Abstract:
Growth in the demand for food has encouraged the use of agricultural methods that are able to use otherwise nonarable land. Greenhouse cultivation is one of the strategies adopted which, besides protecting plants from harsh
climatic conditions, enables growing plants that are not native to a region or during seasons not normally suitable
for plant growth. In cold climates greenhouses are used to maintain an indoor temperature that is warmer than
ambient, however in hot arid climates use of a cooling system they can be used to keep plants at a temperature
lower than the ambient temperature. Greenhouses in hot arid regions currently use evaporative cooling to manage
the internal temperature. However, such systems are water-intensive, yet water is scarce in these regions. By
minimising air exchange with the external environment, a closed greenhouse system is one technology that can be
more energy-e cient and consume less water than an open ventilated greenhouse system. In this paper we study
water-saving by using a closed-loop Earth-to-Air Heat Exchanger (EAHE) to cool a closed greenhouse in a hot arid
Egyptian climate. In the closed greenhouse model, the greenhouse components are treated as lumped masses, and
the air is assumed to be perfectly mixed. A representative day of the summer season's warmest month (August) is
used for the case study. Results show that crops highly in uence the greenhouse interior-climate, which suggests
they should be icluded in greenhouse modelling. It is found that for a minimally ventilated closed greenhouse
operation, evaporative cooling through fogging or misting are not possible due to high relative humidity. Further,
the results indicated that EAHE is a reliable sustainable alternative for temperature regulation.