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ENV-2D02 Energy Conservation

Learn about the importance of energy conservation in building regulations and how it can help reduce carbon emissions and improve energy efficiency. Explore supply and demand factors, methods to reduce heat loss, and the impact of behavioral changes. Discover the Energy Performance of Buildings Directive and the UK's response through the Building Regulations.

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ENV-2D02 Energy Conservation

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  1. ENV-2D02 Energy Conservation Jane Powell (JC) j.c.powell@uea.ac.uk Building Regulations

  2. What is energy conservation? • Supply and Demand • Supply • More efficient production • CHP • Changing demand • More appropriate use • Fuel switching • Use less • Demand management • Reduce heat loss • Low energy appliances • Behavioural change

  3. Why is energy conservation important? • 2030 (EU) • Based on present trends • 90% imported oil • 80% imported gas • Climate change • Limits to fossil fuels • Security • Risks • Threat to our current way of life • Fuel poverty 3 million UK households

  4. Observed and simulated change:natural and man-made factors 1.0 0.5 0.0 -0.5 observed model simulation + Temperature change ºC + 1850 1900 1950 2000 Source: Hadley Centre

  5. UK targets • Kyoto targets • GHG 12.5% below 1990 levels 2008-2012 • 2002 14.4%; 2003 13.4%; 2004 12.6% • UK CO2 Targets • Previous target: 20% below 1990 levels by 2010 • New target: 60% below 1990 levels by 2050 • 50% 2010 target can be achieved by energy efficiency measures • Renewables • 10% electricity generated by 2010 • 3.5% 2004

  6. Reduce heat loss & behavioural change • Of who? • Occupants • Developers, planners, architects • What method? • Incentives • Subsidies • Economic instruments • Voluntary initiatives • Regulations

  7. The Energy Performance of Buildings Directive (EPBD) 2002/91/EC • 40% of final energy consumption in the EC is in the buildings sector. • Improving energy efficiency, carbon emissions from buildings could be reduced by 22%. Objectives of the Directive: • To promote the improvement of the energy performance of buildings within the EU through cost effective measures; • To promote the convergence of building standards towards those of Member States which already have ambitious levels. Measures include: • Methodology for calculating the energy performance of buildings; • Application of performance standards on new and existing buildings; • Certification schemes for all buildings; • Regular inspection and assessment of boilers/heating and cooling installations. Must be implemented by 4 Jan 2006

  8. UK ResponsePart L Building Regulations (2005) • Comes into force in England and Wales on 6 April 2006 (Scotland & Ireland to follow) • Office of the Deputy Prime Minister (ODPM) • Complies with EU legislation • Move away from energy conservation to carbon emission reduction • UK National Calculation Methodology (NCM) for energy performance of buildings

  9. Deficiencies in earlier Building Regulations • Before 1994 if double glazing was used • window area could be doubled • requirements for walls/roof/floor could be relaxed if overall loss < = standard house (type 1 trade off) • From 1995 • Could include incidental gains from appliance use/solar gains • If consumption <= standard house - regulations could be relaxed further • 1994 & 2000 regulations • If triple glazing used window area can be increased by 50% (type 2 trade off) • If higher insulations for walls used, greater window area permitted provided <= standard house. • Traditionally framed for minimum compliance rather than actively promoting energy conservation • Less so by 2000 Regs • 2005 Regs tightened further

  10. Comparison of energy consumption for a standard detached house at various ages and improvements (Heat losses in W0C-1)

  11. Effects of built form on energy consumption (Heat loss WoC-1)

  12. 1994 Regulations • Single glazing could no longer be used routinely for domestic buildings • Glazed area 22.5% of floor area • 50% greater than 1990 regs • 50% potential saving lost • Standard Assessment Procedure (SAP) rating for new buildings • 0-100 – higher the better • No target SAP but requirements relaxed if >60 • SAP 80-84 – Regs automatically satisfied • Includes energy running costs in calculation • Trade offs permitted • Does not specify ventilation rates but advise on estimating • Make allowance for solar water heating • Include hot water requirements

  13. Building Regulations 2000 • Current regulations - implemented April 2002 • Energy rating method • SAP replaced by Carbon Index method for compliance • SAP ratings still to be calculated and notified to building control bodies • Requirement of heating & hot water changed to encompass overall system performance, not just controls • Boiler seasonal efficiency, inspection & commissioning included • New requirements for efficient lighting systems & provision of information for householders • Standards of fabric insulation improved • Lower (better) standards (loft insulation) • Reductions in U values (technical limits) • Changed methods for calculating U values • Lower U values for windows • Based on sealed double-glazed units with low emissivity panes • Area of glazing increased to 25% floor area • Target U-value method retained but provisions for trade-offs improved.

