EPBD – National Calculation Method & SBEMMike JaggsBRE Environment

SBEM produces an Asset Rating• The calculated intrinsic performance of the building as built• Normalised to standard conditions (weather, occupancy)• Recognises different ‘activity areas’• Applicable to both new and existing buildings• Automatically generates the appropriate Notional Building as the

baseline• Used to demonstrate compliance with minimum standard• And perhaps to generate a comparative rating (‘A-G’ or 0-100) • Used to compare one building with others• Also need a ‘Design rating’ before building is built

The rating and compliance test - NCM

Notionalbaseline

2002 Elemental standards

Fabric & plant

CalculationTool

Inputdata

StandardActivity

Schedule

ProjectedCO2/m2/yr

ProposedFabric & plant

Buildinggeometry

The compliance test

Notional xImprovement %

= Target

2002 Elemental standards

Fabric & plant

CalculationTool

Inputdata

StandardActivity

Schedule

Proposed

ProposedFabric & plant

Buildinggeometry

Articles 4 & 5Asset Rating

Is P>T? OKN

Revisedesign

Y

The rating - NCM

Notional2002 Elemental

standardsFabric & plant

CalculationTool

Inputdata

StandardActivity

Schedule

Actual

ActualFabric & plant

Buildinggeometry

Article 7 Asset Rating

Compare

Asset Rating - the calculation methodologyA methodology which calculates ‘integrated energy performance of

buildings’ (Art 1),

• Taking account of (Annex):− Indoor conditions− Fabric performance− HVAC and DHW− Lighting and daylighting− Position and orientation− Passive design features− Renewable and chp options

• For a wide range of non-domestic buildings• For a standardised use of the building (Art 2)

• (Domestic buildings will use SAP)

Definitions and scope

• National Calculation Method (NCM)– Deals with Part L2 Compliance– And with Asset Ratings (not Operational Ratings)– Includes standard databases for building components and activities– Allows the use of different calculation cores, including accredited

simulation tools– Encourages the development of different user interfaces

• Simplified Building Energy Model (SBEM)– Developed by BRE for DCLG

The SBEM development project

• An important project for BRE• Funded by ODPM via Faber Maunsell• To produce a ‘simple’ tool• To comply with the emerging CEN standards• To cover the majority of ‘ordinary’ buildings• To complement more sophisticated simulation-based methods• Based on the Dutch NEN2916 method

Article 10 – who can use SBEM?

• ‘…in an independent manner…’• ‘…by qualified and/or accredited experts..’

• Needed for both Building Regs and EPBD Article 7• Training courses available • Accreditation scheme launched by BRECertification

• Try it – at www.ncm.bre.co.uk

EPBD – National Calculation Method - overview

UserInterfaceiSBEM

Calculation coreSBEM

Interface

Activity Database

Fabricdatabase Service

database

Describing the building - key stages

• Geometry– Overall building layout– Distribution of activity areas

• Construction• Systems • Controls

• Two different input routes:– New build – from plans– Existing buildings – from brief survey and, eg, log book data,

supplemented by inference

Existing buildings: Inference procedures - fabric

• Wall/roof/floor construction• U-values• Glazing areas and performance• Thermal mass effects• Infiltration rates

• Based on available data:– Age (eg Building Regs in force at construction)– Generic system– Building type

Activity areas – distinct areas with distinct impacts on energy use

Will include, for example:

• Cellular office• Open-plan office• Sales area - ambient• Lecture theatre• Sports hall• Storage - chilled• Toilets• Stairs

Activity schedules – to include• Occupancy density

• Occupancy schedule

• Design temperature set-points

• Design ventilation rate

• Target illuminance

• Equipment gains

• DHW requirement

• Humidification if essential

• Standard values for Asset Rating

• (Tailored values for Tailored rating could be possible)

NCM Activity database

NCM Construction database

iSBEM – General information

iSBEM – Help functions

Project database – setting up constructions

Drop-down options

Defining zone geometry and activity

Defining the envelope

Checking the zone envelopes

Defining the services

The domestic hot water system

The compliance check calculation

More detail for the Asset Rating

Part of output information

WHOLE BUILDING ENERGY AND CARBON DIOXIDE PERFORMANCE

Carbon Dioxide Emissions (KgCO2/m2●annum)

91.93 KgCO2/m2●annumBuilding CO2 Emissions Rating (BER) for building as designed

92.65 KgCO2/m2●annumTarget CO2 Emissions Rating (TER)

0.1LZC benchmark

0.2Improvement factor

128.65 KgCO2/m2●annumCalculated CO2 emission rate for the notional building

9 Are the U-values better than the design limits?“Not better than design limits”

* Display windows and similar glazing are not required to meet the standard given in this table.

"No Roof ventilators in project"

0606Roof ventilators (inc. smoke vents)

"No High usage entrance doors in project"

0606High usage entrance doors

"No Vehicle access doors in project"

0401.5Vehicle access & similar large doors

"No Personal doors in project"

0302.2Personnel doors

zone 1/w/g5.2793.35.2792.2Windows* and rooflights

zone 1/c0.240.350.240.25Roof

zone 1/f0.330.70.330.25Floor

zone 1/w0.320.70.320.35Wall

Surface where this maximum value occurs

Calculated individual element U-values [W/(m2 oK)]

Limiting individual element U-values[W/(m2 oK)]

Calculated area weighted U-values [W/(m2 oK)]

Limiting area weighted average U-values[W/(m2 oK)]

Element