The Green Deal Tools -Richard Hartless, BRE


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The Green Deal Tools -Richard Hartless, BRE

  1. 1. The Green Deal toolsRichard HartlessCoRE Learning Event : 25th October 2012Part of the BRE Trust
  2. 2. Overview1. What is Green Deal2. Introduction to BREDEM and SAP3. Developments to SAP4. In-use factors5. Occupancy assessment6. Improvement measures and tool outputs7. Non-domestic Green Deal [If time!]
  3. 3. How does Green Deal work?Part of the BRE Trust
  4. 4. How does the Green Deal work?Example: domestic owner occupier Can happen at the same visitCustomer Accept Installation Assessment Quote interest quote & after Customers choose what work they want done impartial Installers assessors Quotes are Costs work out what personal and charged to households include subsidies electricity bill need Stays with home if move 4
  5. 5. Assessment InstallatiCustomer Assess Accept Quote on & interest ment quote after Customers will get an impartial on-site assessment of their home, from authorised Green Deal Assessor. Assessment is in two parts: • Customers get an Energy Performance Certificate, which is based on standard assessment of how home is used • Green Deal Assessor then has conversation with customer about how they actually use the home • Assessor produces personalised “Occupancy Assessment” so customer can understand what improvements to the house are most appropriate • Assessment is like prescription, it can be used with any business providing Green Deals • “Golden Rule”: Green Deal aims to let householders save at least as much in energy costs as they repay through their electricity bill
  6. 6. Introduction to SAP andBREDEMPart of the BRE Trust
  7. 7. BREDEM - BRE Domestic Energy Model – BREDEM calculates annual energy required for: • space heating • water heating • cooking • lights and electric appliances – From energy cost, carbon emissions – First version in 1980s • subsequent continuous development and testing – Extensively compared with energy consumption for both real houses and detailed simulation models
  8. 8. BREDEMschematicof principlesSAP also estimates:• Hot water energy• Lighting energy• Energy needed for pumps and fansBut not appliances andcooking energy
  9. 9. Basic equationsThe overall heat transfer coefficient, H (W/oC):– Ai is the area of an external element (m2)– Ui is the U-value of an external element (W/m2 oC)– Ltbi is the length of a linear thermal bridge (m)– i is the linear thermal transmittance (W/m oC)– nT is the total air change rate (ach)– V is the volume (m3)Space heating energy use:– H (heat transfer coefficient)– θe mean external temperature– θi mean internal temperature H( i e) ( Gi Gs )– Gi internal heat gains Q– Gs solar heat gains space e– gain utilisation factor– e heating efficiency
  10. 10. BREDEM – comparison with real dwellings(176 dwelling years of data) S p a c e h e a tin g - A ll d a ta (n e w ) (m o n th ly d a ta c o m p a re d w ith B R E D E M 8 p re d ic tio n s ) 7000 6000 5000 y = 1 .0 0 2 2 x 2 R = 0 .8 5 0 1 P re d ic te d (k W h ) 4000 3000 2000 1000 0 0 1000 2000 3000 4000 5000 6000 7000 M e a s u re d (k W h )
  11. 11. BREDEM – comparison with simulation models M O N T H L Y P R E D IC T IO N S O F E A C H M O D E L (S E M I-D E T A C H E D , M O D E R N H E A V Y W E IG H T ) 1400 1200 1000P re d ic tio n (k W h ) ESP 800 HTB2 S E R I-R E S BREDEM 8 600 400 200 0 Jan Feb M ar Apr M ay Jun Jul Aug Sep O ct N ov D ec M o n th
  12. 12. SAP - Standard Assessment Procedure– SAP is a version of BREDEM with some fixed parameters– Not affected by (fixed parameters) • number of occupants (assumed, based on floor area) • ownership of particular electrical appliances • heating patterns and temperatures • geographical location (but in latest version parameters can be adjusted - Green Deal Occupancy Assessment)– Depends on • thermal insulation • ventilation • lighting • dwelling energy generation (e.g. PV panels) • solar gain • heating system efficiency and controls • cost of fuels
  13. 13. SAP 2009 - Standard Assessment Procedure UK Government’s energy rating method for dwellings. Space and water heating, ventilation and lighting, less energy generation. – SAP rating • 1 to 100 based on annual cost (per m2) • Required for all new homes • Energy Performance Certificates (RdSAP) for existing homes • Widely used by social housing providers, encouraged by Govt. – EI (Environmental Impact) rating • 1 to 100 based on annual CO2 emissions (per m2) • Energy Performance Certificates (RdSAP) for existing homes – DER, Dwelling CO2 emission rate • CO2 emissions (per m2) • Must meet TER (Target Emission Rate) to comply Part L1A
