A Model of the Greenhouse with a Storage-Type Heat Exchanger and its Verification

Abstract

A model describing the heat exchange in the plastic greenhouse with a storage-type heat exchanger was made in order to examine the feasibility of the storage-type heat exchanger for controlling the temperature and humidity in the plastic greenhouse. Relatively good agreement was obtained between measured and calculated environmental conditions in the plastic greenhouse with the storage-type heat exchanger.
The magnitude of the heat storage ratio, defined as the ratio of the amount of heat accumulated in water as a heat accumulator to the amount of heat transferred from crop and soil surfaces into the house, was considerably influenced by factors such as short-wave irradiance, ventilation rate and difference in the operation of air circulation system. Sample calculations indicated clearly that under high irradiance the latent heat due to the condensation of water vapor on the inside surface of heat exchange pipes plays an important role for the accumulation of heat.