A METHOD FOR ESTIMATING THE LONG-TERM PERFORMANCE OF DIRECT-COUPLED PV PUMPING SYSTEMS

A method is developed to predict the long-term performance of direct-c oupled PV pumping systems. The method uses only information available from the PV module and pump-motor manufacturers. Weather data are ''ge nerated'' from monthly averages of horizontal radiation and ambient te mperatures using well-known weather data statistics. The method predic ts monthly pumped water to within 6% of TRNSYS predictions based on ho urly weather data. The use of a single monthly-average day is shown to underpredict monthly pumped water at low monthly average radiation le vels and overpredict monthly pumped water at intermediate radiation le vels. Only at high radiation levels does the use of a single monthly-a verage day provide a reasonable estimation of monthly pumped water. (C ) 1998 Elsevier Science Ltd. All rights reserved.