Further cooling evaporative cooled air.... would this work?

In summary, the conversation discusses the effectiveness of using evaporative cooling to chill air even further and the potential challenges such as energy efficiency and melting ice. The process of pumping air through a coil and cooling it with ice water is suggested as a possible solution. The use of 100% outside air for cooling in hot and dry climates is also mentioned. The idea of using wood-shaving or Aspen pads for evaporative cooling is discussed, with the suggestion to use MasterCool rigid media instead. The potential issue of high humidity resulting from further cooling of already cooled air is also brought up.
  • #1
Rich76
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Evaporative cooling is pretty cold, but I wonder how effective the following would be at chilling the air even further, even if not very energy efficient with having to freeze ice, additional air pump, etc. I was thinking that since the air in the air chamber was cooled, the ice would melt at a much slower rate. I imagine the air pump would not be able to move the air as quickly as the fan pulls it in, too.. Any educated thoughts on this?

Thanks
COLDAIR.png
 
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  • #2
Rich76 said:
Evaporative cooling is pretty cold, but I wonder how effective the following would be at chilling the air even further, even if not very energy efficient with having to freeze ice, additional air pump, etc. I was thinking that since the air in the air chamber was cooled, the ice would melt as a much slower rate. I imagine the air pump would not be able to move the air as quickly as the fan pulls it in, too.. Any educated thoughts on this?

ThanksView attachment 205007
Could you explain the process after the evaporative cooler please. It isn't clear to me what is happening. Are you pumping air through the coil and cooling it with ice water?
 
  • #3
russ_watters said:
Could you explain the process after the evaporative cooler please. It isn't clear to me what is happening. Are you pumping air through the coil and cooling it with ice water?
Sorry. Yes, that is exactly right. I haven't tried, nor do I have any idea if it would work, effectively.
 
  • #4
Rich76 said:
Sorry. Yes, that is exactly right. I haven't tried, nor do I have any idea if it would work, effectively.
Well, it's exactly the opposite of how a normal air conditioner works. Since the water has a higher energy density, you need a lower volume of it than you need of air for proper heat exchange. Besides which, compression of the air brings energy losses. So the best way to do it is the normal way: run the cold water through the coil and blow the air across it with a normal fan.
 
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  • #5
russ_watters said:
Well, it's exactly the opposite of how a normal air conditioner works. Since the water has a higher energy density, you need a lower volume of it than you need of air for proper heat exchange. Besides which, compression of the air brings energy losses. So the best way to do it is the normal way: run the cold water through the coil and blow the air across it with a normal fan.
Interesting! Thank you so much.
 
  • #6
You also have to consider the amount of water you are putting in the air with your evaporative cooling. The air being very high humidity produces a large amount of heat when cooled due to condensation.

BoB
 
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  • #7
rbelli1 said:
You also have to consider the amount of water you are putting in the air with your evaporative cooling. The air being very high humidity produces a large amount of heat when cooled due to condensation.

BoB
Thank you for the information. Where I live the air is dry and hot. I plan to test different pad thicknesses, and levels of water saturation to see which combination offers the greatest cooling effect.
 
  • #8
Rich76 said:
Thank you for the information. Where I live the air is dry and hot. I plan to test different pad thicknesses, and levels of water saturation to see which combination offers the greatest cooling effect.
By the way, I didn't comment on your overall concept before, but in hot and dry climates, air conditioners (particularly ones that need to be 100% outside air) do indeed use this exact method of two-stage cooling. I've even seen indirect evaporative cooling (adds the humidity to the exhaust, not the supply airstream) used in the northeastern US.
 
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  • #9
russ_watters said:
...100% outside air) do indeed use this exact method of two-stage cooling.

This is possibly off topic but what necessitated the need for 100% outside air?

BoB
 
  • #10
rbelli1 said:
This is possibly off topic but what necessitated the need for 100% outside air?
Laboratory and industrial ventilation mostly. High occupancy or exhaust driven spaces like commercial cafeterias/kitchens may also have it.

And, of course, when the air outside is cooler/drier than the air inside you can use part time "economize mode" or full time evaporative cooling.
 
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  • #11
Having lived in the desert in the past, I've learned that new wood-shaving pads in an evap. cooler don't work very well the first season. After they have aged and been thru a few dust or sand storms they are substantially improved. When new, you get quite high humidity in the building and only so-so cooling, subsequent seasons they work fine but slowly degrade over several years.
 
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  • #12
russ_watters said:
By the way, I didn't comment on your overall concept before, but in hot and dry climates, air conditioners (particularly ones that need to be 100% outside air) do indeed use this exact method of two-stage cooling. I've even seen indirect evaporative cooling (adds the humidity to the exhaust, not the supply airstream) used in the northeastern US.

That's great to hear. I feel like I'm on the right track then. I too want to use 100% of the outside air. I'm trying to make a very small mobile air cooler to cool just a few cubic feet of space.

Tom.G said:
Having lived in the desert in the past, I've learned that new wood-shaving pads in an evap. cooler don't work very well the first season. After they have aged and been thru a few dust or sand storms they are substantially improved. When new, you get quite high humidity in the building and only so-so cooling, subsequent seasons they work fine but slowly degrade over several years.

Originally, I was going to use Dura-Cool pads until I read negative reviews, and then I thought I'd go with Aspen pads, but now I'm thinking about trying MasterCool rigid media which costs more.
 
  • #13
Further cooling of the air you previously cooled with evaporative cooling is going to result in very high humidity. The temperature will be lower than without the additional cooling, but it probably won't feel much cooler unless it is being mixed with fairly dry air in the house.
What would make more sense would be to skip the difficult to sustain ice in water through coils part and use a heat exchanger to leverage the dry air advantage you have there.
Cool outside air evaporatively and have this precool your inside air through the heat exchanger.
The outside air is either then exhausted or precools the incoming outside air in a regenerative cycle heat exchanger and is then exhausted.
The previous can be repeated in more stages if desired for colder air, at the cost of heat exchangers and fans.
The inside air, once precooled through the heat exchanger can be evaporatively cooled through a wet pad.
 

1. How does evaporative cooling work?

Evaporative cooling works by using the principle of evaporation to lower the temperature of the air. Water is introduced into the air, and as it evaporates, it absorbs heat from the surrounding air, thus lowering the temperature.

2. Can evaporative cooling be used for further cooling already cooled air?

Yes, it is possible to use evaporative cooling to further lower the temperature of already cooled air. By introducing more water into the air, the evaporation process will continue and further decrease the temperature.

3. What factors affect the effectiveness of evaporative cooling?

The effectiveness of evaporative cooling can be affected by factors such as the humidity level of the air, the temperature of the air, and the rate of air flow. Higher humidity, lower temperatures, and faster air flow will result in a more effective cooling process.

4. Are there any limitations to using evaporative cooling for further cooling air?

Yes, there are some limitations to using evaporative cooling for further cooling air. It is most effective in dry climates, and in humid climates, it may not be as effective. Additionally, the cooling effect may not be as significant in already cooled air compared to hot air.

5. Are there any potential drawbacks to using evaporative cooling for further cooling air?

One potential drawback of using evaporative cooling for further cooling air is that it can increase the humidity levels in the surrounding area. This may not be desirable in certain environments, such as a laboratory or electronics room, where low humidity is necessary. Additionally, evaporative cooling may not be as efficient as traditional air conditioning methods in cooling large spaces.

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