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Sustainable refurbishment Dept. Materials and Zoology, Cambridge
Background to the Project Approach to Sustainability Design Challenges
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Introduction
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•1960s/1970s •Post modern Architecture •Dept Metallurgy and Mat Science •Museum of Zoology
Existing west Elevation
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Artists Impression of Existing
• Floor area ~ 15,000m2 •Current Uses: Lecture Theatre, University Computing Service, Materials Science Labs and teaching space, Zoology Department labs, Museum of Zoology, storage •Key materials are concrete, glass and lead •Complex form which steps out as you move up, with overhanging details •The main building connects to the two towers, the Zoology building, and there is a walkway to Chemistry. Also in close proximity to the Corn Exchange building •20th Century Society describe the engineering as “elegantly ostentatious” •Original master plan concept was to link the podium to the grand arcade •Pre-dates lots of our current building regulations relating to thermal performance and structural stability
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Background
• Museum of Zoology and Archive, Department of Zoology, Lecture Theatre •, CCI (Cambridge Conservation Initiative ) Urban Ecologists eg RSPB • Offices & shared facilities •Underpin transformation in work practices •Sustainability Key to influencing users and planners
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Key aspects of Brief
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Sustainability
Benefits of refurbishment
Reduce running and maintenance costs Increases thermal comfort, productivity and happiness Avoids the cost, noise, disruption and environmental impact of demolition Retains the embodied carbon in the existing structure Avoids new land take
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Refurbish vs. demolition
It is important to consider the whole life cycle CO2 when renovating existing buildings We have estimated the embodied carbon in new build to be at least 3.5 times higher than the operational energy consumption in the existing Arup Building. The difference in operational CO2 savings between refurbishment & new-build does not justify this decision.
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Embodied carbon
Gas consumption = 2,780 MWh/yr Electricity use = 2,012 MWh/yr Excluding servers Energy audit at Stage D
Average CO2 emissions of non-domestic buildings in UK
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Baseline performance data
Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09 Aug-09 Sep-09 Oct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10 May-10 Jun-10 Jul-10 Aug-10 Sep-10 Oct-10 Nov-10 Dec-10 Jan-11 Feb-11 Mar-11 Apr-11 May-11 Jun-11 Jul-11 Aug-11 Sep-11 Oct-11 Nov-11 Dec-11 Jan-12 Feb-12 Mar-12
Total gas consumption (kWh)
Total gas consumption area weighted for the Arup Building & DoZ building
500,000
400,000
300,000
200,000
100,000
0
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Gas consumption
700,000
600,000
Department of Zoology Building
Arup Building
0 Apr-08 May-08 Jun-08 Jul-08 Aug-08 Sep-08 Oct-08 Nov-08 Dec-08 Jan-09 Feb-09 Mar-09 Apr-09 May-09 Jun-09 Jul-09 Aug-09 Sep-09 Oct-09 Nov-09 Dec-09 Jan-10 Feb-10 Mar-10 Apr-10 May-10 Jun-10 Jul-10 Aug-10 Sep-10 Oct-10 Nov-10 Dec-10 Jan-11 Feb-11 Mar-11 Apr-11 May-11 Jun-11 Jul-11 Aug-11 Sep-11 Oct-11 Nov-11 Dec-11 Jan-12 Feb-12 Mar-12
Total electricity consumption (kWh)
Total electricity consumption for the Arup Building
100,000
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Electricity consumption
700,000
600,000
500,000
400,000 UCS server room
300,000 HPC server room
200,000 Rest of Arup Building
Aspirations
Challenges
• A pioneering refurbishment which expresses the sustainability credentials of the users
• Working within a typical university budget
• A shared vision from the client, design team & building users • Get the maximum efficiency out of the existing building • Obtain full buy-in from the building users to ensure that long term savings are achieved
• Being ‘green’, but not necessarily the ‘greenest’ in every aspect • Finding the right balance between capital cost and operational savings • Retaining stakeholder engagement and aspirations over the long-term • Resolving potential conflicts in aspiration from a mixture mix of building users
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What sustainability means for the Arup Building
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How to engage users – ask them?
