestic hot water system. • Creating useful EnPIs continues to be a difficult process for the Aviva Stadium and the most useful EnPI is kWh/HDD for the heating system and under-pitch heating system. • One of the most significant opportunity for improvement
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THE IRISH LIGHTER/ YOUNG LIGHTER COMPETITIONS The Irish Lighter and Young Lighter Awards are annual applied research events promoted jointly by CIBSE and the School of Electrical & Electronic Engineering in DIT Kevin St. They are open to all building services professionals, with SLL and ILP members particularly
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Projects must be located in Ireland, and submissions can also be made which are based on lighting research. Best abstracts are selected by a distinguished international panel of assessors and a shortlist of entrants is then invited to submit full papers. For the Irish Lighter Award, entries are encouraged from experienced lighting designers, or engineers who can present a paper about a finished project. • There may be post-occupancy evaluation evidence that is analysed critically and provides insight for the professional lighting community; •
There may be an innovative and/or sustainable design that is at the industry cutting edge;
• Or it may be something worth publishing that will be of interest, and benefit, to the professional community. The Irish Young Lighter competition began in DIT in 2003 when the first students on the programme in Electrical Services Engineering graduated. Ken Winters was the inaugural overall winner and he then went on to represent Ireland at the international Young Lighter in London in 2004, where he won the Best Presentation. Published research papers by winners of both the Irish Lighter and Young Lighter competitions may also feature in the SDAR Journal.
encouraged to participate. Who to contact michael.mcdonald@dit.ie or keith.sunderland@dit.ie
Building Servicesnews
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A new approach to interior lighting design: early stage research in Ireland
James Duff ARUP AND DUBLIN INSTITUTE OF TECHNOLOGY james.duff@arup.com
Kevin Kelly DUBLIN INSTITUTE OF TECHNOLOGY
School of Multidisciplinary Technologies
Building Servicesnews
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Abstract Current standards for interior lighting design are
Introduction
discussed and an alternative design methodology
Lighting designers exercise their creativity against a backdrop of codes1,2,3, standards4, and recommended practice documents5, each specifying a range of lighting parameters for compliance. Foremost among this is a schedule of minimum illuminance values related to various indoor activities. While it is accepted that standards are necessary for general lighting practice, it has been quite common in the past for experienced lighting designers to sometimes disregard these standards as being irrelevant to their work. That attitude has become untenable due to the growth of regulations6 governing energy efficiency and sustainability. The practice of specifying indoor illumination in terms of workplane illuminance has been firmly established by the Commission internationale de l'ĂŠclairage (CIE) and the engineering-based lighting societies, and the energy regulators have followed this practice pretty strictly.
proposed. Cuttle has previously suggested a new criterion be defined as perceived adequacy of illumination (PAI), and that the metric for specifying minimum illumination standards becomes mean room surface exitance (MRSE). This metric specifies the overall brightness of illumination, enabling its distribution to be planned in terms of target/ ambient illuminance ratio (TAIR). This new methodology is explained, analysed and discussed along with on-going research at the Dublin Institute of Technology.
This paper will discuss current standards and their relevance, introduce a new methodology for designing lighting within interiors, and briefly describe some ongoing research that is examining the suitability of the newly-proposed method.
Illumination schedules Although specifying bodies have added various lighting quality criteria to their pronouncements7,8, the central factor remains the workplane illuminance, and it is claimed that this quantity is determined primarily by the category of the visual task. The IESNA Lighting Handbook1 states that “Changes in visual performance as a function of task contrast and size, background reflectance, and observer age can be calculated precisely�. Cuttle has previously9 applied the referenced procedure10 to examine how the illuminance required for a high standard of visual performance relates to various reading tasks. Figure 1 shows that, for the typical reading task of 12-pt type on white paper, it requires just 20 lux to provide for the relative visual performance criterion of RVP=0.98, this value being generally accepted as the highest practical RVP level for lighting applications. It can be seen that the font size would have to be reduced to 6-pt for the required illuminance to exceed 100 lux, or alternatively, reduced to 10-pt but printed onto dark-coloured paper, which has the double effect of reducing the background luminance and the task contrast.
Illuminance (lux)
1000
Light background Medium background
100
Dark background
10 6
8
10 Point size (Pt)
12
14
Figure 1: As previously applied by Cuttle, the illuminance necessary for high levels of RVP under varying illuminance levels, text size and background contrast.
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However, this value of 100 lux falls far short of the levels conventionally provided for applications where reading tasks are prevalent, and which typically fall within the range 300 to 500 lux. It is argued that such levels can be justified on the basis of visual performance only by presuming that either the users are partially visually defective, or that they are persistently required to read very small print with very low contrast on low reflectance backgrounds. If this is not enough, we should not lose sight of the fact that indoor spaces in which reading tasks (or tasks of similar visual difficulty) are prevalent are not the universal norm. There are far more spaces that we pass through, or in which we engage in social or recreational activities, where our visual needs are much more simple, and often comprise nothing more than the ability to be able to navigate through a furnished space freely and safely. How much light do we need to do this? In a study11 of emergency egress from buildings, Boyce conditioned subjects to 500 lux in an open-plan office before plunging them into low, or very low, illuminance levels, with the instruction that they were to find their way out. As well as timing them, he had installed infra-red cameras so he could monitor their progress, and he concluded: “At a mean illuminance of 1.0 lux on the escape route people are able to move smoothly and steadily through the space at a speed very little different from that achieved under normal room lighting.” From the previous paragraphs, it is evident that within indoor spaces where reading tasks are prevalent, such as offices, classrooms and libraries, we commonly provide illuminance levels that are between 15 and 25 times as much as people actually need for high levels of visual performance. As for spaces where finding one’s way is the foremost demand on our visual faculties, such as shopping malls interiors and airport terminals, we over-provide by several hundred fold. There are colossal differences between the illuminance levels required for the visual performance criteria that standards are claimed to ensure, and the levels that the standards specify.
Lighting for human satisfaction, or something else? The Illuminating Engineer published by the IES of Great Britain in October 191112 over 100 years ago includes a report titled Illumination requirements for various purposes. Contained within is a table listing 34 activities along with corresponding illuminance values based on several field surveys. Regarding the aforementioned tasks, reading (ordinary print) is listed at 30 lux; and schoolrooms are also at 30 lux; commercial offices are 40 lux; and libraries range from general, 15 lux, to bookshelves, 25 lux and reading tables 50 lux. Admittedly, none of the indoor activities go as low as the 1 lux finding from the emergency egress research, but broadly, if allowance is made for the fact that these field-measured values precede not only photocopiers and laser printers but also any visual performance studies, it can be seen that general lighting practice of 100 years ago showed substantial agreement with the data presented in Figure 1. This begs the questions, why are the levels demanded for current
lighting practice so substantially in excess of those levels? No serious proposition could be mounted on the basis of deteriorating human visual abilities, or on increasing difficulty of visual tasks. The answer is rather obvious. If any modern buildings were illuminated to such low levels, people would choose to avoid them. If such lighting was to be imposed upon employees, or some other captive group, there would likely be outrage. Public opinion would be united that nobody should have to tolerate such dismal, gloomy conditions. This is the main point of the matter. It is nothing to do with the speed and accuracy with which people are able to detect the critical detail of visual tasks. Rather, it is about meeting people’s expectations that, here in the 21st century, the variety of spaces that we all pass through, occupy and engage in for recreational, social and work activities, should appear to be adequately illuminated. During the past 60 years we have made the transition from providing for visual needs to meeting human expectations.
Perceived adequacy of illumination Do the elevated illuminance levels of current practice mean that the standards have adapted to changing expectations and that the present situation is quite satisfactory? The current standards specify lighting quantity in terms of visual task illuminance and, as we have seen, this is generally interpreted as the average illuminance of the horizontal workplane. It follows that for lighting to be efficient, economical and purposeful, the lamp lumens must be directed onto the workplane with high optical efficiency. Furthermore, to direct light onto walls, ceilings or other features that might catch the eye is deemed inefficient and wasteful. The evidence of this rationale is all around us in general lighting practice, and lighting designers can expect to encounter increasing pressure to follow this trend as providing a specified workplane illuminance with minimal lighting power density is widely recognised as pursuing the holy grail of sustainability. As has been mentioned, there has been a recent tendency among specifying bodies to add lighting-quality criteria to their stipulations, but this is not enough. What is needed is a fundamental re-evaluation of whether or not the users of a space are likely to judge it to appear adequately illuminated, or to put it another way, what is the photometric correlate to the perceived adequacy of illumination?9,13
Mean room surface exitance Cuttle has previously introduced the concept of mean room surface exitance (MRSE) as a metric that serves as an indicator of typical assessment of the brightness of illumination of an indoor space14,15. To understand the concept of exitance, keep in mind that while illuminance is concerned with the density of luminous flux incident on a surface, exitance concerns the flux exiting, or emerging from, a surface. MRSE is, within the volume of the room, the average density of lumens emerging from all of the surrounding room surfaces. Within an enclosed space, this is flux available for vision, and so MRSE could be measured at the eye and includes only light that has undergone at least one reflection (i.e. direct light is
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excluded). It may be thought of as an indicator of the level of the light that brightens the view of indoor surroundings, and which is independent of any effects of bright luminaires or windows.
Designing for appearance
It has been proposed by Cuttle that MRSE may be applied as an indicator for perceived adequacy of illumination (PAI) which is a binary assessment, that is to say, in a given situation, the illumination may be perceived as either adequate or inadequate, so that PAI would be specified by a single MRSE value. However, it is logical that an MRSE level that might be judged adequate in a waiting room or an elevator lobby might be considered inadequate in a workplace or a fast food outlet.
While the PAI criterion is concerned with providing adequate quantities of reflected flux, an illumination hierarchy focuses on how direct flux from luminaires is distributed to create a pattern of illumination brightness. Creating an illumination hierarchy involves devising distributions of illumination to express the visual significance of the contents of the space. Cuttle has previously suggested13 that it be specified in terms of target/ ambient illuminance ratio (TAIR) being the ratio of local illuminance on a target to the ambient illumination, indicated by the MRSE. This may direct attention to functional activities or create artistic
Figure 2a – Meeting room
Figure 2b –Downlight provide 300 lux on the table
Figure 2c – Spots provide 200 lux on the artwork
Figure 2d – Wallwash provides 300 lux on the walls
Figure 2e – The derived illumination hierarchy
Figure 2f – Reflected flux creates ambient illumination (MRSE)
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effects. The designer will select target surfaces and designate values of TAIR based on the desired level of illumination difference required. Figures 2a – 2f walk through a typical design process for a meeting room. Initially the designer will select an amount of ambient illumination he/she believes will be appropriate. This will be given by the MRSE, which in the future may be taken from standards or personal experience, but for this example, 100lm/m2 is used. Following this, objects or surfaces of significance within the space are identified and consideration given to how much brighter, or darker, relative to the ambient illumination the designer would like these to be. Three objects of significance are the table, the side walls and the artwork on the end wall. All three surfaces should be brighter than the ambient illumination. A simple solution might be to place a single downlight in the ceiling to provide 300 lux on the table (a TAIR value of 3), use ceiling spots to give 200 lux on the artwork (a TAIR value of 2), and wash the walls to 250 lux (a TAIR value of 2.5). Each of these is illustrated in Figures 2b, 2c and 2d respectively. Once this is complete, an illumination hierarchy has been established (Figure 2e). The quantity of light reflected from the highlighted surfaces will then determine the ambient illumination (Figure 2f) and is quantifiable through calculation of MRSE. Once MRSE is calculated for the current arrangement, it can be compared with the design intent of 100lm/m2 and additional modifications made as required.
