A typical meteorological day (TMD) approach for predicting the long-term performance of solar energy systems

A method for predicting the long-term performance of solar energy systems, based on the analysis of system performance for one particular day-the typical meteorological day (TMD)-is presented. The TMD is constructed from the cumulative time distribution of insolation values on the collector aperture. The TMD method requires little calculational effort and a small data base relative to standard yearly computer simulations. Good agreement is found between the predictions of the new method and the corresponding results of the F-f-chart method. The TMD method is of particular value for cases that may often be treated inaccurately by simple calculational methods: (1) high threshold problems; (2) systems with short response times (e.g., due to small storage); and (3) systems in which collectors other than flat plates are used (the method is applicable to all solar collector types).