Evaporarive cooling. How to calculate the cooling of the air?

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In summary, the effectiveness of evaporative coolers can be determined by the temperature difference that can be achieved when blowing air with a humidity of 10% through a fan and spraying it with room temperature water (27 C). The amount of humidity can be controlled by adjusting the amount of water sprayed, with a higher amount resulting in 100% humidity and a lower amount resulting in 40% humidity. Further information can be found in the book "Mass Transfer Operations" by Treybel, as well as Wikipedia articles on Wet bulb and Dew point.
  • #1
hacillunation
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Hey,
So I'm trying to figure out how effective evaporative coolers are...

Lets say, I have a box with 3 cubic meters of air with a humidity of a 10%. I blow it out with a fan and spary with water as it leaves the fan.
The water is room temp (which is let's say 27 C).

What temperature difference should I expect?
Is there a way to control the amount of humidity by spraying more or less water? (How can I reach 100% humidity versus 40%)?



Thank you very much!


P.S I read wikipedia about Wet bulb, and Dew point... That didn't really helped me out...
 
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  • #2
See Treybel, Mass Transfer Operations
 

1. What is evaporative cooling?

Evaporative cooling is a process where liquid water is converted into water vapor, which removes heat from the surrounding air and lowers its temperature.

2. How does evaporative cooling work?

Evaporative cooling works through the principle of latent heat. When water evaporates, it absorbs heat from the surrounding air, causing the air temperature to drop. This is because energy is required to break the molecular bonds between water molecules and turn them into vapor.

3. What factors affect the rate of evaporative cooling?

The rate of evaporative cooling is affected by several factors, including temperature, humidity, air flow, and surface area. Higher temperatures and low humidity promote faster evaporation, while high air flow and larger surface area allow for more water to be evaporated.

4. How do you calculate the cooling of the air through evaporation?

The cooling effect of evaporation can be calculated using the formula: Q = m * h, where Q is the amount of heat energy absorbed, m is the mass of water evaporated, and h is the latent heat of vaporization of water. The specific heat capacity of water can also be used in the formula to calculate the change in air temperature.

5. What are some practical applications of evaporative cooling?

Evaporative cooling has several practical applications, such as in air conditioning systems, refrigeration, and cooling towers. It is also used in agriculture for crops and livestock, and in industrial processes to cool machinery and equipment.

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