The heat-pipe solar water heating (HP-SWH) system and the heat-pipe photovoltaic/thermal (HP-PV/T) system are two practical solar systems, both of which use heat pipes to transfer heat. By selecting appropriate working fluid of the heat-pipes, these systems can be used in the cold region without being frozen. However, performances of these two solar systems are different because the HP-PV/T system can simultaneously provide electricity and heat, whereas the HP-SWH system provides heat only. In order to understand these two systems, this work presents a mathematical model for each system to study their one-day and annual performances. One-day simulation results showed that the HP-SWH system obtained more thermal energy and total energy than the HP-PV/T system while the HP-PV/T system achieved higher exergy efficiency than the HP-SWH system. Annual simulation results indicated that the HP-SWH system can heat the water to the available temperature (45°C) solely by solar energy for more than 121 days per year in typical climate regions of China, Hong Kong, Lhasa, and Beijing, while the HP-PV/T system can only work for not more than 102 days. The HP-PV/T system, however, can provide an additional electricity output of 73.019 kWh/m2, 129.472 kWh/m2, and 90.309 kWh/m2 per unit collector area in the three regions, respectively. 相似文献
A new method for bisphenol A (BPA) degradation in aqueous solution was developed. The characteristics of BPA degradation in a heterogeneous ultraviolet (UV)/Fenton reaction catalyzed by FeCo2O4/TiO2/graphite oxide (GO) were studied. The properties of the synthesized catalysts were characterized using scanning electron microscopy, X-ray diffraction, and vibrating sample magnetometry. FeCo2O4 and TiO2 were grown as spherical shape, rough surface, and relatively uniform on the surface of GO (FeCo2O4/TiO2/GO). Batch tests were conducted to evaluate the effects of the initial pH, FeCo2O4/TiO2/GO dosage, and H2O2 concentration on BPA degradation. In a system with 0.5 g L−1 of FeCo2O4/TiO2/GO and 10 mmol L−1 of H2O2, approximately 90 % of BPA (20 mg L−1) was degraded within 240 min of UV irradiation at pH 6.0. The reused FeCo2O4/TiO2/GO catalyst retained its activity after three cycles, which indicates that it is stable and reusable. The heterogeneous UV/Fenton reaction catalyzed by FeCo2O4/TiO2/GO is a promising advanced oxidation technology for treating wastewater that contains BPA.
