By Jonathan Marshall
First in a two-part series
No doubt someone out there is celebrating National Doghouse Repairs Month this July, or Restless Leg Syndrome Education and Awareness Week (July 18-25). But tens of millions of Americans, from the Central Valley to the Eastern Seaboard, are surely celebrating Air Conditioning Appreciation Days (July 3-August 15), whether they know it or not. With heat records falling all around the country, air conditioning is not just providing comfort but saving lives.
The British historian S. F. Markham observed in 1947, “The greatest contribution to civilization in this century may well be air-conditioning — and America leads the way.” Thanks to the genius of engineer Willis Carrier, air conditioning made possible the mass migration to America’s Sunbelt, the creation of high-rise financial districts from New York to Tokyo, and the building of computer data centers that form the bedrock of the Internet.
But with this amazing social impact comes a real curse to the environment. In the words of James Ferguson,
Despite all the improvements since Carrier’s day, air-conditioning remains hopelessly inefficient. In a typical unit, as much as 40 percent of the energy used is lost in the form of heat. A humming locust plague of air-conditioning plants, blasting out hot air in urban backyards and on the roofs of big buildings, are themselves significant local contributors to warming, and one reason that many cities are often several degrees hotter than their immediate environs. . . . And it contributes to global as well as local warming—according to the U.S. Environmental Protection Agency’s own figures, 3,400 pounds of carbon dioxide are emitted each year to cool the average American home.
Air conditioning accounted for 16 percent of all residential electricity demand in 2001—more than any other source of demand. And cooling consumed about 14 percent of all electricity consumption in the commercial and industrial buildings in 2003.
The good news is that dramatic energy-saving improvements are well within reach. Vendors of heating, ventilation, and air conditioning (HVAC) systems say efficiency improvements of 30 percent are achievable. But only California and Maryland currently impose the strictest standards on new installations, so progress is slow.
Even greater improvements may be technically feasible. In January 2011, the Department of Energy (DOE) joined members of the Commercial Building Energy Alliance to issue their first Rooftop Unit (RTU) challenge. It seeks to stimulate designs of commercial air conditioning system that can slash energy use by as much as 50 percent. If universally adopted, such technology could save businesses a billion dollars a year in energy costs while helping to lift the environmental curse.
“Investing in energy efficient products for commercial buildings and factories is one of the most cost-effective ways for businesses to save money and compete in the global marketplace,” said U.S. Energy Secretary Steven Chu. “The Department is proud to have helped bring together buyers and manufacturers to identify these energy saving targets and to make clear the demand for very high performance units. I’m excited to see manufacturers raising the performance bar to meet the genuine demand for energy-saving commercial air conditioners.”
Just two months ago, DOE announced that the first commercial RTU had been certified by a federal laboratory as meeting the challenge standard. Daikin McQuay says its Rebel unit exceeds the existing national standard by 84 percent under partial loads. Company spokesman J. C. Campbell tells me the key technical improvements include the use of variable speed compressors, high-efficiency fans, and large surfaces to pump away excess heat.
Businesses don’t have to rush out and buy a new state-of-the-art rooftop unit to save energy and money. Owners of commercial buildings can save an average of 38 percent on HVAC energy costs just by retrofitting existing units with advanced controls, according to a recent report by the Pacific Northwest National Laboratory. Even if half of existing units were upgraded, the energy savings would be equivalent to removing 16 coal-fired power plants, the report says.
Next: What PG&E is doing to help business customers retrofit cooling systems.
Email Jonathan Marshall at firstname.lastname@example.org.