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1 Buildings in a Changing Climate Energy Science Director HSBC Director of Low Carbon Innovation CRed Carbon Reduction UKERC Seminar 9 th May 2007 CRed.

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Presentation on theme: "1 Buildings in a Changing Climate Energy Science Director HSBC Director of Low Carbon Innovation CRed Carbon Reduction UKERC Seminar 9 th May 2007 CRed."— Presentation transcript:

1 1 Buildings in a Changing Climate Energy Science Director HSBC Director of Low Carbon Innovation CRed Carbon Reduction UKERC Seminar 9 th May 2007 CRed Keith Tovey ( ) MA, PhD, CEng, MICE, CEnv Acknowledgement: Karla Alcantar

2 2 Issues of Sustainable Building Construction – Thermal Performance issues Future Proofing Buildings - Fabric Cooling? – Renewable Energy and Integration of Design – Life Cycle analyses Management of Building Energy Use Behaviour of the Occupants Conclusions Sustainability in Building and Occupation Thermal Performance issues Future Proofing Buildings - Fabric Cooling?

3 3 Thermal performance has improved with better insulation. With better fabric insulation, ventilation can represent up to 80+% of heating energy requirements. Careful design of ventilation is needed Thermal Performance Issues: Future Proofing Index 1960 = 100 Changes in heating and cooling requirements for buildings over last 50 years Heating requirements are ~10+% less than in 1960 Cooling requirements are 75% higher than in Care must now be taken to ensure buildings are now designed to avoid overheating in summer and to minimise active cooling requirements

4 4 Fabric Cooling using Hollow Core Slabs The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures Cold air Draws out the heat accumulated during the day Cools the slabs to act as a cool store the following day Summer night night ventilation/ free cooling

5 5 Warm air Pre-cools the air before entering the occupied space The concrete absorbs and stores the heat – like a radiator in reverse Summer day Fabric Cooling using Hollow Core Slabs The concrete hollow core ceiling slabs are used to store heat and coolness at different times of the year to provide comfortable and stable temperatures No air conditioning is needed even though the norm would have been to install air- conditioning In future, with Global Warming, when air-conditioners may be installed, they will be run over night to pre-cool building and improve efficiency of chillers

6 6 Ground Source Heat Pumps are an effective route to low carbon heating – can save 50 – 60% of carbon emissions. Work most efficiently with under floor heating. Can be used with fabric pre-cooling in summer with very modest air-conditioning Can be to provide some inter-seasonal heat store –i.e. reject heat in summer to acquifer/ground – recover during winter. There is ~ 3 months thermal lag in peak temperature in ground corresponding with early heating season use, and much improved coefficients of performance. Heat Pumps: A solution for a Low Carbon Future

7 7 Issues of Sustainable Building Construction – Thermal Performance issues Future Proofing Buildings - Fabric Cooling? – Renewable Energy and Integration of Design – Life Cycle analyses Management of Building Energy Use Behaviour of the Occupants Conclusions Sustainability in Building and Occupation

8 8 Annual Solar Gain 910 kWh Solar Collectors installed 27th January 2004 Options for Renewable Energy: Solar Thermal

9 9 Performance of an actual solar collector 9 th December 2006 – 2 nd May 2007 Average gain (over 3 years) is kWh per day Central Heating Boiler does not provide Hot Water from Easter to ~ 1 st October More Hot Water used – the greater amount of solar energy is gained Optimum orientation for solar hot water collectors for most houses is NOT due South

10 10 Options for Renewable Energy: Solar Thermal Significant surplus of energy in summer Explore increasing temperature limit provided there is an anti-scald device fitted. Training needed to educate users to get optimum from solar collector in mid- season (setting of Central Heating Hot Water timers) Energy/Carbon benefits to be gained by providing solar hot water on a multi- house basis.

11 11 Options for Renewable Energy: Solar Photovoltaic Data based on Actual ZICER Building PV Costs Actual Situation excluding Grant Actual Situation with Grant Discount rate3%5%7%3%5%7% Unit energy cost per kWh (£) Avoided cost exc. the Grant Avoided Costs with Grant Discount rate3%5%7%3%5%7% Unit energy cost per kWh (£)

12 12 ZICER Building Photo shows only part of top Floor Top floor is an exhibition area – also to promote PV Windows are semi transparent Mono-crystalline PV on roof ~ 27 kW in 10 arrays Poly- crystalline on façade ~ 6/7 kW in 3 arrays