Barriers to implementation Since its introduction, the approach described has received both positive and negative feedback from the lighting community. Some believe that this proposition is doomed to failure due to lack of information available at design stage16,17. While this may hold true, Boyce points out that in the face of such ignorance, it is unreasonable to expect that good-quality lighting will be the outcome of any design method18. Many agree that current codes and standards are long overdue a transformation19,20,21 and indeed some currently choose to ignore them22. Brandston criticises current codes and building regulations for demanding an excessive quantity of illuminance on the task, leaving little remaining power density to light the space22. Others have noted that senior directors within notable building services firms refuse to deviate from standards and codes for the fear that their professional indemnity insurance will be affected23. This demonstrates that current lighting standards are placing substantial restrictions on designing for appearance, thus limiting creative design and potentially impeding good-quality lighting. Loe comments24 that subjects he has studied25 prefer environments that are visually bright and visually interesting. While MRSE may never provide this, it is a fair assumption to state that the IH criterion might produce a visually bright and visually interesting space. Macrae believes the procedure to be “fundamentally flawed” as to apply the methodology correctly requires a good understanding of light and lighting17; but should
this not be mandatory for those involved in lighting? If good-quality lighting is the desired outcome, then the answer must be yes. Critics of Cuttle’s earlier paper16,26,27, based solely on MRSE, voiced concerns that there may be enough light arriving at the observer’s eye, but insufficient illuminance upon a task. If applied correctly and with due thought, the IH criterion would designate strenuous visual tasks with a TAIR of above three and this should, combined with a sensible MRSE, quite comfortably provide adequate illuminance levels for optimum visual performance. Boyce agrees28 that visual tasks have become easier over time, but questions if what people really care about is the perceived brightness of a space. Boyce points out that MRSE is a crude measure of brightness and the range of luminances in the field of view, combined with source spectrum, will also be important28. This raises an important point; producing a simple metric that incorporates all of these variables is a daunting task and would almost certainly go beyond the scope of what lighting standards are expected to do. Raynham states26 that MRSE cannot become the “be-all and end-all of lighting design”, but this statement was made before the introduction of the IH criterion, which adds an additional dimension to MRSE-based design. Despite the initial criticism, there was a substantial amount of positive support. In a more recent publication19, Boyce promotes MRSE and TAIR together as a methodology that shows potential to improve the quality of lighting, so it would appear that as Cuttle’s design theories have progressed to include illumination hierarchies, Boyce has become convinced that this method shows considerable potential. Boyce states that by adopting MRSE-based designs, “light distributions that illuminate the walls and ceiling then become much more energy efficient than those that concentrate their output onto the horizontal working plane”19. Loe agrees with designing for ambience24. Shaw states that “this is one of those blindingly-obvious ideas that we have all missed” 21. Poulton points out that codes and standards are “archaic and should be revised” and that Cuttle’s way of thinking is “long overdue”20. Hogget believes that the proposition is what talented lighting designers have intuitively been doing for years when using a mathematical technique to quantify the task/ambient ratio. Mansfield states that Cuttle’s suggestion to use MRSE as an exploratory tool to define illumination adequacy is a good one and welcomes further dissemination of it as a tool for teaching and as a device to re-align lighting design practice30. Brandston states that the approach is in line with his own. Brandston initially lights the space and then pays attention to the tasks22. Wilde agrees that dumping lumens on a working plane is fraught with problems23. Wilde believes that it is time to change from visibility to appearance and goes on to state that “it must be welcomed by the discerning designer”23. Boyce describes the MRSE/TAIR procedure as “all-encompassing”19 and highlights that the first step towards implementation would be the modification of current software, or development of appropria new software19. This
19
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sentiment is supported by Wilde23. While the importance of this has been recognised, there are other concerns that need to be addressed before this can take place. The first step should be systematically proving that MRSE relates to occupant assessments of illumination adequacy and in turn, devising a range of MRSE values that will relate to PAI for spaces that house various activities. The second step is measurement. Quantifying MRSE in-field is not an easy task. A grid of luminance values can be recorded on each surface of a space and converted to exitance to estimate the total MRSE, but this method is cumbersome and timeconsuming. High Dynamic Range (HDR) imaging has been proposed, but this will need to be modified so pixels within the camera field of view that contain direct luminance can be excluded. If these two steps can be overcome, it is argued that this new methodology shows much potential to improve the quality of lighting within general installations. It directs attention away from the working plane and places emphasis upon the appearance of a space; it pays due attention to levels of brightness and illumination hierarchies; and, with some slight modifications, it could be readily implemented through software, which is how all lighting design is done today.
estimate the MRSE. The accuracy of this technique is currently being tested against real world measurement and also triangulated against simulation data produced in RADIANCE. Early results have sometimes produced percentage errors close to 20% compared to real world measurements. The script is currently undergoing modification with various options being tested. The intention is to improve accuracy such that results within a 10% error margin can be guaranteed.
Figure 3a – Standard HDR capture
Research At the Dublin Institute of Technology (DIT) ongoing research is attempting to better understand the relationship between MRSE and PAI, in addition to devising an accurate and robust methodology to measure MRSE in-field. The following briefly outlines the methods and expected outcomes of each.
Measurement of MRSE MRSE can currently be measured by recording luminance values on a grid of points on all major room surfaces. Each luminance value is then converted to exitance and the average of all values within a space is representative of the MRSE. This method is slow to implement and its accuracy is limited, and influenced, by the number of grid points that are used. Almost all spaces contain large variations in brightness located over short distances and using a grid with too few points will skew results to an unknown degree. An alternative method is being developed using High Dynamic Range imaging (HDRi). HDRi is a set of techniques used in photography to produce a wider dynamic range of luminosity than is typically possible using standard digital imaging or photographing techniques. Essentially, HDRi uses multiple exposures of the same scene to produce images that better represent the perceived luminous environment. At present this can be applied to produce luminance-calibrated (but not exitance) images of the lit environment31,32. This procedure has been utilised in conjunction with RADIANCE and MATLAB to produce estimates of MRSE. For any standard HDR image the written script can be applied which removes direct flux and simultaneously spits out a numerical value for the quantity of indirect flux incident on that camera view (Figures 3a and 3b). The average of multiple views of the same scene can then be used to
20
Figure 3b – Modified image with direct flux removed
The relationship between mean room surface exitance and perceived adequacy of illumination Two pilot studies have been conducted that examined the relationship between MRSE and PAI. The first of these studies used a scale lighting booth (approx. 2m x 1m x 1m) and the second a larger real-world space (approx. 5m x 3m x 3m). Despite being two separate studies, both used matching methodologies and identical subject groups. In each experiment subjects viewed a range of light scenes. Each scene varied the reflectance of surfaces, the light distribution and the quantity of MRSE. When subjects viewed each scene, they were questioned about brightness and whether they believed the lighting was adequate or inadequate. Figures 4a – 4f show generic representations of the typical light distributions subjects were exposed to and subjects also viewed these distributions over a number of levels of surface reflectance and MRSE. These results are presently being analysed to provide a better understanding of the relationship between MRSE and PAI. It is
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Figure 4a – A uniform downlight distribution
Figure 4b – A uniform uplight distribution
Figure 4c – A uniform mixed distribution
Figure 4d – A non-uniform downlight distribution
Figure 4e – a non-uniform rosbuimedia@eircom.net
Figure 4f – A non-uniform mixed distribution
expected that indications of which variables influence subjective assessments under certain conditions will emerge. This is critical to advancing this research and allowing this new method of lighting design to progress. Findings from this work will enable further studies to examine the quantity of MRSE that people believe is appropriate for a range of situations and space usages.
majority now appear to be in favour of a move away from where lighting standards are currently at and towards a method that pays greater attention to the appearance of a space. The method discussed here is seen to show promise because it directs attention away from the working plane, it defines levels of brightness and, if adopted, it could be readily implemented through software. Two barriers to implementing this method in standards are:
Conclusion
– How MRSE is measured in-field;
A new design methodology for general interior lighting practice has been explained and critically examined. It has received positive and negative feedback from the lighting community, but the
– Understanding the relationship between MRSE and PAI. Both of these items are being addressed at the Dublin Institute of Technology and will be reported further in future research papers.
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References Illuminating Engineering Society of North America, The IESNA Lighting Handbook, 10th Edition, New York: IESNA. 2 The Society of Light and Lighting (SLL). 2009. The SLL Code for Lighting. ISBN-978-906846-07-7. London: SLL. 3 Society of Light and Lighting. 2012. The SLL Code for Lighting. CIBSE. Page Bros. Norwich. 4 Committee of European Standards. 2011. EN 12464-1:2011. Light and Lighting - Lighting of workplaces. Part 1: Indoor Workplaces. London: CEN. 5 Society of Light and Lighting, The SLL Lighting Handbook, 2009, London; CIBSE. 6 Committee of European Standards. 2006. EN 15193:2006. Energy performance of buildings — Energy requirements for lighting. London: CEN. 7 Duff, JT (2012) "The 2012 SLL Code for Lighting: the Impact on Design and Commissioning," Journal of Sustainable Engineering Design: Vol. 1: Iss. 2, Article 4. 8 Duff JT and Kelly K. In-field measurement of cylindrical illuminance and the impact of room surface reflectance on the visual environment. Proceedings of the SLL and CIBSE Ireland International Lighting Conference, Dublin, Dublin, 12 April 2013, www.ile2013.com (accessed 16 May 2013). 9 Cuttle C. Perceived adequacy of illumination: A new basis for lighting practice: Proceedings of the 3rd Professional Lighting Design Convention, Professional Lighting Designers Association, Madrid, 2011. 10 Rea, M.S., and M.J. Ouellette, 1991. Relative visual performance: A basis for application. Lighting Research & Technology,23(3): 135144. 11 Boyce P.R., 1985. Movement under emergency lighting: The effect of illuminance. Lighting Research & Technology,17: 51-71 12 Loe, D.L. and McIntosh, R. 2009. Reflections on the last One Hundred Years of Lighting in Great Britain. The Society of Light and Lighting as part of CIBSE. Page Bros. Norwich. 13 Cuttle, C. “A new direction for general lighting practice”, Lighting Research and Technology, February 2013; vol. 45, 1: pp. 22-39. 14 Cuttle, C. Lighting by Design, 2nd edition, Oxford, Architectural Press, 2008. 15 Cuttle, C. “Towards the third stage of the lighting profession”, Lighting Research and Technology, March 2010; vol. 42, 1: pp. 7393. 16 Venning B. Cuttle’s Theory, the profession responds. SLL Newsletter. Vol3, Iss 1. Jan/Feb 2010. pp 7. 17 Macrae, I. Comment 1: A new direction for general lighting practice, Lighting Research and Technology, February 2013; vol. 45, 1: pp. 22-39. 18 Boyce P. R. Lighting Quality: The Unanswered Questions. Proceedings of the first CIE symposium on lighting quality, Ottawa 1998. 19 Boyce, P.R., “Lighting Quality for All?”, Proceedings of the SLL International Lighting Conference, Dublin, April 2013. 20 Poulton, K. Cuttle’s Theory, the profession responds. SLL Newsletter. Vol3, Iss 1. Jan/Feb 2010. pp 7. 21 Shaw, K. Cuttle’s Theory, the profession responds. SLL Newsletter. Vol3, Iss 1. Jan/Feb 2010. pp 7. 22 Brandston, HM. Comment 3: Towards the third stage of the lighting profession, Lighting Research and Technology, March 2010; vol. 42, 1: pp. 73-93. 23 Wilde, MB. Comment 2: A new direction for general lighting 1
22
practice, Lighting Research and Technology, February 2013; vol. 45, 1: pp. 22-39. 24 Loe, DL. Cuttle’s Theory, the profession responds. SLL Newsletter. Vol3, Iss 1. Jan/Feb 2010. pp 7. 25 Loe, DL. “Brightness, lightness, and providing a preconceived appearance to the interior”, Lighting Research and Technology, September 2004; vol. 36, 3: pp. 215. 26 Raynham, P. Cuttle’s Theory, the profession responds. SLL Newsletter. Vol3, Iss 1. Jan/Feb 2010. pp 7. 27 Bedocs, L. Comment 1: Towards the third stage of the lighting profession, Lighting Research and Technology, March 2010; vol. 42, 1: pp. 73-93. 28 Boyce, PR. Cuttle’s Theory, the profession responds. SLL Newsletter. Vol3, Iss 1. Jan/Feb 2010. pp 7. 29 Hoggett, N. Cuttle’s Theory, the profession responds. SLL Newsletter. Vol3, Iss 1. Jan/Feb 2010. pp 8. 30 Mansfield, KP. Comment 2: Towards the third stage of the lighting profession, Lighting Research and Technology, March 2010; vol. 42, 1: pp. 73-93. 31 MN Inanici. Evaluation of high dynamic range photography as a luminance data acquisition system. Lighting Research and Technology, June 2006; vol. 38, 2: pp. 123-134. 32 J. Mardaljevic, B. Painter, and M. Andersen. Transmission illuminance proxy HDR imaging: A new technique to quantify luminous flux. Lighting Research and Technology, March 2009; vol. 41, 1: pp. 27-49.
