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IES <Virtual Environment> Live e-training

Trainee notes

<VE Compliance> England and Wales

VE-DSM 2010

Version 6.4

Introduction

These training notes are to be used in conjunction with your scheduled IES <Virtual Environment> UK Building Regulations Approved Document Part L2 (England and Wales) training. If you attended <VE Compliance> VE-SBEM training, you were shown how to perform Part L2 compliance checks and EPC generation using the SBEM (Simplified Building Energy Model) method within the IES <Virtual Environment>. This training lecture will provide the following information:

1. How to perform Part L2 compliance checks for your building using the ApacheSim method which employs the technique of dynamic thermal simulation

2. How to generate EPC’s (Energy Performance Certificates) for your building using the ApacheSim method

3. What you need to know should you wish to sit the IES <VE Compliance> Accreditation exam (backed by CIBSE, BRE, ecmk and Stroma)

4. How to get answers to frequently asked questions (FAQ’s)

These notes accompany the web lecture and act as a reference point for your further study. You will perform the analyses on a previously created building model, where the geometry has been created using either ModelIT, or the IES VE plug-ins for Google SketchUp™, Autodesk® Revit® Architecture 2009 or Autodesk® Revit® MEP 2009.

The trainer will show you how to perform various functions as shown in the following pages, and images are included to assist you in following the trainer as the session proceeds, and to act as a memory jogger after the session.

For more detailed help you can use the Help menu within the specific IES application, and also you can refer to the user guides accessible from the <VE> Help menu.

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Overview of Part L2 requirements

Before the training lecture please make sure you have read through the Part L2A approved Document – ‘Conservation of fuel and power in new buildings other than dwellings’. Other documents that are recommended include the “National Calculation Methodology (NCM) modeling guide” and the “Non-Domestic Building Services Compliance Guide”.

Similarly, if possible you should be aware of the range of 2nd tier documents mentioned in Part L2A.

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You may also be interested in the following document related to EPCs: (Energy Performance Certificates): “Improving the energy efficiency of our buildings: A guide to energy performance certificates for the construction, sale and let of non-dwellings”

This document is available from the CLG (Communities and Local Government) website at: http://www.communities.gov.uk/publications/planningandbuilding/guidancenondwellings Prior to the training lecture and having read the Part L document you should have a reasonable understanding of the following terms:

The 5 compliance criteria for Part L2A

Understand of how TER is calculated from calculated CO2 emissions

Understanding of the difference between the TER and BER

This training session will concentrate on how to prepare a model for Part L2 assessment via the ApacheSim route and for EPC generation via the ApacheSim route. This session assumes that all users have the ability to create building models with the correct assignation of templates.

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Part L2 background theory For Part L2 compliance checks, two versions of the real building are automatically created in the <VE> Compliance tool; the ACTUAL and the NOTIONAL building. These two versions of the real building are described as follows:

ACTUAL building: same geometry and constructions as the real building but with BRE specified activities (occupancy, internal gains)

NOTIONAL building: same geometry as the real building but with construction U-values, systems and glazing areas as per the NCM guidelines and with the same activities as the ACTUAL building

To achieve compliance, the carbon dioxide emission rate of the ACTUAL building; that is the Building Emission Rate (BER), must be no more than the TARGET Emission Rate (TER), which is calculated from the NOTIONAL building emission rate (Cnotional) . The Target Emission Rate (TER) is calculated as follows: TER = Cnotional

Target CO2

TER

Actual CO2

BER

Actual Building Notional Building

Compliance Tool

Compare

Real Building

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There are various software routes for compliance checking:

This session will cover the use of IES’s accredited simulation tool (ApacheSim) for compliance checking and EPC generation, which employs the technique of dynamic thermal simulation.

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Opening a previously created <Virtual Environment> project First you will be shown how to open a previously created project.

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Selecting the <VE> Compliance application Next you will see how to switch to the Compliance and Ratings group of programs and then to the <VE> Compliance view.

Two main methods for Part L2 checks are available within the <VE> Compliance view; the ApacheSim method, or the SBEM method. In this training session we will be using the ApacheSim method for Part L2 checks and for EPC generation. Performing Part L2 compliance checks using the ApacheSim method. We will select the ApacheSim method, then select the Part L2 compliance route.

