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Old 07-01-2010, 06:29 PM
omerizm omerizm is offline
Junior Member
Join Date: May 2010
Posts: 28

Bending the tube turned out to be difficult without proper tools, so I asked a friend to do it in his toolshop. I hope to have it by tomorrow. I will post pictures.

Let me explain how I have cool water with this evaporative cooler setup. (I find this difficult because English is a second language to me, please forgive me if it does not make sense to you.)

I think you know the concept of evapotative cooling, but I will start with that anyway. Evaporation process requires energy. So as the water evaporates, It takes energy from what is nearby. As a result what is nearby cools down.

So, you want to cool the air. In order to do that, you force air through a pad. You keep the pad wet, so as the air passes by, some water evaporates and draws heat from the air. To wet the pad, you pump water from a reservoir and let it drip on to the pad. The excess water drips down the pad. You collect that water and return it to the reservoir to use it again. So it is a closed system. I don't use the water from the household pipes.

Now this water that is circulated through the pad gets cold in time. It gets down to the exit temp. of the air. Because energy is drawn from the water itself as well as the air passing by. I'm gonna use that water to cool down the nutrient solution. And It will be always cool as long as the evap. cooler oparates, It won't get heated up.

The evap. cooler should always draw fresh air from the outside and that air should have a low relative humidity. If the relative humidity of the incoming air is high, very little or no water will evaporize and thus, no cooling. If you can not get cool air without putting ice in the water, than you are evaporizing no air. Maybe your incoming air is too humid already?

Here is a chart. For example, let incoming air be at 90F. If RH is 10 percent, the air leaving the pad is 67F. And the continuously circulating water will be at 67F as well. But if the RH is 70 percent, than air leaving the pad is 84F, only 6 degrees cooler:
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