Comparative performance analysis of dual spiral and parallel riser tubes in solar flat plate water heater with and without reflector: an experimental study
摘要
Flat plate solar collectors (FPSCs) are fundamental in water heating. They are easy to build, cost-effective, and need minimal upkeep. The efficiency of traditional FPSCs is subpar. To boost efficiency, a detailed study of specific designs is necessary. This study utilized modified dual spiral-shaped tubes instead of the standard plain riser tube. They were evaluated using three distinct mass flow rates: 0.35 lm−1, 0.5 lm−1, and 0.7 lm−1. The highest instantaneous efficiency observed was 70.8% at a mass flow rate of 0.7 lm−1, indicating a 13.7% improvement in efficiency compared to the conventional FPSC. The modified collector attained maximum instantaneous efficiency when the outlet water temperature reached 53.4 °C. Again impact of reflector mirrors on heat transfer enhancement was tested with a fixed mass flow rate of 0.5 lm−1 in two separate days employing with and without a reflector in the modified collector. The optimum instantaneous efficiency achieved is 63.75% and 60.64% using with and without a reflector, representing 11.54% and 8.89% improvement in efficiency compared to the conventional FPSC. The modified collector reaches its peak instantaneous efficiency at an outlet water temperature of 70.8 °C when equipped with a reflector, and at 69.2 °C when the reflector is not used.