Presentation on theme: "ENV-2D02 Energy Conservation"— Presentation transcript:
1 ENV-2D02 Energy Conservation Jane Powell (JC)Building Regulations
2 What is energy conservation? Supply and DemandSupplyMore efficient productionCHPChanging demandMore appropriate useFuel switchingUse lessDemand managementReduce heat lossLow energy appliancesBehavioural change
3 Why is energy conservation important? 2030 (EU)Based on present trends90% imported oil80% imported gasClimate changeLimits to fossil fuelsSecurityRisksThreat to our current way of lifeFuel poverty3 million UK households
4 Observed and simulated change: natural and man-made factors 1.00.50.0-0.5observedmodel simulation+Temperature change ºC+Source: Hadley Centre
5 UK targets Kyoto targets UK CO2 Targets Renewables GHG 12.5% below 1990 levels%; %; %UK CO2 TargetsPrevious target: 20% below 1990 levels by 2010New target: 60% below 1990 levels by 205050% 2010 target can be achieved by energy efficiency measuresRenewables10% electricity generated by 20103.5% 2004
6 Reduce heat loss & behavioural change Of who?OccupantsDevelopers, planners, architectsWhat method?IncentivesSubsidiesEconomic instrumentsVoluntary initiativesRegulations
7 The Energy Performance of Buildings Directive (EPBD) 2002/91/EC 40% of final energy consumption in the EC isin the buildings sector.Improving energy efficiency, carbon emissionsfrom 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 Response Part 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 legislationMove away from energy conservation to carbon emission reductionUK National Calculation Methodology (NCM) for energy performance of buildings
9 Deficiencies in earlier Building Regulations Before 1994 if double glazing was usedwindow area could be doubledrequirements for walls/roof/floor could be relaxedif overall loss < = standard house (type 1 trade off)From 1995Could include incidental gains from appliance use/solar gainsIf consumption <= standard house - regulations could be relaxed further1994 & 2000 regulationsIf 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 conservationLess so by 2000 Regs2005 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 RegulationsSingle glazing could no longer be used routinely for domestic buildingsGlazed area 22.5% of floor area50% greater than 1990 regs50% potential saving lostStandard Assessment Procedure(SAP) rating for new buildings0-100 – higher the betterNo target SAP but requirements relaxed if >60SAP – Regs automatically satisfiedIncludes energy running costs in calculationTrade offs permittedDoes not specify ventilation rates but advise on estimatingMake allowance for solar water heatingInclude hot water requirementsCondensing boiler = less requirement for insulation
13 Building Regulations 2000 Current regulations - implemented April 2002 Energy rating methodSAP replaced by Carbon Index method for complianceSAP ratings still to be calculated and notified to building control bodiesRequirement of heating & hot water changed to encompass overall system performance, not just controlsBoiler seasonal efficiency, inspection & commissioning includedNew requirements for efficient lighting systems & provision of information for householdersStandards of fabric insulation improvedLower (better) standards (loft insulation)Reductions in U values (technical limits)Changed methods for calculating U valuesLower U values for windowsBased on sealed double-glazed units with low emissivity panesArea of glazing increased to 25% floor areaTarget U-value method retained but provisions for trade-offs improved.
14 Compliance procedures 2000 Regulations Three methods to demonstrate compliance with Building Regulations:Elemental approachTarget U-Value methodCarbon Index1. Elemental approach – meet specific conditionsHeating must be gas, oil, heat pump, CHP DH, biogas or biomassU-values < BR2000 standardsArea window, doors, roof lights <=25% floor areaBoiler: 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 Modify target a function of areas of floor, roof, walls, windows etcModify targetgas & oil boilers: actual SEDBUK efficiencystandard SEDBUK efficiencyelectric & coal heating: divide by 1.15No modification for heat pumps, biomass, biogas, CHPModify target if area south facing windows > area north facing windowsCalculate weighted average U-value of all external surfacesWeighted average U-value must be <= Target valueGives flexibility in design – if area of windows is lower than 25% U-values of walls can be reduced – does not encourage higher standards of thermal insulationIf condensing boiler is used – target U value is easier to achieve. What happens if a non-condensing boiler is fitted in the future
16 3. Carbon Index Method Most complex method Replaces SAP energy rating as a method of complianceCarbon index appears to be 0-10Must be >= 8 to complyMax carbon index 10 – but actually 17.7!Reality: 8 out of 17.7 or 4.5 out of 10!SAP procedure is followedup to point of introducing costs of fuelsactual annual energy consumption is used to calculate the annual carbon dioxide emissiontranslated into a carbon index
17 Standard Assessment Procedure (2001) Calculate U-valuesCheck U-values are achievedCalculategross heat requirements (Heat Loss Rate)hot water requirementsincidental & solar gainseffective gainseffective internal temperaturecorrected degree-day parameternet space heating total energy requirementSelect heating method (pumps, appliance efficiency)Calculate Total Energy RequirementEstimate energy costs of total space heating, hot water & pumpsDeflate energy by Energy Cost Factor – ,
18 Carbon Index Calculations (2000 regulations) Attempts to assess the true environmental performance of a buildingFollow Standard Assessment Procedure to calculate Total Energy RequirementCalculate CO2 emissions for buildingCalculate Carbon Factor (CF)CF=CO2 (TFA+45) where TFA is total floor spaceCarbon Index (CI) CI= log10(CF)Complication of scale >10Present regulations (2000) indicate that compliance is 11kg CO2 per m2 – carbon index of 8If true scale was used Zicer & Elizabeth Fry would out perform the theoretical 10 out of 10 building.Scale of 0 for high carbon & 10 for low carbon confuses some people who consider the lower the better
