Overview Dynamic Modelling Tools

Scottish Energy Systems Group www.sesg.strath.ac.uk

Overview of computational tools for

building regulation compliance

Ya Liu


Approved software for compliance

• To calculate the energy performance of buildings and demonstrate compliance with the Building Regulations, only software that has been approved by the Department for Communities and Local Government (CLG) can be used.

Domestic: SAP (Standard Assessment Procedure) 2005

SBEM (Simplified Building Energy Model)

Accredited dynamic simulation software

Non-domestic:



• For non-domestic buildings

iSBEM (v2.0.c)

Carbon Checker (v1.2)

Hevacomp (v23.0)

IES VE (v5.8.1)

Designbuilder (v1.4.0)

DigitalEnergy (v1.0.12)

ECAT (v6.0)

Approved interfaces

Calculation engine

SBEM

Compliance

Part L2 (England & Wales)

Section6 (Scotland)

Part F2 (Northern Ireland)



• For non-domestic buildings

EnergyPlus engineApacheSim

Accredited dynamic simulation software

Dynamic simulation for compliance with Building Regulations:

Part L2 (England & Wales)

Section6 (Scotland)

IES VE (v 5.8)EDSL TAS (v 9.0.9) Hevacomp (design simulation v2)

TAS engine



• For domestic buildings

Part L1 (England &Wales)Section 6 (Scotland)Part F1 (Northern Ireland)

SAP 2005

Approved interfaces

EES SAP Calculator v013NHER plan Assessor v3.0SuperHeat v6.20JPA Designer v4.02SAPPER v7.2Knauf Insulation SAP2005 Calculator v 2.0

Scope for building regulations

Compliance



• For domestic buildings

Part L1 (England &Wales)

Approved interfaces

Hevacomp SAP 2005 v23.0IES VE v 5.6MAXIM5 v1.1BuildDesk v1.3Lifespan SAP2005Cymap 2008

Part L1 (England &Wales)Part F1 (Northern Ireland)

Scope for building regulations

Thermica v1.0

SAP Calculator v3.1 Part L1 (England &Wales)Section6 (Scotland)


1. Calculation method

Dynamic building simulation with a user-specified time step (down to 1 minute as needed)

IESTASHevacomp

Quasi-steady state calculation based on monthly energy balance to obtain annualenergy results (Microsoft Access application)

SBEM

Main differences between approved software

Note: IES – IES VE v5.8; TAS – EDSL TAS v9.0.9;

Hevacomp – Hevacomp Design Simulation v2


2. Climate data

CIBSE Test Reference Year (TRY) climate data for criterion 1 (CO2 emission) and CIBSE Design Summer Year (DSY) climate data for criterion 3 of Part L2 (overheating risk).

These sets of hourly historical weather data need to be licensed from CIBSE

IESTASHevacomp

Monthly climate data incorporated in the software covering 14 UK cities

SBEM



3. Geometry

3D graphics based geometry input: • drawing 3D model directly• importing a CAD plan as a template for drawing walls, creating windows and doors.

IES CAD import: DXF, gbXML and Revit connectionTAS CAD import: DWGHevacomp CAD import: DXF

IESTASHevacomp

No graphic approach in iSBEM. Enter dimensions of building zones in the interface. Can use 3rd party to get graphical inputs to SBEM calculations.

SBEM



4. Orientation

Unlimited orientations

IESTASHevacomp

8 orientations: north, south, east, west,northwest, northeast, southwest and southeast.

SBEM



5. Views of buildings

Views of both actual and notional buildings are available.

IES

Views of actual building are available.TASHevacomp

No images of actual building and notional building in iSBEM. Can view buildings through 3rd party Interfaces

SBEM


Actual building notional building

(Note: Pictures are provided by IES)


6. Air infiltration rate

Infiltration rate can be set up for each zone, which is used for simulation. Building air permeability is only used for BRUKL checking. Conversion from air permeability to infiltration rate can be calculated using CIBSE Guide method.

IESTASHevacomp

No input for air infiltration rate. Instead, building air permeability (m3/hr/m2 at 50 Pa) is introduced to calculate air infiltration rate.

SBEM



7. Solar shading

Internal shading: Mainly curtains and blinds

External shading: External shading devices/surrounding buildings or obstructions can be set up for shading calculation based on each time step of the simulation.� Shading devices can be controlled based on internal air temperatures and occupancy schedules.

TAS

External shading:• Movable solar protection shading system is only considered for calculation.• No consideration of the shading effect from ground, trees, other buildings and building itself (L-shape)• transmission factor = partial shading correction factor for overhangs X partial shading correction factor for fins

SBEM



7. Solar shadingLocal shading devices: balcony, overhang and fin which can either be defined or be modelled as obstructions.

Internal shading devices: curtains and blinds

External shading devices: shutter and Louvre which can either be defined or be modelled as obstructions.

�Both internal and external shading devices can be controlled based on internal air temperature and occupancy schedules.

IES



7. Solar shading

Internal shading: curtains and blinds

External shading:• external shading devices, such as overhangs, fins and shutters etc can either be defined through its shading device library or be modelled as part of construction.• Surrounding buildings can be modelled as obstructions.

