| As the most promising solar energy utilization technology, the BIPV/T technology has been widely used for its high comprehensive efficiency thermoelectric, which by combining with building structure and PV panel, take advantage of the heat come from the solar energy illuminated on the surface of the battery, when using the photovoltaic power generation. This article first to research the composite material which based on the principle of phase change heat storage, Then, selected the suitable phase change materials (PCM) to the new photovoltaic solar-thermal wall system which combined with photovoltaic cells components and architectural component. The system was contrast test of thermal and electrical performance in different tectonic patterns and different working conditions, and analysis the rules and changes of efficiency, discussing the economic and energy saving benefits, summarizing the results of experiment and put forward the reasonable suggestions on optimization of structural unit.According to whether filling the PCM into photovoltaic modules of field, the experiment was divided into two kinds of structure models, which the one structure mode was that the new photovoltaic solar-thermal wall system with the mixture of phase change materials (GR52) and scrap metal (Al).The other one was that the new photovoltaic solar-thermal wall system without the phase change materials. To achieve the test of two structure mode in the test under different working conditions by adjusting the simulating radiation intensity and circulating water flow.Observed the microstructure and character change in high temperature of the three types of phase change materials (GR52 PK52 PX52) by the scanning electron microscopy (SEM), phase change temperature, latent heat and heat capacity of the three materials was test by the Differential scanning calorimetry (DSC). Analyze test results and select an low phase change temperature and the relatively stable proprety material in high temperature, the GR52 was the filling materials of new photovoltaic modules of field to be experimented, and analyses its role in improving the efficiency of the photovoltaic solar-thermal.From the point of collection and photoelectric properties, the new photovoltaic solar-thermal wall system with the thermal conduct and storage materials achieve the maximum average collection thermal efficiency and power efficiency, which is 61.1% and 7.8%, with the simulated solar radiation of 900W/m2and the water flow rate of 6001/h, the instantaneous maximum thermal efficiency and electrical efficiency was at 87.11% and 13.2% under the corresponding condition. Illustrate that the average thermal and electrical efficiency was proportional to the simulated solar radiation, it would be reached the maximum in the optimal flow rate. As to the comparison, the new photovoltaic solar-thermal wall system without the PCM could gain the maximum average collection thermal efficiency and power efficiency at 31.3% and 4.6% with the simulated solar radiation of 300W/m2and the water flow rate of 2001/h, the instantaneous maximum thermal efficiency and electrical efficiency was at 46.67% and 7.9% under the corresponding condition, the average thermal and electrical efficiency was inversely proportional to the simulated solar radiation and the water flow rate. The comprehensive efficiency thermoelectric of new photovoltaic solar-thermal wall system with the thermal conduct and storage materials was at 68.9%, which was improved nearly one times than the value of 35.9% for the system without PCM.After the analysis of the economy and energy saving, the proposed system has a higher initial investment cost at 7945 yuan/m2, but it could saved about 16% of the electricity for domestic hot water load, when gained the maximum heat of 5947 KJ and the daily average maximum power generation of 0.552 KWh under the 8 hours solar radiation. This proposed system has a dynamic investment recovery period of 9.24 years, it could achieved the net investment profit present value of 4399.96 yuan within the full life cycle, thermoelectric value of system was equivalent to reduce the 4.14 t of standard coal in the aspect of energy saving, gained the energy conservation benefit is 1721.91 yuan, so the proposed system has the good economic and energy saving efficiency. |
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