RMIT Master of Energy Efficient and Sustainable Building
This report aims to propose several sustainable technologies which could be implemented in Building 8 of RMIT City Campus, with an analysis of the social, environmental and economic benefits.
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Building 8 Retrofit: Sustainable Building Proposal
RMIT UNIVERSITY MC209 MASTER OF ENERGY EFFICIENT AND SUSTAINABLE BUILDING
Building 8 Retrofit: Sustainable Building Proposal BUSM4467 Sustainable Building Technologies Ramon Joseph Seastres, Meinan Wang, Kim Nguyen
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RMIT Master of Energy Efficient and Sustainable Building
Table of Contents EXECUTIVE SUMMARY...................................................................................................................................................... 3 INTRODUCTION................................................................................................................................................................... 3 BACKGROUND....................................................................................................................................................................... 4 PART ONE: EXISTING SITUATION................................................................................................................................. 6 Building 8 Energy and Water Consumption......................................................................................................... 6 Lighting............................................................................................................................................................................... 6 HVAC.................................................................................................................................................................................... 9 Water................................................................................................................................................................................... 9 PART TWO: PROPOSED IMPROVEMENTS.............................................................................................................. 10 Lighting............................................................................................................................................................................ 10 HVAC.................................................................................................................................................................................. 11 Water................................................................................................................................................................................. 14 Bathroom Fixtures.................................................................................................................................................. 14 Grey-Water and Rainwater Harvesting System........................................................................................... 15 PART THREE: SUSTAINABILITY ASSESSMENT..................................................................................................... 16 Social................................................................................................................................................................................. 16 Environmental............................................................................................................................................................... 17 Economic......................................................................................................................................................................... 17 Lighting....................................................................................................................................................................... 17 Water............................................................................................................................................................................ 20 HVAC............................................................................................................................................................................. 23 Total.............................................................................................................................................................................. 26 Multi-Criteria Assessment........................................................................................................................................ 27 CONCLUSION AND RECOMMENDATIONS............................................................................................................... 27 REFERENCES...................................................................................................................................................................... 29 APPENDIX............................................................................................................................................................................ 32
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Building 8 Retrofit: Sustainable Building Proposal
EXECUTIVE SUMMARY Building 8 of RMIT University's City Campus displays very poor performance in terms of electricity and water consumption, with a Moderate Emissions rating and Very High Water use according to RMIT's Emissions Rating Criteria. Due to its construction in 1993, many of the systems within Building 8 do not abide by current Australian Sustainability standards and there are many opportunities for improvement - in particular, upgrading of T8 fluorescent lights to motion sensor dimmable LED lights, installation of active chilled beam systems and installation of dual flush toilet systems, motion sensor faucets, and greywater and rainwater harvesting plant. Over a ten year period, an estimated value of almost $3million can be saved. In addition to economic benefits, the proposed systems address many concerns raised by staff and students which utilise Building 8 in regards to indoor comfort and overall satisfaction. Sustainable technologies can also encourage users to adopt more sustainable lifestyles and act as a leading example of innovative design across RMIT and other Australian Universities. Reduction in electrical consumption also results in lower Greenhouse Gas (GHG) emissions and water saving technologies, in conjunction with rainwater and greywater harvesting systems, lessen the reliance of the building on mains water supply.
INTRODUCTION 40% of global energy consumption falls under the building category - overtaking industry and transportation as one of the largest energy consuming sectors (Yang, et. al., 2014). Within the building industry, the majority of greenhouse gas emissions comes as a direct result of energy consumption within the building, through the consumption of fuels for heating and cooling and electricity use for HVAC systems, lighting, and other systems (Khan, et. al., 2014). Greenhouse gases produced through these processes have been shown to have significant impact on climate change and are directly responsible for increased greenhouse gas concentrations within the atmosphere (Khan et. al., 2014). These high concentration levels have been shown to create a barrier around the Earth's atmosphere, preventing heat from leaving the Earth's direct perimeter and thus resulting in a global temperature rise and rising sea levels (Dincer, 2000). Sustainability is about sustaining life, which means contemporary people can’t only consider about themselves, they also should take future generations into account (John et al. 2009). John et al. (2009) continued to pointed out in their book that “if something is sustainable, it means we can go on doing it indefinitely. If it isn’t, we can’t.”
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RMIT Master of Energy Efficient and Sustainable Building
In an effort to reduce emissions, Australia has introduced several strategies to encourage more sustainable building - including the implementation of Green Rating system in 2003, aimed at improving building sustainability in environmental, economic and social aspects (GBCA, 2016). RMIT University is also committed to reducing their greenhouse gas emissions, with a pledge of 25% reduced emissions by 2020. The vision of RMIT University is to build an environment which contributes to urban, as well as environmental, sustainability and to set a prime example for innovative sustainable building.
