Accuracy of the European solar water heater test procedure. Part 2: Prediction of long-term performance

Abstract

This paper continues the evaluation of the European test procedure for solar water heaters, by considering what consequences the errors of the parameters (derived in Part 1, the companion paper) will have for the prediction of the long-term performance. A simple criterion is derived for the required length of the test period, as a function of climatic variables and desired accuracy of the long-term performance prediction. Typically a duration of 10 to 50 days will suffice. Since the actural conditions during a test cannot be foressen, it will be more efficient to calculate the error of the long-term performance prediction on line at the end of each test day and terminate the series whenever acceptable accuracy is reached.