Effect of novel PCM encapsulation designs on electrical and thermal performance of a hybrid photovoltaic solar panel

Abstract

Encapsulated phase change materials (PCM) are used to improve the electrical efficiency of photovoltaic (PV) panel by absorbing waste heat during the melting process. Previous investigators reported the melting process of PCM in a rectangular encapsulation and observed four transient regimes of heat transfer in sequence as: conduction, mixed conduction-convection, quasi-steady convection and solid-shrinking regimes. For higher heat extraction from the PV panel, longer duration of quasi-steady convection regime is desirable. However, this steady regime is suppressed in the rectangular PCM enclosure due to the nature of natural convection and consequently, the melting rate of the PCM is arrested. In this paper, we report on electrical and thermal performance of non-rectangular PCM integrated PV panels using an experimentally validated numerical model that enhances the quasi-steady regime by more than 100% compared to the conventional rectangular design. The strategic mass distribution of PCM for better thermal management was achieved with encapsulation designs having profile of right wall varying as y=ax-b1/n,withn=1(linear),2(parabolic)and3(cubic) with different lower thickness ratio. Compared to conventional design, the proposed design increased the PCM melting rate by 17% due to which PV cell temperature dropped by 11.5% and consequently, electrical conversion efficiency approaches to 12%.