Experimental Investigation on Airflow and Water Production in the Integrated Rooftop Solar Thermal System

Abstract

Solar chimney is a passive renewable technology, adopted and followed widely for the application of room ventilation and power production. It requires a wide space for operation. Hence, an effective heat transfer mechanism is required within the available space to improve the performance. The solar chimney is integrated with a solar still using an external condenser to effectively utilize the energy released during the condensation of water vapor in the external condenser. The external condenser acts as an additional heat source besides the solar collector in the solar chimney. The experiments were conducted with the solar chimney of heights 1 m and 2 m, by considering the effects of an external condenser in both summer and winter. Heat transfer studies on the external condenser are also made to determine the effectiveness and the number of transfer units. The temperature and mass flow rate of vapor in the still are the influential parameters on the effectiveness of the external condenser. The condensation energy released from the external condenser increased the daily average air velocity by 14.9% and 22.4% in summer and winter, respectively. However, the overall solar chimney efficiency was improved by 37.1% in summer and 14.5% in winter for the integrated system with the chimney of height 2 m.