Abstract
In the present work, exergy analysis of flat-plate solar collector is presented in details. Flat-plate solar collector is used for heating saline water, which is the first stage of water desalination process by humidification-dehumidification technique. This stage is considered as the most energy intensive stage. Accordingly, it is important to investigate its performance by using exergy analysis. The exergetic efficiency of solar heating system was examined in different ways to determine the most critical parameters that control the solar heating process. A comparison between both traditional energy (based on the first law of thermodynamics) and exergy analyses (based on the second law of thermodynamics) of a flat-plate solar heater type is carried out to show the importance of such exergy analysis and to show the limitations of conventional energy analysis. Exergy analysis gives a comprehensive and detailed behavior of solar heater performance under different conditions.