In the hot weather, the thermal conduction and heat radiation can make 
the temperature in the greenhouse that hasn't been cooled down10-20
degree higher than the external temperature. This will result the 
productive activity can't be carried through normally. So, adopting 
effective cooling measure id the unique approach to obtain high yield, 
high efficiency and stabilization in room temperature production. 

The long time experience can testify that even in the most hot weather, the "damp
curtain-ventilator" system installed well call all the same 
controls the temperature in greenhouse around 30degree. This will 
decrease the loss of production caused by hot weather to minimum. The 
cooling proceed of the damp curtain is finished in its core part Yanfeng 
paper pad. 

There is a thin water film on the moisture surface of the fiber paper, 
when the outside heat air is inhaled through the pad by the ventilator, 
the moisture on the water film will absorb the heat and be vaporized 
into vapor, so the cool and damp air will enter into the house. The 
temperature which the damp curtain can decrease is determined by the temperature
difference between the wet-bulb and dry bulb and the 
efficiency of the damp curtain, their product if the decreased is 
fixed generally. We can see, the hotter the weather is the better the 
effect of the damp curtain will be.