Computational fluid dynamics simulation of earth air heat exchanger combined with the Quonset type greenhouse to develop a sustainable controlled environment

Abstract

The current study aims to evaluate the performance of an earth air heat exchanger (EAHE) combined with a Quonset-type greenhouse in a summer climate to create a controlled environment for optimum crop development and energy efficiency. The integrated systems thermal performance and airflow patterns are analyzed using computational fluid dynamics (CFD) models. The result shows that greenhouse room air can be satisfactorily achieved in the comfortable temperature range (27–37 ℃) for plant growth by combined EAHE even during the hottest summer days. EAHE reduces greenhouse temperature with a minimum temperature gradient of 17 °C between the ambient and air at the exit of EAHEs after the heat exchanging process. It is observed from the analysis that as the flow rate of air entering into EAHE increases, the greenhouse room's temperature decreases up to 0.5 kg/s; after that, there is no significant change in temperature, which makes 0.5 kg/s the recommended flow rate for the model used in the simulation. Pressure loss is reduced in a multi-pipe EAHE system compared to a single-pipe system. This advantage can increase energy efficiency and lower operating costs in greenhouse cooling. The Quonset GiTPV system generates 29.22 kWh of electrical energy daily, making it self-sustaining.