  14. 14. Energy Performance Certificates [Old]– Energy Performance Certificate provides: – An ‘energy’ efficiency rating for a house (actually based on costs) – A CO2 based Environmental Impact rating – Recommendations for efficiency improvements to the dwelling– All this is generated by SAP, following a physical survey by a DEA– EPCs required by law when dwellings are sold or let– Green Deal will piggy-back on the EPC process
  15. 15. Developments to SAPPart of the BRE Trust
  16. 16. RdSAP– RdSAP is not an alternative version of SAP– It is an inference procedure for generating the full set of SAP inputs from a smaller set of data– The inferred data is then run through a normal, full SAP calculation– Devised when EPCs were introduced to make it easier for assessors (to keep costs down)
  17. 17. How SAP and BREDEM have changed over time– Fundamentally, changes have been minor over the years (i.e. the same basic physics applies)– But models now deal with many more systems and technologies than early versions – so lots of add-ons (consequently, there are now many appendices in the SAP specification)– There was a fundamental change in SAP/BREDEM in 2009: monthly calculations– This actually makes the calculation simpler in some respects: 12 simple calculations instead of 1 complicated one
  18. 18. Current developments– SAP 2012 has introduced relatively minor changes: – Updated fuel costs and CO2 emission factors – Climate data extended to allow regional calculations in some circumstances – Height above sea level temperature correction – More primary pipework options (e.g. partially insulated now possible)– Proposed changes to be introduced in SAP 2012 have been consulted upon. An initial analysis of the responses has been undertaken but more remains to be done (key areas of contention are on CO2 emission factors and heat pumps).– Formation of a SAP Scientific Integrity Group to assist by making recommendations on more contentious issues
  19. 19. SAP developments for Green Deal– Essentially a new hybrid of SAP and BREDEM– Based on RdSAP inputs plus data from the Green Deal ‘Occupancy Assessment’: – EPC gives standard savings for improvement measures (on which ‘Golden Rule’ is based) – Includes ‘in-use’ factors to reflect actual performance of measures – Occupancy Assessment gives occupant-specific savings • Low energy users won’t save as much, so we need to warn them! • Unhappy finance providers • Undermine confidence in Green Deal
  20. 20. New EPC- Revised presentation- Refers to Green Deal- Environmental Impact relegatedto page 4- Potentially accompanied by GD‘Occupancy Assessment’- Will contrast standard savingsfor measures with occupantspecific savings
  21. 21. In-use factorsPart of the BRE Trust
  22. 22. These are some of the things you canhave done to your property• Cavity wall insulation • Fan-assisted replacement • Pipe-work insulation• Cylinder thermostats storage heaters • Microgeneration• Draught proofing • Flue gas heat recovery • Chillers devices• Solid wall insulation • Condensing boilers • Heating, ventilation and air-• Condensing boilers conditioning controls • Replacement glazing• Heat pumps • Replacement and secondary • Roof insulation• Heating controls glazing • Sealing improvements• Lighting systems • Under-floor heating • Under-floor heating• Biomass boilers • High performance external • Under-floor insulation• Cylinder thermostats doors • Variable speed drives for • Hot water controls fans and pumps• Draught proofing • Lighting systems, fittings and • and more...!• Duct insulation controls• Hot water • Mechanical ventilation withshowers/systems/taps heat recovery If it is on this list then you would get it in part or whole through GD
  23. 23. In-use factors • Bridge gap between theoretical and actual performance (difference between in-situ and laboratory, poor What are they? installation, comfort taking etc.) • Provide additional consumer protection • Review of published evidence (e.g. NEED, Field trials How were they etc.) • Recommendations from DECC convened expert derived? committee How are they • % reduction factor applied to each measure in the Green Deal tool applied? How will they • Objective is to lower factors over time so will review evidence of performance every year be amended?
