Image Courtesy of Sefaira Systems
Light Load Sefaira Systems compares peak loads and mechanical system size between several building models or iterations to find the best fit.
Image Courtesy of Sefaira Systems

A new web-based tool, Sefaira Systems, combines the U.S. Dept. of Energy's building-energy- modeling simulation program, EnergyPlus, with 3D models to quickly analyze mechanical systems and building-envelope options during a project's early stages.

"Our chief engineers used to calculate all these loads and would crunch through processes and make their best assumptions," says Brian McGuire, director of building-information-modeling services, Edwards and Zuck Consulting Engineers, New York City. McGuire's firm tested London-based Sefaira Inc.'s software before its Jan. 15 release. "Sefaira Systems can make these calculations in real time," he says.

The tool performs its heating, ventilation and air-conditioning (HVAC) analysis in the cloud on modeling programs such as Trimble's SketchUp and Autodesk Inc.'s Revit. Its quick interface lets engineers work directly with the architects' BIM data without using more complex software to rework the model.

"The HVAC system is usually about 10% of a cost of a building budget," says Andrew Corney, product manager for Sefaira. He has 12 years of experience as an HVAC designer. "On general projects, the HVAC engineer will use his experience and give a number that will carry pretty much any architectural form," says Corney. That process can lead to over- or underpriced bids.

Corney sees a push in the industry for improved information during the early stages of a job. That's when he sees Sefaira as being most useful. He says it's not as comprehensive as some of the highly detailed solutions that typically are used later in the building process and often require specialists to operate.

"We're focusing on a product that can be accessible to a wider number of users and engineers," says Corney.

From a project's 3D model, Corney can quickly get the chiller and boiler capacity and air-handling and heat- rejection systems data. When he applies different building materials or changes the envelope size, the calculations readjust in seconds, allowing HVAC options to be dialed up or down accordingly, he says.

Sefaira Systems costs $2,999 per user. Users log on to Sefaira's web-based interface with a user name and password.