We have been working with and installing thermal solar water heaters for about 30 years. In that time, we have seen some good ones and some bad ones. Here, in Costa Rica, this is the best we have found in terms of efficiency and durability.
Consists of three basic elements:
1. A solar collector (panel), which sits in the sun on a roof or on a stand in an open area. The collector is a glass topped metal box and mounted inside is a solar absorber made of copper with copper water tubing going through it.
2. Pump Circulation systems for circulating the water from the cooler part of the tank or tanks through the solar collectors either by use of a pump. We use copper tubing in the solar loop.
3. Storage tank or tanks for holding the hot water gathered during the day for use later in the day or the next morning. These are US made imported glass lined solar storage tanks with an electric heating backup element.