The method of Grutec's cooling system is based on a swing adsorption cycle. Special adsorber fibres, similar to pad and fan, are placed on both sides of the greenhouse. When ambient air is driven through the entry adsorber pad , it takes moisture from the adsorber fibres in order to cool down the stream. When the air is driven to leave the greenhouse on the other side, moisture together with transpiration water is taken up by the exhaust adsorber pad. This process can also be revised in order to take humidity out of the greenhouse.
When during the night no cooling is required, the cycle can be stopped, except if transpiration water and CO2 need to be recovered from the greenhouse. In this case, the air draft can be driven upwards to the roof area, where it hits a cooling poly film which brings the vapor to condensation. The cooling polyfilm is a layer with infrared emitting feature to radiate heat into the space at night. Applying a proper set of filter layers, including the roof skin, up to 1000kJ/m2h of energy is radiated. The water is collected in gutters along the sides of the structure.
Contact GRUTEC for more information on this solution, they can analyze and perform test runs to see if it is suitable for your climate problems as well. "We are capable to produce up to 200 tons of adsorber mass based on our Grutecfibres. This is currently enough to cool up to 40,000 m2 of greenhouse area. However, we are interested to set up a pilot which also includes transpiration water recovery to substitute irrigation water.''
For more information:
Grutec Fibre
Johann Gruber (e-mail)