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Setting the site location You will be shown how to set the site location.

Selecting the site location The site location is selected in APLocate within the Simulation Weather Data tab.

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The available locations are:

These weather data sets need to be licensed directly from CIBSE.

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Setting constructions (opaque and glazed constructions) Constructions for the NOTIONAL building do not need to be created or assigned. The <VE> Compliance module creates these constructions automatically. Any constructions that are used in the real building are used in the ACTUAL building.

Various construction parameters need to be assigned for regulation compliance testing; such as Thermal Bridging Coefficient, the Curtain Wall option and whether a glazed construction is a Display Window. Located at the top right of any opaque or glazed construction there is an option to change the Thermal Bridging Coefficient from the default setting.

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Ground/Exposed floors External floors in the “Ground/Exposed floors” category should be identified as either a ground contact or exposed floor. This is specified via the check box pointed out below. Ground Contact floors should have their U-values corrected in line with EN-ISO 13370 which is based on the perimeter characteristics of the building.

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Internal constructions

An internal construction can be retained (used) in the notional/reference building if required. This is useful if for the actual building, a floor void has been drawn as a zone. If the “Retain in Notional/Reference building” option is used, the construction for the top and bottom surfaces of that void zone are then used in the same void zone in the notional/reference building instead of standard NCM constructions (which potentially could include air gaps themselves).

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For glazed constructions you need to select if the construction is display window or if it will represent a glazed door.

You should apply constructions to the building as appropriate.

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Setting up NCM HVAC systems The CLG prescribes a number of HVAC systems that can be used for Building Regulations compliance testing. These systems have been included in the Apache Systems approach to systems in the <Virtual Environment>. You will be shown how to access the Apache Systems window.

Within the Apache Systems window you must initially use the UK NCM System Wizard to select a system. This will then populate the Apache Systems window with the correct system data which you can then edit if needed (eg the Heating, Cooling and Auxiliary energy data).

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Choosing the NCM system from the System Wizard

Select the system from the drop down list. This shows a list of all the available systems as defined by the CLG and BRE.

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Once this system is chosen, further parameters are required for <VE> Compliance to determine the system performance criteria; these include where appropriate:

Identify heating system parameters

Identify cooling system parameters

Setting AHU & Ductwork leakage and Specific Fan Power

Setting metering data

Setting other ventilation and heat recovery data You can use the default heating and cooling efficiencies, or you can manually enter them. Auxilliary energy values are automatically calculated.

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Centralised balanced A/C or mech vent system – a central air conditioning system or a mechanical ventilation system. Zonal supply system with remote fan: e.g. the building could be naturally ventilated, but some rooms have a mechanical system supplying fresh air. Zonal extract system with remote fan: e.g. the building could be naturally ventilated, but some rooms have extract fans to extract air without supplying fresh air. Local ventilation-only units: units serving a single area, e.g. a toilet extract.

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Editing the data (if required) in the Apache Systems window You can now make final changes to the system data if required (eg updating the heating and cooling efficiencies). You can also specify domestic hot water and solar water heating options (if used by the highlighted system). Note: all heated rooms must have at least a DHW system assigned to them to allow Part L2 checks to be performed.

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Setting NCM building and activity data The actual and notional building use activity data (descriptions of internal gains) as defined by the CLG. In order for <VE> Compliance to be able to automatically assign these activities the user needs to choose both the type of building and activity in the actual building. This is done from the Building Regulations Tab in the Thermal Conditions Template in the Building Template Manager. Select the Building Template Manager (from Tools or the <VE> Templates Menu):

Set the NCM Building Type in the actual building Thermal Conditions Template:

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Set the NCM Activity in the actual building Thermal Conditions Template:

In the System tab, choose the system type for the actual building:

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Applying thermal conditions templates Once your thermal conditions templates are complete, you should apply them to the building as appropriate.

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Renewables If required, you can choose to use renewable energy (PV, wind energy) or CHP.

Building Settings By choosing the regulatory route Building Type, the NCM templates (activities/system/constructions) for the Actual and Notional building are created. It is only after this point that the Room Data for the Actual building can be viewed and (in some instances) edited.

