Department of Energy

HVAC Efficiency Controls Could Mean Significant Savings

April 27, 2012

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According to a new report from Pacific Northwest National Lab, commercial building owners could save an average 38 percent on their heating and cooling bills just by installing a few new controls onto their HVAC systems.

These findings mean significant potential savings for building owners who use commercial rooftop systems – but there’s just one problem: the controls aren’t currently commercially available.

Srinivas Katipamula, the PNNL engineer leading the study, says the report makes “a convincing case for manufacturers to produce more advanced HVAC controllers and for building owners to adopt these energy-saving methods.” The PNNL team hopes the report will encourage manufacturers to begin producing the four different control methods. Three companies currently manufacture HVAC controllers, but only one company offers a product with all the control options that resemble the team’s simulations. To help the manufacturer's better understand their market, PNNL's report examines potential pricing options for the controllers and how long it would take for building owners to recoup that cost. Since packaged HVACs regulate more than 60 percent of the commercial building floor space in the United States, the potential savings from retrofitting advanced controls on these systems is enormous.

The following four different control methods were considered by Katipamula and his PNNL colleagues:

  • Air-side economizers cool outside air to chill the building instead of creating cool air with the HVAC compressor.
  • Supply fan speed controls slow or speed up the ventilation fan that circulates the building’s air based on whether or not a desired temperature or amount of fresh air has been reached instead of continually running the fan at full speed.
  • Cooling capacity controls run the HVAC compressor at different speeds based on need.
  • Demand-controlled ventilation slows or speeds up fans and air intake based on carbon dioxide levels inside the building instead of running ventilation fans at a constant rate.

In general, the researchers found that installing a multi-speed fan control had the greatest impact on energy savings in hotter cities (think Miami), and demand-controlled ventilation created the best possible energy savings in colder cities like Chicago or Seattle.

For more information about the study, read the full report.