Publication Details
Issue: Vol 3, No 9 (2026)
Pages: 21-31
ISSN: 2997-9382

Abstract

This research contributes to improving the efficiency of a fully evacuated glass-tube solar water heater using phase change material. Paraffin wax utilized as the PCM. A theoretical investigation was performed to evaluate the thermal behavior of the system, which is integrated with a thermal energy storage system operating under solar thermal flux. Two separate cases were studied; without the PCM and with the PCM. The theoretical evaluation involved modeling the hourly change in tank water temperature from 6:00 AM to 12:00 PM. In both cases, system performance was analyzed using energy efficiency, quality of the consumed energy, and the hot water supply temperature. The results indicated that the maximum temperature reached to 71°C when using the PCM, compared to the case without the PCM, it was 60°C.
Furthermore, the overall energy efficiency improved from 57.1% for the system without PCM  to 62%, for the system with PCM. This significantly improvement in energy storage and system's performance.

Keywords
solar water heater PCM Evacuated tube solar collector energy efficiency