what is a solar thermal/hot water system and how does it work?

A solar thermal/hot water system consists of panels of evenly spaced evacuated (vacuum) tubes that collect solar energy and convert it into usable heat. Free energy from the sun is used to heat water for use in floor heating or showers, laundry, sanitation, pools, and more--or to run space heating systems such as radiators. Solar thermal/hot water can be used in homes, businesses, education or medical facilities, municipal buildings, and other places.

Solar thermal panels are installed where sunlight can reach them anytime it’s sunny outside. When the tubes are exposed to the sun, its energy heats up a copper heat transfer pipe inside each tube. Heat travels up the tube and warms water running along the top of the panel through a copper “header” pipe. A pump circulates this water through the copper header pipes, heating it throughout the day for use inside the building. This same system can also be used to heat buildings with radiant heat.

To learn more about solar thermal basics, visit this page on the US Department of energy web site.