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Viewing the actual building room data Room data is accessed for the actual building in the same way as all the Thermal Applications. The difference in <VE> Compliance is in whether the data being viewed is editable. Room data is accessed by selecting the Room Data Query button.

The rules for room based data are as follows:

Notional Building: all data is determined from BRE/CLG rules therefore data can not be edited, but can be viewed.

Actual Building: room conditions, internal gains, activity profiles (except lighting) and Air Exchange data are determined from BRE/CLG rules, therefore some data can only be viewed but not edited, and other data should not be edited.

Actual Building: Building Regs data, lighting data and HVAC system data can be edited via the Room Data Query button.

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In the Building Regs tab you can change the building area type and activity and the NCM lighting data controls (if “NCM simple lighting control” is enabled in the lighting defined in the Internal Gains tab).

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NCM lighting data Certain activity types will also have display lighting associated with them. A new requirement in the 2010 regulations is to have a display lighting efficacy of at least 22 lumens/circuit watt. Occupancy and Photoelectric controls play an important role in reducing the energy consumption of a building. If you wish to use NCM simple lighting controls, details of any control measures should be specified here.

In the System tab you can set ventilation and exhaust data and specify if there is Demand Controlled Ventilation (DCV).

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Lighting gains You can edit lighting gains here using various input modes.

For compliance purposes the Full Design Lighting data MUST be entered. For EPCs where less information regarding the building design is known, it is permissible to specify the lighting efficacy or simply the lamp type

As with all other thermal applications, grouped room data can be changed using the Edit Group Attributes facility.

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Viewing the Notional building If you wish you can view the notional building and its associated data.

Setting the Building and System data

Submission of the calculation of building regulations compliance is via a Building Regulations Certificate generated by a BRE tool BRUKL that generates the Appendix A Checklist from ADL2. Further data is required to fill in this checklist. This data includes:

Details of the building, the building occupier and certifier

Predicted air leakage data

Management feature adjustments

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Setting the Building Details

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Simulation settings Also in the Building and System Data dialogue is the Simulation Settings tab.

The assessment procedure for both the actual and notional building is via two separate ApacheSim dynamic thermal simulations. The options for these two simulations need to be assigned here. The actual building can use the following model links to take into account energy efficient mechanisms modeled using the detailed procedures in other <VE> modules:

Solar shading analysis (SunCast Link)

Natural Ventilation (MacroFlo Link)

Special systems (ApacheHVAC Link)

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Performing Part L2 compliance calculations Three criteria can be assessed by IES’s Part L2 software using the ApacheSim method: Criterion 1: CO2 Emissions Criterion 2: Limits on Design Flexibility (U value limits and performance of building services systems). Criterion 3: Limiting the Effects of Solar Gains in Summer Criterion 1 produces a synopsis of the BER and TER emission rates (CO2 Emissions test) and assesses whether compliance is met. A pass or fail for criterion 1 will be displayed within the <VE> interface. Criterion 2 is assessed when a Criterion 1 test is performed. If Criterion 2 fails (for U-values for instance) the Criterion 1 test will be disabled until the Criterion 2 problem is resolved; in this instance by changing the construction properties. Criterion 3 assesses whether solar gains in zones exceed benchmark limits.

You will be shown how to perform the compliance calculation:

Criterion 1 results will be displayed.

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Creating the compliance document You will be shown how to generate the BRUKL (the BRE tool for creating Appendix A compliance checklists) document outlining the five criteria for Part L2 Building Regulations compliance.

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A Technical Data Sheet is included in the compliance document, showing global parameters, data for the actual and notional building and the building use categories.

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Reviewing Criterion 3 data and results

You can review the data results from a Criterion 3 check in a report format:

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Viewing results in Vista (optional)

Depending on the IES licences you have purchased, a further option is available to investigate the dynamic simulation results for both the notional and actual buildings. Results can be interrogated in Vista, and a summary report generated, showing compliance results and comparison of data for the actual and notional buildings.

