Key points are not available for this paper at this time.
In residential and industrial areas, a flat plate solar collector (FPSC) is an important technology that allows for direct solar energy utilisation for heating water. Conventional FPSCs have relatively low efficiency. More study is needed to increase the efficiency of FPSC by using novel designs. Modifications to the design of solar collectors are always a viable option for improving thermal efficiency significantly. In this study, dual spiral-shaped flow tubes were constructed instead of the usual flat plate solar collector's number of riser tubes and headers and tested with three different mass flow rates (0.0058, 0.0083, and 0.0117 kg/s). The optimum instantaneous efficiency achieved is 70.8% at a flow rate of 0.0117 kg/s, representing a 13.7% improvement in efficiency compared to the conventional collector. The modified collector achieves its highest instantaneous efficiency when the outlet water temperature is measured at 53.4°C. The modified collector improves heat transfer by increasing surface contact area of water and increasing the flow residence time. This results in a higher absorption of heat by the water, leading to a significant enhancement in the efficiency. When all other parameters are kept the same as in a conventional design, highly encouraging results in modified solar collector have been recorded.
Kumar et al. (Tue,) studied this question.