The Importance of the Construction Sector Low Carbon Technologies

1. CRed Carbon Reduction Norfolk Association of Architects CPD Seminar 23rd October 2008 Low Carbon Architecture The Importance of the Construction Sector Low Carbon Technologies Recipient of James Watt Gold Medal 5th October 2007 N.K. Tovey (杜伟贤) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук Energy Science DirectorCRedProject HSBC Director of Low Carbon Innovation 1 1 1

2. The Importance of the Construction Sector Low Carbon Technologies Solar Thermal Photo Voltaic Ground source heat pumps Bio fuels Impacts of strategies on Code for Sustainable Homes Wind/ Micro Hydro/ CHP generation Thermal Mass Embodied Energy/Life Time Energy Issues 2 2

3. Responding to the Challenge: Technical Solutions Solar Thermal Energy Basic System relying solely on solar energy Optimum orientation is NOT due South! The more hot water used the more solar energy is gained. 3 3

4. Responding to the Challenge: Technical Solutions Solar Thermal Energy Solar tank with combi boiler indirect solar cylinder 4 4

5. Responding to the Challenge: Technical Solutions Solar Thermal Energy Solar Pump Normal hot water circuit Solar Circuit Dual circuit solar cylinder 5 5

6. Responding to the Challenge: Technical Solutions Solar Thermal Energy Solar Collectors installed 27th January 2004 Annual Solar Gain 910 kWh 6 6

7. It is all very well for South East, but what about the North? House on Westray, Orkney exploiting passive solar energy from end of February House in Lerwick, Shetland Isles with Solar Panels - less than 15,000 people live north of this in UK! 7 7

8. Responding to the Challenge: Technical Solutions Solar Thermal Energy 2007 2008 Output from a 2 panel Solar Thermal Collector 8

9. Responding to the Challenge: Technical Solutions Solar Thermal Energy • Optimum size for a collector will be 2 – 3 panels depending on household size. • In winter, limited solar gain • Although few days without any benefit at all. • Increased size of collector area increases gain in winter • But 2 panels already give too much hot water in summer. • An optimum size in financial terms needs to be considered. • Most cost effective solution and most carbon reduction in a Housing Association context: • Have neighbouring houses hot water connected – say 3 houses with ~ 5 panels • Winter: system supplies most (if not all) requirements for one house. Other two use conventional means for hot water • Summer: all houses have hot water solely from Solar 9 9

10. How has the performance of a typical house changed over the years? Bungalow in South West Norwich built in mid 1950s 10

11. Changing Energy Requirements of House First attempt to address overall consumption. SAP introduced. House constructed in mid 1950s Part L first introduced ~>50% reduction In all years dimensions of house remain same – just insulation standards change As houses have long replacement times, legacy of former regulations will affect ability to reduce carbon emissions in future 11 11

12. Changing Energy Requirements of House As Existing but with oil boiler House constructed in mid 1950s Existing house – current standard: gas boiler Improvements to existing properties are limited because of in built structural issues – e.g. No floor insulation in example shown. House designed to conform the Target Emission Rate (TER) as specified in Building Regulations 2006 and SAP 2005. 12 12

13. Changing Carbon Dioxide Emissions As Existing but with oil boiler House constructed in mid 1950s Existing house – current standard: gas boiler Notice significant difference between using gas and oil boiler. House designed to conform the Target Emission Rate (TER) as specified in Building Regulations 2006 and SAP 2005. 13 13

14. Improved Fabric / standard appliance Performance SAP 2005 standard reference Responding to the Challenge: 14 14

15. The Future: Code for Sustainable Homes Improvements in Insulation and boiler performance Code 1 Code 2 H nearly makes code 3 15 15

16. Responding to the Challenge: Solar Thermal Improvements using solar thermal energy Code 1 Code 2 Note: little extra benefit after 3 panels, but does depend on size of house 16 16

17. Responding to the Challenge: Technical Solutions Solar PhotoVoltaic S Low Energy Building of the Year Award 2005 awarded by the Carbon Trust. Heating Energy consumption as new in 2003 was reduced by further 50% by careful record keeping, management techniques and an adaptive approach to control. Incorporates 34 kW of Solar Panels on top floor 17 17