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If you wish, compliance simulation results files can be further interrogated in Vista using the graphical, tabular and range checking features. Results files for reading in Vista have a naming convention as follows:

a_FILNAME.aps: actual building results for the CO2 emissions test

n_FILNAME.aps: notional building results for the CO2 emissions test

s_FILNAME.aps: actual building solar gain check results

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Creating Energy Performance Certificates (EPCs) using the ApacheSim method You will next be shown how to generate EPCs (Energy Performance Certificates) for your building, using the ApacheSim method. For EPC generation, three versions of the real building are automatically created in the <VE> Compliance tool; the ACTUAL building, a NOTIONAL building, and REFERENCE building. First we will select the ApacheSim - EPC method, then we will select the Part L2 compliance route.

Most of the data used to prepare the building for EPC generation via the ApacheSim method (including site location, constructions, systems, templates and regulatory route Building Type) is the same as for the Part L2 checks via the ApacheSim method.

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However, in the NCM System Data Wizard, the System Controls tab needs to be completed accordingly.

Viewing the Notional, Reference or Typical buildings If you wish you can view the Notional or Reference buildings and their associated data.

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Setting the Building and System data

Submission of the EPC certificate requires further data. This data includes:

Details of the building, occupier and certifier

Management feature adjustments

Simulation settings

EPC Recommendation data

Setting the general data

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Setting the Building Details With the ApacheSim method you can modify the building air permeability.

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Simulation Settings

The assessment procedure for the actual, notional and reference buildings is via three separate ApacheSim dynamic thermal simulations. The options for these simulations need to be assigned here. The actual building can use the following model links to take into account energy efficient mechanisms modeled using the detailed procedures in other <VE> modules:

Solar shading analysis (SunCast Link)

Natural Ventilation (MacroFlo Link)

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EPC Recommendations settings Here you can choose which recommendations will be incorporated into the Recommendations Report.

You can add your own recommendations in addition to the automatic recommendations. You may wish to run an initial EPC generation so that you can first determine what recommendations to suggest, and then enter them before generating the final EPC.

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We are now ready to generate the EPC:

Once the three separate dynamic thermal simulations are complete, the results will be displayed within the <VE> interface showing the following CO2 emission rates: the Target Emission Rate (TER, calculated from the Part L2 notional building), a Standard Emission Rate (SER, created for EPC calculations) and the Actual building Emission Rate (BER). From NCM methodology, the Standard Emission Rate (SER) is calculated from the Reference building Emission Rate (RER) as follows: SER = RER *0.765 Asset Rating bands (A+ to G) are shown for the Part L (TER) building and the Actual building. The Asset Rating value for the Actual building is displayed. Asset Rating values for a particular building type are calculated as: Asset Rating = (emission rate of that building type / Standard Emission Rate) * 100/2 Hence the Asset Rating (EPC rating) of the Actual building is: Asset Rating of the Actual building = (BER/SER) * 100/2

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Viewing the Energy Performance Certificate (EPC) You will next be shown how to view the EPC. The EPC also shows the asset rating for a Typical building (typical of existing UK stock).

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Viewing the Recommendation Report (and Supplementary Report) You will see how to view the Recommendation Report (and Supplementary Report). The Recommendation Report contains recommendations for improving the rating of the building (if applicable).

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Archiving your <VE> project (creating a .cab file) You will be shown how to archive and subsequently extract your <VE> project by creating a .cab file. This is useful if you wish to transfer your project easily to another PC (eg via a memory stick) or to send it via email.

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VE-DSM Workflow To aid users to perform compliance analyses a set of workflows is available to assist users through an analysis. Workflows prompt users through a logical workflow to ensure no step is omitted. Navigators also act as a QA tool tracking the progress of a project and recording when and who completed an action. Notes can be recorded at each action as a reminder to the user or to convey information to other team members.

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IES <VE> Compliance Accreditation Once you have had your IES Part L2 and EPC training and have gained some experience in the use of the software, you can sit the IES <VE> Compliance Accreditation exam (backed by CIBSE, BRE, ecmk, Elmhurst and Stroma). <VE> Compliance Accreditation enables successful candidates to enroll as an Energy Assessor with one of these Schemes. For further information, please visit the Compliance>Accreditation area of the IES website. Frequently asked questions (FAQs) Naturally, questions will arise when you first use the IES software. Examples are:

Why do I fail the criterion 2 U-value check?

