Understanding Solar Thermal Systems

In the simplest solar thermal application, one or more solar collector absorbs solar radiation and converts it to heated air or water for domestic, commercial or industrial use. The solar collector is typically a flat plate panel that consists of a metal box with a glass or plastic cover and a special black absorber plate at the bottom.

Solar collectors are usually mounted on the roof oriented towards the true-south at an appropriate angle, and are connected to a circuit containing water with propylene glycol (anti-freeze). The heated liquid flows through the circuit with the aid of a pump typically supplied with energy with a small photovoltaic module attached to the collectors. The heated liquid is stored into a solar water storage tank that then feeds in-floor heating systems or the hot water tank.

This method of capturing solar energy is the most economical available, offering the quickest return using the simple payback method, often in the range of 5 - 6 years.

References

1. Natural Resources Canada. "Solar Water Heating Systems - A Buyer's Guide". 2003.
2. David L. Ryan. "Getting into Hot Water". Summer 2005.
3. C. Aguilar, D.J. White, and David L. Ryan. "Domestic Water Heating and Water Heater Energy Consumption in Canada". Department of Economics, University of Alberta. April 2005.