Solar Power for Hot Water Heaters

Water Panels

• Solar water panels are completely different than solar electric panels. While solar electric panels are made of silicon and convert sunlight into electricity, solar water panels are constructed of pipes through which water flows so that it can be heated directly by the sun. The pipes that the water flows through are contained within an insulated box that is topped with a clear sheet of glass or plexiglass to increase the trapped heat around the pipes. Solar panels are connected directly to the interior plumbing system of a house, and, with the exception of pumps to move the water, are completely separate from the domestic electrical system.

Preheating

• In most climates, solar hot water panels can't supply 100 percent of domestic water heating needs. Particularly during the winter and at night, other forms of energy to heat water are needed. Water enters the domestic plumbing system, runs through the solar hot water panels where it is heated to a certain extent, and then enters a conventional water heater that is usually powered with electricity, natural gas or propane.The more heat that is gained from the sun, the less work the conventional water heater has to do. When there is no sun available, the conventional water heater does all the work, just as in a house with no solar water panels.

Closed Loop Systems

• In climates where the temperature falls below freezing for prolonged periods, solar hot water systems can't have water running through externally mounted panels or the water will freeze and cause damage. Instead, an antifreeze solution is run through the external panels and then run through a heat exchanger that transfers the heat from the antifreeze solution to the water.While systems such as these are more expensive and complicated to install, they work nearly as well as a direct water heating system.

Insulation

• Good insulation is critical to the effective functioning of a solar hot water heating system. Without insulation, the heat that is gained from the sun will simply escape through gaps and cracks and the water will not be heated sufficiently. By insulating the interior conventional water heater, all of the pipes through which the hot water flows and the solar hot water panels themselves, you can greatly increase the efficiency of your solar hot water heating system.