Why does my CO2 emission rise when I improve my U-values?

What are the system efficiency parameters? You can view FAQs via the support area of the IES website.

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Appendix A – Key Changes in Part L2A 2010

The Target Emission Rate

Much of the difference between Part L2A 2006 and Part L2A 2010 stems from the change in calculating a Target Emission Rate (TER). Under the 2006 Regulations the TER was calculated based upon a 2002 Notional Building with a series of Improvement Factors applied. Under the 2010 regulations the Notional Building is the Target. There are however, significant differences between the old and new Notional Buildings, making the TER harder to achieve.

The Notional Building Form

The form of the Notional building has changed. Where under the 2002 framework the Notional Building had both Windows and Rooflights, the 2010 will have one or the other and be determined from the assigned activity. This reduced glazing area will reduce both heating and cooling loads in the notional building.

The Notional Building Fabric

The Notional Building will have much more stringent fabric properties than in the old Notional Building. As the Notional building now forms the target, if the Actual building design does not have comparable fabric properties it will need to make up the deficit elsewhere in the design. 2006 values:

2010 values:

As well as improved fabric properties the Notional Building will also have an improved Air Permeability of 5m3/h.m2 @ 50Pa

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The Notional Building Systems The system efficiencies for the Notional building have in many instances improved significantly from the previous Notional Building. Some indicative examples include the following:-

System 2006 Notional 2010 Notional

Gas Boiler – Space Heating 73% SCoP 79.2% SCoP (63% bio)

Gas Boiler – DHW Heating 45% SCoP 83.6% SCoP (66.5% bio)

Elec heat pump heating 265.5%

Space Cooling 167% SSEER 360% SSEER

Heat Recovery Effectiveness

0% 70%

Mechanical Vent SFP 2 W/l/s 1.8 W/l/s

A significant change in the Notional building’s system performance is that the Notional building is no longer restricted to gas or oil. Generally the Notional building will adopt the same fuel type used within the Actual building. This is likely to have significant consequences for buildings employing systems such as biomass boilers as they will not receive the same credit that they currently yield.

Notional Building Lighting Gains

The method for establishing the notional Lighting Power Density has changed significantly since the 2006 Regulations. Under the previous regulations the Notional building would use a Lighting Power Density (LPD) of either 3.75 W/m2/100 lux or 5.2 W/m2/100 lux depending on the space usage. Under the new regulations a curve based on the ratio of wall to floor area is used. Under this methodology, open plan zones will have the most stringent targets feasibly as low as 2.11 W/m2/100 lux. Conversely smaller cellular zones will have easier targets to achieve and in some cases have less stringent targets than the 2006 Regulation methodology. In addition to the reduced LPD’s the Notional building will now incorporate dimming control and also display lighting in certain spaces depending on their activity assignment.

Carbon Emission Factors (CEF)

Between the 2006 and 2010 Regulations, Carbon Emission Fuel factors have been changed in Compliance calculations. A summary of these changes can be seen in the table below. These have been highlighted to indicate which values have risen and which have fallen. Fuel 2006 Part L2A (kg.CO2/kWh) 2010 Part L2A (kg.CO2/kWh) Biomass 0.025 0.013

Biogas 0.025 0.018

Waste Heat 0.018 0.058

Natural Gas 0.194 0.198

Dual Fuel 0.187 0.206

LPG 0.234 0.245

Fuel Oil 0.265 0.297

Anthracite 0.317 0.318

Smokeless Fuel 0.392 0.344

Coal 0.291 0.350

Grid Supplied Electricity 0.422 0.517 Grid Displaced Electricity 0.568 0.529

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The increase in the CEF for grid supplied electricity is much greater than the CEF increase for other fuels. This could mean that the overall Emission rate will be more weighted more by its Electrical demands than in the previous regulations. There is now a much smaller difference between Grid supplied and Grid Displaced Electricity. This will mean that Renewable technologies won’t generate as great a carbon saving as they would have

done under the 2006 regulations.