An impact of phase change material type on photovoltaic-thermal collector performance and economy: A comparative study

Abstract

Hybrid and renewable energy systems, particularly photovoltaic technologies, play a crucial role in combating climate change. Integrating phase change materials (PCMs) into photovoltaic-thermal (PVT) systems offers a promising approach to improving thermal management and energy efficiency. The behavior of various PCMs was investigated using numerical analysis to identify an effective solution for the thermal management of PVT collector system design. Based on the empirical investigations and the validated, comprehensive numerical model, the study delved into the PVT collector’s performance under unstable weather conditions when subjected to different phase change materials. The impact analysis of phase change materials included assessing the PVT collector’s thermal behavior, electric performance, and the economic feasibility of implementing PCMs. The research utilized the Ansys Fluent software for simulating thermal behavior, while electrical output was modeled using the Shockley diode equation, yielding results in strong agreement with experimental data. Four organic PCMs were analyzed: pork fat, RT58, RT35, and n-octadecane. Involved materials cover a wide melting range, different latent heat levels, and unit costs. In terms of thermal performance, n-octadecane proved to be the best, considering that the PVT collector was up to 6.1 °C cooler than other designs at peak heat load. Consequently, based on the estimation of electrical outputs, the design with n-octadecane generated the most electricity, 1,037 Wh. However, the electric power production for all designs was within a 1 % difference, therefore emphasizing the importance of the economic aspect. The pork fat PCM proved to be most economically feasible by a large margin with a calculated levelized cost of energy in the amount of 0.0692 € kWh⁻¹. However, its relatively low latent heat and wide melting range might be limiting factors for a thermal component of the PVT system. These findings underscore the trade-offs between thermal performance, electrical output, and economic feasibility in selecting the most suitable PCM for PVT applications.