| About 3% of all US energy consumption is | | | | three. Most active water heating systems consist |
| dedicated to the activity of heating water. | | | | of various pumps, controls, and valves. The idea |
| Weather in industry or in the household, water | | | | behind active solar heating systems is to pump |
| must be heated for all sorts of necessary | | | | water through these solar collectors on the roof |
| activities. Fortunately, solar heating is the most | | | | for it to be heated. The water is then pumped |
| efficient and cost effective of all of the solar | | | | back to a holding tank to be used by the |
| technologies. Depending on what kind of system | | | | household. Some systems have a solar powered |
| you use, solar water heating can be about 60% | | | | pump to run the water through the collectors. |
| efficient. In its simplest form, this technology is | | | | There are three types of active solar water |
| the idea of exposing a water container to sunlight | | | | heating systems: drain-down, drain-back, and |
| to heat the water up. But solar water heating | | | | closed loop antifreeze systems. Each of these |
| systems range in complexity. | | | | systems varies in complexity and maintenance. |
| The basic types of solar water heating systems | | | | Active water heating systems were designed to |
| are: | | | | be used in very cold climates to prevent water |
| 1) Passive | | | | from freezing. There is still a chance water may |
| 2) Active | | | | freeze in the pipes leading to and from the water |
| 3) Thermo Siphon | | | | tank, thus needing to be freeze protected. |
| The differences between these systems consist | | | | Because of the many parts to these systems, |
| in cost, complexity, efficiency, and maintenance. | | | | they require much maintenance and oversight. |
| Passive Solar Water heating Systems | | | | The Thermo Siphon System |
| Passive heating systems are characterized by | | | | These systems consist of a large water storage |
| very simple ingenuity. This system consists of a | | | | tank mounted above a solar water collector. The |
| water tank that is painted black to absorb more | | | | water collector is exposed to the sun and is |
| heat from the sun's rays. The water tank is then | | | | sealed and insulated so that the heat accumulates. |
| encased in a sealed wooden box with a big | | | | Since the heated water is less dense than cold |
| window facing south. The box is completely | | | | water, it starts to rise through pipes up to the |
| sealed and insulated to trap the heat in. This | | | | storage tank above the collector. It's a very |
| system is the most inexpensive but also the | | | | simple yet ingenious system. |
| most inefficient. It usually takes a while for the | | | | Because of the simplicity factor, most people |
| sun to fully heat up the tank. But it's the perfect | | | | today are more likely to go with a passive solar |
| system for the do-it-yourself person. | | | | water heating unit. And if you really want to save |
| Active Solar Water Heating Systems | | | | money, you can even make your own. |
| This system is by far the most complex of all | | | | |