Figure 1: RMIT Sustainability Initiative (RMIT University 2014)
This report aims to analyse the current state of energy and water consumption in Building 8 of RMIT University's City campus and thus suggest appropriate measures for improving its overall sustainability in accordance with RMIT's sustainability policies and outlook. The primary focus will be around improvements in regards to lighting, HVAC, and water fixtures. This report will analyse the proposed technologies to be implemented and discuss its potential benefits and feasibility of implementation, as well as an analysis of the proposal's social, environmental, and economic implications.
BACKGROUND RMIT's City Campus is located in the Melbourne CBD, with Building 8 located at 360 Swanston Street. Built in 1993, the building contains 15 floors, 10 of which are available for public access. Table 1 (below) outlines data relating to the space and utilisation of Building 8, extracted from RMIT's Property Central database (2016). Table 1: RMIT Building 8 floor space information
Space Planning 32,096.30m2 30,780.55m2 18,645.14m2
Total Int. Gross Area Total Room Area Total Usable Area
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Building 8 Retrofit: Sustainable Building Proposal
Table 2: RMIT Building 8 utilisation
Utilisation (Building) Average Frequency Rate (All Teaching Spaces 2015) 57.4% Average Occupancy Rate (All Teaching Spaces 2015) 40.1% Average Utilisation Rate (All Teaching Spaces 2015) 23.0% According to RMIT's Emissions Ratings criteria, Building 8 scores a rating of 3 (Moderate Emissions) for emissions and a rating of 5 (Very High Water Use) for water consumption. A group of students undertook a series of interviews throughout the building to further understand occupants' current attitudes and levels of satisfaction with the performance of Building 8 through asking staff and students questions regarding their comfort within the building and what the primary problems or concerns were surrounding Building 8's performance. Table 3 outlines several comments that were made by occupants, sorted into appropriate categories.
Table 3: Building 8 student conducted interview comments
Category Lighting
Comments Lights are often unclean and neglected Lights often burn out and remain unreplaced for long periods of time, calling maintenance to replace bulbs can be very difficult and time
Cooling
Other
consuming Lighting colour changes from warm to cool in some places There is a need for more natural sunlight Generally comfortable Sometimes uncomfortably warm Cooling system has a very long response rate Cooling does not properly combat large amounts of heat gains from rooms such as computer labs Heating and cooling is inconsistent Lack of control over temperature in immediate surroundings Doors are constantly opening High levels of noise Areas can become very stuffy to work within
PART ONE: EXISTING SITUATION Building 8 Energy and Water Consumption According to Eriksson (2014), Building 8 of RMIT consumes the most electricity energy per year in all buildings of the city campus. The electricity consumption can reach 5 GWh per year, making Building 8 one of ten buildings across RMIT with an annual electricity consumption over 1GWh
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RMIT Master of Energy Efficient and Sustainable Building
(Eriksson, 2014). As shown in the Figure 1, the historic electricity use remained almost stable from 2007 to 2010 with the number of 3 GWh to 3.5 GWh per year, with no significant energy consumption variations throughout the year.
Figure 2: RMIT Building 8 Historical Electricity Use (Eriksson 2014)
The electricity balance as seen in Figure 3 shows that the primary energy consuming sectors include AHU's & PAC (28%), ITS Equipment (23%) and Lighting (22%).
Figure 3: RMIT Building 8 Electricity Balance (Eriksson 2014)
Lighting As stated in Eriksson's (2014) report and through visual observations, Building 8 uses primarily 36W T8 fluorescent lights. Table 4 outlines some key characteristics of T8 lights. Table 4: T8 Fluorescent light typical specifications
Fluorescent lights (T8 36W) Lamp nominal wattage Mean service life
36W 1,300 h
Average lifespan
20,000 h
Lamp shape Colour temperature
Tube, two bases 6,500 K
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Building 8 Retrofit: Sustainable Building Proposal
A short study conducted by some students at RMIT University involving the collection of lighting data in Building 8 and Building 80 showed the results as seen below in Table 5. Figure 4 shows the lux values, where each point represents a measured level and the orange area of the graph representing appropriate lux levels for a University (Australian Standards, 2014). Of the 27 measured levels in Building 8, 14 are measuring lux which is beyond appropriate levels suggesting an unnecessary amount of light fixtures and/or light bulbs which are brighter than required. Areas such as submission desks where administrative staff are performing routine office tasks (lux requirement 320), measured lux levels reach as high as 861. Many of these submission desks are also illuminated by large decorative lights.
