ESTIMATION OF COLLECTOR PERFORMANCE PARAMETERS FROM DAILY SYSTEM TESTS

A test procedure to estimate the daily mean values of the linear colle ctor characteristics, F-R(tau alpha) and FRUL, from the measured varia tion of the storage tank temperature was investigated The Levenberg-Ma rquardt algorithm was used for parameter estimation. Two fiat-plate co llectors were tested over a period of II days each to study the feasib ility of the test procedure. The tests were conducted under variable w eather conditions and infer water temperatures. The standard deviation for the daily mean values of F-R(tau alpha) and FRUL were about 2.8 p ercent and 4 percent, respectively. The differences between the daily mean values obtained by the proposed method and the steady-state test values for F-R(tau alpha) were about 4 percent to 7 percent, while for FRUL the differences were 9 percent to 13 percent.