ABSTRACT
Plants are biological air-conditioners, which cool their own immediate surroundings. However, during hot and sometimes warm weather, heat builds up inside the greenhouse due to high solar radiation loads; and if quality crops are to be grown, it is required to provide greenhouses with appropriate cooling. Cooling may be provided by different means starting from the most cost-effective options such as whitewashing the greenhouse exterior, shading screens, and natural ventilation, and moving toward relatively costly options such as mechanical ventilation, evaporative cooling, ground cooling, and refrigerated air-conditioning.
This chapter briefly goes over the theoretical aspects of estimating cooling loads in greenhouses first, and then moves to the passive and active greenhouse cooling techniques. The techniques covered include whitewashing the greenhouse exterior, shading curtains, natural and mechanical ventilation, evaporative cooling, heat pump cooling, and Watergy concept. Real world design examples are provided for natural ventilation, mechanical ventilation, and fan and pad type evaporative cooling systems for different greenhouses and climatic regions.