Figure 4: RMIT Building 8 lux levels
Table 5: Lux and CCT levels throughout RMIT Building 8 and Building 80
Level 2 3 3 2 3 4 5
Location Building 8 Level 2 Foyer (near stairs) City Fitness Foyer Free Dance Classes Foyer Lift Foyer L2 Ramp to Level 4 L4 Vending Machine L5 Escalator
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Lux(lx)
CCT(K)
667 228 220 131 68.9 230 295
3260 3903 5438 5251 4780 5327 5557
RMIT Master of Energy Efficient and Sustainable Building
6 7 7 7 7 8 8 8 8 8 8 9 9 9 9 10 10 11 11 11 2 2 9 9
L6 Escalator L7 Foyer L7 Submission Desk L7 Corridor L7 AV Rental L8 Escalators L8 PCPM Submission Desk L8 Corridor L8 PCPM Lounge L8 PCPM Relax Space L8 PCPM Relax Space 2 L9 Escalator L9 Submission Desk L9 Corridor L9 Corridor (broken light) L10 Stairs L10 Submission Desk L11 Stairs L11 Corridor L11 Skylight Building 80 Building 80 L2 Coffee Shop Building 80 L2 Locker Building 80 L9 Lift Lobby Building 80 L9 Portal Study Area
615 182 524 233 292 418 395 125 194 770 501 530 861 238 40.5 652 567 940 562 381
3869 3719 3551 3910 3762 4584 3902 3884 3831 3970 3932 4662 3758 3877 3584 4763 3706 5552 4047 4371
103 171 244 284
2749 2969 2972 3126
HVAC The cooling system implemented in Building 8 is powered by York chillers in Building 12, which are fuelled by electricity. Table 6 below shows a breakdown of the measured values of electricity consumption through the cooling system (Eriksson, 2014) and Table 7 shows EER ratings: Table 6: Building 8 electricity consumption due to cooling
Measured Values Cooling System
Usage [kWh] 1,381,297 453,604 495,460 54,554 136,831
AHU's&PAC Pumps Chiller Cooling Tower Ventilation Total
Usage MWh
2,521.75
Table 7: Chiller EER Ratings
Chiller 1
Make York
Nominal EER 6.15
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Seasonal EER 6.15
SSEER 6.42
Building 8 Retrofit: Sustainable Building Proposal
2 3 4 5
York York Powerpax Powerpax
6.15 6.15 5.52
6.15 6.15 5.52
6.42 6.42 -
Water The building has a two handle faucet system and a single flush 11L toilet system as shown in figures 5 and 6. Through the 12 floors of the buildings it is estimated that 120 fixtures of the faucet and 120 fixtures of the toilet system are installed in the building.
Figure 5 (left) & Figure 6 (right) : Building 8 currently installed bathroom fixtures (Seastres 2016)
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RMIT Master of Energy Efficient and Sustainable Building
PART TWO: PROPOSED IMPROVEMENTS Lighting In place of the current T8 fluorescent lights, it is suggested to install a series of LED tube lights. As shown in table 8, LED tubes have a far higher lifespan of 50,000 hours compared to a T8 fluorescent tube which has a lifespan of 20,000 hours. This reduces the replacement period of the bulb from once every 2 years to once every 5-6 years. Table 8: Typical T8 LED Tube light specifications
Movement Sensor T8 LED Tube Lamp nominal wattage Mean service life Lamp shape Colour temperature
18W 50,000 h Tube 4,500 - 6,000 K
The use of a lighting control system or sensor system can also be introduced to effectively decrease energy consumption in Building 8 of RMIT through ensuring lights are on only during necessary periods of time. Such sensors have already been installed in RMIT's Building 56 and 57, allowing the lights to automatically turn off in bathrooms which are unoccupied. In Building 8, areas such as Level 4 and Level 5 are illuminated at all times despite the Level 5 library being closed after 12am Monday to Thursday and after 8pm from Friday to Sunday, with maintenance staff cleaning only for approximately one hour before opening time. Areas such as this show a lot of potential for energy saving as lights can be automatically turned off during closed hours. In terms of level 4(outside RMIT Connect), almost no students remain here after 12am (2am to 2.30am during busy periods) and it is used as a passageway. A sensor system can allow for the space to be illuminated only when students are passing through instead of being illuminated at all times. Dimmer switches can also potentially reduce energy consumption by controlling the quantity of light to fit specific tasks, moods, or situations. Table 5 shows many instances where inappropriate levels of light are supplied (for example, relax spaces with a lux level of 770 which is recommended for very difficult tasks such as paint retouching) and dimmer switches can allow students and staff to control the light levels and make them more appropriate. LED lights, as opposed to fluorescent lights, also perform better with controls as the lifespan of LED lights are not affected by being turned on and off. In addition, it is also suggested to use a dynamic lighting strategy. Dynamic lighting can use LED lighting to achieve the regulation of light color. Daylight can also be well utilised, particularly on
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Building 8 Retrofit: Sustainable Building Proposal
higher levels where adjacent buildings are not shading the windows. An installation of Lutron systems in Building 8 can allow for automatic dimming of lights which are closer to a natural light source, balancing the levels between sunlight and artificial light. This can reduce the amount of energy used on lighting and make use of natural sunlight.