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Leveraging Lean in construction: A case study of a BIM-based HVAC manufacturing process
Colin Conway SCHOOL OF ELECTRICAL AND ELECTRONIC ENGINEERING, DIT colin.conway@dit.ie
Colin Keane MERCURY ENGINEERING
Sean McCarthy MERCURY ENGINEERING
Ciara Ahern SCHOOL OF MECHANICAL AND DESIGN ENGINEERING, DIT
Avril Behan SCHOOL OF MULTIDISCIPLINARY TECHNOLOGIES, DIT
School of Multidisciplinary Technologies
Building Servicesnews
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Abstract The impetus towards efficiency in the AECO
Glossary AECO: Architecture, Engineering, Construction and Operations
(Architecture, Engineering, Construction &
Autodesk Navisworks: project review software that
Operations) sector is driving the implementation of
enables AEC professionals to “holistically review
Lean practices. BIM technologies and BIM processes
integrated models and data with stakeholders to gain
provide methods by which this can be achieved.
better control over project outcomes. Integration,
Major clients of building services contractors have
analysis, and communication tools help teams
begun to mandate the use of BIM and some are using
coordinate disciplines, resolve conflicts, and plan
BIM preparedness/experience as pre-tender
projects before construction or renovation begins.�
qualification criteria. In this case study, an initial
(Autodesk, 2014)
review has been conducted of the achievements of a
BIM: Building Information Modelling/Management
major Irish M&E contractor in implementing BIM. The
BIM4M2: BIM for Manufacturers and Manufacturing
firm purpose-built a facility for the off-site manufacture of building services components. The operations of the plant are efficient and qualityassured through the use of an appropriately skilled workforce at all stages of manufacture, and tracking
BOM: Bill of Materials CITA: Construction IT Alliance Eida: Tracking software used to record and document the progress of spools from time of issue to
software that has developed as the knowledge of the
installation
contractor grew. Standardised processes have been
IFC: Issued for Construction (process specific) or
developed which have resulted in greater efficiencies
Industry Foundation Classes
and lower costs for the contractor as a result of fewer
Tool: a set of connected components carrying out the
requirements for onsite modifications (such as those
function of routing a particular service through an
caused by clashes), less waste, and greater flexibility.
area of a building
Despite some initial objections, the employees of the
SAP: Systems, Applications & Products in Data
company are now more satisfied with their working
Processing software for data warehousing
conditions and are, as a result, more productive. Through investment in BIM-based, Lean processes, the contractor can now better compete when tenerding for large-scale projects in Ireland and worldwide, including the rapidly-increasing number where BIM experience and preparedness is mandated.
24
Spools: the subdivisions of service lines in manageable lengths varying from a single component to a 6m pipe-run WBS: Work Breakdown Structure
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Leveraging Lean in construction: A case study of a BIM-based HVAC manufacturing process
1. Introduction Large scale manufacturing facilities, due to the nature of operations and the processes undertaken, frequently require additional building services that might include ammonia, acid waste, solvent waste, helium and argon (Gulledge et al., 2014). Design, fabrication, installation and management of these services are complex operations. While the design of such systems has long been carried out digitally using CAD-based software, due to inconsistencies and uncertainties in the process (Eastman et al., 2011), onsite fabrication of services prior to installation is still necessitated. This is, by its nature, inefficient due to, inter alia, the influence of remote stock locations, clashes with other trades, weather, etc. Building information modelling (BIM) is a relatively new process and set of software tools that has the potential to improve the current situation. BIM is a shared knowledge resource for information that can be defined as “a digital representation of physical and functional characteristics of a facility” (National BIM Standard, 2014). The advent of BIM-based design and build processes enables the use of off-site fabrication through the “creation of a single source of truth” for all parties (Saxon, 2013) where potential clashes between services are identified and resolved in the virtual model and not onsite where their occurrence is much more costly. This enables more efficient work practices that leverage BIM for speed, economy, quality control, and health and safety improvements (Saxon, 2013). While perhaps best-known as assisting at the design stage of a project, the 2014 McGraw Hill Business Value of BIM report (McGraw Hill Construction, 2014) found that between 59% (UK) and 97% (Japan, Germany, France) of contractors who had
IFC Industry Founda on Classes IFD Interna onal Framework Dic onary IDM Informa on Delivery Manual iBIM Integrated BIM CPIC Construc on Project Informa on Commi ee AIM Architectural Informa on Model SIM Structural Informa on Model FIM Facili es Informa on Model BSIM Building services Informa on Model BrIM Bridge Informa on Model
Much of the pressure to adopt BIM processes is being applied by building owners because the improvements in operational processes and the associated costs achievable through BIM have the greatest potential for financial benefit (Azhar, 2011; Carmona and Irwin, 2007). In America, contractors who do not use BIM tools are no longer able to compete in tendering processes on even lowvalue contracts (AGC, 2010). This has changed from the situation in the mid-2000s when the use of BIM was recommended, rather than required, but with contractors who were not BIM-enabled having to add their services last during fit-out (AGC, 2006). Thus, many owners and operators, for example Irish Water and the Grangegorman Development Agency, are requiring that the design and build of new and retrofitted facilities be implemented though BIM. The developers are required, as part of the final handover, to deliver a virtual building that is compatible with the PAS 1192-3
Moving up through the levels of technology use leads to seamless working and effec ve data and process management
Level 3
Level 2
iBIM
2D Level 0
CAD
Drawings, lines, arcs, text etc.
3D
BIMs Standards for interoperability: IFC, IFD, IDM
AIM SIM FIM BSIM BrIM
Level 1
CPIC Avan BS 1192:2007 User guides:CPIC, Avan , BSI
ISO BIM
Models, objects, collabora on
Asset life cycle management
Key
adopted BIM practices reported a positive return on investment (ROI). The variation in success was dependent on the levels of overall adoption of BIM in individual markets. The report also recommends that throughout the developed world, for contractors to remain competitive, they must “embrace emerging uses for leveraging model data” among which are “simulation and analysis to optimise logistical planning and decision-making”. Enabling contractors to benefit from BIM adoption is being facilitated by groups such as BIM for Manufacturers and Manufacturing UK (BIM4M2 Task Group, 2014), who focus on the standardisation of interfaces between BIM and existing systems and processes and, in Ireland, by the Construction Information Technology Alliance’s Construction Technology Series, BIM-2-Win, and Smart Collaboration Challenge events (CITA, 2014).
Data management
Process management
Integrated, interoperable data Source: Bew and Richards, 2008
Figure 1: The Bew and Richards BIM Maturity Levels Model (Bew and Richards, 2008)
25
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Standard for Information Modelling for the Operational Phase of Assets (British Standards Institute, 2014). BIM for asset and facilities management is sometimes called 6D or 7D BIM and PAS 1192-3 is facilitating a move towards the “integrated interoperable data” and “asset life cycle management” defined by Bew & Richards (2008) as Level 3 BIM Maturity. Major component fabrication plants are among the types of facility seeking operational BIM compatibility upon completion of building and retrofit works. Thus an Irish-based mechanical and electrical contracting firm has developed an off-site HVAC manufacturing facility to support the implementation of BIM-based processes. This paper describes the manufacturing facility, its associated work practices, and the initial impacts of implementing this new method. The optimisation and streamlining of the processes resulting from lessons learned on two major building servicing campaigns are detailed in Section 2. Section 3 examines the impact of BIM-based practices on the staff and the necessity of staff “buy-in” to enable the realisation of new work processes from the ground up. Section 3 also evaluates the associated business benefits and Section 4 discusses the potential of BIM-enabled off-site manufacture for the mechanical and electrical building services sector.
2
The Process
In this case study, the contractor’s aim is to provide a “right-firsttime” service where delivery to and installation on site is timely and defect-free. The workshop process discussed in detail in the following requires that all elements of design and reworking are completed prior to issuing fabrication information from site to the manufacturing facility. Thus, at the client’s site in the BIM control and modelling facility, the designs, which include pipework, valves, meters, flanges, bends, welds, etc, are iteratively reviewed while being modelled in connection with existing on-site components (e.g. to main lines known as laterals). These components were measured via high-end surveying and laser scanning techniques. The BIM-based modelling process also
leverages the abilities of the associated software, in this case Autodesk’s Navisworks, to carry out clash detection between all planned installations. Although the work in the assembly line of the fabrication facility only begins when the design is finished at Day 28, an “early detailing start point” occurs just after the kick-off meeting in order to facilitate the take-off of materials and long lead-in components. Even before the 45-day process begins in relation to the fabrication of any tool, there is a 60-day period in which all long-lead components are procured. These components are specialist items that would not be stored in general stock and without this 60-day period delays would be unavoidable. Fabrication of all tools is limited to four weeks but, as the number of tools under fabrication at any time can vary, there is a fluctuation in the workload for the workshop over time. Once the on-site design review is completed, each service line is split into “spools”, examples of which are shown in Figure 3 in modelled form, during manufacture, and ready for transfer to site. Spools can range from a single component to a 6m pipe-run. To avoid cutting and welding on-site, the selection of splitting points for spools is crucial because if the spools are too large it may not be possible to install them on site. By contrast, if the spools are too small, on-site installation work will require more effort than necessary. The service requirements for the manufacturing “tools” are numerous. In this case study an average of 168 spools and over 1000 components were used per tool totalling 67,200 spools and 400,000 components for a single facility. A number of key components and software functions are required in order to facilitate the BIM manufacturing process: a. Isometrics: all fabrication takes place using 2D isometric drawings generated directly from the 3D model as shown in Figure 4. This is an automated function and represents another advantage of using BIM software. Where an issue of interpretation arises with the isometrics, a supervisor can access the 3D model in Navisworks. However, this is not part of
45 DAY PROCESS TO IFC Day 17: Cut Off Point For Change Day 1 Is s ue of “W ork In P rogres s ” LS P bas ed on reference pack. DESIGN START
Day 19
Day 24
Day 27
Design Review
Design Review
DESIGN FINISH
2DR
2DR/IFS TO FYI
IFS
Design Review KICK OFF MEETING ISSUE LSP TO TRADES
1DR (CRITICAL LINE IFF APPROVAL)
Day 45 DIFFERENCE FORM APPROVAL (LOCALIZATION OF PACK)
IFC
REVISIONS TO LSP POST IFF ISSUE DATE COULD HAPPEN AT ANY TIME ?
