Thermal modelling and performance assessment of a circular greenhouse with solar chimney assisted ventilation and fog Cooling

Abstract

This paper presents a conceptualized model of a solar chimney-assisted naturally ventilated circular greenhouse applicable for hot and arid regions. Instead of conventional rectangular shape, a circular shape is chosen which makes the greenhouse independent of wind direction and orientation with regards to the wind-induced ventilation. Pressurised fogging system is considered as the mode of distributed evaporative cooling. A circular twin-wall solar chimney is centrally mounted which is suitably sized to provide buoyancy-induced natural ventilation. The solar induced ventilation is sufficient, giving 0.6-0.75 air change per minute (ACM). The analysis revealed that during the peak ambient temperatures, the greenhouse inside temperature could be lowered by 4 to 6 ⁰C below the ambient employing an optimized fogging cycle with spray time/interval period of 1.5 min/2 min.