Building ENERGY MODELLING

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Why do I need to think about energy code compliance?

Many Canadian jurisdictions require new buildings and new building square footage (additions) to conform with energy efficient design and construction requirements set out in a provincial or national energy code. In Alberta, energy code compliance is governed by section 9.36 of the Alberta Building Code 2014 (ABC) or the National Energy Code of Canada for Buildings 2011 (NECB). These codes allow for three methods of compliance: prescriptive, trade-off, or performance.

Performance compliance of a building with the relevant energy code is demonstrated by way of energy modelling. These building codes utilize relative compliance standards through comparison to a reference building. This means a proposed building’s compliance is relative to the energy consumption of the reference building.

The reference building to which a proposed building (the modelled building) is compared is intended to represent a building of equivalent size, form, and occupancy, but constructed using prescriptive code requirements for the building’s envelope, mechanical, and electrical systems.

What is Building Energy Modelling?

Energy modelling utilizes computer software to calculate the amount of energy that a building will consume. Building energy modelling software takes into consideration the properties of the building envelope, the function of the HVAC system, the lighting system, plug and appliance electrical loads, onsite power generation systems, the building’s occupancy, and schedules of operation. Production of an accurate energy model requires input of accurate information that is representative to how these systems will perform once installed.

Accurately determining representative values for input into an energy model is key. This is an intricate process affected by numerous factors. Throughout the design and construction process, it is important to have a knowledgeable team such as Orata’s Energy Modelling Experts who can determine the impact of changes made during the Envelope Design and construction on performance, and by extension, the in-service energy use of the building. Inaccurate or faulty calculations by an inexperienced or unskilled consultant can lead to costly mistakes, inaccurate energy models, and unnecessary increased operating costs.

Orata’s team of experts determines whether targets are realistically achievable within the project’s scope, budget, and schedule to ensure compliance and deliver an accurate energy model to our clients.

How does Energy Modelling benefit me?

Builders often choose to energy model to demonstrate energy code compliance because it gives them greater freedom of design. Prescriptive requirements may be relaxed (or not followed) in one portion of the design if made up for by exceeding prescriptive requirements elsewhere in the design. For example, use of high efficiency mechanical equipment can provide the designer with flexibility to utilize building envelope assemblies with lower thermal resistance, which in turn decreases construction costs of the building envelope.

National Energy Code of Canada for Buildings 2011

Orata Engineering uses the ANSI/ASHRAE 140 compliant software to perform modelling of buildings that are being designed to comply with the NECB. These buildings are typically not designed under Part 9 of the ABC and require detailed scrutiny of all the building’s energy consuming systems as well as the thermal performance of all building envelope components.

Section 9.36, Alberta Building Code 2014

To conduct performance compliance analysis within section 9.36, Orata Engineering uses software that is better suited for application to the residential construction that is typically regulated by Part 9 of the ABC.

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If you would like to learn more about Orata Engineering and our full selection of services including Energy Modelling, speak with an expert today!  As Calgary’s premier building science engineers, we are happy to answer all of your questions.