WATER VAPOUR TRANSFERS AND DEHUMIDIFICATION IN A INFLATABLE PLASTIC GREENHOUSE

Th. BOULARD, A. BAILLE, J. LAGIER, M. MERMIER
Greenhouse energy saving technics -for example, better insulation, double inflated wall greenhouse- leads to changes in the microclimate of greenhouse cultivations. The decrease of air exchange rate induces an increase of the air humidity, condensation on the roof and dripping on the crops. Consequently, the occurence of fungal diseases and physiological disorders increases and greenhouse air deshumidification is necessary.

In this paper, the greenhouse air dehumidification possibilities are analysed with both experimental and theoretical evaluations of the water vapour transfer between the different sub-systems (soil, crop, inside air, roof, outside air, heat pump), considered as sources or sinks of water vapour.

A dynamic model of water vapour exchanges is developed and compared to the experimental results. It shows that the heat pump does not reduce significantly the inside air humidity, but eliminates almost completely the water condensation on the roof (and dripping on the crops).

This model allows the determination of the power of dehumidification heat pump and the comparison with other dehumidification devices according to the characteristic parameters of the greenhouse and of the crop : air temperature and humidity set points, air exchange rates, crop leaf area index, stomatal and aerodynamic resistances, etc.

BOULARD, Th., BAILLE, A., LAGIER, J. and MERMIER, M. (1989). WATER VAPOUR TRANSFERS AND DEHUMIDIFICATION IN A INFLATABLE PLASTIC GREENHOUSE. Acta Hortic. 245, 462-469
DOI: 10.17660/ActaHortic.1989.245.62
https://doi.org/10.17660/ActaHortic.1989.245.62

Acta Horticulturae