Passive air conditioning of a greenhouse with the use of a soil air heat exchanger

With this study, the climate conditions in greenhouse production, which is among the agricultural sector activities, were investigated and it was aimed to improve energy efficiency. Numerical analysis of passive air-conditioning system of a greenhouse using earth-air heat exchanger (THID) system in Eskişehir province (Turkey) is aimed. In order to continue the production without interruption in summer and winter seasons in greenhouse cultivation, which has become a part of the agricultural sector, aluminum pipes with a length of 66 meters, a wall thickness of 0,002 meters and a diameter of 0,2 meters were used within the scope of this study. The temperature of the outdoor air entering the ground-air heat exchanger at 0°C was increased by 19°C at the system exit and it was ensured to enter the greenhouse at this temperature. Analysis was performed using the SST k-𝜔 (Omega) turbulence method. In this greenhouse integrated with the ground-air heat exchanger, the heat exchanger is buried at a depth of (h=3) meters. Additional heating was provided to the greenhouse, which is caused by solar radiation, by decreasing the amount of radiation of 170 W/m2 in winter. Therefore, the required temperature for the greenhouse was obtained. Natural convection passive heating of the system was made. The time taken for all the air in the greenhouse to change was found to be 17 hours. As a result of the cost analysis, the amortization period was calculated as 18 months. Using the mathematical model, energy saving, efficiency and cost benefits are discussed in this study.