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

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Discussion Overview

The discussion revolves around the effectiveness of further cooling air that has already been subjected to evaporative cooling. Participants explore the potential methods and implications of using ice and air pumps in conjunction with evaporative cooling systems, considering energy efficiency and humidity effects.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • Some participants propose using ice to further cool air after it has been evaporatively cooled, questioning the effectiveness and energy efficiency of this method.
  • Others seek clarification on the cooling process, specifically whether air is pumped through coils cooled by ice water.
  • One participant explains that the method discussed is contrary to how traditional air conditioning operates, emphasizing the need for proper heat exchange between air and water.
  • Concerns are raised about the humidity introduced by evaporative cooling, which can produce heat due to condensation, particularly in high humidity environments.
  • Another participant shares their intention to experiment with different pad thicknesses and water saturation levels in a dry climate to optimize cooling effects.
  • Indirect evaporative cooling methods are mentioned as being effective in certain climates, suggesting a potential model for the discussed cooling system.
  • One participant notes the performance of new wood-shaving pads in evaporative coolers, indicating that they may not work effectively until they have aged through use.
  • A suggestion is made to use a heat exchanger to leverage the advantages of dry air, proposing a system that could pre-cool incoming air before it is evaporatively cooled.

Areas of Agreement / Disagreement

Participants express a range of views on the effectiveness and practicality of further cooling methods, with no consensus reached on the best approach. Some agree on the challenges posed by humidity, while others propose different cooling strategies without resolving the overall effectiveness of the initial concept.

Contextual Notes

Participants highlight limitations related to energy efficiency, humidity effects, and the performance of cooling pads over time. The discussion also reflects varying environmental conditions that may influence the effectiveness of the proposed methods.

Who May Find This Useful

This discussion may be of interest to individuals exploring innovative cooling solutions, particularly in dry climates, as well as those involved in HVAC design or experimental cooling systems.

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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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?
 
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.
 
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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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.
 
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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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.
 
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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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
 
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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.
 

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