18. 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 18 18 18

19. Load factors Performance of PV cells on ZICER Output per unit area Little difference between orientations in winter months On roof ~100 kWh/ m2 per annum In Norwich, domestic consumption is ~ 3700 kWh per annum >>> Need ~ 37 sq m 19 19 19

20. Performance of PV cells on ZICER - January All arrays of cells on roof have similar performance respond to actual solar radiation Radiation is shown as percentage of mid-day maximum to highlight passage of clouds The three arrays on the façade respond differently 20 20

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22. Arrangement of Cells on Facade Individual cells are connected horizontally If individual cells are connected vertically, only those cells actually in shadow are affected. As shadow covers one column all cells are inactive 22 22 22

23. Use of PV generated energy Peak output is 34 kW 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 23 23 23

24. The Future: Code for Sustainable Homes Responding to the Challenge: Solar PhotoVoltaic Improvements using solar Photovoltaic Code 1 Code 2 Code 3 Note: 2 panels of solar thermal have same benefit as 5 sqm of PV 24 24

25. The Importance of the Construction Sector Low Carbon Technologies Solar Thermal Photo Voltaic Ground source heat pumps Bio fuels Impacts of strategies on Code for Sustainable Homes Wind generation Thermal Mass Embodied Energy/Life Time Energy Issues 25 25

26. Responding to the Challenge: Technical Solutions The Heat Pump Images from RenEnergy Website 26 26

27. Responding to the Challenge: Technical Solutions The Heat Pump • Any low grade source of heat may be used • Coils buried in garden 1 – 1.5 m deep • Bore holes • Lakes/Rivers are ideal • Air can be used but is not as good • Best performance is achieved if the temperature source between outside source and inside sink is as small as possible. Under floor heating should always be considered when installing heat pumps in for new build houses – operating temperature is much lower than radiators. Attention must be paid to provision of hot water - performance degrades when heating hot water to 55 – 60oC Consider boost using off peak electricity, or occasional “Hot Days” 27 27

28. The Future: Code for Sustainable Homes Responding to the Challenge: The Heat Pump Code 3 Code 4 Improvements using Heat Pumps Code 1 Code 2 Code 3 28 28

29. The Future: Code for Sustainable Buildings Responding to the Challenge: Biomass Boilers Code 1 Code 2 Code 3 Code 4 Code 4 Improvements using Biomass options Note: Biomass with solar thermal are incompatible options 29 29

30. Ways to Respond to the Challenge: Technical Solutions Micro CHP • Micro CHP plant for homes are being trialled. • Replace the normal boiler • But there is a problem in summer as there is limited demand for heat – electrical generation will be limited. • Backup generation is still needed unless integrated with solar photovoltaic? • In community schemes explore opportunity for multiple unit provision of hot water in summer, but only single unit in winter. 30 30 30

31. Other Renewable Technologies Micro Wind Vertical Axis Mini Wind 31 31

32. Horizontal Axis Mini Wind 6 kW Proven Turbine powering a Heat Pump providing heating for Parish Kirk, Westray In 2007/8, mini wind turbines had a load factor of ~ 10.5% on average >>> annual output of approximately 5500 kWh/annum 32

33. Other Renewable Technologies Micro Hydro Scheme operating on Syphon Principle installed at Itteringham Mill, Norfolk. Rated capacity 5.5 kw 33 33

34. Medium to Large Scale Turbines – sensible option in new developments, provided they are connected by Private Wire Sub-station Load Factor for large on-shore in 2007 - 8 ~ 26.5% Connection to Distribution Network 34 34

35. The Importance of the Construction Sector Low Carbon Technologies Solar Thermal Photo Voltaic Ground source heat pumps Bio fuels Impacts of strategies on Code for Sustainable Homes Wind/ Micro Hydro/ CHP generation Thermal Mass Embodied Energy/Life Time Energy Issues 35 35

36. Ventilation Issues? Thermal Mass • As fabric insulation levels improve, ventilation starts to become the dominant issue in heat loss/heat gain • Can be in in excess of 60+% of heating/cooling requirements • Adequate ventilation is needed for health and well being • BUT, outside air has to be heated/cooled and can be a significant energy requirement in uncontrolled natural ventilation. • Consider heat recovery using regenerative heat exchangers • Buildings with thermal mass allow pre-cooling of building overnight reducing cooling demand.

