CIBSE LOW CARBON CONSULTANTS REGISTER SESSION 3 CALCULATING CARBON PERFORMANCE. I Prophets energy services

Transcription

1 CIBSE LOW CARBON CONSULTANTS REGISTER SESSION 3 CALCULATING CARBON PERFORMANCE I Prophets energy services

2 The National Calculation Methodology (NCM) The Simplified Building Energy Model (SBEM) Interfaces to SBEM Slide 3 Slide 7 Slide 31 SESSION3 -SBEM ANDTHENCM 2

3 The National Calculation Method for the EPBD (Energy Performance of Buildings Directive) is defined by the department for Communities and Local Government (CLG). As part of the revisions to Part L, the National Calculation Methodology (NCM) will also be changed. SBEMis a software tool that provides an analysis of the energy consumption of buildings other than dwellings. It calculates monthly energy use and carbon dioxide emissions, given a description of the building which is entered through its interface isbem.since 2006 it has been used to demonstrate compliance with Part L of the Building Regulations and, since 2008, has provided Energy Performance Certificates on construction, sale or rent. SBEM ANDTHENCM 3

4 Background to NCM What is it? Where is it.. See article 3 of EPBD. SBEM ANDTHENCM 4

5 Approved Methodologies: Dwellings on construction SAP 2009 A dwelling sold or rented out RDSAP Non-dwellings on construction SBEM All other buildings being constructed, sold or rented out SBEM Public buildings requiring a DEC Operational Rating methodology National Calculation Methodologies 5

6 NCM is UK approach to meeting energy calculation requirements of EPBD It calculates the Integrated energy performance of buildings Based on a Dutch model Allows calculation by accredited software Dynamic simulation models, or SBEM/iSBEM based tools THE NATIONAL CALCULATION METHOD 6

7 SBEM is the UK calculation algorithm SBEM is suitable for use with the majority of buildings Allows compliance checking against Building regulations and production of ratings for Energy Performance Certificates Designed to produce consistent evaluations of energy use It may assist in the design process, but is not a design tool SBEM was developed for the CLG by BRE THE SIMPLIFIED BUILDING ENERGY MODEL(SBEM) 7

8 Requires the input of the following: Fabric elements Geometry Building services Building activity Renewable options Uses locked data bases for: Weather data Activity data THE SIMPLIFIED BUILDING ENERGY MODEL(SBEM) 8

9 Information Building geometry Source Assessor input from drawings or survey Weather data Internal database, select from 12 weather files Occupancy profiles for activity areas Zoning of activity areas Building envelope HVAC systems Lighting Assessor selects by choosing building type and activity for each zone Assessor determines zones from building drawings or survey Assessor selects from internal database or inputs directly Assessor selects from internal database or inputs directly Assessor selects from internal database or inputs directly THE SIMPLIFIED BUILDING ENERGY MODEL(SBEM) 9

10 Free to download from Simple Microsoft Access based front end to SBEM From the creation of the entered Actualbuilding the software generates a: Notional(or Target) Building Reference Building THE INTERFACE TO SIMPLIFIED BUILDING ENERGY MODEL(ISBEM) 10

11 11 NOTIONAL BUILDING SPECIFICATION

12 NCM Notional Building Fabric The notional building uses an air permeability figure of 50 Pa 12

13 NCM Notional heating efficiency 13

14 NCM Notional heating efficiency 14

15 NCM Key notional building specifications Element Side Lit/ No glazing Top Lit Central Mechanical Ventilation SFP (W/l.s) Heat Recovery (sensible effectiveness) % 70% Lighting (Lumens/W) Cooling seasonal energy efficiency ratio SBEM ANDTHENCM NOTIONAL BUILDING 15

16 The NCM activity database now: Includes a key which determines which specifications of notional building are selected based upon the use of the space. Limits the choice that users have of the allocation of activity areas, Activities are restricted and linked to Planning Use Class appropriate to the building. SBEM ANDTHENCM NOTIONAL BUILDING 16

17 SBEM ANDTHENCM NOTIONAL BUILDING NCM Key notional building specifications 17

18 18 NOTIONAL BUILDING SPECIFICATION

19 Used as the comparison for an Energy Performance Certificate the Referencebuilding is same as notional building but with gas heating and seasonal mixed mode cooling when temperature exceeds 27oC - Cooling only counted when needed to avoid overheating - Same regardless of HVAC system in actual building THE REFERENCE BUILDING Being based on comparison reduced impact of - survey error - modelling assumptions (zoning etc)

20 NCM Reference Building Fabric 20

21 The NCM Reference Building HVAC The heating and hot water service are always met by natural gas irrespective of whether a fuel other than natural gas is used in the Actual building, or is even available in the locality. A fixed servicing strategy regardless of the strategy adopted in the Actual building : Each space is heated as defined in the activity database. The heating SCoPis 0.73 Each space is cooled, with the cooling setpointfixed at 27⁰C irrespective of whether the particular space in the Actual building has cooling provision or not. The cooling SEER is fixed at