HVAC As chiller plants typically have a 15-20 year lifespan, there is a definite need for the chillers which deliver to Building 8 to be replaced with more efficient systems. In place of the York chillers, Smardt-Powerpax air cooled chillers will be installed, reducing the building's energy consumption due to a higher EER of 13, compared to the current system's EER of 6.15. In conjunction with an upgraded chiller plant, it is proposed to upgrade the temperature controlling systems. In order to increase efficiency and address concerns raised during interviews, the current ducted cooling system is proposed to be replaced with a series of active chilled beams. For analytical purposes, it will be assumed that the system to be installed will be Frenger Eco active chilled beam (figure 4). Active beams consists of a coil that is housed within a series of fins which is suspended from the ceiling. As cool water passes through the coil, the fins disperse the cooled air which descends and is reintegrated into the system once it has been warmed (Roth et. Al., 2007). To assist in the circulation of the cool air, small fans located above the coil pushes air throughout the space, and due to the smaller amount of air required to be circulated, much of this be drawn from fresh air sources. By allowing natural convection to cool the space in place of standard variable-air-volume (VAV) system, electrical power demand can be greatly decreased particularly in terms of pumps, fans, and other air transport loads. The operational efficiency of the pumps are also higher than fans, leading to reduced energy losses (Vastyan, 2011).
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RMIT Master of Energy Efficient and Sustainable Building
Figure 7: Active Chilled beam diagram (Rumsey 2011)
Chilled beam systems can additionally combat concerns raised during the building interviews of high draught levels and inconsistent temperature control. As the hydronic system contains fewer fan elements than a typical VAV system, air velocity is reduced to a maximum of 0.25m/s as specified in the Frenger technical data sheet. This value remains within the comfortable level for people within buildings (ASHRAE, 2013). Designing the cooling system with more localised zoning and controls will also eliminate dissatisfaction with inconsistent cooling needs as well as allow occupants to experience more control over their surroundings. Exposed chilled beams, as opposed to recessed within the ceiling, will allow building users an opportunity to witness and have a greater understanding of the cooling system in place - allowing occupants to visually engage with the system. Occupant exposure to sustainable building technologies has the ability to positively script a person's behaviour towards more environmental choices (Jelsma, 2003) and over time can encourage more sustainable lifestyle choices.
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Building 8 Retrofit: Sustainable Building Proposal
Figure 8: Frenger Eco Active Chilled Beam (Frenger 2016)
RMIT has already successfully integrated chilled beams into the design of building 9 and 80, with building 9 installing chilled beams as part of a retrofit and building 80 integrating them into the initial design. The re-design of Building 9, completed in 2009, also considered the heritage listing of the building and was primarily focused on upgrading existing services without compromising its historical value. The project was considered very successful and has since been recognised as an award winning design - achieving the Public Buildings Alterations and Additions - architecture aware & heritage buildings - John George Knight award (APM Group, 2016). Adopting design elements, including the chilled beam system, in the retrofit of Building 8 allows for greater energy efficiency with verified precedent.
Figure 9: RMIT Building 9 chilled beams (APM Group 2010)
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RMIT Master of Energy Efficient and Sustainable Building
Water Bathroom Fixtures The first part of the proposed improvements involves updating the bathroom fixtures currently installed throughout the building. Replacing the fixtures with a motion sensor faucet system and dual flush toilet system will greatly reduce water consumption. A motion sensor faucet system will automatically shut off after hand washing and will only activate when the user presents their hands(Allianceforwaterefficiency.org, 2016) and a simple diagram is provided in Figure 10. This allows the user to fully control how much water to use. The second part involves the installation of a dual flush system. This will give the user the option of using a half-flush in which it uses less water, thereby reducing the buildings overall water consumption. The proposed system will use less volume of water decreasing from a 11L flush to a 3-6L flush(City West Water Limited, 2010). The system has a pre-selected volume of water and uses gravity to activate the flushing. Since it doesn't use siphoning like other toilet system, there are less chances of clogging, therefore reducing maintenance(Sperando, 2014). The proposed bathroom fixtures are not difficult to install but different brands provide slight differences to their fixtures. Choosing the right the system will depend on the brands reaction time, water flow, and the amount of water used for flushing.
Figure 10: Motion Sensor Faucet diagram (Autotaps 2016)
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Building 8 Retrofit: Sustainable Building Proposal
Grey-Water and Rainwater Harvesting System Installation of a grey-water system, such as seen in Figure 11, in the building will allow water consumed from bathroom faucets to be used for toilet flushing. In conjunction to using recycled water, an installation of a rain harvesting system will greatly reduce the building’s overall water consumption. The grey-water system will use a treatment system that will filter water coming from the sinks and processed through a grey-water treatment and a disinfection plant, treated grey water will then be flowed through the toilet cisterns for use(Wahaso.com, n.d.). Monitoring and control of the grey-water system will be done though a programmable logic controller that fully controls the entire grey-water process.
Figure 11: Greywater treatment diagram (Level 2016)
An integrated rain harvesting system will provide water for bathroom sinks reducing reliance of water from the main pipelines. Rainwater will be collected from the roof and will stored in rainwater tanks, the water collected will then be pumped throughout the building for use(Renewableenergyhub.co.uk, 2016). The proposed system can be easily installed in an existing building. Combining a grey-water system and rain harvesting system will reduce the building reliance on water and as a result reduce the buildings overall main line water consumption and water bill.
