Boston — You've heard about the sun so hot you could fry an egg on the sidewalk. Well, now there is talk about using the sun to fry something else -- potatoes. And not only that, but to concentrate orange juice, dry fish fillets, and evaporate milk as well.
Solar energy -- already harnessed to heat homes and water -- is making heat waves in the food processing business, the seventh largest user of industrial energy in the United States, according to the Department of Energy (DOE).
Under a four-year-old, experimental DOE program, sun power is now being used -- or is planned to be used -- to French-fry potatoes at an Ore-Ida plant in oregon; to heat water to wash soup cans at a Campbell's Soup plant in California; to thaw blocks of frozen orange juice at a Tropicana plant in Florida; and to process sugar on Hawaiian plantation.
The projects, which are being done on a demonstration scale, are part of a push to find ways solar power can be used in industry, which accounts for 40 percent of US energy consumption, according to DOE statistics. (Food processing makes up 5 to 10 percent of industrial usage).
Although researchers say sun-powered food processing is still costlier than the gas and oil methods used today, they maintain than it is one of the best applications of solar energy.
And they predict that within 20 to 30 years -- as fossil fuel prices continue to rise and solar technology is further developed -- solar power will be widely used within the food processing industry.
"When it becomes economically feasible, or, in grass-roots terms, when a guy can do it and make money from it, it'll be done," says Dr. Robert Berry, who coordinates several small-scale solar projects funded by the DOE and administered by the US Department of Agriculture (USDA). "As fuel prices increase, you're going to see more and more food processors turning to solar energy sources."
Under the DOE program, more than a half-dozen model programs have been funded for an estimated $1 million each since 1976. Another four proposals costing approximately $2 million each were recently approved for partial funding.
Although the DOE supplies the money and organizes the experiments, it is up to private solar designers to bid for the projects, and to supply a detailed proposal for a system -- as well as to find a food processor willing to let a portion of his plant be used as a guinea pig.
And while the experiments have provided valuable data, there remain many kinks to be ironed out. At Goldkist Soy in Decatur, Ala., for example, where a solar energy collector installed as part of a DOE experiment in drying soybeans has been turned over to, and is still operated by, the company, officials do not plan to expand their use of sun power.
The reason, according to Max Madison, a company manager: the expense of installing new collectors and the fact that solar power doesn't dry soybeans fast enough for Goldkist, which processes 7,000 to 9,000 bushels of beans per hour.
But at TRW, the California firm which is designing the solar power system for French-frying potatoes, widespread industry interest has already been expressed -- even though the Ore-Ida project is not expected to begin operation until October.
According to Jack Cherne, TRW's manager of solar energy, a series of ads ("Introducing Solar French Fries") which ran in several national magazines last fall prompted some two dozen phone calls from other French fryers interested in finding out more.
In addition to these projects, the DOE has joined with the USDA in sponsoring 10 small-scale solar energy projects aimed primarily for use on the farm.
The experiments -- being funded for $50,000 each -- are being developed at universities across the country. They include: a University of Washington, Pullman, project which uses the sun to pasteurize apple and grape juice; a Michigan State University experiment which involves using already-existing solar technology to run a dairy farm; a University of Florida, Gainesville, plan to dry and smoke fish with sun power; and a University of Massachusetts, Amherst, project that uses solar energy to concentrate orange juice and cool lettuce.
And for the do-it-yourself solar enthusiast, the USDA has written a booklet on how to build a home fruit-and-vegetable solar dryer for just $10.