The effect of dynamic solar heat load on the greenhouse microclimate using CFD simulation

Abstract

Indoor greenhouse temperature exceeds tolerable range for plants growth mostly during the summer in Ahvaz-Iran. Attempts for improving ventilation in summer was not adequate despite a huge energy consumption. Computational fluid dynamic models of a full scaled gable greenhouse covered by semitransparent materials among several adjacent greenhouses inside a greenhouse paradise for predicting the dynamics of its microclimate during a day as well as a year 2017–2018 were developed. The accuracy of the models was approved by comparing to the physical experiments and meteorological reports. The results approved the capability of the model for predicting variable solar heat load and higher indoor temperature than ambient in several hours of a day as well as surface heat transfer coefficient of the walls as affected by regional dominant wind profile. This study enhanced the understanding of required solar heat load removal during the hot months while the average temperature exceeds 40 °C for more than 11 h a day. This finding also indicates the critical periods in which the fan assisted natural ventilation system can be applied to cool down the greenhouse from more than 40 °C to 25–35 °C.