Hot Water Solar Panels – Cost Effective Hot Water Alternative

Tuesday, March 16th, 2010 at 12:31 am

Solar water heaters can be a cost effective way to generate hot water for homes and businesses. These heaters operate quite efficiently in any climate, and the fuel is free. They operate using hot water solar panels.

There are two systems used for this process: a passive system, which has no pumps or controls; and an active system, which has the extras. Both systems employ storage tanks and solar collectors. Either system may have one or two tanks.

The storage tank should be insulated well to hold the heat. Other than the two connections for water coming into the tank and going back out, the solar water heater has separate in and out connections to the collector. In two-tank systems, the water heats before it enters the conventional water heater, whereas in the one tank system, the conventional heater is combined with the solar storage tank.

There are three types of collectors used in commercial and residential applications.

* The flat-plate collector is a waterproof insulated box. It has a dark absorber plate under layers of glass or plastic covers. These are usually employed in swimming pool heating.

* The ICS (integral collector-storage system) has one or more black tubes in an insulated box. Cold water goes through the tubing and preheats before it enters the conventional water heater. These are only used in mild climates because the pipes might freeze in colder areas.

* Evacuated-tube solar collectors have parallel rows of glass tubes. An outer tube and absorber attaches to a fin that absorbs sun energy. The fin retards heat loss. This is an application primarily used in commercial systems.

Circulating systems can be either direct or indirect. In the direct system, pumps circulate cold water through collectors that return to the conventional water heater. This system is used primarily where freezing temperatures are at a minimum.
In the indirect system, pumps circulate a non-freezing fluid through collectors and a heat exchanger. Water then flows into the home. Indirect systems are used in colder climates.
Active water heater systems are more expensive than passive ones. The passive system is not as efficient as the active, but it tends to last longer and have better reliability.
The two types of passive water systems are integral collector-storage and thermosyphon. The former is best in areas where temperatures only rarely fall to freezing. Thermosyphon systems work on the scientific fact that warm water rises. The solar collector is positioned lower in elevation than the tank to allow the warmer water to be at the top of the tank where the outlet water line can carry it through the house.

It is necessary in almost all cases to have a backup water heating system. Typically, the conventional water heater is a part of the overall system where it can automatically kick in if the demand is greater than the solar supplied hot water.

Hot water solar panels provide a safe and effective way to heat water. They may not be practical in all applications. Before you purchase a solar water heating system, check with local plumbers and solar professionals to ascertain if it is right for you.