Thermal performance of solar flat plate collector using energy storage phase change materials

The present study has been carried out to improve the overall efficiency of a conventional flat plate solar collector (FPSC) using two different heat storage phase change materials (PCMs). Two grades of paraffin wax-Paraffin-P116 (PCM-1) and Paraffin-5838 (PCM-2) as PCM are selected for the analysis based on their high heat fusion rate, low thermal conductivity, and suitable phase transition temperature. The present code has been validated with experimental results and it showed a maximum error of 6.43% in predicting the water outlet temperature. Absorber plate temperature, useful heat transfer rate, water outlet temperature and efficiencies are estimated to improve the performance of FPSC with and without PCM for various flow rates (15 lph and 30 lph) with two different weights of PCM (9 kg and 14 kg) for three different locations in India, [Chennai (13.0827 degrees N, 80.2707 degrees E), Bengaluru (12.9716 degrees N, 77.5946 degrees E), and Delhi (28.7041 degrees N, 77.1025 degrees E)]. The maximum increment in the efficiency of FPSC with the use of PCM-1 is 19.59% and with the use of PCM-2 is 16.53%. Using 14 kg of PCM-1 with the conventional FPSC at water inlet flow rate of 15 lph increases the overall thermal efficiency up to 19.59% compared with conventional FPSC. The maximum increase in the percentage of efficiency with PCM-1 from conventional FPSC for different cases of 15 lph-09 kg is 16.34%, 15 lph-14 kg is 19.59%, 30 lph-09 kg is 14.57% and 30 lph-14 kg is 18.45%. From the present study, it can be concluded that the overall efficiency of FPSC is increased with the use of 14 kg of PCM-1 with conventional FPSC at the inlet water flow rate of 15 lph.