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• A PVT collector with a roll-bond absorber is designed for rural home application. • Thermo-laminating is a novel and convenient method for PV-absorber connection. • The validated PVT model can simulate the roll-bond PVT performance accurately. • The model is available for predicting the dynamic performance of PVT systems. This paper mainly investigated the performance of a low-cost roll-bond water-type photovoltaic thermal (PVT) collector from both experimental and modelling approaches under the climatic conditions of Sichuan Basin of China. The design and manufacturing process of the PVT prototype adopted the available commercial PV panels for convenience and for reducing the manufacturing cost. The experiment measured all the main properties of the developed PVT module. The excellent heat transfer performance of its roll-bond absorber plate was also validated by outdoor steady-state tests. Then, the steady-state numerical models were used to simulate the performance of the PVT prototype in TRNSYS. By comparing the simulation and experimental results, two robust models were selected which have their own advantages in charactering the thermal and electrical properties of the PVT collector. Through validating the numerical models with experimental data, the deviation between the simulated and the measured values was further reduced. In addition, a complete photovoltaic thermal–domestic hot water (PVT-DHW) system with such PVT collectors was developed in TRNSYS, by which the annual system output and efficiency were predicted and analysed. [ABSTRACT FROM AUTHOR]

Due to the continuous development of underground engineering (underground surrounding rock stability, hot dry rock production, etc.), the thermal damage of granite has attracted much attention. In order to explore the effect of heating up to 800 °C on the physical properties, such as mass, color, roughness, wave velocity, thermal diffusivity, and thermal conductivity, of granite in China, the results indicate that the physical properties of granite change significantly with an increase in temperature. The surface roughness, cracks, heat capacity, lightness, and coordinates a ⁎ (green-red) and b ⁎ (blue-yellow) show a significant increase between 400 °C and 600 °C. However, the thermal diffusivity, thermal conductivity, and P-wave velocity decrease as the heat treatment temperature increases, especially after 400 °C. By using numerical simulation, it is found that the heat transfer in the Luhui granite is affected by the heat treatment temperature and thermal conductivity. When the heat treatment temperature is lower than 500 °C, the heat transfer rate increases with an increase in temperature; on the other hand, when the heat treatment temperature is higher than 500 °C, the heat transfer rate decreases with an increase in temperature, and 500 °C is considered as the critical temperature. • Temperature has a great influence on the granite surface color, roughness and cracks. • The thermal conductivity and thermal diffusivity decrease significantly above 400 °C. • Thermal damage affects the heat transfer rate, and 500 °C is the turning point. [ABSTRACT FROM AUTHOR]