There are many ways to provide hot water for different uses, from heating water for home use or heating swimming pools, but it is becoming more popular to install solar water heating units to help reduce the cost. The power to operate these systems is not only free, it is also a renewable energy source and is non-polluting. The simplest way to view solar water heating is after a garden hose has been left in the sun for a short time. When the hose is first turned on, the water in the hose is warm until all of the water heated by the sun has been evacuated.
This same theory is often used for solar water heating for swimming pools, especially in areas that will not allow the use of non-renewable energy to be used to heat water for swimming pools. Coils of black plastic or rubberized tubing are exposed to the sun and water from the pool is pumped into the tubes where it is held for a short time until it reaches a certain temperature. Once it warms up it is pumped back into the pool, using solar water heating to heat the pool water.
Other systems essentially pre-heat the water by exposing a storage tank to the sun. As the water warms in the tank it rises to the top and flows out of the tank and into a traditional hot water tank, forcing colder water from the bottom of the tank into the solar water heating tank outside. This pre-heated water requires less energy to heat it for appropriate use in the household.
Flat Panel Systems Offer Even Heating
When heated pools were first thought of, solar covers were popular, allowing the sun to heat this thin layer of plastic with tiny air bubbles, focusing the heat from the sun into the water. This type of solar water heating offers even dissipation of the warm water over the entire surface covered by the plastic. The biggest problem is the heated water is mostly at the surface.
Some of the direct solar water heating systems use metal in the tanks and outdoor pipes and are very efficient at pre-heating water for the hot water tank or for supplying a clean source of warm water. The downfall of these systems is that they cannot be used in colder climates. At night, if the temperature drops low enough water in these systems can freeze, damaging the pipes or the tank.