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RMIT Master of Energy Efficient and Sustainable Building
PART THREE: SUSTAINABILITY ASSESSMENT Social Interview results in Table 3 show that many of the problems surrounding quality of the building can be addressed by upgrading of technology. For example, occupants were unsatisfied with the level of maintenance throughout the building and expressed their unhappiness in regards to difficulty in contacting maintenance to replace burnt out light bulbs. Due to the longer lifespan of LED lights, bulbs will be burnt out less often and the need to call for maintenance will be greatly reduced. Studies have also shown that the ability to dim lights within a workspace results in more satisfied and productive occupants. The colour of the light is also an important factor in occupant productivity, with higher CCT levels associated with a decreased sense of sleepiness, increased body temperature, improved memory and promotion of individuals' attentiveness. As levels 4 to 11 of Building 8 are primarily study spaces, LED lights with higher CCT levels can promote higher brain stimulation while areas such as lounges should install lights with lower CCT levels. Control over temperature is also a large factor in occupant satisfaction, as many people have variable preferences surrounding temperature a system which can be zoned and controlled can cater for each occupants individual wants. Interviews also show that occupants were unhappy with the application of the cooling system and by installing chilled beams, there is a capacity for cooling load variation as required. Chilled beam systems also have more immediate responses than conventional HVAC systems, which will address occupant dissatisfaction with cooling response rates. The motion sensor faucet allows more accessibility and is more hygienic. For people with limited mobility the motion sensor allows elderly and disabled people to use and access the bathroom faucet with ease. Disease transmission is also greatly reduced since the system is hands free, thereby making it more hygienic than other faucet systems and reducing the likelihood of students and employees contracting sickness (Sustainability-certification.com,2014). The dual flush system allows inhabitants of the building to be more conscious about water use. The system provides the user a half flush that uses less water and gets the user thinking of situations when to use and when not to use. Since the system has a less risk of clogging in comparison to other systems, the need for maintenance is greatly reduced. The grey-water system is controlled and monitored through programmable logic controller, this allows a full control of the systems operation, thereby reacting to peak demand times. The system will understand the occupants movements and will fully operate at the buildings busiest and will stop operating when the building is not in use. The rainwater harvesting system uses rain water which
does
not
have
added
minerals
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unlike
water
from
main
supply
line
Building 8 Retrofit: Sustainable Building Proposal
(Renewableenergyhub.co.uk,2016). Since the water is untreated and natural, it can be more appropriate for occupants that have sensitive skin.
Environmental There are several environmental benefits that come from reduced disposal due to upgraded systems, longer LED life spans greatly reduces the quantity of bulbs which are disposed and the aluminium and copper structure of chilled beams allows for 100% recyclability. The current T8 lights also contain mercury which causes health and environmental hazards when broken or discarded. The reduction of energy consumption through more efficient lighting and cooling also results in decreased emissions of greenhouse gases such as CO 2, CO, and SO2 (Stansbury and Mittelsdorf, 2001). The emission of air pollutants is detrimental to the health of not only individuals but also the environment (Stansbury and Mittelsdorf, 2001). Motion sensor faucets and dual flush systems can reduce water consumption throughout the building. The faucet system wastes less water as water can only flow when the user’s hands are present, therefore water wasted from applying soap is avoided and up to 70% of water can be conserved (Heldmann, 2016). The dual flush system allows a half flush which uses less amounts of water for flushing. The system can conserve water by using the half flush when it is appropriate. Installing these water conservation systems can greatly reduce the building’s demand on water and in turn reduce the overall environmental impact of the building. The grey-water system and rain water harvesting system allows a building to reduce its reliance on the main water supply and on certain occasions such as high rain fall, completely run off the main water supply. Since the grey water system uses recycled water and the rainwater harvesting system gathers rainwater, the buildings water demand is significantly reduced. In turn the pressure from drawing water from existing freshwater sources are also reduced and the overall environmental impact of the building is significantly lowered.
