Consultant evaluates the pros and cons of simulation software systems for construction

Energy simulation software has come a long way in a short time to help building designers reduce the cost of energy in buildings.

Its users, too, have grown on how and when to employ that software.

Sustainability consultant Oleksandra Onisko recalls an instance about eight years ago when a building project team didn’t request energy modelling until it began the concrete pour.

Today, she gets calls for her service as early as schematic design, says Onisko, principal of Pratus Group Inc., a Toronto-based project management company. 

“It is great because it (modelling) has the ability to positively influence the design.”

She says the major components examined under modelling include building enclosures; active systems such as HVAC, electrical and lighting; hot water; renewables; and internal loads (occupants).

Onisko addressed the topic of modelling recently at the Better Built Buildings workshop organized by Sustainable Buildings Canada.  In her presentation she spoke about the pros and cons of several key simulation software systems.

She says the “most popular” system is eQuest, free software that can be used for the most complex building systems. The detailed software comes with wizards to help novice users set up models.

Being open source, eQuest allows users to link to other tools to automate parametric modelling, she adds.

But one of eQuest’s downsides is that changes to a model’s geometry are limited and the program has little technical support, Onisko says, noting users can get help with the program through online user groups.

The consultant says her company prefers to use IES Virtual Environment which offers an advanced graphic interface, ties into BIM and has a potential interface with AutoCAD and Revit.

Pratus has employed IES for contracts ranging from a 12,000 square foot building to a four million square foot multi-building development.

But while it offers “responsive technical support,” users will have to pay for the software, she points out.

Software popular in B.C. is EnergyPlus which is “partially free” but the required graphical-user interface comes at a price. The open source package is “extremely flexible” and can model complex systems such as geothermal, she says, but EnergyPlus has limited technical support.

“It is fairly complex for beginners.”  

A fourth energy modelling program is HOT2000, Canadian software tailored to single family residential.

While modelling will continue to evolve as building technology and energy regulations change, Onikso hopes the methodologies will move to standardization at municipalities and other governing agencies across Canada.  

Currently, it is a challenging for energy modelling consultants working in various regions because few municipalities request the same modelling.

She says a lot of energy incentive programs require owners to quantify savings for their buildings, a factor in why they turn to her or other energy modelling consultants for help.

“Sometimes engineers do this work to support their incentive applications.”

Much of the Pratus Group’s work is with clients in southern Ontario, including the City of Toronto which is upping energy requirements to a zero-emissions standard by 2030.

One of the company’s specialities is energy modelling for code compliance or design optimization. This includes modelling OBC SB-10, Toronto Green Standard plus retrofit and incentive analysis.

She says energy modelling in large retrofits, such as envelope and complete HVAC upgrades, is largely driven by incentive programs.

In new projects, modelling assists designers who might want to exceed the 40 per cent glazing requirement or they want other tradeoffs between the HVAC and building envelope.

Industrial warehouses such as big box projects are one of the few building types that get a pass on energy modelling requirements, Onisko points out.     

First used primarily as a tool for high-performance buildings in the 1990s, energy modelling took off in the 2000s with the introduction of programs such as LEED that required modelling performance criteria. Today, the LEED reference guide specifies modelling protocols and it provides a list of “acceptable software and how it should be done for consistency in the industry,” Onisko points out.