Comparative experimental analysis and modelling of a flower greenhouse equipped with a desiccant system

Two identical flower greenhouses operating near Bergamo (northern Italy) have been equipped with an innovative and a traditional air conditioning system respectively.The innovative air conditioning system based on H2O–LiCl desiccant consists of an integrated dehumidification and regeneration unit. In the dehumidification part the strong solution absorbs the ambient air humidity. Heat recovery is performed on the desiccant regeneration process enabling to heat the ambient air previously dehumidified. Auxiliary unit heaters driven by hot water complete the sensible heat needs of the greenhouse. The same unit heaters are used to perform sensible heating in the traditional greenhouse.Natural ventilation through roof opening is the only method to control the humidity in the traditional greenhouse but it is also used in the innovative one to integrate the desiccant system.The experimental comparison shows a 10% average primary energy saving for the desiccant-based system with respect to the traditional one in the winter season.The numerical model allowed to simulate the greenhouses and to evaluate the savings potential of the desiccant-based system with different operating approaches. The dependance of performance of the greenhouse cover material on the humidity condensation was shown to strongly affect the contribution of the desiccant system.

► Analysis of energy performance of an innovative flower greenhouse air conditioning system.
► Experimental comparison of a liquid desiccant equipped greenhouse and a traditional one.
► Validation and use of a simulation model to investigate different control strategies.
► Comparison of cover materials with high and low long wave radiation transmittance.