  24. 24. In-use factors Domestic Measures Sources of Evidence In-use factor (%) Cavity Wall Insulation Field trials and NEED 35 Internal Solid Wall Insulation (pre-1966 solid brick walls) Field trials and NEED 33 Internal Solid Wall Insulation (all other solid walls) Recommendation 25 External Solid Wall Insulation (pre-1966 solid brick walls) Field trials and NEED 33 External Solid Wall Insulation (all other solid walls) Recommendation 25 Loft insulation (including loft hatch, rafter insulation) Field trials and NEED 35 Flat roof insulation Recommendation 15 Room in roof insulation Recommendation 25 Floor insulation Recommendation 15 Heating controls Field monitoring 50 Non condensing to condensing gas or oil boiler Field trials and NEED 25 Biomass boiler Recommendation 25 Biomass room heater Recommendation 25 Flue Gas heat recovery device Recommendation 10 Hot water cylinder insulation Recommendation 15 Double Glazing Recommendation 15 Secondary glazing Recommendation 15 High thermal performance external doors Recommendation 15 Draught-proofing Recommendation 15 Cylinder thermostat Recommendation 10 New or replacement storage heaters Recommendation 10 Replacement warm-air unit Recommendation 10 Waste water heat recovery devices Recommendation 10 Solar water heating Field trial 0 Photovoltaic panel Recommendation 0 Ground source heat pump Field trial 10 Air source heat pump Field trial 25 Micro CHP Recommendation 25 Building mounted wind turbine Field trial 0
  25. 25. Occupancy assessmentPart of the BRE Trust
  26. 26. Occupancy assessment dataNumber of occupantsShower type, showers and baths per dayHeating system and heating in each roomTemperature in living roomHeating patternsAppliances & cookersFuel tariffs and consumption together with reliability
  27. 27. How occupancy data is used • Used to calculate hot water, appliance and cooking Number of uses occupants • Affects space heating requirement to via gains • Used to calculate hot water use Shower type, • Electric showers add to shower appliance consumption frequency, bath frequency • Affects space heating requirement via gains
  28. 28. How occupancy data is used • If an alternative system has been chosen, heating efficiency, controls and responsiveness are adjusted Heating systems accordingly • Directly affects space heating energy requirement • Used to estimate proportion of dwelling Heating in each that is unheated room • Used to calculate average internal temperature
  29. 29. How occupancy data is used • Used as starting point to Living room temperature calculate average internal temperature • Used to calculate average internal temperature to Heating pattern (times) estimate how much dwelling cools down between heating periods
  30. 30. How occupancy data is used Proportion of • Used to estimate tumble dryer energy consumption (together with number of drying done in occupants) tumble dryer • Affects space heating consumption via gains Number of fridges • Used to estimate cold appliance consumption and freezers • Affects space heating consumption via gains Cooking type and • Used to estimate energy required for cooking fuel • Affects space heating energy via gains
  31. 31. How occupancy data is used • Used in place of SAP default Fuel tariffs values to obtain more accurate estimate of running costs • Where reliable, used to reconcile Fuel calculated energy consumption by consumption each fuel with actual amount used data • Software scales all uses of that fuel up or down accordingly
  32. 32. Improvement measuresPart of the BRE Trust
  33. 33. Improvement measures – standard savings– Model is run with standard SAP occupancy assumptions– Model is re-run with energy efficiency measures added (sequentially)– The saving for each measure is calculated – The amount of Green Deal finance available for each measure is based on this
  34. 34. Improvement measures – tailored savings– Model is run using the occupant specific information– Model is re-run with improvement measures added– Savings for each measure are calculated – These are used to advise occupant on what they are likely to save if they installed these measures – Warns them if this would mean they are unlikely to ‘pay for themselves’ even if they are eligible for GD finance – But they can still go ahead if they want to