22 The reference building carbon emissions is then improved by fixed factor (0.235) to produce the Standard Emission Rating Rating calculated as ratio BER/SER carbon x 50 (The value 50 represents a building to 2006 standards) Converted into a rating bank (A_G) but numerical rating too BASIS OF CALCULATION FOR AN EPC

23 The Asset Rating AR = 50 x BER/SER Where: BER = Actual Building Emissions Rate SER = Standard Emissions Rate and SER = RER x RER = Reference Building Emissions Rate AR Scale is linear so: 0 = net zero annual co2 emissions 50 = B/C Grade Boundary 100 = D/E Grade Boundary 23

24 The Asset Rating Benchmarks New Build = TER (or the Notional Building) Typical = (2 x Notional Building ) / 0.75 which is approx = 2006 TER x 2 24

25 Design Information Building geometry Actual Fabric & plant (Proposed) Input data Calculation Tool Proposed Building Carbon CALCULATION FOR COMPLIANCE Activity Schedule Standards Fabric & plant (Notional Building) Notional Building Carbon

26 Design Information Building geometry Actual Fabric & plant (Design) Input data Calculation Tool BER = Building Emission Rate BER CALCULATION FOR COMPLIANCE Activity Schedule Standards Fabric & plant (Notional Building) TER TER = Target Emission Rate

27 Design Information Building geometry Actual Fabric & plant (Design) Input data Revise design Calculation Tool N BER = Building Emission Rate BER Is BER <TER Y OK CALCULATION FOR COMPLIANCE Activity Schedule Standards Fabric & plant (Notional Building) TER TER = Target Emission Rate

28 Calculation for certification Design Information Building geometry Actual Fabric & plant (Design) Input data Calculation Tool BER or Typical Reference Building Carbon EPC Rating CALCULATION FOR CERTIFICATION Activity Schedule Standards Fabric & plant (Notional Building) Notional Building Carbon Gas Heating and Seasonal Mixed Mode

29 Design Information Building geometry Actual Fabric & plant (Design) Input data Measure s Filter Calculation Tool Assessor Review Advisory Report BER or Typical Reference Building Carbon EPC Rating CALCULATION FOR CERTIFICATION Activity Schedule Standards Fabric & plant (Notional Building) Notional Building Carbon Gas Heating and Seasonal Mixed Mode

30 There are two options for calculation of CO 2 emissions: isbem or other approved interface to SBEM Dynamic simulation tools (Simulation tools use more accurate thermal simulation to calculate the CO 2 emissions) Simulation tools provide annual CO 2 emissions based on hourly standard weather data SBEM is based on steady state calculations using monthly weather data SBEM VS DYNAMIC MODELS 30

31 Current software versions support 2010 Building Regulations Provides Building Regulations compliance and Energy Performance Certificates in England, Wales, Scotland, Northern Ireland, Republic of Ireland and Jersey SBEM ANDTHENCM Produce the EPC & RR All software regardless of provider MUST be approved for use 31

32 Compliance Output - Ratings tab SBEM ANDTHENCM 32

33 BRUKL technical data sheet SBEM ANDTHENCM 33

34 EPC Output - Ratings tab

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36 isbem is a simple interface, not best suited to complex buildings Significant amounts of information need to be assembled prior to the assessment The benefits of some technologies are not wholly considered by SBEM ISBEM CONCERNS Features not well represented in isbem Feature SBEM/iSBEM applicability Night ventilation strategy Ventilation with enhanced thermal coupling to structure Automatic blind control or Solar Shading Can be approximated with SBEM but not with the current version of isbem Not currently available Not currently available Variable speed pumping Basic implementation not fully modeled 36

37 isbem is a free download from BRE, other commercially available packages include: CIBSE does not promote the use of any individual tool selection should be based on assessors own assessment of suitability (and commercial constraints). All software tools are all regularly updated always check you are using the current version.

38 Simulation tools use the same standard activity data as SBEM and provide an output in exactly the same format complies with the procedures set down by the Secretary of State Simulation tools allow additional features such as: external shading natural ventilation scenarios Simulation tools allow all the key features in the Actual Building to accurately model almost every energy saving feature Simulation tools provide a visual feedback of model geometry Especially relevant with complex building geometry Indications are that some building types are more difficult to comply when high lighting loads and large glazing areas in the actual building (retail) buildings can pass in one geographical location, but an identical building can fail in another due to difference in weather data SBEM VS DYNAMIC MODELS 38

39 isbem is suitable for use with simple buildings SBEM not entirely transparent Dynamic models suitable for use with all buildings regardless of shape, use, size or complexity Dynamic models more accurate? Dynamic models will help the design of lower carbon buildings SBEM VS DYNAMIC MODELS 39

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