Economic Lighting When looking at economic benefits of installing LED lights, the financial savings come in the form of a reduced running cost due to higher energy efficiency and reduced costs from disposal and replacement of light bulbs. According to Figure 2, the approximate electricity consumption in 2010 was 3,100,000kWh. Given that lighting accounts for 22% of the building's consumption, that results in a usage of
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RMIT Master of Energy Efficient and Sustainable Building
approximately 682,000kWh dedicated to lighting. Eriksson's (2014) report outlines an approximate 2,374 fittings which are replaced every second year (Table 4). This means that the total cost of replacing all the T8 light fixtures will be 2374 x $8 per bulbs = $18,992 every second year The cost of electricity consumption will be under the assumption of a cost of 28c per kWh, which under the do nothing scenario is calculated as follows: 0.28 x 682,000 = $190,960 per year It will be assumed that maintenance callouts are required for 8 hours every six months and costs $40 per hour. Therefore the maintenance cost in the Do Nothing scenario is calculated as: 8 x 40 x 2 = $640 per year Similarly, the Install All situation for lighting will assume a maintenance requirement of once every second year with the same cost and duration. The total cost is calculated as: 8 x 40 x 1 = $320 every second year The cost of replacing the LED light bulbs will use the assumption that it will cost $39 per unit and replacement occurs every 5 years and the installation cost will assume the same number of light bulbs as in the Do Nothing scenario. Electricity consumption in the Install All situation will take into account that the wattage for the LED lights is half of that of the T8 fluorescent. Therefore the cost of electricity consumption will be approximated as half of that in the Do Nothing scenario ($190,960/2 = $95,480). This calculation will not take into account the possibility that there will most likely be fewer lights required or the energy used by sensors or dimmers. As seen in the Life Cycle Cost worksheets (Table 9 and 10) below, there is a potential saving of $464,942.64 through installing sustainable lighting systems.
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Building 8 Retrofit: Sustainable Building Proposal
Table 9: Life Cycle Cost Worksheet (Do Nothing Lighting)
Table 10: Life Cycle Cost Worksheet (Install All Lighting)
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RMIT Master of Energy Efficient and Sustainable Building
Water The main selling point of a motion sensor faucet and the dual flush system is that by reducing the buildings water consumption, the buildings water bill will also be lowered. Upgrading to a dual flush system reduces the water usage from a 12L to 3-6L of flushed water and combined with the proposed faucet system which can conserve up to 70% of water, these system definitely offer a significant financial benefit(Autotaps.com, 2016). The grey-water system and rainwater harvesting systems offers significant economical benefits. Both the systems offer the building less reliance of the main water supply which reduces the demand and in turn reduce the buildings overall water bill. The lifecycle cost worksheet presents a economical assessment of the current and proposed system in a span of 10 years, taking into account its capital cost, ongoing income elements and ongoing cost elements. Do Nothing Scenario The do nothing scenario represents the current net present value of the existing systems. Table 11 presents a life cycle cost worksheet for the do nothing scenario. It is shown that the net present value (NPV) is a net cost of $ -2,854,495.09. Table 11: Life Cycle Cost Worksheet (Do Nothing Water)
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Building 8 Retrofit: Sustainable Building Proposal
Installation of Proposed Water Systems Table 12 presents a life cycle cost worksheet for the installation of the proposed water systems. It is shown that the NPV, which is a net cost is $ -1,180,818.65. The calculations are formed by assumptions that: 
Annual rain data will be drawn from the Bureau of Meteorology
Taken from the Building 8’s recent water usage data the average daily water usage is 200.58 kL. The water usage charge from 1 January - 30 June is $3.3285 kL/per day and the water usage charge from 1 July - 31 December is $3.1693/kL/per day. The annual service charge is $332.08(Southeastwater.com.au, 2016). 200.58 x [1 Jan - 30 Jun(181 days)] x 3.3285 = $120,841.126 p.a 200.58 x [1 July - 31 Dec(184 days)] x 3.1693 = $116,968.468 p.a The sewage disposal charge is $1.7914 kL/per day and the annual sewage service charge is $446.84 and the will be the same amount of the average daily water usage. 200.58 x 365 x 1.7914 = $131,151.439 p.a There is an estimate of 120 faucet fixtures and toilets existing in the building. The motion sensor faucet system cost $100 each and the dual flush system cost $450 each, both include the installation cost. 120 x 100 = $12,000 capital cost for faucet 120 x 450 = $54,000 capital cost for toilet Efficiency of the proposed bathroom fixtures will reduce daily water usage by 30%. Therefore, 250.58 x 0.7 = 140.406 kL/per day, to be used for the water usage and the sewage disposal charge. The average annual rainfall in Melbourne is 540 mm and the roof area of the building is around 2000m2. The efficiency of a flat roof for rain catchment is 50%. Since 1mm of rain = 1L per m2, 540 x 2000 x 0.5 = 540 kL p.a (540/365) x [1 Jan - 30 Jun(181 days)] x 3.3285 = $891.31 p.a (540/365) x [1 July - 31 Dec(184 days)] x 3.1693 = $862.74 p.a Total Water Usage Savings = $1754.05 p.a Installation of a grey water system will reduce daily water usage by 30%. Therefore, 200.58 x 0.3 = 60.17 kL 60.17 x [1 Jan - 30 Jun(181 days)] x 3.3285 = $36,249.93 p.a
