Optimizing Evaporative Cooling via Sweat in Dry Desert?

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In summary: However, if evaporation cools the air itself, we would still want to allow it to evaporate so that the air is as cool as possible.Thanks for your input.
  • #1
shane2
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Assume a nearly full length thin robe open at top and bottom and largely, somehow, held off a couple inches away from bare naked skin underneath to maximize unrestricted vertical airflow.

Assume desert 120F hot and very dry air can enter/exit at either bottom around ankles or at top around open neck.

When sweat evaporates or vaporizes off skin, cooling the skin there, that resultant vapor exits and more 120F dry air is drawn into replace it.

Is that sweat created moist vaporized air likely to be warmer or cooler than the outside 120F dry desert air?

Which way does it want to naturally flow, up or down?

If vapor is cooler than 120F, would it be preferable then to not move it out too overly fast, which would only draw in even more 120F against skin even faster, adding even more heat load to skin?

I understand additional evaporation requires more dry air replacing that moist vapor, but am trying to optimize just how fast/slow you'd want to do so.

Just fast enough that all sweat presented gets fully evaporated before dripping away to ground, but not so fast that skin gets excessive 120F desert air blast that adds even more heat to skin even quicker, is my thinking here.

Am I missing anything so far?

Next, if any sweat does get onto inside of garment, would it be more efficient for micro-environment there, in cooling skin, if it was impermeable to where when garment sweat evaporated that cooling process (and vapor) was contained onto the inside?

Finally, if from above impermeable garment we could expect the air temp inside garment to be cooler than outside 120F air, would there then not be additional benefit maintaining that cooler micro-environment temp if garment was also insulated against conductive heat gain, too?

Thank you for any thoughts.
 
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  • #2
shane2 said:
Is that sweat created moist vaporized air likely to be warmer or cooler than the outside 120F dry desert air?
Cooler.

That's the basis for "Swamp Coolers", or Evaporative Coolers, used as a cheaper alternative to Air Conditioning in desert areas.
 
  • #3
Tom.G said:
Cooler.

That's the basis for "Swamp Coolers", or Evaporative Coolers, used as a cheaper alternative to Air Conditioning in desert areas.

I thought the cooling of the air was because of the air being blown past the now-cooler surface, not because the evaporated water cooled the air it evaporated into.
 
  • #4
I'm a little unclear about that process, too.

When a swamp cooler has hot/dry air blown through it, it cools that air that went through that wet medium via evaporation, yes?

When sweat on skin evaporates from 120F hot/dry desert air moving atop it, if that vapor created then is cooler than 120F, wouldn't we want to have that not whisked away too quickly?

Quick enough for new dry air to evaporate more sweat, yes, but not so quick skin heats up from excessive blast of more hot/dry air?
 
  • #5
Drakkith said:
I thought the cooling of the air was because of the air being blown past the now-cooler surface, not because the evaporated water cooled the air it evaporated into.

shane2 said:
I'm a little unclear about that process, too.

After a bit more reading, I think that evaporation cools both the surface and the air itself when it evaporates. But I'm really not certain.

shane2 said:
When sweat on skin evaporates from 120F hot/dry desert air moving atop it, if that vapor created then is cooler than 120F, wouldn't we want to have that not whisked away too quickly?

If evaporation cools the surface of the skin, then yes, we would want to whisk away that now-humid air so that more sweat can evaporate.
 

Related to Optimizing Evaporative Cooling via Sweat in Dry Desert?

What is evaporative cooling and how does it work in dry desert environments?

Evaporative cooling is a process by which a liquid, such as sweat, absorbs heat from the surrounding environment and evaporates, thereby reducing the temperature of the surface it is in contact with. In dry desert environments, the low humidity allows for faster evaporation, making it a more effective cooling mechanism.

What factors affect the efficiency of evaporative cooling in dry desert environments?

The efficiency of evaporative cooling in dry desert environments can be affected by several factors, including temperature, humidity, wind speed, and the amount of sweat produced by the body. Higher temperatures, lower humidity, and stronger winds can all increase the rate of evaporation and therefore improve the efficiency of cooling.

How does sweat production vary among individuals and how does it impact evaporative cooling?

Sweat production can vary significantly among individuals due to factors such as genetics, fitness levels, and acclimation to heat. Some people may sweat more than others, which can impact the effectiveness of evaporative cooling as a cooling mechanism. Those who produce more sweat may experience more efficient cooling, but they also risk dehydration if they do not replenish the lost fluids.

Can clothing affect the effectiveness of evaporative cooling in dry desert environments?

Yes, clothing can have a significant impact on the effectiveness of evaporative cooling in dry desert environments. Clothing that is tight or made of materials that do not allow for air circulation can hinder the evaporation of sweat, making it less efficient as a cooling mechanism. Loose, breathable clothing can help facilitate evaporation and improve cooling.

Are there any potential risks or limitations to relying on evaporative cooling as a means of regulating body temperature in dry desert environments?

While evaporative cooling can be an effective means of regulating body temperature in dry desert environments, there are some potential risks and limitations to consider. If sweat production is not enough to keep up with the body's cooling needs, heat exhaustion or heat stroke may occur. Additionally, relying solely on evaporative cooling may lead to dehydration if adequate fluids are not consumed. It is important to monitor both sweat production and fluid intake to ensure safe and effective cooling in dry desert environments.

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