  14. Compliance procedures 2000 Regulations Three methods to demonstrate compliance with Building Regulations: • Elemental approach • Target U-Value method • Carbon Index • 1. Elemental approach – meet specific conditions • Heating must be gas, oil, heat pump, CHP DH, biogas or biomass • U-values < BR2000 standards • Area window, doors, roof lights <=25% floor area • Boiler: SEDBUK efficiency >=78% gas, 80% LPG, 85% oil • [SEDBUK – Seasonal efficiency of domestic boilers in the UK. The average annual efficiency achieved in typical domestic conditions.]

  15. 2. Target U-Value method • Calculate Target U-Value • a function of areas of floor, roof, walls, windows etc • Modify target • gas & oil boilers: actual SEDBUK efficiency standard SEDBUK efficiency • electric & coal heating: divide by 1.15 • No modification for heat pumps, biomass, biogas, CHP • Modify target if area south facing windows > area north facing windows • Calculate weighted average U-value of all external surfaces • Weighted average U-value must be <= Target value

  16. 3. Carbon Index Method • Most complex method • Replaces SAP energy rating as a method of compliance • Carbon index appears to be 0-10 • Must be >= 8 to comply • Max carbon index 10 – but actually 17.7! • Reality: 8 out of 17.7 or 4.5 out of 10! • SAP procedure is followed • up to point of introducing costs of fuels • actual annual energy consumption is used to calculate the annual carbon dioxide emission • translated into a carbon index

  17. Standard Assessment Procedure (2001) • Calculate U-values • Check U-values are achieved • Calculate • gross heat requirements (Heat Loss Rate) • hot water requirements • incidental & solar gains • effective gains • effective internal temperature • corrected degree-day parameter • net space heating total energy requirement • Select heating method (pumps, appliance efficiency) • Calculate Total Energy Requirement • Estimate energy costs of total space heating, hot water & pumps • Deflate energy by Energy Cost Factor – 0.96 1994, 1.05 2001

  18. Carbon Index Calculations (2000 regulations) • Attempts to assess the true environmental performance of a building • Follow Standard Assessment Procedure to calculate Total Energy Requirement • Calculate CO2 emissions for building • Calculate Carbon Factor (CF) • CF=CO2 (TFA+45) where TFA is total floor space • Carbon Index (CI) CI=17.7-9.0 log10(CF) • Complication of scale >10 • Present regulations (2000) indicate that compliance is 11kg CO2 per m2 – carbon index of 8 • If true scale was used Zicer & Elizabeth Fry would out perform the theoretical 10 out of 10 building.

  19. SAP U-values Total Energy Requirement Energy costs Energy Deflator 1-100 1-120 (SAP 2001) CARBON Index C02 emissions Carbon Factor >=8

  20. Carbon emissions for same house designed to different standards

  21. Critique of the Standard Assessment Procedure (SAP) • Energy efficiency index – but gives a rating that is monetary based not energy based • Assumes a general heating level in house – no variation • Hot water requirements based on floor area formula not occupancy • Incidental gains based on floor area not occupancy • Standing charge ignored for electricity, included for gas. Oil doesn’t have a fixed charge (1994 & 2000) • Lower efficiency oil heating can give a higher SAP rating than more efficient gas • Energy Cost Deflator • Unnecessary complication that allows for inflation • 1994 Regs – possible SAP rating of over 110 • SAP of 100 achievable • 2000 Regs – widen scale (over 120) to keep houses at similar value • Better to have max of 100 for zero energy house

  22. Effective changes in SAP rating with specific changes (1994 regulations) Source: Monahan, J (2002) MSc Dissertation UEA; Turner, C. (2003) BSc Dissertation UEA

  23. 2006!!!