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RMIT Master of Energy Efficient and Sustainable Building
60.17 x [1 July - 31 Dec(184 days)] x 3.1693 = $35,088.21 p.a Total Water Usage Savings = $71,338.14 p.a 60.17 x 365 x 1.7914 = $39,342.82 p.a (sewage disposal charge savings) Total Water Bill Savings = $110,680.96 p.a Comparing the life cycle cost worksheet of the do nothing scenario and the installation of the proposed water systems, the results show that the better economical option is to install the proposed water systems as it will have an economical benefit of $1,673,676.44. Table 12: Life Cycle Cost Worksheet (Install All Water)
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Building 8 Retrofit: Sustainable Building Proposal
HVAC Throughout the lifespan of a building, HVAC maintenance costs in a typical commercial building will compose of element replacement and cleaning, with the frequency of maintenance in a commercial building cooled by a fan coil unit will also be higher than that of a chilled beam system. Table 5 compares a standard estimate of life cycle maintenance costs between standard fan coil units and chilled beams (REHVA, 2004). Due to the multiple cooling units at the University, costs from Table 13 will be multiplied by 5 for the Life Cycle Cost worksheet to accommodate for the five chillers. Table 13: Maintenance cost comparison (REHVA, 2004)
Fan Coil Unit
Chilled Beam
Filter Changes Frequency Cost per Change Cost over Lifetime (20 years)
Twice a year $30.00 $1,200.00
N/A
Clean Coil and Condensate System Frequency Cost per Event Cost over Lifetime
Twice a year $30.00 $1,200.00
Every four years $30.00 $150.00
Fan Motor Replacement Frequency
Once during
N/A
life $400.00 $400.00
Cost per Change Cost over Lifetime Life Cycle maintenance cost
$2,800.00
$150.00
In addition to this, the running cost of the cooling system will be greatly reduced due to increased efficiency of the system and a lower reliance on fans and pumps. It is assumed that 3 of 5 chillers will be replaced. If the Chiller electricity usage is known to be 495,460 kWh and the EER is known to be 6.15, the energy output is calculated to be EER= output cooling energy/electrical input energy 495,460 x 6.15 = 3,047,079BTU Knowing the output amount (although BTU is not standard measure in Australia, it will be used in this equation for the sake of calculation), the electrical input required for an upgraded chiller with an EER of 13 can be calculated: 13 = 3,047,079/electrical input
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RMIT Master of Energy Efficient and Sustainable Building
Electrical input = 3,047,097/13 = 234,390 kWh Figure 10 shows how a chilled beam system can reduce a building's electrical demand on pumps and fans from 45% of the system to 33%, showing a difference of a 27% reduction after installation. Therefore, the energy used by Building 8 on AHU's & PAC and pumps will be reduced by 27%. AHU's & PAC: 0.73 x 1,381,297 = 1,008,346.81 kWh Pumps: 0.73 x 453,604 = 331,130.92 In the Life Cycle Cost Worksheet for HVAC, the cost of running the cooling system will be calculated with the assumption that electricity will cost 28c per kWh.
Figure 12 Table 14: Estimated electricity consumption values after retrofit
Calculated Values after Retrofit Retrofitted Cooling System
AHU's&PAC Pumps Chiller Cooling Tower Ventilation Total
Usage [kWh] 1,008,346.81 331,130.92 234,390 54,554 136,831
Usage MWh
1,765.25
A study into chilled beams showed that in a large commercial building, the average cost of chilled beam installation was $459/m (Weiger, 2008). The floor plans of Building 8 were used to determine the amount of area which would need to be cooled by chilled beams (approximately 160.8m per floor), which were areas which included enclosed classrooms, offices, and other workspaces. Given that chilled beams do not work effectively on areas with high air velocity, it is proposed to be installed only between levels 5 to 11 (total of seven floors) which has the majority of enclosed work spaces.
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Chilled beam cost = $459 x 160.8 x 7 = $514,080 Life Cycle Cost Assessments of the proposed HVAC installations, as seen in Table 12 and 13, show that, despite a high capital cost, installing chilled beams will produce a reduced running cost by an amount of $767,509.67 over a ten year period. Table 15: Life Cycle Cost Worksheet (Do Nothing HVAC)
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Table 16: Life Cycle Cost Worksheet (Install all HVAC)
Total The combined economic benefit of installing all three sustainable technologies would be $2,906,128.75 over a ten year period according to the Life Cycle Cost assessments.