  35. 35. Occupancy Assessment report– All this information (and more) is presented in the Occupancy Assessment report
  36. 36. Summary– SAP is normally used with standard occupancy assumption so we can compare dwellings fairly– For GD we need something specific to the occupants– Occupancy information is collected and entered it into a modified version of SAP– This estimates savings from improvement measures specific to household– In-use factors are also applied– Avoids overestimating savings and potentially undermining confidence in the scheme
  37. 37. Non-domestic Green DealPart of the BRE Trust
  38. 38. The Green Deal for non-domesticproperties Scheme is broadly the same for both homes and non domestic buildings, and available at the same date. Some variations: •Assessment: non domestic buildings often have more varied characteristics than homes, so the assessment methodology will need to be more complex; •Measures: for simplicity, a single comprehensive list of qualifying improvements for both homes and non domestic buildings. •Calculation of Green Deal finance: more flexibility for the non domestic sector by allowing for specialist assessments to provide a more detailed savings estimate.
  39. 39. Step 1– Starts from the existing SBEM calculation tool, which uses standard conditions to calculate energy performance metrics and recommendations for improvement.– Generate an EPC for the target building, along with the accompanying Recommendations Report.
  40. 40. Step 2Tailoring– Have reviewed which parameters within the Activities Database (operating hours, occupancy density, equipment loads, etc.) are most sensitive in terms of their effect on actual energy use and likely savings.– Allow user to modify some or all of these parameters to create new Activities specific to the building– One key element of tailoring is the level of energy management currently employed – links to normalisation
  41. 41. Step 3Handling Recommended Measures– Modified interface (iSBEM) to allow the assessor to amend the building model to incorporate one or more of the recommendations – and keep track of the effect– Package measures in different scenarios– Require the assessor to input a value for the marginal cost of each unit of each fuel as currently paid by the building occupier.– Tool produces comparative tables of energy, carbon and costs savings for each scenario– One scenario to be selected as proposed GD package – used to create Green Deal Report
  42. 42. Step 4Normalisation– Assessor is required to enter either the results of a DEC assessment (preferred), or actual meter readings for the previous year.– Assessor needs to assess and enter a measure of how well (or otherwise) the building appears to be being managed, in different areas of operation (policy, HVAC, etc)– With this information, the tool recalculates figures obtained above, normalised to match the actual management and usage of the building.– It will also calculate the likely savings from improving management alone
  43. 43. Energy management– Assessment is based on well-established Energy Management Matrices– Assessor matches observed behaviour to a series of questions, to obtain a score– Covers different topic areas– Based on material developed under the Energy Efficiency Best Practice programme, then Carbon Trust – and a new BRE Trust Report
  44. 44. Results– This version of the tool will provide the building owner and any potential GD provider with enough information to know – a) whether a GD solution could save energy and – b) which sort(s) of measure would be worth pursuing – c) the scale of likely savings
  45. 45. Current stagePublic trial versions– Pilot version has been available for trial by key stakeholders since November 2011 at– Latest version (v5.0.b) released on 21st August 2012– Final version scheduled for October
  46. 46. The Green Deal toolsRichard HartlessCoRE Learning Event : 25th October 2012Part of the BRE Trust