How Solar Water Heater Work How Solar Water Heater Work
For a homeowner interested in reducing their dependence on the power and natural gas grids, solar water heaters are a cost effective form of renewable energy and a relatively easy way to enter the world of solar power. A solar water heater can be built or purchased for a relatively low cost, either as a primary or secondary water heater.
To understand how a solar water heater works, it is helpful to imagine a hot car on a summer day. Bright sunlight shining into the car causes the temperature in the car to rise. Similarly, sunlight shining on a solar water heater will raise the temperature of water. Solar water heaters include systems that compensate for overcast days. The hot water produced by a solar water heater can be used for showering, dishwashing, and other daily chores that require hot water.
Step 1 - Solar Collectors
Every solar water heater contains a solar collector. A solar collector is the portion of the water heater that collects the sun's rays and heats the water. Collectors can be affected by weather and location, so many different types of collectors exist to compensate for these conditions. Generally, solar collectors consist of glass or metal tubes that are heated by the sun. Water is pushed through the tubes, and the heat of the tubes is diffused through the water.
Circulation systems move the water through the collectors. Active circulation systems use electric pumps, valves, and controllers to force water through the collector. Passive systems use natural convection to move water through the collectors.
Solar water heaters usually contain a tank that stores the water after it has been heated. Since a solar water heater is dependent on the sun, it will heat more water on a sunny day than on an overcast day. Hot water stored in the tank will compensate for days when less water is heated.
Savings and Benefits
Solar water heaters can be used to supplement an existing water heater or as a stand-alone water heater system. Either option will save you money on your gas or electric bills - usually at least $200 per year. Large families with greater hot water needs will save even more money. Federal tax credits can help offset the price of a solar water heater, and some states also offer state tax credits. A quality solar water heater will last twenty years on average, far longer than a standard gas or electric water heater.