Annual Efficiency - Easy Understanding of Collector Performance
Abstract
The Solar Keymark certification with the now mandatory data sheet 2 shows an annual collector output for reference locations and reference conditions. This enables the determination of a new parameter called annual efficiency a (m) for collectors, which is typical for the respective climate zone and the belonging temperature level or applications with this temperature requirement. A study of the range of collectors available on the market from the simplest non-selective to the high vacuum collector at various locations worldwide shows an almost linear dependence of the annual efficiency on climatic conditions. This confirms that annual efficiency is a technical parameter that determines the performance of collectors. It can be used as a simple and single parameter for comparisons in a first selection process without the need for complex simulations. Moreover, a comparison to the efficiency of PV is possible too. Keywords: Solar Keymark, annual collector output, annual efficiency