• Stakeholder workshop with representatives from 15 organisations • Aim was to engage with building users and establish what really matters to them in terms of sustainability for the Arup Building
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Stakeholder engagement workshop
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Themes arising from the workshop A rich mixture of responses were obtained from the stakeholder workshop
14
These responses were categorised into various themes
40
2
24
Key Energy & Carbon
22
11
Materials
All Groups
Water Waste Health & Wellbeing Heritage & culture Collaboration & Inclusion
12
12
Transport & Mobility Education & Outreach Pollution Biodiversity & Ecology
30
21 9
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Pre-assessment was carried out, achieved a “very good� score Stakeholder workshops identified that users wanted to set targets for many social & collaborative factors, not captured in BREEAM
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Relationships with BREEAM
Base target
Stretch target
Measurement process
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Description
Project timing
Stretch target constraint
Responsibility
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Development of target
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Next steps – topics requiring input
Energy • ICT – computer types, diversity factors, server space requirements • Ventilation strategy vs. layout
Biodiversity • Green roofs / living walls – identifying CCI experts
Transport • Cycle facilities • Remote working – teleconferencing / offsite ICT requirements
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Focus groups – some topics requiring input
Health & Wellbeing • Sustainable food choices • User control
Collaboration & inclusion • Collaboration plans within CCI • Collaboration plans within all users
Education & outreach • Need to confirm baseline museum visitor numbers • Concepts for visitor education • Post occupancy evaluation – plans for monitoring & dissemination
Bespoke plan
In-use energy targets Monitoring and management - controls and bills Building Fabric Building Services IT
Flooding Run-off Air quality Low emission boilers
Embodied Carbon Responsible procurement Environmental impact of production Loose fit – long life
Mitigation Carbon emissions Embodied carbon Energy impacts Renewable Energy
Efficient use Alternative sources
Adaptation Green roof Flooding Increased temperatures Resilience
Construction Waste Operational Waste
Museum engagement CCI engagement University Public
Targets Composting Reduce generation Recycling Closed-loop
Reduce travel Working practices
Right to Light Wayfinding Food choices
Mode shift Walking / cycling / car club
Collaborative working Technology & tools Accessibility Extending user group
Value of Museum Architectural Heritage
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Local / Global Roofscape, Atrium Green/ Brown Roof Butterfly house CCI Impact on Global Ecology
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Key design issues
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Enabling Natural ventilation
Open plan
Open plan
Cellular
Cellular
Cellular
Cellular
Cellular
Cellular
Cellular
Cellular
Cellular
Cellular
Cellular
Cellular
Open plan
Open plan
Open plan
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Cellular Vs. Open plan
Bays with cellular office core
Heat gains from 16 people
Bays with cellular & open plan core
Heat gains from 12 people (25% less risk of overheating)
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Thermal comfort in naturally ventilated perimeter bays
Length of office is approximately 25m – too long for effective cross ventilation Mechanically assisted solution is required
Stagnation
Draughty
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Ventilation
•
Risk of draughts in window bays, causing control difficulties
•
Additional infrastructure would be required for the extract
•
Higher demand for fresh air in winter
•
No heat recovery in winter
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Option 1: Natural intake with mechanical extract
•
System utilises already existent supply & extract infrastructure
•
Allows for improved control in both perimeter & core areas
•
Heat recovery system will be present
•
Can utilise chilled water system during peak cooling conditions
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Option 2: Single sided natural ventilation with mechanical supply & extract
•
Feasibility is unclear due to additional riser space requirements
•
Additional infrastructure would be required
•
Fresh air intake will require additional heating component in winter
•
No heat recovery in winter
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Option 3: Single sided natural ventilation with mechanical assisted chimney
• Energy is not the main driver for being open plan •Instead it will provide improved thermal comfort, better collaboration and less cramped working environment in the window bays •Assisted ventilation solution can be achieved with no added infrastructure •Baseline framework target can be achieved with mech. assisted ventilation solution •Will be important to invest in modern ICT equipment over the next 3 years leading towards the move – standard equipment increases overheating risks •Lighting & ventilation to be linked to occupancy sensors in cellular areas •Spatial allowance for chilled water infrastructure & electrical resilience is also being designed to deal with future climate change.
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Summary
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Constraints of Existing Facade Condition, performance & planning
Improvement of thermal performance of building envelope as compared to current performance: % reduction in heat loss through building envelope
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Thermal performance of the building envelope
Challenge in understanding current performance Envelope inspection – build ups Performance estimation – U-value calc Establish achievable improvement Benchmark against part L Consideration of feasible improvements
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Thermal performance of the building envelope
Limited by space, structure & access Limited by planning constraint Improvement beyond Part L where possible to compensate
Envelope performance estimation tool
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Outcome is a middle ground based on improvement where reasonable
Tool to calculate heat loss through the building fabric
70% reduction feasible based on building regulations 80% reduction possible if more insulation is specified and hard-to-treat areas are addressed.
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Target development example
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Constraints of Existing Frame
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ICT Strategy
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ICT loads Generic desktop computer (with LCD monitor)
99 Watts
Laptop
Thin client computer
(with docking station + LCD monitor)
(with LCD monitor)
38 Watts
33 Watts
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Thin client computers
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Laptop computers
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Generic desktop computers
- Developed Bespoke Sustainability Framework - Good level of User Engagement - Helps define the Problem - Possible to Deliver Natural Ventilation to >60% of Building - Targetting 70% reduction in Conduction Heat Losses (thermal bridges still an issue) - LAM (Laser Assisted Modelling) survey of Existing Frame successful but watch the briefing !
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Lessons learned so far...
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Laser Survey Model
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Central Model Development
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Existing Vertical Services Distribution – 1st Floor Plan
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Existing Horizontal Services Distribution
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Access & Maintenance
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