Thermal management in photovoltaic-thermal systems: advances, challenges, and cross-domain applications

• Advanced thermal management technology in photovoltaic thermal. • The improvement of the multi-faceted performance of the heat transfer medium. • Study on evaluation indicators for economic and environmental performance. • Cross-field applications of photovoltaic thermal technology. With the continuous growth of global energy demand and the urgent need to improve the efficiency of photovoltaic (PV) systems, effective thermal management of photovoltaic thermal (PVT) systems is becoming increasingly important. A comprehensive review of the thermal management technologies in the PVT system was conducted, and their collaborative applications in different fields were discussed. This paper systematically classifies and analyzes the six main thermal management methods of the PVT system: air, water, nanofluid, phase change material (PCM), heat pipe and refrigerant cooling. For each strategy, key performance indicators including thermoelectric efficiency and economic-environmental benefits, as well as the feasibility of integrated application, were evaluated. The comparative analysis highlights the relative advantages and limitations of each technology: air cooling offers simplicity and low cost, but only generates a moderate temperature drop, while water-based cooling enhances cooling efficiency. The integration of nanofluid coolants and heat pipes significantly enhances heat transfer and overall efficiency, while the PCM integration offers thermal stability at the cost of slower heat dissipation. Active cooling achieves maximum heat removal, but it requires additional energy input and system complexity. The potential for multi-domain integration was also discussed, including the coupling of PVT with building heating, product drying or industrial processes, demonstrating the synergy between specific thermal management strategies and specific application requirements. It is worth noting that the combination of complementary technologies (for example, nanofluid heat transfer and PCM heat storage) can enhance system performance by taking advantage of the synergy effect. The research results show that the selection and combination of thermal management technologies significantly affect the electrical output and effective heat recovery of the PVT system. The maximization of the overall efficiency of the PVT system is achieved through the optimization of technology selection and integration. The quantitative comparison of the review highlights the effective hybrid configuration and provides guidance for the design of efficient PVT systems. Future research directions include the development of new nanofluid and PCM composite materials, as well as adaptive control strategies, to further enhance the performance of PVT under different conditions. This paper outlines the key trends and performance trade-offs, providing a reference framework for technology coupling and scenario optimization in future advanced PVT applications.