Abstract:
To study the performance of flat-plate photovoltaic/thermal system. The thermal side is a sheet and tube type using water to transfer heat. The panel area is 0.79 m² and connected to the insulated tank which storage 120 litres of water. The test divided in two cases, the small-size circulating pump was used in the first case and the natural circulating in the second case. The panel system was installed on the roof deck of building 5 in Chulalongkorn University at the angle of 15 degrees to the horizontal plane and facing the south direction. The important parameters that affect the system are solar intensity, initial water temperature, inlet water temperature and ambient temperature. The data were collected during 8.00 AM-4.00 PM in two minutes interval and convert the data into hourly and daily basis. Then the daily data was used to calculate thermal efficiency and electrical efficiency. The efficiency equation was obtain as ηth = 0.2532 -0.0579 (Ti-Ta)/H and this equation is applied to calculate the annual thermal energy. The average thermal efficiency was 25%. The electrical efficiency was also obtain as ηel = 0.0306-0.0105 (Ti-Ta)/H. The average electrical efficiency was 3% and average total system efficiency was 28%. For the calculation of yearly energy that received from the system on the solar intensity and ambient temperature data of Thai Meteorology Department at Bangkok station since December, 2010 to November, 2011 is used. The result showed that the average thermal energy and electrical efficiency was 1,023 MJ and 127 MJ respectively.