EARLY DETAILING START Contractor Start
AE RFI & DAILY WHITEBOARD PROCESS
Continuous Activity 28 Days to IFF Day 11/14 DETAILING START
Day 28 TOOL
CRITICAL LINES CRITICAL LINES IFF
Contractor Trigger point to Model
POSTED/REVIEWS
Day 1
Day 7/12
Issue LSP to contractor; take off of materials, long lead, in line components etc.,
DETAILING START
TOOL MODEL IFF,
CONSTRUCTION MODEL
ISO/BOM EXTRACTION FROM
TOOL OWNER FYI
IFF
MODEL
Day 26
Laser Scan Assessment ? Targeted or Continuous
AUTO BOM FROM TOOL MODEL ISSUED TO CONTRACTOR PURCHASING
ISO DRAWINGS ISSUED TO WORKSHOP
“IS S UE D T O WOR K S HOP ” FAB START POR
Figure 2: 45-Day Process to IFC (Issued for Construction)
26
Tool Owner Discretionary Changes
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the standard process and most staff are not trained in the use of the software; b. SAP software: used for stock management to ensure that all required components are available prior to the beginning of the manufacturing process; c. Eida software: used for tracking the manufacturing progress of all spools.
a
Figure 4 illustrates an isometric drawing of a spool manufactured from 2” PVC and designed to carry acid waste water. Isometric drawings, including all of the annotations, can be extracted automatically from the 3D model provided that the model has been developed at a sufficient level of detail. No separate redrawing is required. Under the cutting list section, the lengths of the seven pipe sections are shown in millimetres. This allows cutting to commence immediately as part of the processing steps set out below. This is a direct improvement on site work where the length of each pipe must be determined on the basis of installation conditions before being cut. The isometric also includes the following information: • Bill of materials (BOM) providing information on each component such as 90o and 45o elbows, reducers and tees; • Unique identifying and traceable scan code (QR code), tracked by the staff using iPad minis which send live updates to the Eida tracking software;
b
• Date and time of receipt; • Rework Indicator, completed on-site in case of failure. The QA, recording and actions that form part of the workshop process are detailed in Figure 5 which follows on from Day 28 of the 45-day process presented in Figure 2. 1. Isometric drawings of all spools and a bill of materials (BOM) are issued to the workshop; 2. The BOM is cross-referenced with the previous list of long-lead items as a QA procedure before the tool is recorded into the
c
“IS S UE D T O WOR K S HOP ”
1
FAB START POR
2
Figure 3: Various components in modelled form (a), during manufacture (b) and ready for transfer to site (c).
BOM REVIEW BY
TOOL LOADED
ENGINEER
ONTO EIDA SYSTEM
3
BOM RESERVED AGAINST TOOL WBS
4
LINE ISSUED TO PROGRAMME FOR FABRICATION
QR SCAN TO EIDA
5
LINE PICKED & BAGGED FOR FABRICATION
QR SCAN TO EIDA
6
LINE FABRICATED
7
LINE QA CHECKS
8
FAB FINISH POR
DATA ENTERED ON EIDA
‘L ine A vailable’
‘L ine P ic ked’
QR SCAN TO EIDA ‘F ab S tart’
QR SCAN TO EIDA ‘F ab & QA C omplete’
SITE SUP REQUESTS LINE SPOOL VIA EIDA
LINE STORED QR SCAN TO EIDA
9
LINE SPOOL
‘Dis patc h’
DISPATCHED TO SITE & SIGNED FOR
Figure 4: An example isometric drawing showing a single spool, its associated Bill of Materials, the QR code used for scanning and populating Eida, and the Rework Indicator, in case of errors at point of installation.
Send to Site for Install 10
DATE/DOC # ENTERED INTO EIDA
Figure 5: Numbered workshop process at manufacturing facility
27
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stock management software. The requirements for the tool are compared to what is already in stock and what has already been ordered. The software then lists the required elements for completion of the tool. The goal is to finish fabrication with as little left-over stock as possible, thus creating a lean process. The information for every spool is sent to Eida, which produces .pdf files containing a unique QR (Quick Response) code for each spool. This QR code is used to track the progress of the spool during fabrication, delivery, and installation; 3. The BOM is then reserved against the tool's WBS (Work Breakdown Structure code) and the date is entered onto Eida under the "material reserved" column. As shown in Figure 6, components that are in stock become reserved specifically for an individual tool facilitating the tracking of costs; 4. The next step is another QA procedure. All isometric drawings are reviewed by engineers to check for constructability, corruptions, omissions, etc. Once the isometric is approved by the engineer, the QR code is scanned and the "Line Available" column in Figure 6 is populated. At this point some spools may be identified and prioritised as more urgent than others; 5. A general operative (GO) collects and bags all items for a spool. This part of the process means that skilled tradespeople do not waste valuable time collecting items for fabrication. An engineering technician or experienced GO checks the bag before it is scanned to make sure all items are correct. Once the bag has been scanned, the "Line Picked" column in Figure 6 is populated and the bag is placed on a shelf ready for fabrication; 6. An engineering craftsperson selects a bag from the shelf and scans it, thus populating the "Fab Start" column. Fabrication takes place at a workstation where all tools are readily available and where each worker has plenty of workspace (Figure 3(b)). Once the spool is complete and the event scanned, it is passed to another table where all spools are QA checked; 7. At this point the spools are checked for accuracy of length, angles, joints, welds, etc. If any problems are identified the spool is returned to the technician. If the spool passes QA, the QR code is scanned and the "Fab & QA Complete" column in Figure 6 is populated; 8. The completed spool is “bagged and tagged” and placed in
storage for up to a month, depending on when it is needed on site; 9. The foremen on site can order spools to be delivered once the “Fab & QA Complete” step (8) has finished. They can log into Eida and select the spools which they require and enter the desired delivery date. This step fills in the “Load Plan Request” column in Figure 6. Due to the in-house logistics involved in loading trolleys with spools for delivery, a 48-hour turnaround between order and delivery is the norm, except for urgent requirements. The foreman decides the order in which the spools should be installed and how many he wants delivered each day. The goal on site is to install spools on the day they arrive, thereby reducing the storage requirements by the contractor on the client’s site; 10.The spools are scanned when they are dispatched and again when delivered on site as proof of delivery; Each isometric drawing has a Rework Indicator checklist which is populated during installation on the rare occasions when a spool is incorrect. This step provides feedback as to the source of the problem. Issues can result from fabrication, tools not meeting with specification, or bracket issues. Using traditional processes clashes with other new or existing services frequently but the ability to carry out clash detection in the virtual world of the BIM software practically eliminates that problem. Issues of this nature only occur if the As-Built model used during design is different to the As-Built conditions at the time of delivery. Using the Rework Indicator checklist the source of any problem can be identified and operational improvement can be promptly achieved; thus enhancing the leanness of the process.
3
The Impact of New Processes
The significant changes in the day-to-day operations of the M&E contractor achieved through BIM-based, Lean processes has resulted in improvements in relation to financial returns and employee satisfaction. However, there was a steep learning curve for all concerned and this caused more problems for some employees than others. This impact will now be evaluated from both a business point-of-view and in relation to the human and behavioural aspects.
Figure 6: Progress of the fabrication of individual spools from reservation of materials (Material Reserved) to delivery to site based on Isometric Number via Eida software.
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3.1 Business Appraisal The Eida tracking system that is central to the fabrication process provides a level of traceability previously impossible for the contractor. When first used the software did not have all of the functions currently available but the M&E contractor’s engineers, in conjunction with the developer of the software, customised and developed it to optimise the solution and to ensure that it supported rather than hindered the workflow. Among other items, the software records who fabricated and QA checked each spool, and how many spools each employee fabricated daily. If a problem arises on site in relation to a faulty element, the system can reveal the identity of the fabricator and the checker. This acts as an incentive to improve the quality of each individual’s work. It also ensures that staff maintain comparable levels of productivity and enables management to identify areas in the pipeline where problems may be occurring and/or personnel changes (including increases and decreases in numbers carrying out particular tasks) may be required. The data recorded on a perpetual basis facilitates the continuous improvement of the fabrication workflow and associated inputs and outputs. It also supports more accurate cost estimation, thus impacting on operational costs. Although there are still some occurrences of failures that require reworking, as indicated by the fields on the Isometrics (Figure 4), the amount is significantly lower than would have occurred using traditional practices. During one month this year, 1311 spools were dispatched with only 26 spools needing to be remade. However, 24 of these spools were required only because they were lost on site while the other two had been incorrectly fabricated. Therefore, less than 0.2% of spools required reworking as a result of failures in the fabrication process. It should also be noted that, despite protocols that discourage the practice, minor issues related to fabrication may have been fixed on site because installation engineers chose to carry out necessary works rather than return the spools to the workshop. No statistics on these occurrences are available. Some additional costs have been incurred by the contractor, for example, parts are now stored in 40-foot containers external to the main building. Most containers hold a specific pipe type: high purity, low purity, PVC etc. while a quarantine store is used to prevent parts that do not belong in any other store causing mix ups. Despite this additional requirement, materials in these stores are now retained for shorter periods as a result of the just-in-time process meaning that overall efficiency has improved.
3.2 Human and Behavioural Aspects The new process has had a profound impact on the work practices of individuals and the contractor’s workforce as a collective. Prior to implementation of BIM-based Lean processes, tradespeople were involved in many trivial tasks in relation to the acquisition and maintenance of components and tools. Skilled workers can now focus solely on fabrication because they work at secure, wellequipped benches in a purpose-built facility where the components required for each fabrication task are delivered in a Quality Assured state.
The workshop environment is very different to the traditional onsite conditions known to most tradespeople. Those fabricating the spools simply select a bag containing all the required parts and immediately work on it at a bench where all tools and power are available. When stopping for breaks, tools and equipment can be left unattended without fear of theft. Canteens and toilets are of a standard expected in offices. Workshop conditions are quieter and more comfortable. Hard hats are replaced with bump caps which are lightweight and comfortable. Upskilling is also encouraged where staff rotate between functions to learn new skills. This has the dual benefit of motivating staff and allowing management to re-allocate staff as necessary, depending on requirements at different times during a project. The tracking aspect of the process, which is considered a major positive from the business perspective, was initially considered to be very invasive by some of the workers. Some fabricators thought that the new processes undervalued their skills by requiring so much QA and adherence to stringent practices. However, after a short period these methods became embedded and accepted. During the early stages of implementation of the process, a point of failure was identified in the ordering of spools by the site foremen over the phone. Each spool has a unique code but these were often miscommunicated via this process resulting in the wrong spools being delivered to site. This created delays on site until the correct spool arrived, necessitated extra delivery runs, and served to undermine the entire operation by reducing confidence in the system, particularly among the onsite installers. Management responded quickly by implementing an online spool selection mechanism which the site foremen can access from anywhere and this has significantly reduced these errors and resulted in a corresponding increase in confidence in the system. Anecdotal evidence suggests that tradespeople at the fabrication facility preferred the new conditions over site work. This favourable response has allowed the contractor to attract and retain the most skilled tradespeople available on the market. The contractor reports a significant increase in efficiency through the use of Lean processes when compared with a traditional installation. Metrics on the value of this increase will be evaluated in the future. The current evidence enables the firm to tender more competitively for new work thus providing increased stability of employment for its workforce.
4.
Conclusions and Future Developments
The case study presented here demonstrates the results of applying BIM on a large scale in the M&E manufacturing context for the first time in Ireland. It has shown that innovation and streamlining of the process can be achieved, particularly through working closely with software developers and valuing your workforce. The introduction of a BIM-based process has enabled this M&E contractor to apply and benefit from the principles of Lean Construction including: • Elimination of waste;
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• Clear identification of the elements of operation that deliver what the customer values, i.e. the value stream, and eliminates all non-value-adding steps; • Not making anything before it is needed and then making it quickly; • Striving to achieve perfection by continuously monitoring and improving performance (Lean Sigma 60, 2014). The Eida tracking system that has been developed and implemented in support of the process agrees with the Association of General Contractors of America’s assertion that “any wellplanned and well-executed BIM project should necessarily include procedures and protocols for creating a detailed audit trail” (AGC, 2006, p. 38). Continually reviewing operations and processes with a view to achieving improvement has become embedded within the firm’s psyche. At present, for example, the laser scanning and BIM modelling portions of the workflow are under examination as part of a Construction IT Alliance (CITA) technology challenge. As a result of this project, the firm has built a uniquely-skilled team, experienced in the production and installation of components using the Lean BIM process that was developed and improved by the company. It is envisaged that these factors will enable the contractor to be successful in tendering for, and engaging in future large-scale projects within and outside Ireland, both where BIM competence is a criterion for pre-qualification to tender (SEC GROUP, 2012) and where BIM-based Lean processes provide an advantage over competitors who have not engaged in similar upskilling. This may also result in a significant shift in operational methods for a large number of other contractors who will need to adopt leaner processes in order to compete in the new BIMfocussed market.
