Effect of simultaneous & consecutive melting/solidification of phase change material on domestic solar water heating system

The foremost challenges in heat pipe ETC are low heat transfer rate between absorber tube & heat pipe, overheating of heat pipes, and its inability to supply hot water during off-pick hours. The incorporation of latent heat storage material (LHSM) between absorber tube and heat pipe is the efficient solution to overcome these challenges. Also, along with energy and exergy analysis, economic & environmental analysis to be done to ensure whether utilization of LHSM with ETC system is viable for the commercial utility. Thereby, in this study, energy, exergy, economic & environmental analysis of stearic acid integrated ETC for two different modes (ETC/Mode-I & II) have been done and distinctly in comparison to the reference system. The daily energy efficiency of ETC/SA for ETC/Mode-I and ETC/Mode-II improved by 37–45 and 65–81% respectively, whereas, improvement in exergy efficiency was observed by 21–29 and 57–73% respectively. The positive value of NPV shows that investment in ETC/SA will be highly profitable. The ETC/SA mitigated CO₂ emission in the range of 26–37 and 8–12 tCO₂/lifetime based on energy and exergy approach respectively. Thus, ETC/SA working for ETC/Mode-II system was found to be more economical, highly energetic & exergetic efficient, and more environmentally friendly.