A solar water heating system, in theory, is a very simple water-heating system that consists of a solar collector and a storage tank.  You have two choices of the type of solar water heating system to use: 1) an active system with circulating pumps and controls, or 2) a passive system without circulating pumps and controls.

The foundation of a solar water heater is a well-insulated storage tank with an additional outlet and inlet connected to and from a solar collector. Systems come in a two-tank version and a one-tank version. If you chose a two-tank system, the solar water heater works to preheat water that, after heating, enters your conventional water heater to pump that hot water into your home.  A one-tank system combines the back-up heater with the solar storage unit in one tank but basically works the same as the two-tank version and takes up less space. 

If you chose to go with an active solar water system, you can install either a direct circulation system which works to pump circulated household water through collectors into your house and works well in locations where the temperature rarely dips below freezing; or an indirect circulation system that has a pump that circulates a non-freezing, heat-transferring fluid through collectors and a heat exchanger into your house and works well in freezing climates.
 
As for passive solar water heating systems, these are usually less efficient than the active ones and less expensive as well.  But, on the plus side, passive systems are more reliable and last longer than their active counterparts.

For a passive system, you have two basic choices, integral collector-storage or thermosyphon systems.  The integral collector-storage passive system works best in climates where freezing doesn’t occur often and in households in which the occupants use their most significant amount of hot water in the daytime and evening.  With a thermosyphon system, the water flows through the collector by warm water rising in the solar take as cooler water sinks. Consequently, the collector in a thermoshpon system must be installed below the storage tank so the warm water rises into the tank.  A reliable system, a thermoshpon system requires the use of tanks that are heavy, are more expensive and a bit of a challenge to find a location where they fit, if you have a steep roofline on your house.

While solar water heating systems are fuel-efficient, you will need a backup system for times of increased demand of hot water or on cloudy days.  Most people who use a solar system have a conventional storage water heater as a backup.  In fact, solar system installation companies typically offer packages that include a backup system to accompany their particular solar water heater products.

Post provided by:  Water Heater Plumbers Marietta, GA