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References AGC (2006) The Contractors’ Guide to Building Information Modeling, Association of General Contractors of America, Arlington, VA. Available. AGC (2010) The Contractors’ Guide to Building Information Modeling. Available. Autodesk (2014) Navisworks Overview [Online]. Available: http://www.autodesk.com/products/navisworks/overview [Accessed November] Azhar, S (2011) Building Information Modeling (Bim): Trends, Benefits, Risks, and Challenges for the Aec Industry. Leadership and Management in Engineering, 11(3), 241-52. Bew, M and Richards, M. (2008). Bim Maturity Diagram Model: BuildingSmart,Construction Product Information Committee (CPIC),. BIM4M2 Task Group (2014) Bim for Manufacturers and Manufacturing [Online]. Available: http://www.bim4m2.co.uk/ [Accessed November] British Standards Institute. (2014). Pas 1192-3 Specification for Information Management for the Operational Phase of Assets Using Building Information Modelling (Bim): British Standards Institute,. Carmona, J and Irwin, K. (2007). Bim: Who, What, How and Why: Facilitiesnet.com. CITA (2014) Bim Events [Online]. Available: http://www.cita.ie/events.asp [Accessed November] Eastman, C M, Teicholz, P, Sacks, R and Liston, K (2011) Bim Handbook: A Guide to Building Information Modeling for Owners, Managers, Designers, Engineers and Contractors, 2nd ed, Wiley, Hoboken, N.J. Gulledge, C E, Conyers, R S, Poe, B M and Kibby, C M (2014) Design Build Manufacturing Plant. ASHRAE Journal, 56, 32-9. Lean Sigma 60 (2014) Lean Construction [Online]. Available: http://www.leansigma.ie/education-items/lean-construction [Accessed November] McGraw Hill Construction (2014) The Business Value of Bim for Construction in Global Markets: How Contractors around the World Are Driving Innovation with Building Information Modeling, McGraw Hill Construction, Bedford, MA. Available. National BIM Standard (2014) What Is Bim? [Online]. Available: http://www.nationalbimstandard.org/faq.php#faq1 [Accessed November] Saxon, R G (2013) Growth through Bim, Construction Industry Council, London. Available. SEC GROUP (2012) First Steps to Bim Competence: A Guide for Specialist Contractors BIM Academy Ltd. . Available
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w w w. c i b s e i re l a n d . o rg
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Ruth Kelly Waskett DE MONTFORT UNIVERSITY, LEICESTER, UK ruth.waskett@email.dmu.ac.uk
Birgit Painter DE MONTFORT UNIVERSITY, LEICESTER, UK bpainter@dmu.ac.uk
John Mardaljevic LOUGHBOROUGH UNIVERSITY, LOUGHBOROUGH, UK j.mardaljevic@lboro.ac.uk
Katherine Irvine JAMES HUTTON INSTITUTE, ABERDEEN, UK bkatherine.irvine@hutton.ac.uk
School of Multidisciplinary Technologies
Building Servicesnews
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Abstract Electrochromic (EC) glazing is now considered a viable
1. Introduction
alternative to fixed transmittance glazing. It has the
Buildings with highly-glazed facades often suffer from problems of visual discomfort and solar gain. Typically, internal blinds are used to control solar ingress, but these are regularly left closed for extended periods [Van Den Wymelenberg, 2012], leading to reduced access to daylight and views for occupants. External shading devices are often employed as a solution to control solar overheating as well as visual discomfort. However, a fixed shading device rarely provides optimal control for solar ingress because of the wide extent and constant variation in sun position. A “heavy” brise soleil can be an overpowering presence in façade architecture, often appearing as an afterthought rather than an integral feature of the building design. A variable shading device is likely to perform better than a fixed brise soleil, but these are rarely considered due to increased cost and maintenance issues compared to static devices.
potential to enable occupants to control daylight glare and solar heat gain without the use of blinds or external shading devices, giving users more access to daylight with all its inherent benefits. Furthermore, EC glazing can reduce energy consumption by decreasing cooling loads and electric lighting usage. Most research to date has studied the effects of EC glazing in scale models, computer simulations and full scale test rooms, and some of these studies have included human participants. However, there is a general lack of understanding regarding the performance and suitability of EC glazing in real-world working environments. A case study of the first UK retrofit application of EC glazing is being conducted in two adjacent offices in a university campus building. The offices are occupied by administration staff and have large southeastfacing windows. The existing double glazed units were replaced with commercially-available EC glazed units in 2012. Over a period of more than 18 months, the rooms were monitored intensively to record the effect of the EC glazing on both the physical room environment and the occupants themselves. A large amount of data from the monitoring programme is currently undergoing detailed analysis. Initial findings emerging from the installation and post-installation
Electrochromic (EC) glass changes transmittance in response to a small applied voltage (less than 5 volts DC). An EC window can be operated automatically or manually to control light penetration, without compromising the view out. By providing unobtrusive dynamic shading in this way, EC glazing has significant potential to improve daylighting and energy use in new and existing buildings. Unsurprisingly, EC glazing has attracted significant research since its inception in the 1980s [Lampert, 1984; Svensson & Granqvist, 1984]. However, most of these studies have been simulation-based [Sullivan et al, 1994; Moeck et al, 1998] or lab-based using scale models or full-scale rooms [Piccolo et al, 2009; Lee et al, 2006; Clear et al, 2006; Zinzi, 2006; Lee at al, 2012 and others]. Only a few of these have included a systematic assessment of the experience of human users of the technology [Clear et al, 2006; Zinzi, 2006; Weinold, 2003]. However, those that did include human participants were lab-based, so that participants only experienced the technology for short periods of time (i.e. hours), and not in their normal work setting. This paper describes a case study of the retrofit application of EC glazing in an administration office of a university campus building in the UK. The case study has a number of novel features: • It is the first installation of EC glazing of its kind in the UK.
period are described in this paper.
• At the time of writing, it is one of only two published studies of EC glazing that has been carried out in a real-world setting (see also Lee at al, 2012).
Key Words:
• It utilises high dynamic range (HDR) photography as part of the physical monitoring of the room luminous environment.
Electrochromic glazing, smart windows, visual comfort, daylighting, daylight glare.
• It employs a mixed-methods approach, designed to capture both the subjective experience of occupants and the physical effects on the room environment.
2. EC glazing operation In a double-glazed electrochromic (EC) window, a nanometers-thin coating on the inside surface of the outer pane allows the glass to
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3. Case-study outline
Solar Heat Gain Co-efficient
0.60 Tinted
0.50
Low-e 2
0.40 Tinted low-e
0.30
Low-e 3
ing
0.20
EC
Reflective
z Gla
0.10 0.00
0
10
20
30
40
50
60
70
80
The case study is centred on two open plan offices with large southeast-facing windows. In 2012, the windows were replaced with commercially-available double-glazed EC windows (described in Section 2). The windows are made up of several panes, and the control system is zoned so that individual panes (or pairs of panes in the case of the larger windows) can be controlled independently. Figure 3 shows the interior of the two rooms before and after the EC glazing installation.
Visible Light Transmission (%)
Figure 1: The dynamic properties of EC glazing compared with traditional glazing types. Image reproduced with permission from SAGE Electrochromics Inc.
change transmittance in response to a small applied voltage. The electrochromic coating is made up of several layers that essentally operate like a battery, with electrons moving between layers when the voltage is applied, effecting a change in overall glazing transmittance. The EC windows at the focus of this study were manufactured by SAGE Electrochromics Inc in 2012. The visible transmittance of the glass varies from 62% in the fully bleached (un-tinted) state to 2% in the fully tinted state, with two intermediate states (20% and 6%). Figure 1 illustrates the dynamic properties of EC glazing when compared with traditional static glazing types. Many contemporary glazing products can perform very well under certain external conditions. However, when conditions change, other devices are necessary to control the internal enviornment satisfactorily. Thus, the ability of EC glazing to adapt to changing external conditions without the use of moving parts is clearly a key advantage of the technology. The control stimulus can be linked to any sensor input, depending on the type of control desired. For example, the trigger for tinting the window could be an increase in internal room temperature, internal light level, or, as in this case, external light level on the façade. The EC window is normally operated automatically, and can also be manually controlled using the wall-mounted switch shown in Figure 2.
Figure 2: EC window wall switch (above left) and a wall sign mounted in the rooms explaining how to use the switches (right).
Figure 3: The interior of the case study rooms before and after the EC glazing retrofit. (Note that in the “after” photos the electric lighting is switched on because the daylight-linking control system had not yet been commissioned).
Each room accommodates four people whose work is administrative in nature, and who are office-based for most of their working hours. The two rooms share three windows between them, with a partition down the centre of the middle window. The exterior is shown in Figure 4. The study assesses the direct impact on the visual and thermal environment as well as end-user experience of the technology. A programme of monitoring was undertaken for over 18 months to
Figure 4: The exterior façade of the two case study rooms.
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ensure that a range of seasons and sky conditions were included. The main study participants are occupants of these rooms.
As well as capturing visual scene luminance via HDR, the other physical measurements are as follows: 1. Room temperature
4. Method A mixed methods approach was used to assess the impact of the EC glazing on the physical environment (non-subjective) as well as the experience of the room occupants (subjective). Subjective measures The main challenge of the subjective study design was to achieve a balance between minimising participant burden while capturing good-quality information at regular enough intervals. The need to minimise intrusion to occupants is particularly important in this case due to the small number of participants. The study design is layered, with each layer having a different density of observation. This ranges from a daily but coarse-grained evaluation of the windows (“good”, “neutral”, “bad”), to a more detailed but less frequent online questionnaire. In addition, a one-to-one interview was carried out every three months, in which a deeper exploration of the subjective narrative was possible. The subjective study design is explained in more detail in a previously published work [Kelly et al. 2012]. Each layer of observation has been carefully designed with the aim of collecting data at a useful level of depth and frequency to enable a realistic picture of the users’ experience to emerge, and so provide the basis for a meaningful analysis. Non-subjective measures In parallel to the subjective assessments, a set of repeated meausrements were made to capture the impact of EC glazing on the physical environment of the offices. High Dynamic Range (HDR) imaging with a fish-eye lens was used to capture and quantify the luminous environment. Figure 5 shows a sample HDR image taken in one of the case study rooms before the EC window retrofit. As it was not practical to locate the HDR cameras at the occupants’ eye position, the cameras were positioned as close as possible to the participants head position, at seated eye height. Where possible, one camera was shared between two participants, e.g. between adjacent workstations.
Figure 5: A test HDR image taken in one of the offices before the EC window installation.
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2. Air conditioning status 3. Heating status 4. Interior illuminance 5. EC window status 6. EC window manual overrides 7. Blind position 8. Electric lighting energy use 9. EC window energy use 10. Weather data via a local weather station It should be noted that, although electric lighting current has been monitored as part of this study, the focus is on the user experience of EC windows, and as such the effect on electric lighting energy use will not be investigated in depth. The potential of EC glazing to reduce electric lighting energy use, as well as cooling load, has been studied previously by others, e.g. (Lee et al., 2006).
