Performance enhancement of flat plate solar collector system with eutectic form phase change material

The utilization of flat plate solar collectors (FPC) is widespread in the field of solar power, but their intermittent nature due to fluctuating solar radiation and unavailability at night poses a challenge for consistent thermal output. Various organic phase change materials (OPCMs) are limited in their thermal properties, but eutectic options could improve the stability of the system. An experimental analysis considering the influence of eutectic organic phase change materials (EO-PCM) and expanded graphite-based composite eutectic organic phase change materials (EG-EOPCM) integrated with a FPC water heating system has been carried out for solar collector application for day and night. For the present analysis, Beeswax and PEG1500 are considered as PCM, and eutectic mixture developed with varying percentage of each PCM. Form stable material developed having both PCM separately and in its eutectic form are added with Expanded Graphite to develop Form stable O-PCM and EO-PCM. PCM properties are identified considering solid and liquid density and for thermal behaviour DSC test was conducted. Using PCM leads to a greater and more consistent output temperature, as seen by the exit temperature profiles of water. For both Eutectic and form stable eutectic system the water supply at night was around 48-50 degrees C, but duration for maintaining the temperature at that level is more in case of EOPCM's with Form stable EOPCM's provided leak proof system. While comparing PCM's, PE20BW80, PE40BW60, EGPE40BW60 and EG-PE20BW80 have been founds more suitable. The outcomes demonstrated that FPC was able to supply warm water for an extended time when PCM was used. The results indicate the increment of daily efficiency, while having O-PCM, EO-PCM and EG-EOPCM. The efficiency of a collector with a mixture of 60 % PEG and 40 % beeswax was significantly enhanced by 15.45 % compared to a collector without PCM.