Design Modification of Domestic Solar Water Storage Tank with Central and Circumferential PCM for Performance Improvement

Abstract

This study experimentally investigates enhancing a domestic solar water storage tank's thermal performance by integrating phase change materials (PCMs) in central (C-PCM), circumferential (A-PCM), and dual (C+A-PCM) configurations. A control tank without PCM was used for comparison. Results demonstrated that the circumferential PCM arrangement (A-PCM) performed optimally, improving heat retention by 73% over the control due to its superior surface-area-to-volume ratio, which extended hot water availability. The dual-PCM system offered only a marginal gain of 8% over the A-PCM configuration, while the central PCM (C-PCM) lagged significantly due to limited thermal interaction. These findings align with previous research on annular PCM geometries. Economically, the high initial capital cost for PCM integration remains a challenge. However, the system's projected payback period is 2.3 years, with a lifetime return on investment exceeding upfront by 220%, indicating strong long-term viability. The study concludes that a circumferential PCM configuration is the most effective and economically motivating design for improving thermal energy storage in residential solar thermal systems.