Solar thermal energy collectors

The collector is a key part in a solar thermal heating installation. The following sections discuss the working principle of collectors, and the most common collector types. Most relevant for the application in domestic hot water and space heating systems are glazed flat plate and evacuated tube collectors. A collector should be selected based on the quantity and quality (temperature) of the demanded heat.

In principle, heat gain and loss mechanisms in different collector types are the same. In general, one differentiates between optical losses (reflection, absorption) and thermal heat losses due to heat transfer mechanisms (conduction, convection and radiation). Figure 3.9 shows the mechanisms for a flat plate collector (FPC).