| With the global energy shortage increasing,the use of renewable energy has received much attention.In particular,solar energy has become an important source of energy exploitation and utilization because of its wide distribution,abundant reserves,clean and pollution-free characteristics.However,the problems of single energy supply,low space interest rate and low degree of building integration are obvious in traditional solar energy utilization,which make the development of solar energy and building integration limited extremely.In view of how to improve the utilization of solar energy in buildings,this paper combines theoretical analysis and experimental research from the perspective of building energy generation and building space utilization.Therefore,this study has carried out the following work:First,based on the research reviews of ventilation facade and PV/T cogeneration system at home and abroad,and the development status of solar energy and building integration,this paper has summed up the shortcomings of them,and proposed a PV/T building fa?ade system.Second,according to the working principle of the PV/T building facade system,the important components of the PV/T cogeneration system have been analyzed theoretically to determine the influencing factors of the system performance.Meanwhile,the heat transfer characteristics of the PV/T ventilated facade have also been analyzed,including the solar radiation acquisition characteristic on the vertical facade and the heat transfer models of PV/T ventilated facade.Third,based on the working principle and analysis above,the design and construction of corresponding experimental platform have been completed,including PV/T heating system,photovoltaic power generation system and ventilated fa?ade system.Moreover,an experimental test plan was proposed and the experimental error analysis was completed.Fourth,the experimental study on the cogeneration performance and the heat transfer performance of ventilated facade of the PV/T building facade system have been done in Dalian in October.The results show that the PV/T cogeneration system can guarantee the production of hot water above 40°C in 5 days per week under the average solar radiation of370 W/m~2,and the average heating COP of the system is about 1.8.The photovoltaic system has a daily average power generation of 1.5 kWh,and the photovoltaic efficiency is nearly8.1%.The experimental results demonstrate the feasibility of the proposed PV/T fa?ade cogeneration system.Meanwhile,the heat transfer performance analysis of the PV/T fa?ade has been completed,concerning the external influence factors on the fa?ade system performance,such as solar radiantion intensity,ambient temperature,wind velocity and wind direction,and the influence of ventilation of the fa?ade on the thermal performance of PV/T building fa?ade has also been considered.Finally,according to the aforesaid experimental research,some shortcomings have been summarized of the original experimental system.To improve the system performance,another experiment research of the improved system has been done in May,and the heating performance,photovoltaic performance and overall performance are analyzed.The results show that the temperature difference between the upper and lower PV/T module can be reduced to around 0.5°C due to the redesign of PV/T connection.The improved PV/T cogeneration system has an average thermal efficiency of 26.1%,an average photovoltaic power generation efficiency of 10.4%,and the average overall efficiency is around 43.1%.When there is a PV/T fa?ade with a heat collecting area of 4.87 m~2,it can consume 1.82 kWh of electric energy to heat 150 L water from 21.4°C to 43.9°C,and its photovoltaic power generation is 1.88 kWh,which can basically achieve self-sufficiency in equipment electricity consumption.This study has shown that the PV/T building fa?ade system driven by refrigerant pump is feasible and energy-efficient,which can make full use of building fa?ade space to produce electric and thermal energy for building.Meanwhile,the external PV/T skin can effectively reduce the cold and heat load of the building in winter and summer,which has great research value and application prospect. |
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