Forced-circulation solar water heating system using heat pipe-flat plate collectors: Energy and exergy analysis

Abstract

Seeking innovative methods is critical for efficient solar energy utilization. In this study, a promising alternative to the conventional systems is introduced by integrating heat pipes to widely used flat plate collectors as a means of heat extraction devices. It is expected that such configuration can avoid some of the drawbacks that inherently exist in the traditional flat plate collectors. Transient performance analysis was performed for a complete forced circulation solar water heating system operating with a heat pipe flat plate collector (HPFPC). In addition, thermal behaviour of the whole system and its daily energetic and exergetic performances were discussed considering hourly weather data from the coldest month of the year with the mean daily temperature of 9.56 °C in Fez, Morocco. Moreover, a simulation environment was introduced and dynamic simulations were performed to assess the overall performance under worst-case scenario. Performance factors including solar fraction, collector thermal and exergetic efficiencies were evaluated on hourly and daily basis. The simulation results were compared to the experimental results found in the literature and they showed a good agreement. These results proved that the solar water heating system was capable of maintaining reasonable thermal efficiencies of up to 33% and exergetic efficiencies of up to 4% with a daily solar fraction above 58% during the coldest month of the year in the studied location.