A University of California-Davis contest to build more energy-efficient air conditioning has led Trane to launch a new product.

The challenge spurred the manufacturer to build a rooftop air conditioner that is 40 percent more energy efficient than conventional units, according to Trane officials.

Trane is the second manufacturer to achieve Western Cooling Challenge certification. The challenge, established in 2008 by the U.C.-Davis Western Cooling Efficiency Center, aims to help manufacturers develop more efficient cooling technologies, particularly for hot, arid climates like California. The program also helps building owners install and use those products.

Trane achieved certification for the Voyager DC, a hybrid rooftop air conditioner that uses indirect, evaporative cooling to increase cooling capacity and reduce peak electrical demand. 

“Since air conditioning is the largest portion of electricity used during hot weather, the potential for 40 percent savings is enormous,” said U.C.-Davis Western Cooling Efficiency Center associate engineer Jonathan Woolley. “Many are not yet aware that new electric utility rates will saddle commercial building owners with large additional charges for power used during peak periods. Trane’s Voyager DC met our performance goals on the mark, and promises to be one of the most cost-effective, climate-appropriate cooling technologies available for commercial buildings.”

Much as sweat cools the human body, the Voyager DC uses water evaporation to cool outside air for the condenser on an otherwise conventional air conditioner. The air conditioner then uses the water chilled by evaporation to cool the hot outside air used for building ventilation. Such techniques increase the number of hours a system can use “free cooling” to cool a space, and reduce the amount of time a system has to operate at full speed. In addition, the Trane Voyager DC incorporates variable speed fans, staged compressors, and other measures to maintain high-efficiency rates.