Those big rooftop heating and cooling systems you see on supermarkets and strip malls could produce big savings for building owners. New research has found that commercial building owners can chop their heating and cooling costs nearly in half by implementing a few energy efficient controls.
Researchers at Pacific Northwest National Laboratory in Richland, Wash., studied buildings across the country. They used computer simulations to find an average savings of 25 to 35 percent after retrofitting existing heating, ventilation and air conditioning systems, also known as HVAC. One small office building in San Francisco saved 67 percent.
Srinivas Katipamula led the study. He says milder climates typically saw more cost savings. A supermarket he studied in Seattle saved 28 percent. That’s above the average for supermarket savings nationwide. Researchers looked at four different types of buildings:
- Stand-alone retail, like Home Depot or Walmart
- Strip malls
- Small office buildings
Katipamula says 60 perecnt of commercial buildings around the country use these types of HVAC systems.
“If half of those units that are operating now were retrofitted with this particular technology, you could avoid 16 power plants that are about 200-megawatt size,” he says.
HVAC systems often use more energy than is needed because they are often neglected, Katipamula says. Researchers studied four different control methods to help improve energy efficiency:
- Air-side economizers: These are currently mandated by some building codes. They make use of colder temperatures outside to cool buildings, “economizing” the energy used.
- Supply fan speed controls: Monitor ventilation fans so that once a building reaches the temperature you want, the fans do not continue running.
- Capacity controls: Multiple HVAC compressors can vary speed along with ventilation fan control speed.
- Demand-controlled ventilation: Systems can match ventilation needs based on the number of people inside. That means HVAC systems only use energy that is needed, instead of constantly running full-throttle
These retrofits are costly and in rare use. But Katipamula hopes demonstrated savings will convince building owners to install these energy saving methods.
“One of the biggest issues with commercial buildings is that the tenant is not the owner in most cases,” Katipamula says. “So the owners tend to install equipment that is less expensive or least costly. But they consume more energy.”
That leaves tenants footing unnecessarily large bills, he says. Most of these retrofits would pay themselves out after three years, Katipamula says. The HVAC systems can last up to 15 years.
Katipamula hopes to work with larger retailers that are a part of the Department of Energy’s Commercial Building Energy Alliance. That includes large, national businesses that usually own their buildings, providing a financial incentive to upgrade, Katipamula says.
Researchers are beginning to install retrofits to existing buildings, including one at Pacific Northwest National Laboratory. They hope to find out if actual savings match the computer simulations.
“I think there will be significant savings can get if people deploy this technology en masse,” Katipamula says.