Thermodynamic Analysis and Optimization Design of a Novel Building Facade Featuring Embedded Annular Heat Pipe Heat Exchangers and an Integrated Solar Photovoltaic-Thermal System

The challenges associated with single energy supply, low efficiency, low space interest rate, and inadequate building integration are evident in traditional solar energy utilization. In this study, a novel annular heat pipe heat exchanger embedded in building facades was proposed, along with an integrated solar photovoltaic (PV)-thermal system. At first, the thermodynamic model of the system was built. The system performance was investigated and compared under different diameters of heat pipe heat exchangers and different pipe spacings. Furthermore, a multiobjective optimization of the overall efficiency and the cost of the system was carried out. It is revealed that when the pipe diameter is 0.024 m and the pipe spacing is 0.06 m, the system achieves its highest electrical efficiency, thermal efficiency, and overall efficiency. It is interesting to note that the optimal pipe diameter is found to be 0.024 m and that the optimal pipe spacing is 0.14 m, when the overall efficiency of the system is weighed against the cost of the heat pipe heat exchanger. Meanwhile, RE347 was identified as the optimal working fluid for the system. Furthermore, the corresponding overall efficiency of the system is 68.92%, and the cost of the heat pipe heat exchanger is ¥232.62.