Dehumidification of Greenhouses at Northern Latitudes

Three dehumidifying methods, being condensation on a cold surface, forced ventilation using a heat exchanger, and an absorbing hygroscopic dehumidifier, were compared with ventilation as the conventional way to dehumidify a greenhouse. The calculations were performed using a dynamic physical simulation model with a single- and a double-layer greenhouse under Dutch weather conditions. The comparison was made based on the energy consumption and the costs. The methods with a cold surface or an absorbing hygroscopic material are less attractive than the conventional method, mainly because of the high investment costs. Dehumidification by forced ventilation with a heat exchanger can be competitive. The success of this system depends on the efficiency of the system in terms of energy consumption and the effectiveness of the heat exchanger.