Solar Water Heaters

How do they work?

The solar collectors are usually a flat metal box with pipes inside. These pipes, which are often made of copper, are attached to a metal sheet which is painted black to help it absorb the sun`s heat. The top of the box is covered with a sheet of glass, and the box is insulated to reduce heat losses. There are several variations on this type of collector, including an all-plastic collector, and collectors made by several manufacturers filled with a special anti-freeze liquid that transfers heat into the water.

When the sun shines on the collector panels, heat is absorbed by the water in the collector panel’s pipes. As the water heats up, it starts to rise up the pipes, in the same way that hot air rises. When it gets to the top of the collector panel, it flows out of the panel and back into the storage tank. Colder water from the bottom of the tank then flows down to the bottom of the collector panels. Water continues to cycle through the system, and on sunny days can easily exceed the temperature required for home hot water.

The water storage tank is similar to that of most gas or electric water heaters. The tank is usually made of either stainless steel or enamel-coated mild steel, though some tanks are made of copper or even plastic.