37. The Climate Dimension: Cooling Issues Index 1960 = 100 Thermal Comfort is important: Even in ideal environment 2.5% of people will be too cold and 2.5% will be too hot. Estimated heating and cooling requirements from Degree Days Heating requirements are ~10+% less than in 1960 Cooling requirements are 75% higher than in 1960. Changing norm for clothing from a business suite to shirt and tie will reduce “clo” value from 1.0 to ~ 0.6. To a safari suite ~ 0.5. Equivalent thermal comfort can be achieved with around 0.15 to 0.2 change in “clo” for each 1 oC change in internal environment.

38. Operation of Main Building Regenerative heat exchanger Mechanically ventilated using hollow core slabs as air supply ducts. Incoming air into the AHU 38 38

39. Operation of Main Building Filter Heater Air passes through hollow cores in the ceiling slabs Air enters the internal occupied space 39 39

40. Space for future chilling Return air passes through the heat exchanger Operation of Main Building Recovers 87% of Ventilation Heat Requirement. Out of the building Return stale air is extracted 40 40

41. Operation of Regenerative Heat Exchangers Fresh Air Fresh Air Stale Air Stale Air B Stale air passes through Exchanger A and heats it up before exhausting to atmosphere Fresh Air is heated by exchanger B before going into building A After ~ 90 seconds the flaps switch over B Stale air passes through Exchanger B and heats it up before exhausting to atmosphere Fresh Air is heated by exchanger A before going into building A 41 41

42. Fabric Cooling: Importance of Hollow Core Ceiling Slabs Warm air Warm air Hollow core ceiling slabs store heat and cool at different times of the year providing comfortable and stable temperatures. Air Temperature is same as building fabric leading to a more pleasant working environment Heat is transferred to the air before entering the room Slabs store heat from appliances and body heat Winter Day 42 42

43. Fabric Cooling: Importance of Hollow Core Ceiling Slabs Cool air Cool air Hollow core ceiling slabs store heat and cool at different times of the year providing comfortable and stable temperatures. In late afternoon heating is turned off. Heat is transferred to the air before entering the room Slabs also radiate heat back into room Winter Night 43 43

44. Fabric Cooling: Importance of Hollow Core Ceiling Slabs Cold air Cold air Hollow core ceiling slabs store heat and cool at different times of the year providing comfortable and stable temperatures. night ventilation/ free cooling Draws out the heat accumulated during the day Cools the slabs to act as a cool store the following day Summer night 44 44

45. Fabric Cooling: Importance of Hollow Core Ceiling Slabs Warm air Warm air Hollow core ceiling slabs store heat and cool at different times of the year providing comfortable and stable temperatures. Slabs pre-cool the air before entering the occupied space concrete absorbs and stores heat less/no need for air-conditioning Summer day 45 45

46. Good Management has reduced Energy Requirements 800 350 Space Heating Consumption reduced by 57% 46 46

47. Life Cycle Energy / Carbon Emissions Materials Production Transport of Materials On site Energy Use Transport of Workforce Constructionof Building On site Electricity Use Specific Site energy – landscaping etc Furnishings including transport to site Functional Electricity Use Operational heating Operation of Building Intrinsic Refurbishment Energy Operational control (electricity) Functional Refurbishment Energy Intrinsic Energy Site Specific Energy Demolition Functional Energy Regional Energy Overheads 47 47

48. Life Cycle Energy Requirements of ZICER compared to other buildings 48 48

49. Life Cycle Energy Requirements of ZICER as built compared to other heating/cooling strategies Naturally Ventilated 221508GJ Air Conditioned 384967GJ As Built 209441GJ Materials Production Materials Transport On site construction energy Workforce Transport Intrinsic Heating / Cooling energy Functional Energy Refurbishment Energy Demolition Energy 28% 54% 34% 51% 29% 61% 49 49

50. Comparison of Life Cycle Energy Requirements of ZICER Comparisons assume identical size, shape and orientation Compared to the Air-conditioned office, ZICER recovers extra energy required in construction in under 1 year. 50 50