Solar-Power Innovator Who Weathered Booms and Busts

By STEPHEN MILLER
Using his family as human guinea pigs, George Löf created two of the first solar-heated homes in America. A voluble apostle for all things sun-powered, he was known to hand out plastic Fresnel lenses -- the kind used to start fires with the sun -- imprinted with his name like a business card.
Mr. Löf, who died Oct. 12 at the age of 95, conducted his first experiments with solar-power homes during World War II. The heat-transfer technologies he pioneered are part of many of today's solar-heating systems.
Colorado State University
Mr. Löf had to dismantle the solar-heating system on his first house in order to sell it.
Mr. Löf built two solar-heated homes for his family at a time when such systems were all but unheard of. For decades, Mr. Löf's solar research found little practical application beyond the homes he constructed himself. It wasn't until the 1970s, when soaring oil prices spurred interest in alternative energy, that he sought to commercialize the technology he had developed.
His first forays into solar research were financed by U.S. War Production Board grants, a wartime effort aimed at oil conservation. He relied on those grants to add a solar-heating system to his home in Denver in 1945. It consisted of a large glass roof panel and a series of pipes that led to a cache of gravel in the basement. Energy from the sun produced hot air that then heated the gravel. The gravel stored the heat, which was then used to heat the house. Mr. Löf reported that his oil use dropped about 30%.
Mr. Löf next built a home around the technology instead of retrofitting an old one, and reported even higher fuel savings. But solar heating was so unusual that he ended up having to dismantle the system on his first house in order to sell it.
Still, Mr. Löf saw a bright future in solar power, and in 1955 he predicted that within two decades 13 million homes would be solar-heated. The actual number turned out to be a tiny fraction of that -- perhaps around 5,000, according to one estimate.
Born in 1913 in Aspen, Colo., when it was still a mining town, Mr. Löf was the son of a country doctor who had emigrated from Sweden. He studied chemical engineering at the University of Denver and earned a doctorate at Massachusetts Institute of Technology.
Mr. Löf taught chemical engineering first at the University of Colorado and then for two decades in the 1950s and 1960s at the University of Denver, where he was director of an industrial research institute.
In 1967, Mr. Löf moved to Colorado State University, where he went on to found the Solar Energy Application Laboratory. Led by Mr. Löf, scientists on the project built a series of demonstration houses that they said were the first to be both heated and cooled by the sun. Cooling works by using solar-heated water to drive a chemical refrigeration unit, or by chilling a pebble bed with cool night air.
The SEAL project allowed engineers to compare the efficiency of different solar technologies and develop industry standards. The scientists found their research to be in hot demand, as interest in solar heating surged in response to the oil shocks of the 1970s. Federal tax credits authorized during the administration of President Jimmy Carter added to the boom.
"There were a lot of hucksters out there selling bad systems," said Byron Winn, a Colorado State engineering professor who worked with Mr. Löf. "George was a gentleman in every sense but not at all reluctant to point out when there was snake oil out there."
Eventually, Mr. Löf decided to pursue commercial applications of his research, founding Denver-based Solaron Corp. in 1974 to design and install solar-heating systems in homes and farms.
More than 100,000 homes nationwide had solar-heating systems by 1980, according to U.S. Department of Energy statistics, and it looked like the industry was set to take off. But the tax credits were allowed to lapse in 1985 as oil prices retreated, and demand for solar panels withered. Mr. Löf's Solaron filed for bankruptcy in 1987.
While Mr. Löf focused primarily on home heating, he sought to develop other applications for his research, including, most notably, a solar cooker. Crafted from metallized plastic sheeting and shaped like an umbrella, his solar cooker's precise parabolic form focused the sun's rays, creating enough heat to broil a steak. Mr. Löf joked that it would cook in the sunshine, and act as an umbrella in the rain. But the "Umbroiler," as he dubbed it, was a commercial failure.
Mr. Löf worked on other solar cookers that were distributed in developing countries by Unesco, and he patented a system for using solar heat to distill freshwater from seawater.
The family home Mr. Löf built in Denver became a model for emerging solar home heating systems and attracted engineers from around the world.
Other than replacing occasional cracked glass panels on the roof, the system needed virtually no maintenance, and was still going strong at Mr. Löf's death, more than half a century after he had installed it, his son, Larry Löf, said.
Write to Stephen Miller at stephen.miller@wsj.com