Excessive humidity in the glasshouse limits crop evaporation and thus nutrient uptake . In addition , it can precede to a high peril of fungal diseases . This can be foreclose in a traditional glasshouse by open up the window and opening a cover crack . CRT screen break often give ascent to undesirable air flows in the nursery , leave in declamatory horizontal temperature differences . By using systems that actively blow in dry , nerveless air , the use of screen gaps can be limited . The Business Unit Greenhouse Horticulture and Flower Bulbs of Wageningen University & Research enquire the software of these type of systems in the cultivation of chrysanthemum , rise and tomato plant .
The air above the vigor screen is drier than the aura at the bottom of the greenhouse . By impart the screen fabric ajar , the two breeze layer mix and the relative humidity ( RH ) in the crop decreases . Because a screen is never totally horizontal , CRT screen gaps are almost always accompanied by many horizontal strain movements in the nursery , which can do significant temperature differences ( up to 5 ° C ) .
Uniform statistical distribution of the dry airA solution for this is to suck in the air above the screenland and bollocks it out below the screen . In that case , a more undifferentiated statistical distribution of the dry melodic phrase is potential . WUR investigated such systems at a number of finish companies and at the research locations of WUR and Delphy : Airmix from Van der Ende Groep ) , VentilationJet from Hinova ) and a external respiration installing from Technokas . The research showed that these organisation each have their own characteristics , such as the blowing direction and amount . It bet on the grower ’s destination and the requirements of the crop which system and which content is sound . At an outside air temperature of 12 ° C or more , the capacity of the installations is often no longer sufficient to optimally dehumidify the aviation .
The greenhouse air can also be dehumidified with an air handling building block with a cold pulley . This installation suck in lovesome , moist greenhouse atmosphere . The wet in the nursery tune condenses against the inhuman occlusion . The cool air contains less moisture and can be returned to the greenhouse . Such a semi - closed system has the vantage that CO2 can remain in the greenhouse and that warmth is also harvested . This is one direction to accomplish a fossil - free glasshouse .
Danger with dehumidificationRegardless of which proficiency is used , there is a danger with dehumidification . Many growers are used to setting a desired RH of , for example , 85 % , but this percentage is seldom viable with traditional greenhouses . With alive dehumidification , this set percentage point can be reach , which mean that more is dehumidified and more get-up-and-go is used than the crop really require . This means that the fit point of the climate induction must be critically examined .
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