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111 1 The Importance of the Construction Sector Low Carbon Technologies Norfolk Association of Architects CPD Seminar 23 rd October 2008 Low Carbon Architecture.

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Presentation on theme: "111 1 The Importance of the Construction Sector Low Carbon Technologies Norfolk Association of Architects CPD Seminar 23 rd October 2008 Low Carbon Architecture."— Presentation transcript:

1 111 1 The Importance of the Construction Sector Low Carbon Technologies Norfolk Association of Architects CPD Seminar 23 rd October 2008 Low Carbon Architecture CRed Carbon Reduction N.K. Tovey ( ) M.A, PhD, CEng, MICE, CEnv Н.К.Тови М.А., д-р технических наук Energy Science Director CRed Project HSBC Director of Low Carbon Innovation Recipient of James Watt Gold Medal 5 th October 2007

2 222 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 The Importance of the Construction Sector Low Carbon Technologies

3 33 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

4 444 Responding to the Challenge: Technical Solutions Solar Thermal Energy indirect solar cylinder Solar tank with combi boiler

5 555 Normal hot water circuit Solar Circuit Responding to the Challenge: Technical Solutions Solar Thermal Energy Dual circuit solar cylinder Solar Pump

6 666 Annual Solar Gain 910 kWh Solar Collectors installed 27th January 2004 Responding to the Challenge: Technical Solutions Solar Thermal Energy

7 777 House in Lerwick, Shetland Isles with Solar Panels - less than 15,000 people live north of this in UK! 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

8 88 Responding to the Challenge: Technical Solutions Solar Thermal Energy Output from a 2 panel Solar Thermal Collector

9 999 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

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

11 11 House constructed in mid 1950s Part L first introduced ~>50% reduction First attempt to address overall consumption. SAP introduced. Changing Energy Requirements of House 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

12 12 House constructed in mid 1950s Changing Energy Requirements of House 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 As Existing but with oil boiler

13 13 House constructed in mid 1950s Changing Carbon Dioxide Emissions 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 As Existing but with oil boiler

14 14 Improved Fabric / standard appliance Performance SAP 2005 standard reference Responding to the Challenge: ItemSAP reference Improved Value 1 Improved Value 2 WindowsU-value = 2U-value = 1.4 WallsU-value = 0.35U-value = 0.25 U-value = 0.1 FloorU-value = 0.25 RoofU-value = 0.16 Boiler efficiency 78%83% default90% SEDBUK

15 15 The Future: Code for Sustainable Homes CO 2 Emissions (kg)Reduction ASAP Reference BBoiler η = 83% (default) 23775% CBoiler η = 90% (SEDBUK) % Dη = 90%: Walls: U = % Eη = 90%: Walls: U = % Fη = 90%: Windows: U = % GC + D + F % HC + E + f191923% Improvements in Insulation and boiler performance Code 1 Code 2 H nearly makes code 3

16 16 CO 2 (kg)Reduction ASAP Reference BBoiler η = 90% (SEDBUK) % Cη = 90%: Solar Thermal – 2 panels dual cylinder % Dη = 90%: Solar Thermal – 2 panels separate cylinder % Eη = 90%: Solar Thermal – 3 panels separate cylinder % Fη = 90%: Solar Thermal – 4 panels separate cylinder % Gη = 90%: Solar Thermal – 5 panels separate cylinder % 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

17 17 S Responding to the Challenge: Technical Solutions Solar PhotoVoltaic 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 Low Energy Building of the Year Award 2005 awarded by the Carbon Trust.

18 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

19 19 Load factors Fa ç ade (kWh) Roof (kWh) Total (kWh) Output per unit area Little difference between orientations in winter months Performance of PV cells on ZICER WinterSummer Fa ç ade2%~8% Roof2%15% On roof ~100 kWh/ m 2 per annum In Norwich, domestic consumption is ~ 3700 kWh per annum >>> Need ~ 37 sq m

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

21 21

22 22 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.

