Water Tank Stores Fireplace Heat

Water Tank Stores Fireplace Heat ENERGY Wood Burners (65) 33-1-32 Ted Boice's fireplace keeps his house warm long after the fire has gone out, thanks to a 140-gal. hot water storage tank. A heatilator blows heat into the living area, while a heat exchanger transfers heat to a tank. There the heat is stored until needed to warm his 1,060 sq. ft. home. "I haven't bought propane to heat my house for 15 years or more," says the retired Montanan. Wood use is minimal too, running only half a cord of wood a month. Boice's cement block home is designed for energy efficiency with the rear side built into 6 to 7 ft. of dirt, heavily insulated walls, and high-grade windows. Boice's heat exchange coil is made out of 1-in. stainless steel pipes that feed steam to brass pipes and then copper. He uses lengths of rubber heater hoses periodically in the system to cut down on electrolysis between the steel and copper and to give some "slack" in the system. He acknowledges that if he used antifreeze in a closed system, he wouldn't have needed stainless steel. The coil itself is a "ladder" of 14 1-in. pipes that lay beneath the burning wood. When water in the coil reaches 160 degrees, cooler water is pumped through it to the water tank in a utility room at the back of the house. With entrance and exit points well below the surface of the water, air in the pipes is not a concern. "The water temperature in the tank stratifies," says Boice. "The top can be so hot that I can't keep my hand in it while the bottom will be 80 degrees. After heating a while, it will be hot all the way to the bottom, and then I'll shut down the fireplace." He usually heats the water in two 4-hour spans to 140 degrees or more. The open top tank prevents pressure from building in the pipes. At the same time, it serves as a constant source of passive heat release to the house. When the temperature in the living area drops, such as overnight, a fan kicks in, moving warm air from the utility room throughout the house. "The surface of the water tank never gets below 80 degrees during the winter," says Boice. He also designed the heatilator system in his fireplace. Fans switch on when air in the tubes at the back of the fire reach 90 degrees. As the fire burns down and the temperature in the tubes drops below 90 degrees, the fans shut down. "It's not rocket science," he says. "You can build a heatilator into almost anything and capture heat that would just go up the chimney." Boice's system was built at practically no cost, with a friend doing the welding and providing the steel in exchange for use of a trailer. Even the thermostat for the heatilator was salvaged from a furnace. Contact: FARM SHOW Followup, Ted Boice, 540 McIver Rd., Great Falls, Montana 59404 (ph 406 452-5713).

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