  24. Draft 2005 Building Regulations • Comes into force 6th April 2006 • Will use SAP 2005 • Technical changes • Changes in how U values are calculated • Thermal bridging – weighted average to be considered, not just design • Pressure testing of buildings for developments over a specific size • U-values windows – include frames • Information on lighting use • Estimates of overheating in summer included • Shading issues relating to solar gain must be addressed

  25. Draft 2005 Building Regulations: Compliance Greatest change is how compliance is achieved - five criteria: • Dwelling Emission Rate (DER) • Gives considerable latitude in design • Limits on design flexibility • limits trade-offs • Limit effects of solar overheating • South facing windows, ventilation • Quality of construction – evidence of actual performance • Quality of workmanship • Pressure testing of large buildings & developments • Providing information • Maintenance and operation of the building • (Home Information Pack)

  26. Dwelling Emission Rate (DER) • Is equal to CO2 emissions per unit floor area for space and water heating and lighting less emissions saved by energy generation • New dwellings & extensions • Non Dwellings & large dwellings >450m2 • Building Emission Rate

  27. SAP U-values Total Energy Requirement Energy costs Energy Deflator 1-100 1-120 (SAP 2001) CARBON Index C02 emissions Carbon Factor >=8 Target Emission Rate C02/m2 Dwelling Emission Rate DER<TER

  28. UK National Calculation Methodology (NCM) for energy performance of buildings • Compliance with the 2006 amendments to Part L of the Building Regulations in England and Wales (similar for Scotland and N. Ireland) • Dwellings: NCM new version of the existing Standard Assessment Procedure (SAP) • Non domestic buildings: Simplified Building Energy Model (SBEM) • prototype www.ncm.bre.co.uk • user interface called iSBEM. • Purpose: to produce consistent and reliable evaluations of energy use in non-domestic buildings (and some domestic buildings) • for building performance certification purposes (eventually) • (Home information packs - 1 June 2007)

  29. SAP 2005 Regulations • Basic methods similar to previous regulations • Calculations more complicated • Takes into consideration • window frames • solar gain • energy for lighting • effect of thermal bridges • energy generated by micro CHP, photovoltaics, etc • Problems with monetary values remain • Recalibration of scale • A house with a previous SAP rating will be reduced • SAP 2005 rating is related to the energy cost factor (ECF) by: • If ECF>=3.5, SAP 2005 = 111-110*log10(ECF)(1) • If ECF<3.5, SAP 2005 = 110-13.96*ECF (2) • SAP rating scale (1-100) - SAP100 is achieved at zero ECF • Can be >100 if house is net exporter of energy

  30. Summary Table of U-values for different Building Regulations

  31. English housing tenure by SAP rating, 2001ODPM (2003)

  32. Effects of Building Regulations Part L • 2002, 2005 & 2008 amendments should increase efficiency of new build and extensions by 25% • …but will it?

  33. What are the barriers to using building regulations to reduce energy use and carbon emissions ?

  34. UK residential sector accounts for 30% total UK energy demand • 1990 – 2003 • Total UK energy demand increased 7.3% • Residential energy increased 17.5% • Since 1970 • Energy use per household changed little • Overall energy use for residential sector increased by 32% • At household level • Reduction in heat loss – energy saving • Increases in energy demand – lights & appliances

  35. Population & households • UK population • current aprox 60 million • 2050 62.5 – 72 million • Age structure • 2003 – 76.2 men, 80.6 women • 2031 – 81.0 men, 84.9 women • Total population over 65 • 2002 10.9 m, 2031 12.7 m, 2060s 17 m • Household size • 1961 3.01; 2004 2.33 • One person households: 1971 18%, 2002 29%

  36. Effects of household size on energy useFawcett et al (2000)

  37. Construction & demolition • Building regulations are for new houses & extensions • In UK very low levels of construction & demolition • 2002/3 167,000 housing starts • 1996 – 2004 nearly 160,000 dwellings demolished – 20,000/year • If we continued at this rate the average house will last 1000 years!

  38. Future of household energy supply lies in the hands of: • Central government • 400 local authorities • 25 million households • Appliance and fuel supply industries • Construction building services • Fragmented • Multiple suppliers of specialist products • Huge number of sub contractors • Costs saved by: • reducing capital costs • standard components • standard practices

  39. Whole life costs/life-cycle costs • typical costs for owning a building are in the ratio of : • 1 for construction costs • 5 for maintenance costs • 200 for building operating costs Source: Royal Academy of Engineering

  40. Life cycle cost (LCC) • LCC = Capital Cost + Present worth of Maintenance and Energy Cost  - Present worth of Salvage value • Capital cost • initial capital expense for equipment • the system design, engineering, and installation. • Maintenance: operation and maintenance costs/year • Energy cost: yearly fuel cost. • Salvage value: net value in the final year • http://wcm.nu/LCC/lcc_calculation.html

  41. Thank you

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