Thermal Performance Analysis of Thermosyphon Solar Water Heating System Using Overlapped and Reverse Flow.

A suggested absorption tube was designed for a thermosyphon solar water heating system (TSWHS) to enhanced the ability of the solar receiver to capture solar energy. The proposed design was based on overlapping and reversed flows, and its correctness was confirmed by conducting experimental simulations of the incident solar radiation and projecting heat flux on the proposed receiver tube models (Rt). Five receiver tube models were proposed as the standard, designed, and manufactured models which were tested under constant boundary conditions for all modeled flow rates (100, 150, 200, and 250 mL), flow directions (px and py), and constant heat flux. The most favorable thermal enhancement outcomes were achieved with the Rt4 model that exhibited a thermal efficiency of 70.5%, featuring an inner tube diameter of 12 mm and outer tube diameter of 35 mm, incorporating a py flow path. The selected model (Rt4) was employed, utilizing a py flow path for manufacturing the flat-plate collector (SRT2). The model was then compared with a normal model (SRT1) through Tests that were conducted for each model under similar weather conditions. The thermal gradient within the horizontal tank displayed an improvement by increasing 17% in heat transfer compared with the normal model. [ABSTRACT FROM AUTHOR]