Solar hot water - cost-effective solution for wineries(2)
The collector consists of a thin sheet of thermally stable copper to which a black or selective coating is applied, and a grid or coil of copper tubing held in an insulated casing with a glass or polycarbonate cover. Fluid is circulated through the tubing to transfer heat from the absorber to an insulated water tank.
Heat transfer to the hot water tank may be achieved directly, or though a heat exchanger. In the latter system, pumps circulate fluid through the copper tubes inside the collectors. This heated fluid then moves through a heat exchanger (either internal or external) to an insulated tank, where the fluid heat is transferred to potable water. This solar pre-heated water is then fed into the building regular water heater, reducing the amount of fuel (natural gas, electricity, or propane) typically used to heat water.
Some advantages of solar thermal systems are: Very high liquid temperatures may be achieved; By concentrating sunlight, these systems can get better energy efficiency than simple solar PV cells; During cloudy conditions and overnight, insulated tanks can store fluids heated by the collectors;
Materials and installation time are less expensive than solar PV;
●50 flat-plate solar thermal collectors on Kunde Family Estate south-facing roof send hot glycol to a 1,040-gallon water storage tank inside the winery, heating enough water to cut the winery annual bill for natural gas by half.
●14 solar thermal collectors on the rooftop at Williams Selyem Estate Winery face due south on tilt racking to catch maximum solar exposure. Inside the collectors is copper piping filled with glycol to collect the heat, and send it down into the building hot water system.
