Design challenges of agricultural greenhouses in hot and arid environments – A review

Protected Agriculture (PA) presents a sustainable solution for food production in hot and arid environments. Harsh climate and the water deficit are obstacles to all year round cultivation. The greenhouse design should provide adequate control of its microclimate, such as temperature, relative humidity, CO₂ concentration, and lightning depending on ambient conditions and the type of cultivation. This paper provides a thorough review of previous research on greenhouses design features, deemed important for efficient operation in hot and arid environments, such as dimensions, orientation, shapes, covering and shading materials. Effective greenhouse cooling methodologies and operation strategies to achieve and maintain satisfactory climate conditions in hot and arid conditions are investigated. Namely, natural and forced ventilation, evaporative cooling and fogging systems. Furthermore, the paper discusses the greenhouse control methods (field, remote, direct and combined) to monitor and regulate the indoor climatic parameters. Finally, the paper focuses on current greenhouse sustainable technologies and clean energy applications that contribute towards minimizing dependency on fossil fuels and leading to efficient water management. Namely, storage systems, humidification/dehumidification systems and Photovoltaic Panels. The future challenges facing the protected agriculture sector are identified. Suggestions of future scientific research and development topics are proposed.