�Both internal and external shading devices can be controlled based on internal air temperature and occupancy schedules.

Hevacomp



8. Natural ventilation

Natural ventilation can be calculated in two ways:• Additional Free Cooling Flow CapacityIt indicates the maximum intake of outside air that is available for free cooling, whose value represents the additional outside air intake over and above the minimum ventilation level.

• MacroFlo linkControl window openings according to internal air temperatures and occupancy profiles

IES

Assumed value based on standard occupancy for each zone.

SBEM



8. Natural ventilation

Natural ventilation is modelled by using EnergyPlusmulti-zone air flow model. Mixed-mode operations can be simulated.

Hevacomp

Natural ventilation can be modelled by openingwindows/vents to control internal air temperatures. It has wind and stack driven bulk air flow simulation integrated with the building simulation.

Additionally, it can simulate mixed-mode ventilation.

TAS



9. Avoidance of summer overheating (criterion 3 of Part L2 for England & Wales)

Can be done by predicting the number of hours that exceed targets.

IESTASHevacomp

Not available. Use additional software or other methods e.g. CIBSE TM37

SBEM



10. Daylighting

Do daylight simulation to obtain daylight factors. With these daylight factors daylight available in the zones for each hour of the year will be calculated, which will then be used with a range of switching and dimming controls to determine lighting energy use for each hour.

IESTASHevacomp

L solar (light transmittance) is used for daylighting calculations.L solar = f (T solar, reduction factor)SBEM


Window shading system

Thermal transmittance(glass type)


11. Lighting and lighting control

Lighting is handled differently due to the nature of dynamic thermal simulation. Sensors can be placed in zones and a wide range of switching and dimming controls allow complex controls to be modelled at each time step of the simulation.

IESTASHevacomp

A dedicated lighting dialogue allows for a range of lighting control options to be specified at a basic level.

SBEM



12. Plant system• Pre-defined types of plantsystem• Editable plant performanceparameterse.g. seasonal heating/cooling energyefficiencies, heat recovery efficiency

• Plant performance is calculatedbased on total annual heating and cooling loads and plant performance parameters, such as Heating Seasonal Coefficient of Performance (SCoP),Seasonal System Energy Efficiency Ratio for cooling (SSEER) and auxiliary energy efficiency.

SBEM



12. Plant system

• Individual plant components system can be set up.• Plant system is dynamically modelled using plant part load efficiency curves.

Hevacomp

• Individual plant components system can be set up.• Hourly dynamic plant simulation is carried out.

TAS

• Similar pre-defined types of plant system as those in SBEM• More editable plant performance parameters, e.g. auxiliary energy efficiency, heating/cooling delivery efficiencies, heat rejection pump & fan power• No dynamic modelling of plant components involved.

IES



13. Renewable technologies

•Solar panelsSolar conversion data, inclination, parasitic power, manifold to air temperature difference, 3D model

• PV (Photovoltaic)Power generation curves, power reduction, panel aging, inverter efficiency, 3D model

TAS

• Wind generatorsTerrain type, diameter, hub height and power and number

• Solar panelsArea, orientation, inclination and number

• PV (Photovoltaic)Type, area, orientation, inclination and number

SBEM



13. Renewable technologies

• Wind generators • Solar panels • PV (Photovoltaic)Hevacomp

• Wind generatorsSet up your own power curve

• Solar panelsArea, Azimuth, tilt, shading factor, degradation factor, conversion efficiency at ambient temperature, flow rate, pump power, heat exchanger effectiveness, first/second order heat loss coefficients and solar panel storage cylinder

• PV (Photovoltaic)Type, degradation factor, shading factor, electrical conversion Efficiency and performance parameters from PV array type

IES



How do results from different tools compare?

Identical building model

SBEM Accredited dynamic tools

IES TAS Hevacomp

Compliance checking

Results ?

• CIBSE TM33 Tests –standard tests for the assessment of building services design software

• EN ISO 13791 – Thermal performance of buildings (General criteria and validation procedure)

• NCM (National Calculation Method)


How do results from different tools compare?Guidance stated in NCM:

“ Certain advanced building features are currently not well represented in SBEM. It is difficult to give

absolute rules about when SBEM can and cannot be used, but as broad guidance, the results of using SBEM

are likely to be less robust if the building and its systems have features that are

• not already included in iSBEM (or for which acceptable approximations have not been demonstrated)

• have properties that vary non-linearly over periods of the order of an hour

In such cases, an accredited simulation tool will need to be used to demonstrate compliance.

The following are building features that iSBEM /SBEM does not represent very well at present. If these are

significant in respect of the performance of the proposed building, then an alternative approved tool should

be used.

• Night ventilation strategy • Automatic blind control

• Ventilation with enhanced thermal –coupling to structure

• Demand-controlled ventilation • Variable speed pumping

• Light transfer between highly glazed internal spaces such as atria or lightwells ”


Thanks for your attention.

Overview Dynamic Modelling Tools

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