Impact Of Built-in PV-Trombe Wall For Indoor Ventilation Characteristics

At present, China’s building energy consumption accounts for about35%of total energy consumption, where consumption of heating, ventilation and air conditioning account for almost half of the total building energy consumption. Solar energy is clean, renewable energy, solar energy and building integrated is important to reduce building energy consumption. The new built-in PV-Trombe wall which photovoltaic panels attached to the outer surface of the building wall studied in this paper, is the improvements on existing PV-Trombe wall technology,this structure can simultaneously achieve the use of solar thermal and photovoltaic,and has an important engineering application value and academic research value.Computational fluid dynamics (CFD) numerical simulation of the natural ventilation and convection heat transfer performance of the room with built-in PV-Trombe walls is done in the paper. Selection a winter room with3.5m x3m x2.8m in Shanghai. The PV-Trombe wall set in the south room, and the chimney channel width0.2m, the vertical height of2.3～ 2.7m.Realizable k-ε turbulent model was used to simulate the air flow and DO radiation model was used to calculate the heat transfer between the air and wall surfaces. SIMPLEC algorithm was used for the calculation. The CFD model was first validated by published experimental data and good agreement between the present CFD results and experimental data demonstrated that the present method was reasonable.The flow field, pressure field and temperature field in the workshop were simulated. The influence of structural parameters of the building and the formation mechanism of natural ventilation was discussed. The main conclusions are as follows:(1) By comparing the distribution of overall temperature and speed in the room, the built-in PV-Trombe wall could promote the indoor natural ventilation and had the higher efficiency in the use of solar energy. Compared with ordinary Trombe wall system, the built-PV-Trombe wall system indoor average temperature has increased by about2℃, while the indoor ventilation rate increased by11%. The PV-Trombe wall is the worst to enhance the indoor temperature because there is a shielding on solar radiation.(2) Increasing the height of built-in PV-Trombe wall outlet improved indoor ventilation and the average wind speed, but when the outlet height was above2.5m, the indoor ventilation and average wind speed began to decline. The average indoor temperature increased with the increases of the outlet height. When the outlet height was higher than2.5m, the average indoor temperature increased significantly.(3) Increasing the size of built-in PV-Trombe wall inlet and outlet improved indoor ventilation and the average wind speed. With the increase of the size of the inlet and outlet of the chimney, the indoor average wind speed and the indoor ventilation were increased. The average indoor temperature increased with the increases of outlet size. The larger the size of the outlet, the higher the average temperature of the room was.(4) Built-in PV-Trombe wall outlet depth had little effect on improving indoor ventilation and average temperature, the difference of average velocity level between different outlet depths was slight. When the indoor height Y＞2m, the smaller the depth of the outlet, the higher the average speed became, but on the whole it can be considered the different outlet depth did not have a big impact on the distributed of interior flow field.