2012 - Volume #36, Issue #4, Page #14
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Solar Unit Keeps Dairy In Hot Water
“With my creamery, I’m required to have 145-degree or hotter water all the time,” says Trantham. “The well water comes out of the ground at 50 degrees. Even on a cloudy day this winter, the Microsolar unit would bring it to 120 degrees, and my gas water heater did the rest. As the months have passed, it’s been getting even more efficient.”
With an on-farm creamery and dairy store, Trantham has more hot water needs than most 85-cow, grass-fed dairies.
“My milk only travels 48 ft. from the cows to bottles,” he says. “It’s full fat (not homogenized) and I use a low temperature (145-degree) pasteurization process that leaves the milk tasting better.”
While processing his own milk products has increased profits, it also increased his need for hot water. When sterilizing storage tanks, bottling lines and other equipment, he boosts water temperatures to 160 degrees.
The two rooftop Microsolar units have 75-gal. insulated, stainless steel tanks at the top of solar collector units. Well water passes through heat exchangers in the tanks on its way to the creamery’s 100-gal., propane-heated, hot water tank.
The Microsolar unit uses a “thermosyphon” design. Each tank is heated by water moving through 20 triple layer, parallel glass tubes. The innermost layer is a 20-mm diameter tube that runs inside a 47-mm black glass tube from the bottom of the storage tank down the slope of the unit. The black glass tube is surrounded by a 5-mm vacuum layer and a 58-mm glass tube.
As the sun strikes the collector, water in the middle tube absorbs the heat and begins to rise toward the tank. Cold water in the tank is siphoned down through the innermost tube to replace the rising hot water.
“It’s the tube within a tube that makes the units so efficient,” says Larry Jordan, American Microsolar. “There’s no mixing of hot and cold water and no dead spots. Water only moves through the collection tubes if it’s warmer than water in the tank.”
The heating tubes are mounted between a double glazed upper layer glass panel and nickel chrome mirror finish floor panel. Solar rays not absorbed by the tubes as they pass through are reflected back at the underside of the heating tubes.
Jordan says the units retail for around $4,250.
Contact: FARM SHOW Followup, American Microsolar, 100 Helmsman Way, Suite 114, Hilton Head Island, S.C. 29928 (ph 843 422-6018; www.americanmicrosolar.com) or Happy Cow Creamery, 332 McKelvey Rd., Pelzer, S.C. 29669 (ph 864 243-9699; www.happycowcreamery.com).
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