A numerical study on the performance of a hybrid ventilation and power generation system

Ventilation, cooling and power are essential requirements of buildings. Integration of solar chimney, earth-air heat exchanger and photovoltaic panel forms a new hybrid system, which is able to provide simultaneous ventilation, cooling capacity and electricity in an effective manner for buildings. The contribution of this study is to quantitatively identify the thermal and electrical performances of the hybrid system using a comprehensive validated numerical model. In addition, a parametric study was also performed to examine the effect of the number of EAHE pipe and solar collector on the performance of the hybrid system in order to further enhance the system performance. The results revealed that the peak daytime ventilation of the proposed hybrid system is reduced by 22.05 % compared to the ventilation system of solar chimney integrated with earth-air heat exchanger, and the outlet air temperature is reduced by 0.12 degrees C in average; the indoor temperatures for the hybrid and ventilation systems are slightly different. Moreover, the minimum electrical efficiency of hybrid system is 1.34 % higher than that for stand-alone photovoltaic system. Increasing the number of earth-air heat exchangers leads to more than 36.43 % increase in peak ventilation volume and 3.7 % improvement in electrical efficiency. In addition, increasing the quantity of solar chimney-photovoltaic modules can effectively increase the induced ventilation volume, and the outlet air temperature, but has slight effect on the temperature and electrical efficiency of photovoltaic panel. Therefore, the hybrid system not only can supply appropriate ventilation but also can generate electric power to buildings. The findings provide a preliminary guidance for optimizing design of the hybrid system.