23 23 Use of PV generated energy 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

24 24 CO 2 (kg)Reduction ASAP Reference BBoiler η = 90% (SEDBUK) % Cη = 90%: Solar PV 5 sqm % Dη = 90%: Solar PV 10 sqm % Eη = 90%: Solar PV 5 sqm + 2 panel solar thermal % Fη = 90%: Solar PV 7.4 sqm + 2 panel solar thermal % The Future: Code for Sustainable Homes Improvements using solar Photovoltaic Code 1 Code 2 Code 3 Note: 2 panels of solar thermal have same benefit as 5 sqm of PV Responding to the Challenge: Solar PhotoVoltaic

25 25 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 The Importance of the Construction Sector Low Carbon Technologies

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

27 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 – 60 o C Consider boost using off peak electricity, or occasional Hot Days

28 28 CO 2 (kg)Reduction ASAP Reference25040 BBoiler η = 90% (SEDBUK)222911% CGround to Water Heat Pump (Radiators)166134% DAir to Water Heat Pump (Radiators)196222% EGround to Air Heat Pump160636% FAir to Air Heat Pump190724% GGround to Water Heat Pump (Under floor)155338% HAir to Water Heat Pump (Under floor)183027% The Future: Code for Sustainable Homes Improvements using Heat Pumps Code 1 Code 2 Code 3 Code 4 Code 3 Responding to the Challenge: The Heat Pump

29 29 CO 2 (kg)Reduction ASAP Reference25040% BBoiler η = 90% (SEDBUK)222911% CBiomass Boiler67373% DBiomass Boiler with Solar Thermal67073% EBiomass Boiler with 5m Photovoltaic49680% FBiomass Boiler with 10m Photovoltaic31887% G Biomass Boiler + 10m PV + improved insulation + 100% Low Energy lighting 14794% The Future: Code for Sustainable Buildings Improvements using Biomass options Note: Biomass with solar thermal are incompatible options Code 1 Code 2 Code 3 Code 4 Responding to the Challenge: Biomass Boilers

30 30 Micro CHP Ways to Respond to the Challenge: Technical Solutions 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.

31 31 Other Renewable Technologies Micro Wind Vertical Axis Mini Wind

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

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

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

35 35 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 The Importance of the Construction Sector Low Carbon Technologies

36 36 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. Ventilation Issues? Thermal Mass

37 37 The Climate Dimension: Cooling Issues Heating requirements are ~10+% less than in 1960 Cooling requirements are 75% higher than in 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 o C change in internal environment. 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 Index 1960 = 100

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

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

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

41 41 Operation of Regenerative Heat Exchangers Fresh Air Stale Air Fresh Air Stale Air A B B A 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 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 After ~ 90 seconds the flaps switch over

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

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

44 44 Fabric Cooling: Importance of Hollow Core Ceiling Slabs Hollow core ceiling slabs store heat and cool at different times of the year providing comfortable and stable temperatures. 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 Cold air

45 45 Fabric Cooling: Importance of Hollow Core Ceiling Slabs 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 Warm air

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

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

48 48 Life Cycle Energy Requirements of ZICER compared to other buildings All values in Primary energy TermodeckComparison Based on a GFA of 2573 m 2 ZICER as built (GJ) Naturally Ventilated ZICER (GJ) Air conditioned ZICER (GJ) Materials Production Transport of materials On site construction energy2793 Workforce transport2851 Operational Heating/Hot Water Plant Room Electricity Functional Electricity e.g. from lights, computers etc (60 years) Replacement energy - materials Demolition TOTAL embodied energy over 60 years (GJ) Total excluding the functional electricity (GJ)

49 49 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%

50 50 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

51 51 How can low carbon homes be provided at an affordable cost? Energy Service Companies (ESCos) Home costs same initial cost as traditional home Any additional costs for providing renewable energy, better insulation/controls are financed by ESCo Client pays ESCo for energy used at rate they would have done had the house been built to basic 2005 standards ESCo pays utility company at actual energy cost (because energy consumption is less) Difference in payments services ESCo investment When extra capital cost is paid off Client sees reduced energy bills ESCO has made its money Developer has not had to charge any more for property The Environment wins Responding to the Challenge:

52 52 The Behavioural Dimension Social Attitudes towards energy consumption have a profound effect on actual consumption Data collected from 114 houses in Norwich between mid November 2006 and mid March 2007 For a given size of household electricity consumption for appliances [NOT HEATING or HOT WATER] can vary by as much as 9 times. When income levels are accounted for, variation is still 6 times

53 53 Significant Improvements can be achieved Better Insulation Standards Heat Pumps Biomass Boilers Solar Thermal Solar PV Responding to the Challenge: Conclusions But avoid incompatible options Too large a Solar thermal Array Biomass with solar thermal CHP with Solar Thermal Lao Tzu ( BC) Chinese Artist and Taoist philosopher "If you do not change direction, you may end up where you are heading." This presentation is available at Follow Academic Links


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