Experimental Investigation of Salt Hydrate Phase-Change Material (Shape-Stabilized) Applied to a Solar Collector

A complex element of water heater by solar power involves the requirements of storage tank, which not only occupies considerable space but also adds complexity to the plumbing and installation procedures; this research marks the initial endeavor to practically utilize shape-stabilized (SS) phase-change material (PCM) within a tank-less, evacuated tube with direct absorption (ET-Direct Absorption) solar collector. The primary objective was to tackle challenge of storage of the solar power. A PCM (salt hydrate) was proposed, with different component concentrations explored to determine the most effective mixture. Once the optimal compound was identified, it underwent rigorous testing over numerous cycles to ensure its sustainable its storing capabilities. Additionally, the planetary system was charged in dormancy mode (without flow of water) and subsequently discharged at the rate of flows of 15, 25, and 35 liters per hour (LPH). Results indicated a noteworthy improvement in efficiency of the heat system in the stasis mode, which increases from 62 to 80% with the utilization of this heat storing cum collecting unit. Moreover, it was observed that transitioning from a rate of flow of 15–25 LPH had minimal impact on the collector’s heat gain, but using a rate of flow of 35 LPH significantly reduced efficiency of discharge.