Thermal Management Performance of Phase Change Material Coupled with Heat Pipe for Photovoltaic Modules: Experimental Exploration

Solar photovoltaic (PV) power generation has become an important source of global renewable energy. The photoelectric conversion efficiency of crystalline silicon PV modules decreases as their surface temperature rises, while excessively high operating temperatures can also affect their service life. Therefore, reducing the temperature of photovoltaic modules is one of the effective methods of enhancing their photoelectric conversion efficiency. Passive thermal management methods, such as the use of phase change materials (PCM) and heat pipes (HP), can be used to control the temperature of PV modules, but they manifest the problems of poor thermal conductivity and low heat transfer efficiency at low heat flux density, respectively. On the other hand, previous experimental studies have mostly focused on small-scale non-standard PV cell modules, without considering encapsulation and installation issues in practical applications. Meanwhile, passive cooling technology exhibits strong regional characteristics, with significant variations in temperature control and energy efficiency improvements under different climatic conditions. To address these issues, this paper proposes a novel PV module temperature control unit that couples PCM and HP. Standard commercial PV cell modules are used as experimental subjects, and tests are conducted in four different regions of China to study the adaptability and effectiveness of the coupled PCM and HP control method. The experimental results show that the power generation pattern of PV modules is consistent with the variation in solar radiation intensity. When the operating temperature of the PV module is below 40 °C, the high thermal conductivity of the heat pipe plays a dominant role in dissipating heat. When the operating temperature of PV rises above 40 °C, the phase change material begins to play a role in heat storage and temperature control. Compared to using PCM alone for temperature control, the coupled method further enhances the cooling effect, preventing a sharp temperature increase after the PCM has completely melted, and increases the power generation of PV by 4–5%. The temperature control effect of the PV module is influenced by local ambient temperature and wind speed. The coupled temperature control method exerts a relatively low improvement effect under high-temperature and low-radiation environmental conditions, but it performs better when used under low-temperature and high-radiation environmental conditions.