Abstract:
A survey on different methods for rating the thermal performance of solar collectors in transient conditions has been made. Two inexpensive methods (Saunier's and Exell's) have been selected for an extensive comparative study. The methods are discussed in detail and test sequences are explained. The methods are applied to a flat-plate solar collector, and their output results are compared with the steady state ASHRAE standard. It is seen that a very good estimation of collector performance characteristics could be obtained from Saunier's method, but Exell's method may not be suitable for testing conventional collectors. Results of not more than 7% deviation from steady state values are obtained from Saunier's test despite some inconveniences in conducting the tests. (C) 1997 .