Greenhouse design and cooling technologies for sustainable food cultivation in hot climates: Review of current practice and future status

Greenhouse technology is becoming an increasingly indispensable and a viable solution for modern methods of crop production. Technological advances have lessened the effect of severe weather conditions on the yield of greenhouse crops in hot climates. Cooling is crucial to guarantee the required range of temperatures and humidity inside the greenhouse. The purpose of this work is to review the design and systems used for greenhouse cooling applications in hot climates. Theoretical and practical aspects related to greenhouse cooling techniques are presented: working principles, working conditions and performance parameters. The review revealed that the combination and simultaneous usage of natural ventilation, evaporative cooling and shading has the potential to reduce greenhouse energy requirement and provide optimum indoor conditions required to maximise crop yields in greenhouses in hot climates. Hybrid cooling systems must be assisted by an effective control strategy to ensure that the required temperature and humidity levels and distributions are maintained in the greenhouse. The status of the research on the use of numerical modelling for the design of greenhouses in hot climates or conditions was investigated and the future challenges facing the development of greenhouses in hot climates identified. Recommendations for future research and development are proposed. (C) 2019 IAgrE. Published by Elsevier Ltd. All rights reserved.