5. Initial findings As a result of this case study, a large and varied dataset has been obtained, the detailed analysis of which is currently underway. Nonetheless, some findings have already emerged, and these are outlined below. Installation From the point of view of installation, a key difference between EC windows and traditional windows is the need for wiring (power and communications). The cables are low-voltage and there is nothing particularly novel or challenging about the wiring required … it simply needs to be scheduled as part of the installation process. For openable windows (as they are in this case), the wires to the EC glazing should of course be at the hinged side. For the installation described here, the offices have a partition wall that divides the central EC window frame. Despite not being the most straightforward of scenarios for the deployment of a novel glazing technology, the windows were installed in two days, which seems reasonable even for traditional double-glazed windows of the same size. Commissioning of the control system was carried out as each unit was installed, and was completed within the week of the installation. The control system ran with default settings for the first few months, after which time the settings were adjusted in response to feedback from occupants and observations of the system operation. Room layout Roller blinds were left in place after the EC window installation. They were fully retracted when the occupants moved back into their office after the work was completed. It was interesting to note that the occupants in one room did not use the blinds at all until around the beginning of December, and then only rarely. Because of the orientation of the façade, at low sun angles the solar disc is visible in the middle of the windows. For occupants facing the
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windows, this has produced some visual discomfort even with the EC windows at full tint. Under these conditions, the minimum transmittance of 2% was not enough to control glare adequately for some occupants, though the sensitivity to this may depend on individual sensitivities. This finding supports previous studies [Lee et al, 2002] which indicated that a minimum transmittance of 1% was desirable. (It should be noted, however, that SAGE’s latest product achieves a minimum transmittance of 1%, which should provide better glare control for occupants with a direct view of the window). Occupants who sit with their backs to the windows reported fewer instances of visual discomfort. This finding suggests that space layout could be optimised to avoid any requirement for blinds in an office with EC glazing, e.g. occupants could be positioned so that they are not normally facing a window, and/or that they can easily change their position to avoid direct sun in their eyes. In any case, from a glare control point of view, it is good practice to locate office work stations perpendicular to windows where possible. View and connectedness to outdoors Feedback from participants suggested that they value the ability to see through the windows continously. Theirs is an urban view, comprising a parking area, a road and nearby buildings. During interviews, they commented positively about the ability to see people and vehicles coming and going. Before the installation of the EC windows, participants indicated that with the blinds drawn, the room had a tendency to feel “closed in”. Several participants observed that when the windows are tinted, the sky looks darker than it is in reality, giving the false impression that it might rain, for example. However, the windows should not normally be tinted under cloudy conditions, and if so, only briefly, so this may not be a significant issue for other installations.
findings also indicate that EC glazing could be particularly effective when used in sloped/horizontal glazed openings such as large glazed roofs or rooflights.
6. Conclusions A large data set has emerged from the 18-month monitoring campaign undertaken as part of this case study. This includes qualitative and quantitative data; measured data from the physical room environment and self-reported data from human participants. The process of retrofitting EC glazing into a typical UK office and the subsequent settling-in period has already highlighted several practical considerations which might be useful for future adopters of the technology. Detailed analysis of the data collected during the monitoring period is currently being undertaken, and it is anticipated that this will increase our understanding of the effect of EC glazing on its end users.
Acknowledgements EC windows and associated technical support provided by SAGE Electrochromics, Inc. and Saint-Gobain Recherche.
Window tinting, daylight spectrum and colour When questioned about their window-tint preferences in interviews, several participants indicated that they preferred to have the lower row of window panes (which are in their eye-line when seated) un-tinted, except when direct sun was visible through those panes. There are likely to be several factors at play in this preference, including a desire for an ‘un-darkened’ view to outside, and/or a perception that daylight that is not filtered through tinted glass is more natural. To explore the second issue in more depth, a hypothesis was put forward: If at least one pane of the EC windows is not tinted, the resultant spectrum of daylight in the room is close to that of a room with completely un-tinted windows. A set of field measurements was made of daylight spectra in the case study room under various tint-pane combinations. This was compared with a set of theoretically modelled spectra, with very good agreement, thus supporting the hypothesis. This work is described in detail in a paper to be published by Lighting Research & Technology, Mardaljevic et al (2014). Other implications Latitude is obviously a key factor; in a more southerly location with higher year-round sun angles, it seems likely that the need for blinds could be significantly reduced or completely eliminated. The
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References CR. D. Clear, V. Inkarorjrit, E.S. Lee, Subject responses to electrochromic windows, Energy and Buildings 38 (2006) 758-779. S. K. Deb, Optical and photoelectric properties and colour centres in thin films of tungsten oxide, Philosophical Magazine, Volume 27, Issue 4 (1973). C. G. Granqvist, Oxide electrochromics: An introduction to devices and materials, Solar Energy Materials & Solar Cells 99 (2012) 1–13. R. Kelly, J. Mardaljevic, B. Painter & K. Irvine, The long-term evaluation of electrochromic glazing in an open plan office under normal use: project outline, Proceedings of Experiencing Light 2012, Eindhoven, The Netherlands. C. M. Lampert, Electrochromic materials and devices for energy efficient windows, Solar Energy Materials & Solar Cells 11, Issues 12, (1984) 1–27. E.S. Lee, E.S. Claybaugh, M. LaFrance, End user impacts of automated electrochromic windows in a pilot retrofit application, Energy and Buildings 47(2012) 267-284. E.S. Lee, D.L. DiBartolomeo, Application issues for large-area electrochromic windows in commercial buildings, Solar Energy Materials & Solar Cells 71 (2002) 465–491. E.S. Lee, D.L. DiBartolomeo, S.E. Selkowitz, Daylighting control performance of a thin-film ceramic electrochromic window: Field study results, Energy and Buildings 38 (2006) 30-44. J. Mardaljevic, R. Kelly Waskett, and B. Painter. Neutral daylight illumination with variable transmission glass: Theory and validation. Accepted for publication in Lighting Research and Technology in 2014. M. Moeck, E.S. Lee, M.D. Rubin, R.T. Sullivan, S.E. Selkowitz, Visual quality assessment of electrochromic and conventional glazings, Solar Energy Materials and Solar Cells 54 (1998) 157-164. A. Piccolo, Thermal performance of an electrochromic smart window tested in an environmental test cell, Energy and Buildings 42 (2010) 1409–1417. A. Piccolo, A. Pennisi, F. Simone, Daylighting performance of an electrochromic window in a small scale test-cell, Solar Energy 83 (2009) 832–844. A. Piccolo, F. Simone, Effect of switchable glazing on discomfort glare from windows, Building and Environment 44 (2009) 1171– 1180. R. Sullivan, E.S. Lee, K. Papamichael, M. Rubin, S. Selkowitz, Effect of switching control strategies on the energy performance of electrochromic windows, Proceedings of SPIE International Symposium on Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XIII, April 18-22, 1994 in Friedrichsbau, Freiburg, Germany. J.S.E.M. Svensson, C.G. Granqvist, Electrochromic tungsten oxide films for energy efficient windows, Solar Energy Materials 11, Issues 1-2, (1984) 29–34. K. Van Den Wymelenberg, Patterns of occupant interaction with window blinds: A literature review, Energy and Buildings 51 (2012) 165–176. J. Wienold, Switchable façade technology: Building integration – Final report. Report number: swift-wp3-ise-jw-030616, Fraunhofer Institute for Solar Energy Systems, Heidenhofstr. 2, D-79110 Freiburg (2003). M. Zinzi, , Building and Environment 41 (2006) 1262-1273.
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2015 Call for Abstracts THE SDAR AWARDS is a joint initiative between CIBSE Ireland and DIT, supported by Building Services News, and sponsored by John Sisk & Son. The awards are unique in that they were devised to disseminate knowledge, encourage research in sustainable design of the built environment, and raise the quality of innovation and evaluation of such projects. Entries are required to critically evaluate real life data, and examine both successes and challenges within leading-edge projects throughout Ireland or further afield. This competition is open to architects, engineers and all professionals involved in construction projects. Entries are now being sought for the SDAR Awards 2015 and, to begin the process, short abstracts (between 100
and 200 words max) must be submitted by email directly to Michael McDonald at michael.mcdonald@ dit.ie and/or Kevin Kelly at kevin.kelly@dit.ie, to arrive no later than Monday, 15 December 2014, Today more than ever, as positive signs ripple through the built environment, this unique synergy between industry and academia allows greater potential for integration of modern low-carbon technologies and low-energy design methodologies. The SDAR Awards competition represents a platform for the growth of applied research in the expanding green economy. Post-occupancy evaluations and similar critical appraisal of low-energy projects facilities the transition from ideologically-driven innovations,
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sometimes offering poor value, to evidence-based applied research that proves value or identifies weaknesses that the industry can learn from. These successes and failures help inform the professional community across all the building industry disciplines. From the abstracts submitted by the Monday, 15 December 2014 deadline, a shortlist will be selected by peer review, and those selected will be invited to prepare final papers for submission by 30 January 2015. The presentation of the awards is scheduled for March 2015 and candidates that present at the awards final also have a chance of their papers being published in the SDAR Journal (see http://arrow.dit.ie/sdar/). For further information contact: michael.mcdonald@dit.ie or kevin.kelly@dit.ie
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A Cost-Optimal Assessment of Buildings in Ireland Using Directive 2010/31/EU of the Energy Performance of Buildings Recast
Christopher Pountney CHRISTOPHER.POUNTNEY@AECOM.COM
David Ross AECOM, UK
Sean Armstrong DEPARTMENT OF THE ENVIRONMENT, COMMUNITIES AND LOCAL GOVERNMENT, IRELAND
School of Multidisciplinary Technologies
Building Servicesnews
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Abstract This paper describes the first cost-optimal assessment of national energy performance standards for buildings in Ireland undertaken in accordance with Article 5 of the Energy Performance of Buildings Directive (EPBD) Recast [Council Directive 2010/31/EU]. This paper focuses on new-build standards which are set out in Part L of the Building Regulations in Ireland. A set of representative residential and nonresidential building models were selected. The impact on primary energy demand of a wide range of energy efficiency measures and renewable technologies was evaluated for each building model and the corresponding lifecycle costs were calculated. The results show that the new-build residential standards in Ireland are in the cost-optimal range, while the new-build non-residential standards deliver a greater primary energy demand than the cost-optimal range.
Key Words: Cost-optimal, Part L, Lifecycle cost
1. Introduction In Ireland energy use and CO2 emissions associated with the built environment continue to be significant and measures to reduce their impact in both new and existing buildings will continue to be an important component of Government energy and climate change policies. The latest data in respect of CO2 emissions estimated that a total of 12.6 million tonnes of CO2 equivalent was generated by the buildings sector in Ireland in 2010 [DECLG, 2012]. In 2010, this accounted for 28.8% of emissions in Ireland that were not included in the EU Emissions Trading System. Against this background, improvements in energy efficiency within the buildings sector, in tandem with the increased use of renewable energy technologies, constitute important policy measures needed to facilitate a reduction in Ireland’s energy dependency on fossil fuels and associated greenhouse gas emissions over the period to 2020 and beyond. A key policy is Part L of the Building Regulations which sets standards for primary energy use and CO2 emissions for new buildings (as well as setting standards for the energy efficiency of building works on existing buildings). The domestic and nondomestic standards were last updated in 2011 and 2008 respectively. Article 5 of the Energy Performance of Buildings Directive (EPBD) Recast assesses the suitability of national building energy performance standards. It requires all EU member states to determine cost-optimal standards for building energy performance and to compare these with their national standards. This assessment should be conducted using the comparative methodology framework, which is defined in the Cost-optimal Regulations (the “Regulations�) [Commission Regulation (EU) 244/2012] and expanded upon in the associated Cost-optimal Guidelines [Guidelines accompanying (EU) 244/2012]. The methodology stipulates how various building measures should be evaluated, including both energy efficiency options and renewable technologies, based on the primary energy benefits and the associated lifecycle costs. Applying these rules to a range of typical reference buildings gives an indication of the cost-optimal, minimum energy performance which should be compared against that of the national standards applied to the same reference buildings. This paper presents the first cost-optimal assessment of buildings and building elements in Ireland undertaken in accordance with the framework. For each reference building, the various building measures are plotted with primary energy on the horizontal axis and lifecycle costs on the vertical axis. Figure 1 gives a typical example. For each level of primary energy, there are likely to be many options with different lifecycle costs. For any particular primary energy consumption, the points plotted in red are those which have the lowest lifecycle cost. These are used to determine the cost-optimal curve. Since the cost-optimal curve may reasonably be expected to vary based on uncertainties in the input data, a range of sensitivity analyses are undertaken. The range of minimum points from each of these cost-optimal curves forms the cost-optimal range. The
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Cost (£/m²)
A cost-optimal assessment of buildings in Ireland using Directive 2010/31/EU
Primary Energy (kWh/yr/m²) All Solu ons
Op mal Solu ons
Cost-Op mal Range
Cost-Op mal Point
Current Standard
Figure 1: Example cost-optimal curve for a reference building.
cost-optimal point is the point within the cost-optimal range with the lowest primary energy. Applying the Part L standard to the example reference building is also shown in Figure 1. The final part of the assessment is a comparison of the cost-optimal point with the current national standards. The primary energies of both the cost-optimal points and the national standards are averaged over the reference buildings. The average of the national standards should be no greater than 15% above the average of the costoptimal points. The member state should either give a justification for any exceedance or outline a plan of action to reduce the deficit.