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Multi-Criteria Assessment The multi-criteria assessment shows several comparative criteria separated into three separate categories. The comparative assessment displays a + where the retrofit shows a better than typical result and a - where the retrofit shows a worse than typical result. As shown in Table 15, the retrofit outperforms the Do Nothing scenario across all areas; social, environmental and economic. The only negative comparative assessment is from a high capital installation cost. Table 17: Multi Criteria Assessment
CONCLUSION AND RECOMMENDATIONS There are several social, environmental and economic benefits to the proposed installations. Chilled beams will be most useful in places with low air velocities, such as enclosed classrooms or offices above street level, but may perform poorly in spaces where air velocity is widely variable, such as the Level 4 foyer, thus it is recommended for installation between levels 5 to 11 where the majority of zoned work spaces are located. However, with proposed lighting and water upgrades, there are no major risks or limitations to the systems and the proposals are economically beneficial, with a saving of $1.5 million on water bills and $465,000 on electricity bills. Lighting upgrades are also very low effort and can be quickly installed, thus are definitely recommended for all areas of Building 8. Bathroom fixture upgrades are also capable of installation on every level. The only limitation which may be detrimental to its performance is the rainwater tank's reliance on regular rainfall, which is typical of a Melbourne climate but due to the risk of climate change events, this may not be the case in the far future. These improvements will be verified through analysis of electricity and water bills of Building 8 and the proposed savings can be compared with actual savings. Social improvements can be
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analysed through another series of interviews after the retrofit, asking similar questions and comparing answers before and after the retrofit. Overall, all aspects of the proposal show potential for the improvement of Building 8 and the age of the building suggests that there is an urgent need for upgrade in order to abide by current Australian Sustainability Standards. Sustainable technologies will also encourage staff and students to adopt more sustainable lifestyle choices and thus create not only a sustainable building but also a sustainable urban environment.
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REFERENCES Active Chilled Beams - Frenger Australia | Chilled Beams Manufacturer. 2016. Active Chilled Beams -
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[Accessed 18 October 2016]. Dincer, I., (2000), 'Renewable energy and sustainable development: a crucial review', Renewable and Sustainable Energy Reviews, vol. 4, pp. 157-175. Discover Lighting! The Science of Light > Color. 2016. Discover Lighting! The Science of Light > Color. [ONLINE] Available at: http://www.ies.org/lighting/science/color.cfm. [Accessed 15 October 2016]. Eriksson, L, (2014), 'The impact of calculation methods on the gap between predicted and actual energy performance of buildings: Using a thermal simulation model of a building', Master of Engineering: Energy and Environmental Engineering, Karlstad University, Karlstad. Green Star | Green Building Council of Australia. 2016. Green Star | Green Building Council of Australia. [ONLINE] Available at: http://new.gbca.org.au/green-star/. [Accessed 16 October 2016]. Heldmann,
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John, D.A, (2011), 'Selecting Air-Distribution Outlets: Designing for Comfort', ASHRAE Journal, pp. 38-46 Khan, M.A., Khan, M.Z., Zaman, K., Naz, L., (2014), 'Global estimates of energy consumption and greenhouse gas emissions', Renewable and Sustainable Energy Reviews, vol. 29, pp. 336-344. Level.org.nz.
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benefits.html#jump_183. Roth, K, PhD., Dieckmann, J, Zogg, R & Brodrick, J, PhD. 2007, "Chilled Beam Cooling", ASHRAE Journal, vol. 49, no. 9, pp. 84-84,86. Southeastwater.com.au. (2016). Prices and charges - South East Water. [online] Available at: http://southeastwater.com.au/Business/Pages/Water-prices-and-charges.aspx. Sperando, R. (2014). The Benefits of Adding a Dual Flush Toilet to Your Home. [online] Black Diamond Plumbing & Mechanical Inc. Available at: http://blackdiamondtoday.com/blog/benefitsadding-dual-flush-toilet-home. Stansbury J, Mittelsdorf AM, (2001), “Economic and environmental analysis of retrofitting a large office building with energy-efficient lighting systems�, Department of Civil Engineering, University of Nebraska-Lincoln, www.ncbi.nlm.nih.gov/pubmed/11393324. Sustainable Urban Precincts Program - RMIT University. 2016. Sustainable Urban Precincts Program - RMIT University. [ONLINE] Available at: https://www.rmit.edu.au/about/ourstrategy/values/living-our-values/sustainability/sustainable-urban-precincts-program. [Accessed 17 October 2016]. Sustainability-certification.com. (2014). Automatic Faucets for Water Conservation. [online] Available at: http://sustainability-certification.com/automatic-faucets/.
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Trox
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<http://www.troxaustralia.com/passive-chilled-beam/type-pkv-3841cf747198a25b> Vastyan, J, (2011), 'Chilled-beam basics', Heating Plumbing Air Conditioning, vol. 83, no. 7, pp. 26 42. Virta, M, Butler, D, Graslund, J, Hogeling, J, Kristiansen, E.L, Reininkainen & M, Svensson, G, 2004, Chilled Beam Application Guidebook, 2nd edn, Federation of European Heating, Brussels. Wahaso.com. (n.d.). Greywater (Gray Water) Harvesting | Wahaso - Water Harvesting Solutions. [online] Available at: http://wahaso.com/greywater_system.php. Weiger, D., (2008), 'Chilled Beam Cost & Schedule Impact', Master of Architectural Engineering, Penn State University, Pennsylvania. www.rojay.com.au. 2016. APM Group | Projects | RMIT Building 9. [ONLINE] Available at:http://www.apmgroup.com.au/projects/rmit.html. [Accessed 15 October 2016]. Yang, L., Yan, H., Lam, J.C., (2014) 'Thermal comfort and building energy consumption implications - A review', Applied Energy, vol. 115, pp. 164-173.
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APPENDIX
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