Interactions of crop and cooling equipment on greenhouse climate

Experiments combining natural ventilation, shading and low-pressure fog system, with and without crop, were carried out with the aim of evaluating the interactions of crop transpiration and cooling equipment on greenhouse temperature. The relationships among the different variables were analysed with a climate model. Crop transpiration was observed to be a significant factor in greenhouse cooling, reducing the temperature of the greenhouse by 0.8 degrees C as an average over the different combinations of equipment. However, the effect of the crop was negligible with high doses of fog where the air is nearly saturated with vapour. Fogging above the screen seemed to be an interesting method for greenhouse cooling without vapour saturation of the air. The energy model produced mean absolute errors lower than 1 degrees C; it can be used for evaluation of climate control strategies, even without including transpiration.