Energy, Exergy and Efficiency Analysis of a Flat Plate Solar Collector Used as Air Heater

Air heating by solar collectors is renewable technology providing hot air for different purposes. The present research emphasizes on analysis of energy, exergy and efficiency of a flat plate solar air heater. The analysis model was tested on five different air mass flow rates of 0.5 (Natural), 1.31, 2.11, 2.72 and 3.03 kgs(-1) under three different tilt angles of 25, 35 (Recommended) and 50 degrees. The data was replicated three times making a total of 45 treatments. A two factorial completely randomized design was used to find if there is any significant difference among the treatments. The results showed that the solar collector gave better performance at air mass flow of 3.03 kgs(-1) under tilt of 35 degrees. At maximum air mass flow rate of 3.03 kg s(-1) and optimum tilt angle of 35 degrees the maximum energetic efficiency of 51%, while minimum exergetic efficiency of 24% and maximum overall efficiency of 71% were recorded. It was concluded that to get maximum thermal efficiencies of 71% from flat plate solar collector used as an air heater must be operated at high air mass flow rates of 3.03 kg s(-1) under 35 degrees tilt angle at Peshawar, Pakistan.