Yes you are right, its the kind of pad that is used in swamp coolers. They are commonly used in greenhouse cooling.
http://www.igcusa.com/greenhouse_coo...nformation.htm
The water dripping down the cooling pads is cool, actually it is equal to the exit temp. of the air.
For example, right now the outside temperature is 33, the temp of the air leaving the pads is 22, water in the cooling tanks is 22 as well, and the temp in the middle of the greenhouse is 26. The
nutrient solution is 27. (all in celcius)
This is a 15 meter square hobby greenhouse in my terrace, I am not on the ground. I am in Europe, so don't worry about the name of the department, we probably don't have it here anyway.
It is true that since the temperature diff. is small, I need a lot of tubing and flow rate.
I will look for steel tubing formed in coils.
Thank you for your help.