Simple validation method of a TRNSYS model for a thermosyphon solar water heating system

A thermosyphon solar water heater consisting of two flat plate collectors of total aperture area of 2.7 m² and 150-lt storage tank is modelled using TRNSYS. Simple experiments were conducted in order to validate the model. During the experiments, the weather conditions were measured every 10 minutes and integrated over an hour. The temperature of the water in the storage tank is also measured at the beginning and end of the day. The storage tank temperature rise was used to validate the model by using the actual weather data as input to the program. Validation tests were performed for 25 days spread over 6 months and the mean deviation between the predicted and the actual values of water temperature rise is 4.7% which is very satisfactory.