The reference buildings were based upon typical building models (not actual buildings) provided by the Department of the Environment, Community and Local Government (DECLG). These dwellings were based on a review undertaken of new-build dwelling construction between 2003 and 2006. Sources included the DECLG Annual Housing Statistics Bulletin, the Central Statistics Office Construction and Housing Statistics, DKM Economic Consultants Ltd Annual Review of the Construction Industry, and Sustainable Energy Authority of Ireland’s Energy Consumption and CO2 Emissions in the Residential Sector. Further details of current new-build dwellings were supplied by OMP Architects, DTA Architects and MosArt to confirm typical area, form, glazing ratios, and construction methods [DEHLG, 2007]. A summary of the floor areas for these buildings is shown in Table 1, where the floor areas were calculated by taking linear measurements between the finished internal faces of the walls. New buildings are assumed to be of cavity wall construction as DECLG advised that this is the most common new-build construction type in Ireland.
Table 1 – Selected residential reference building models Building Category Single-family buildings
Apartment blocks
2.
Methodology
This section describes the application of the cost-optimal methodology in Ireland. Although the analyses of residential and non-residential buildings were undertaken separately, most of the methodology is consistent. Both parts are presented together.
2.1 Reference buildings For the purpose of this work, it has been assumed that the reference buildings are constructed in Dublin. The greater Dublin region contributes to a significant proportion of newly-constructed dwellings and is also the focus of current non-residential construction activities. Hence, we have used climate data for Dublin, as defined within the Irish building energy assessment procedures, as well as initial investment cost data for Dublin as provided by AECOM cost experts.
2.1.1 Residential buildings The regulation stipulates that member states should define reference buildings for both single-family dwellings and either apartment blocks or multi-family dwellings. In this case, reference buildings were selected for five different dwelling types – • Bungalow • Detached house (2-storey) • Semi-detached house (2-storey) • Mid-floor flat • Top-floor flat
Reference Building Bungalow Detached house Semi-detached house Mid-floor flat Top-floor flat
Floor Area 104m² 160m² 126m² 54m² 54m²
2.1.2 Non-residential buildings According to Annex 1 of the regulation, member states should establish at least one reference building for office buildings, as well as for certain other non-residential buildings for which specific energy performance requirements exist. In Ireland, energy performance requirements are set for all non-residential buildings. Reference buildings based on the following four building categories were selected – • Office buildings • Educational buildings • Hotels and restaurants • Wholesale and retail services buildings A summary of the buildings, construction type and servicing strategy is shown in Table 2. The office building, hotel and restaurant building, and wholesale and retail services building, were based on
Table 2 – Selected non-residential reference building models Building Category Retail (Air Conditioned) Office (Natural Ventilation) Office (Air Conditioned) School (Primary – Natural Ventilation) Hotel (Air Conditioned)
Construction type Cavity Wall – 1500 m² – 2300 m² 2500 m²
Steel Frame 1250 m² – 1500 m² – –
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building models used to develop building regulations for energy performance requirements within the UK. The floor areas of these models were amended to reflect the mean area of the planning permissions granted in Ireland in 2010. The school building was based on an exemplar primary school building provided by the Department of Education and Skills [DES, 2013].
2.2 Building energy measures A list of potential measures was compiled using the cost-optimal guidelines and design experience for both residential and nonresidential buildings. Since it is impractical to evaluate every permutation of the selected measures, the measures were grouped into packages. For residential buildings, three sets of packages were created (see Table 3), representing three different components of a dwelling design (fabric, heating, photovoltaics (PV)). PV is selected here as the primary renewable energy technology, since it is often one of the lowest-cost alternatives, is usually independent of building features and is applicable to a wide range of building forms. Selecting one package from each component forms a complete dwelling design. Taking account of all of the permutations, 80 alternative dwelling designs have been modelled in each reference dwelling. In non-residential buildings, building services measures were explicitly included as a fourth component (see Table 4). In total, 225 alternative building designs have been modelled in each reference building, with the exception of air conditioned offices
Table 3 – Measures included in residential analysis Fabric Wall U-value (W/m²K) Roof U-value (W/m²K) Floor U-value (W/m²K) Window U-value (W/m²K) Thermal Bridging (y-value) Air Tightness (m³/m².hr @ 50 Pa) Ventilation Strategy
F1 0.27 0.16 0.20 1.6 0.15 10
F2 0.20 0.14 0.18 1.4 0.08 7
F3 0.13 0.11 0.13 0.9 0.04 5
Natural Ventilation
F4 0.13 0.11 0.13 0.9 0.04 2 MVHR
Heating H1 H2 H3 H4 H5 Condensing Gas Biomass GSHP ASHP Space Heating Source Space Heating Efficiency 91% 80% 396% 374% Communal option for flats? No Yes (all houses have individual heating systems) Controls Full time and temperature Full time and zone control, weather temperature compensation, modulating zone control boiler with interlock Emitters Radiators Underfloor Heating Electric Immersion Heater NO NO NO YES YES Solar Hot Water NO YES NO NO NO PV PV Installation (% foundation area)`
44
PV1 0%
PV2 10%
PV3 20%
PV4 30%
where that number was doubled due to the inclusion of optional free-cooling as a fifth component. The values selected for each of the measures (e.g. the fabric Uvalues and building services efficiencies) within the packages have been chosen to give a large spread of primary energies and lifecycle costs. This helps to obtain a clear cost-optimal curve, making it easier to identify the cost-optimum range. Some packages include solutions that, taken together, might comprise a building design that performs more poorly than the primary energy standard set by the current Part L regulations. This is necessary to show whether the current standards are already at, or beyond, cost-optimal. It should be noted that some possible measures have been omitted from these packages. There are a number of reasons for this – • Site specific measures: Various measures are particularly dependant on site constraints. For example, building orientation and the feasibility of wind turbines are likely to depend on the site and the surrounding context. Our assumption is that the cost-optimal point should be based on measures that any designer can typically adopt. If not, achieving the cost-optimal point may be unrealistic in many real cases.
Table 4 – Measures included in non-residential analysis Fabric Wall U-value (W/m²K) Roof U-value (W/m²K) Floor U-value (W/m²K) Window U-value (W/m²K) Improved Thermal Bridging Air Tightness (m³/m².hr @ 50 Pa)
F1 0.3 0.25 0.25 1.8 NO 7
F2 0.25 0.2 0.2 1.4 YES 5
F3 0.2 0.15 0.15 0.9 YES 3
Services Lighting (llm/cW) Daylight Lighting Control Occupancy Lighting Control Heat Recovery Chiller Efficiency (SEER) AHU SFP FCU SFP Demand Control Ventilation
S1 55 NO NO NO 3.5 2.2 0.6 NO
S2 60 YES YES NO 4.5 2 0.3 NO
S3 65 YES YES 65% 5.5 1.8 0.3 YES
Additional Services Free Cooling (FC)
FC1 NO
FC2 YES
Heating Heating Source Space Heating Efficiency Solar Hot Water
H1 H2 Gas boiler 86% 91% NO YES
H3 CHP 45% NO
H4 GSHP 400% NO
H5 GSHP 400% NO
PV PV Installation (% foundation area)
PV1 0%
PV3 20%
PV4 30%
PV5 40%
PV2 10%
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• Design measures: Some measures impact on design constraints that do not affect the building primary energy demand. For example, modifying the percentage of glazing or introducing shading to optimise the primary energy demand may result in inadequate daylight levels. Furthermore, this is building-dependent – a particular percentage of glazing may provide appropriate day lighting in one building design but not another. Therefore, such measures have not been considered in the list of packages. • Default measures: There are other measures that are likely to be included in new buildings by default, for example in non-residential buildings, monitoring and metering, variable speed pumps and power factor correction. These have not been treated as options; they are simply added to the base building models where appropriate. Since these measures do not vary, there is no need to separately identify costs for them.
2.3 Energy performance assessment The EPBD Recast requires member states to develop a methodology for calculating the energy performance of buildings. There are a range of European standards recommended for the calculation of various loads and energies in buildings, including EN ISO 13790 for heating and cooling. In Ireland, this methodology has been implemented in the Domestic Energy Assessment Procedure (DEAP) and the Non-domestic Energy Assessment Procedure (NEAP). Both DEAP and NEAP reflect the additional requirements regarding conservation of fuel and energy in Part L. The Irish Government publishes a software implementation of DEAP, which is available as a standalone tool and as a spreadsheet tool. For this analysis, the reference dwellings were constructed in the spreadsheet tool, so that evaluating the various packages of measures could be automated. Similarly, the NEAP is implemented in the Simplified Building Energy Model (SBEM) calculation engine. To undertake this analysis, a custom modelling environment was developed using VB.NET to automatically edit the SBEM building model input files to reflect each package of measures. The energy end uses (i.e. heating, cooling, lighting, domestic hot water and auxiliary energy) were recorded directly from the SBEM output files. In both cases, the end-use energies were then summed for each energy carrier to find the delivered energy requirement. Any onsite generated energy was also determined at this stage. The associated primary energy for each package of measures was calculated by multiplying the delivered energies by the appropriate primary energy factor. The projected primary energy factors (PEFs) were averaged over the calculation period (see section 2.4).
2.4 Lifecycle calculations The calculation of lifecycle costs was undertaken according to the detailed procedures laid down in Annex 1 of the Regulations. The lifecycle cost (CL) is defined in the equation below. ( )=
+
,
( )
( )+
,
( ) −
,
( )
(1)
where:
, , ,
( ) ( ) ( )
calculation period initial investment cost annual cost for package of measures during year cost of carbon for package of measures during year residual value of package of measures at the end of the calculation period (discounted to starting year )
( ) is the discount rate in year and is calculated as follows: ( )=
1 1+
(2)
100
where: number of years from starting year the real discount rate
Following the Regulations, the calculation period was set to 30 years for the residential and public buildings (i.e. the primary school) and 20 years for all other non-residential buildings. The initial investment costs were provided by AECOM cost experts based on industry data. Similarly, they provided the maintenance and replacement costs for inclusion as part of the annual costs. Asset lives were taken from IS EN 15459 [NSAI, 2007]. However, since the calculation periods are similar to or less than many of the component asset lives, few replacements were required. The annual costs also include the annual energy cost. The baseline energy costs were taken from the Energy Trends 2009 document [European Commission, 2010] referenced in the Regulation. The cost of biomass in the residential analysis was taken from the BioEnergy Supply Curves for Ireland report [SEAI, 2012]. Similarly, solid multi-fuel (coal assumed) costs were taken from the DECC Interdepartmental Analyst Group tables [DECC, 2013], converted to Euros and 2013 prices. For the societal calculation, the cost of carbon was calculated using carbon emission factor projections provided by DECLG. The baseline cost of traded carbon emissions were taken from Annex 2 of the Regulation. This projection assumes the implementation of existing legislation, but does not account for any further future decarbonisation. The residual value at the end of the calculation period was calculated assuming a linear depreciation over the component asset life. The lifecycle costs were evaluated from both the private investor perspective and the societal perspective. In practice, this requires a slight modification to the equation above for the private investor calculation, since the cost of carbon is not included. Furthermore, for the private investor calculation, Value Added Tax (VAT) is also applied as appropriate. From the societal perspective, taxes are not included in the lifecycle cost calculation. The discount rate varied depending on the lifecycle perspective. For the private investor, the baseline discount rate was set at 7% and was based on an assessment of the current financial landscape. The
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societal baseline discount rate was set at 4%, the value used by the Irish Government in policy-impact assessments. A series of sensitivity analyses were undertaken on the initial investment cost, discount rates, energy prices and primary emission factors to assess the potential variation depending on reasonable uncertainty in input data.
3. Results This section presents the results of the cost-optimal assessment of the various packages applied to each reference building.
