Experimental investigation of circular flat-panel collector performance with spiral pipes
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The performance of solar water heaters can be enhanced via a number of different methods. One such method involves altering the geometry of the collector. In this study, a symmetrical flat-panel solar collector with circular geometry has been experimentally evaluated. The collector has an area of one square meter, is free of risers and features spiral tubes that flow into the collector from the side and exit from the center. The collector was tested according to ASHRAE standards in Aghajari, southern Iran. The experiments focused on quantifying the efficiency and thermal performance of the collector at various conditions, such as different water flow rates and solar radiation. The results show that, like other flat-panel collectors, the collector efficiency increases with increase in water flow rate and solar radiation. The efficiency increase in this collector is higher than that of rectangular collectors owing to the presence of secondary currents. Furthermore, the maximum efficiency of this collector is around 75.3%, with a maximum temperature difference between the inlet and outlet of around 19 °C. This study offers a simple way to improve the performance of solar water heaters.
KeywordsExperimental investigation Solar collector Efficiency
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