MEASUREMENT OF THE CONDENSATION FLUX IN A VENLO-TYPE GLASSHOUSE WITH A CUCUMBER CROP IN A MEDITERRANEAN AREA

Roof water condensation frequently occurs in greenhouses in Mediterranean areas, especially in low temperature conditions at night during the winter cropping period.
Condensed water on the inner roof surface of a Venlo-type glasshouse was collected during the second half of an autumn-winter cucumber crop cycle (February and March 2008) by means of a system of mini-gutters attached to the lower part of the glass panes.
The condensed water collected was first recorded with a rain gauge, then accumulated in a tank and measured daily with a water meter.
Condensation occurred on over 96% of the days observed.
Daily condensation flux values were highest during February, reaching up to 147 ml m^-2 d^-1, whereas they were clearly lower at the end of the cropping cycle in March.
Hourly values of condensation flux ranged from 0 to 15.6 ml m^-2 h^-1 and were also clearly higher in February than in March.
In both periods, most of the condensation flux occurred during the night-time period, but the condensation flux continued to be high during the first half of the morning (until 10:00) in February, whereas in March it decreased rapidly from sunrise, reaching almost zero at noon and increasing again from sundown.

International Symposium on High Technology for Greenhouse Systems: GreenSys2009

M.R. Granados, B. Ortega, S. Bonachela, J. Hernández, J.C. López, J.J. Pérez-Parra, J.J. Magán

air humidity, dewpoint temperature, vapor pressure deficit

https://doi.org/10.17660/ActaHortic.2011.893.54