Performance of solar collectors - An evaluation of standard ratings

This paper is a critique of the Solar Energy Industry Association (SEIA) Collector Rating Method and Directory. Yearly average collector output values calculated using the FCHART method for a domestic water heating system with two collectors rated by SEIA are compared to calculated values for a domestic water heating application using SEIA certified data and recommended procedures. Results indicate that both collector energy output and relative output vary substantially from FCHART predictions and vary with location and system size. It is concluded that use of the SEIA rating method in its present form is a very poor method of selecting a solar collector; suggestions for improving the rating method are included.