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is it possible to acheave 100% relative humidity at the outlet of an evaporative cooler by precooling the air about 2 or 3 degrees?

asked 2017-05-17 07:51:25 -0500

amirrezaheydari gravatar image

updated 2017-05-17 12:06:18 -0500

is it possible to acheave 100% relative humidity at the outlet of an evaporative cooler by precooling the air about 2 or 3 degrees?

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answered 2017-05-18 11:47:47 -0500

Ricardo GAllegos gravatar image

Even if you do not precool,you would need a 100% efficient device.

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Dear Sir Thank you for your answer, but it is not obvious for me. Do you mean that using an evaportative pad alone, I need a 100% efficient pad, but by precooling I can achieve 100% relative humidity? Thank you

amirrezaheydari gravatar imageamirrezaheydari ( 2017-05-19 02:59:26 -0500 )edit

The efficiency of an evaporative cooler is by definition ; e= (tdi - tdo) / (tdi - twi)

tdi= Dry bulb temperature at inlet

tdo = Dry Bulb tempeature at outlet

twi= Wet bulb temperaature at inlet.

The minimum outlet temperature would be twi, and at that point you have 100% saturation. But at the same time, it implies that e=1 (100%) So if you precool, you lower tdi, but only if tdo=twi you can have 100% saturation, and 100 % efficiency, which is not posible. In a pshychrometric chart, you will have two paralel lines, but none touches to the saturation curve.

Ricardo GAllegos gravatar imageRicardo GAllegos ( 2017-05-19 13:48:32 -0500 )edit

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Asked: 2017-05-17 07:51:25 -0500

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Last updated: May 18