13 13 Arrangement of Cells on Facade Individual cells are connected horizontally As shadow covers one column all cells are inactive If individual cells are connected vertically, only those cells actually in shadow are affected. Options for Renewable Energy: Solar Photovoltaic

14 14 Sometimes electricity is exported Inverters are only 91% efficient Most use is for computers DC power packs are inefficient typically less than 60% efficient Need an integrated approach Peak output is 34 kW Options for Renewable Energy: Solar Photovoltaic

15 15 –Potential to substantially reduce CO 2 emissions –Significant reduction is losses from transmission but –problem of heat disposal in summer –Does not make sense to provide CHP with solar hot water heaters Consider using absorption chilling to provide cooling where required Options for Low Carbon Technologies: Micro CHP

16 16 Issues of Sustainable Building Construction – Thermal Performance issues Future Proofing Buildings - Fabric Cooling? – Renewable Energy and Integration of Design – Life Cycle analyses Management of Building Energy Use Behaviour of the Occupants Conclusions Sustainability in Building and Occupation

17 17 Life Cycle Issues – an issue in Sustainability –Does local sourcing of materials necessarily lead to a low carbon construction? –In case of PV it emits LESS CO 2 if cells are manufactured in Spain and transported to UK! – despite the transport!!!! –Need to be aware of how fuel mix used for generation of electricity affects CO 2. UK ~ 0.52 kg/kWh, Spain ~ 0.46 kg/kWh France ~ 0.06 kg/kWh To what extent does embodied carbon from construction and demolition affect total carbon emission? –Example: ZICER Building Sustainability in Building and Occupation

18 18 As Built GJ Air Conditioned GJ Naturally Ventilated GJ Life Cycle Energy Requirements of ZICER as built compared to other heating/cooling strategies Materials Production Materials Transport On site construction energy Workforce Transport Intrinsic Heating / Cooling energy Functional Energy Refurbishment Energy Demolition Energy 28% 54% 34% 51% 61% 29%

19 19 Comparison of Life Cycle Energy Requirements of ZICER Compared to the Air-conditioned office, ZICER recovers extra energy required in construction in under 1 year. Comparisons assume identical size, shape and orientation

20 20 Issues of Sustainable Building Construction – Thermal Performance issues Future Proofing Buildings - Fabric Cooling? – Renewable Energy and Integration of Design – Life Cycle analyses Management of Building Energy Use Behaviour of the Occupants Conclusions Sustainability in Building and Occupation

21 21 Careful Monitoring and Analysis can reduce energy consumption. Conservation: management improvements – Cost ~6% more but has heating requirement ~25% of average building at time. Building Regulations have been updated: 1994, 2002, 2006, but building outperforms all of these. Runs on a single domestic sized central heating boiler.

22 22 The space heating consumption has reduced by 57% Good Management has reduced Energy Requirements Acknowledgement: Charlotte Turner

23 23 Issues of Sustainable Building Construction – Thermal Performance issues Future Proofing Buildings - Fabric Cooling? – Renewable Energy and Integration of Design – Life Cycle analyses Management of Building Energy Use Behaviour of the Occupants Conclusions Sustainability in Building and Occupation

24 24 Household size has little impact on electricity consumption. Consumption varies by up to a factor of 9 for any given household size. Allowing for Income still shows a range of 6 or more. Education/Awareness is important Average Norwich Electricity Consumption Data from 114 houses in Norwich

25 25 Personal Attitudes to Energy Use can be significant

26 26 Social Awareness of Occupational Impact on Climate Change

27 27 Social Awareness of Occupational Impact on Climate Change

28 28 Provide optional environmentally efficient systems within all new buildings – even if they are not mandatory. Revise way we address costs and benefits. –Is traditional Cost Benefit Analysis the correct way to appraise low carbon systems? –Lower capital costs vs lower environmental running costs. –Are ESCOs a way forward? Improved control – Smart (Sub) Metering The Future

29 29 Sustainable Buildings require: Initial sound design addressing: high insulation standards, effective control of ventilation: Attention to Future Proofing. Integration of use of building with provision of services. Avoidance of combining novel technologies which are incompatible. Use of most sustainable materials: Local provision of materials is NOT ALWAYS best – careful Life Cycle Assessments are needed. Provision of optional extras for all buildings including renewable technologies etc perhaps with alternative financing methods. Provision of SMART sub metering to inform the user. Improvements in training of users where newer technologies are used. a need for awareness raising. Conclusions (2) Lao Tzu ( BC) Chinese Artist and Taoist philosopher "If you do not change direction, you may end up where you are heading."


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