3.1 Residential results Figure 2 provides an example Residential result. It is a societal analysis for the Semi-Detached House. The red dashed line marks the current standard, which intersects the cost-optimal curve at a lower primary energy than the cost-optimal point. Table 5 summarises the results for each of the residential buildings, including the range of cost-optimal energies based on the various sensitivities. For most building types, the national standard is within the cost-optimal range. Over the build mix, the national standard meets the requirement of being less than 15% above the average cost-optimal primary energy. An analysis was also undertaken of the technology solutions on the cost-optimal curve: • Heating technology: The solutions were segregated with typically the lowest primary energies achieved using gas heating with solar hot water. Gas heating solutions appeared at greater energies, while some biomass heating solutions were towards the right hand side of the cost-optimal curve.
Table 5 – Residential cost-optimal primary energy values Building Category
National Standard Cost Optimal Sensitivity Range (kWh/m2/yr) (kWh/m2/yr) (kWh/m2/yr) Bungalow 67 110 33-139 Detached house 55 90 45-113 Semi-detached house 54 89 49-110 Mid-floor flat 57 79 57-94 Top-floor flat 65 92 68-105
3.2 Non-residential results Figure 3 shows the results of the societal perspective analysis, using the baseline discount rate and costs, for the NaturallyVentilated Office. The red dashed line marks the current standard, which is greater than the cost-optimal primary energy. Table 6 summarises the results for each of the non-residential buildings, including the range of cost-optimal energies based on the various sensitivities. For all building types, the national standard is above the cost-optimal range. Over the build mix, the national standard is greater than 15% above the average cost-optimal primary energy. An analysis was also undertaken of the technology solutions on the cost-optimal curve. This was more complex for non-residential buildings given the greater range of building types. • Heating technology: Typically, the heating technology with the lowest primary energies was GSHP heating. In the Hotel, this included the addition of solar hot water also. The solutions with the highest primary energies always used gas heating. CHP did not feature in the cost-optimal solutions in any of the reference buildings.
• Fabric and PV: On the curve, there were several solutions for each heating technology with differing fabric and PV packages. The solutions with the lowest primary energy pushed the fabric to package F4 and the PV to 30%.
600
Macroeconomic Cost (EUR/m²)
• Cost-optimal: From a societal perspective, the cost-optimal solution was fabric package F2, no PV and either biomass for homes and gas for flats. From a private investor perspective, gas heating was the preferred technology for all dwelling types.
700
500
400
300
200
100
0
600
0
50
100
150
200
250
300
Primary Energy (kWh/m²)
Macroeconomic Cost (EUR/m²)
500
Figure 3: Office (NV) (Societal Perspective, 4% Discount Rate). 400
Table 6 – Non-residential cost-optimal primary energy values 300
Building Category
200
100
0 0
20
40
60
80
100
120
Primary Energy (kWh/m²)
Figure 2: Semi-Detached House (Societal Perspective, 4% Discount Rate).
46
National Standard Cost Optimal Sensitivity Range (kWh/m2/yr) (kWh/m2/yr) (kWh/m2/yr) Retail (Air Conditioned) 726 239 227-338 Office (Natural Ventilation) 247 52 35-103 Office (Air Conditioned) 366 102 101-179 School (Primary – Natural Ventilation) 111 55 8-80 Hotel (Air Conditioned) 507 284 243-330
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• Fabric, Services and PV: On the curve, there were several solutions for each heating technology with differing fabric, services and PV packages. The solutions with the lowest primary energy pushed the fabric to package F3, the services to package S3 and the PV to 40%. • Cost-optimal: At the cost-optimal point, GSHP was the selected heating technology in most cases, although the School used gas heating. The fabric varied from F1 to F3 and similarly the services varied from S1 to S3. In all cases the maximum-sized PV array was selected, except for the School where no PV was used.
3.3 Sensitivity analysis It is useful to review in more detail the results of the sensitivity analysis. Both reducing the energy prices and increasing the discount rate reduced the cost of energy over the calculation period. This tended to have two impacts. • It made solutions with higher primary energy demand relatively more attractive with the cost of energy consumption over the calculation period becoming cheaper in terms of net present value. Indeed, for some non-residential buildings, increasing the discount rate from 3% to 6% as much as doubled the cost-optimal level of primary energy. • It often changed the preferred heating technology. In residential buildings, gas tended to be the cost-optimal solution for lower energy prices, while biomass was preferred at higher energy prices. It is noted that the gas and biomass energy prices do come from different sources and this analysis assumes their comparability. The sensitivity analysis of PEFs and the price of carbon showed little impact when averaged over the calculation period. In both instances, the sensitivity case simply increased the cost-optimal primary energy, without changing the optimal technology for the lowest cost solution. Only in one non-residential building (Airconditioned Office) did the cost-optimal solution change. In this case, a less efficient services package was selected. No learning rates were included in this analysis and it would be expected, for example, that PV would become more cost-effective over time, which would affect the cost-optimal primary energy and the associated technology solution.
4. Discussion The results presented in the previous section show that the national standard for residential buildings is near, or in some cases, beyond cost-optimal. The standard in non-residential buildings is far above the cost-optimal point in all cases. This section discusses these two results in further detail.
4.1 Residential buildings As the requirements for new dwellings are already in the costoptimal range and are better than the cost-optimal level in many cases, there is no plan to review the current requirements for new
dwellings to achieve cost-optimal levels. These cost-optimal calculations will be used to inform the roadmap to Nearly Zero Energy Buildings and associated NZEB targets as required by the EPBD Recast. Nonetheless, this analysis does highlight an important issue regarding the role of biomass heating in Nearly Zero Energy Buildings. The analysis shows that biomass heating has, at best, only a marginal benefit in primary energy terms. The primary energy factor for biomass is similar to natural gas, but the efficiency of biomass boilers is poorer than that of equivalent natural gas boilers. No doubt biomass heating will be an important alternative in Ireland in future, especially since the gas network is relatively limited. However, to achieve Nearly Zero Energy Buildings, alternative heating sources or additional on-site generation technologies will be required.
4.2 Non-residential Part L for non-domestic buildings was last revised in 2008 to include a maximum permitted whole building energy performance coefficient and a carbon dioxide performance coefficient, calculated in comparison with a reference building. The regulation and guidance is currently undergoing a review process due for completion in 2014. The Department of Environment Community and Local Government is committed to the new regulation and guidance achieving cost-optimal levels. This will be the first milestone on the roadmap for non-residential buildings to Nearly Zero Energy Buildings, which is due for public buildings in 2018 and for all buildings by 2020. While there are clearly considerable opportunities for improvement across all non-residential buildings, the revised standard will need to consider additional factors beyond cost-optimality, such as buildability, technology supply chain or the robustness of newer technologies. Indeed, setting a cost-optimal standard in non-residential buildings is not straightforward due to the varied energy demand profiles. For example, the Naturally-Ventilated Office and the School are similar in terms of servicing strategy and have a similar total primary energy demand at the cost-optimal point (52 kWh/m² for the Naturally-Ventilated Office and 55 kWh/m² for the School). However, in the Naturally-Ventilated Office lighting is the predominate energy demand, far exceeding the heating demand (28 kWh/m² against 13 kWh/m²). The School is the opposite, with the heating energy demand three times the lighting energy demand (28 kWh/m² against 9 kWh/m²). At the cost-optimal point, the different energy profiles have a clear impact on the selected packages. In the Naturally-Ventilated Office the cost-optimal point is achieved with the maximum-sized PV array and GSHP heating, while the selected fabric package is the minimum, package F1. In the School, the cost-optimal point does not require any PV, selecting gas heating and improving the fabric to package F3. This serves to illustrate the great diversity between non-residential buildings, since apparently similar building types may have quite different cost-optimal solutions. It should also be noted that adding PV often achieves large primary energy reductions, while incurring very little additional lifecycle
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cost. Adding PV was most cost-effective in the School. Beyond the cost-optimal point, increasing the PV array from 0% to 40% reduced primary energy from 52 kWh/m² to 4 kWh/m², with a macroeconomic cost increase of only 8 EUR/m². Adding PV to the Air-Conditioned Office had a similarly high cost-effectiveness, although the size of the primary energy reduction was limited by the available roof area. The precise cost and benefits depend on the both the estimation of long-term primary energy factors and electricity costs, nonetheless, PV is a favourable addition when viewed over the lifecycle calculation period.
References
5. Conclusion
Department of Energy and Climate Change. 2013. The Interdepartmental Analysts’ Group (IAG) Toolkit Supporting Tables. [Online]. [Accessed: November 2013]. Available at: http://tools.decc.gov.uk/en/content/cms/about/ec_social_res/iag_guid ance/iag_guidance.aspx.
This paper has described the first cost-optimal assessment of buildings in Ireland undertaken in accordance with Article 5 of the EPBD Recast. The results show that for residential buildings the current national standard is within, or beyond, the cost-optimal range. However, for non-residential buildings the current standards lie outside the cost-optimal range. Consequently, there are various implications for future updates to the national standard. This analysis showed that some solutions on the cost-optimal curves in residential buildings may contain biomass heating. However, the impact of biomass heating in Nearly Zero Energy Buildings will be limited by the primary energy factor of the fuel and the efficiency of the boilers. The analysis of non-residential buildings showed more variability in the cost-optimal solution. In most cases, adding PV and selecting GSHPs was preferred, although the cost-optimal solution for the School maximised fabric improvements. Meanwhile, in several cases, and for very little additional lifecycle cost, significant primary energy reductions were achieved through the inclusion of the largest-sized PV arrays.
Acknowledgements This paper contains material taken from the full cost-optimal calculations report [DECLG, 2014] and is reproduced with the consent of the Department of Environment, Community and Local Government.
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Commission Regulation (EU) No. 244/2012 of 16 January 2012 on the Energy Performance of Buildings by Establishing a Comparative Methodology Framework for Calculating Cost-Optimal Levels of Minimum Energy Performance Requirements for Buildings and Building Elements. Council Directive 2010/31/EU of 19 May 2010 on the Energy Performance of Buildings (Recast). Department of Education and Skills. 2013. Exemplars and Template Designs. [Online]. [Accessed: November 2013]. Available at: http://www.education.ie/en/School-Design/Exemplars-TemplateDesigns/Exemplars-and-Template-Designs.html.
Department of the Environment, Community and Local Government, 2014. Report on the Development of cost-optimal Calculations and Gap Analysis for Buildings in Ireland under Directive 2010/31/EU on the Energy Performance of Buildings (Recast). Dublin: DECLG. Department of the Environment, Community and Local Government, 2012. Towards a New Climate Change Policy: Interim Report of the NESC Secretariat. Dublin: DECLG. European Commission, 2010. EU Energy Trends to 2030 – Update 2009. Luxembourg: Publications Office of the European Union. Guidelines accompanying Commission Regulation (EU) No. 244/2012 of 16 January 2012 on the Energy Performance of Buildings by Establishing a Comparative Methodology Framework for Calculating Cost-Optimal Levels of Minimum Energy Performance Requirements for Buildings and Building Elements. National Standards Authority of Ireland. 2007. IS EN 15459:2007. Energy performance of buildings – Economic evaluation procedure for energy systems in buildings. Dublin: NSAI. Sustainable Energy Authority of Ireland, 2012. BioEnergy Supply Curves for Ireland 2010-2030. Dublin: SEAI. UCD Energy Research Group, 2007. Energy Efficiency Regulations for New Dwellings and Options for Improvement. Dublin: Department of Environment, Heritage and Local Government.
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Institiúd Teicneolaíochta Átha Cliath Dublin Institute of Technology School of Multidisciplinary Technologies The School of Multidisciplinary Technologies supports and facilitates the education of engineering, built environment and technology students in the College of Engineering and the Built Environment, from undergraduate to post graduate, whole time and part-time, in a multidisciplined approach for holistic outcomes grounded in research. It promotes multidisciplinary themes such as energy, sustainability, information technology (including BIM) and engineering/built environment educational research in the college. It also facilitates the design and delivery of innovative programmes (see panel below) that are attractive to students in a cost-effective way. In addition, the School bridges the gap between engineering and the built environment, resulting in holistically-designed, healthy and low energy buildings for a modern sustainable world.
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College of Engineering & Built Environment Part time and CPD programmes in
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