19 Total Energy Requirement SAPU-valuesTotal Energy RequirementEnergy costsEnergy Deflator1-1001-120 (SAP 2001)CARBON IndexC02 emissionsCarbon Factor>=8
20 Carbon emissions for same house designed to different standards
22 Critique of the Standard Assessment Procedure (SAP) Energy efficiency index – but gives a rating that is monetary based not energy basedAssumes a general heating level in house – no variationHot water requirements based on floor area formula not occupancyIncidental gains based on floor area not occupancyStanding 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 gasEnergy Cost DeflatorUnnecessary complication that allows for inflation1994 Regs – possible SAP rating of over 110SAP of 100 achievable2000 Regs – widen scale (over 120) to keep houses at similar valueBetter to have max of 100 for zero energy house
23 Effective changes in SAP rating with specific changes (1994 regulations) SAP changes by:Change U-values by 10%2 – 3Change window area by 10%1 – 2Change floor area by 10%4 – 5Change heating from mains gas to LPG (little change in energy consumption)- 15Change heating from condensing gas to inferior oil+5-10 !!!!!Source: Monahan, J (2002) MSc Dissertation UEA;Turner, C. (2003) BSc Dissertation UEA
25 Draft 2005 Building Regulations Comes into force 6th April 2006Will use SAP 2005Technical changesChanges in how U values are calculatedThermal bridging – weighted average to be considered, not just designPressure testing of buildings for developments over a specific sizeU-values windows – include framesInformation on lighting useEstimates of overheating in summer includedShading issues relating to solar gain must be addressed
26 Draft 2005 Building Regulations: Compliance Greatest change is how compliance is achieved - five criteria:Dwelling Emission Rate (DER)Gives considerable latitude in designLimits on design flexibilitylimits trade-offsLimit effects of solar overheatingSouth facing windows, ventilationQuality of construction – evidence of actual performanceQuality of workmanshipPressure testing of large buildings & developmentsProviding informationMaintenance and operation of the building(Home Information Pack)
27 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 generationNew dwellings & extensionsNon Dwellings & large dwellings >450m2Building Emission Rate
28 SAP CARBON Index Target Emission Rate U-values Total Energy RequirementEnergy costsEnergy Deflator1-1001-120 (SAP 2001)CARBON IndexC02 emissionsCarbon Factor>=8Target Emission RateC02/m2Dwelling Emission RateDER<TER
29 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)prototypeuser 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)
30 SAP 2005 Regulations Basic methods similar to previous regulations Calculations more complicatedTakes into considerationwindow framessolar gainenergy for lightingeffect of thermal bridgesenergy generated by micro CHP, photovoltaics, etcProblems with monetary values remainRecalibration of scaleA house with a previous SAP rating will be reducedSAP 2005 rating is related to the energy cost factor (ECF) by:If ECF>=3.5, SAP 2005 = *log10(ECF)(1)If ECF<3.5, SAP 2005 = *ECF (2)SAP rating scale (1-100) - SAP100 is achieved at zero ECFCan be >100 if house is net exporter of energySAP rating of 100 for something which is zero cost is an improvement on previous versionsBut fundamental problem of trying to relate performance to energy prices is a serious limitation particularly due to widely fluctuating energy prices
31 Summary Table of U-values for different Building Regulations
32 English housing tenure by SAP rating, 2001 ODPM (2003)
33 Effects of Building Regulations Part L 2002, 2005 & 2008 amendments should increase efficiency of new build and extensions by 25%…but will it?
34 What are the barriers to using building regulations to reduce energy use and carbon emissions ?
35 UK residential sector accounts for 30% total UK energy demand 1990 – 2003Total UK energy demand increased 7.3%Residential energy increased 17.5%Since 1970Energy use per household changed littleOverall energy use for residential sector increased by 32%At household levelReduction in heat loss – energy savingIncreases in energy demand – lights & appliances
36 Population & households UK populationcurrent aprox 60 million– 72 millionAge structure2003 – 76.2 men, 80.6 women2031 – 81.0 men, 84.9 womenTotal population over 65m, m, 2060s 17 mHousehold size;One person households: %, %
37 Effects of household size on energy use Fawcett et al (2000)
38 Construction & demolition Building regulations are for new houses & extensionsIn UK very low levels of construction & demolition2002/3 167,000 housing starts1996 – 2004 nearly 160,000 dwellings demolished – 20,000/yearIf we continued at this rate the average house will last 1000 years!
39 Future of household energy supply lies in the hands of: Central government400 local authorities25 million householdsAppliance and fuel supply industriesConstruction building servicesFragmentedMultiple suppliers of specialist productsHuge number of sub contractorsCosts saved by:reducing capital costsstandard componentsstandard practices
40 Whole life costs/life-cycle costs typical costs for owning a building are in the ratio of :1 for construction costs5 for maintenance costs200 for building operating costsSource: Royal Academy of Engineering
41 Life cycle cost (LCC) Capital cost + Present worth of Maintenance and Energy Cost - Present worth of Salvage valueCapital costinitial capital expense for equipmentthe system design, engineering, and installation.Maintenance: operation and maintenance costs/yearEnergy cost: yearly fuel cost.Salvage value: net value in the final year
Your consent to our cookies if you continue to use this website.