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Having a rag of cold water on you will cool you regardless of evaporation. It is a thing that is cooler than the environment. The water from our taps at least i
by donatj 3y ago
Having a rag of cold water on you will cool you regardless of evaporation. It is a thing that is cooler than the environment. The water from our taps at least is a pretty constant like 50°F
- ethanbond 3y agoNice living in the wealthiest country in human history, ain’t it. Do you think this is the case for the billions of people closer to the equator or in poorer countries?
- torstenvl 3y ago[flagged]
- ethanbond 3y agoGood point. Once you look past ideology, water is everywhere to be found. “You just dig up water! Duh!” - Person from The Land of 10,000 Lakes Brilliant. Couldn’t make it up.
- torstenvl 3y agoEverywhere there are people, yes, it is. People cannot survive without water, heat wave or no. EDIT: To respond to your edits: I'm not from Minnesota. And it's hard to imagine what kind of formation would lead you to believe wells only work in places like that.
- ethanbond 3y agoDoes heat increase, decrease, or not affect people’s need for water? > Everywhere there are people, there is water LOL. Yeah bud, that’s because people have to leave when they run out of water, otherwise they die. That is the whole problem.
- deleted 3y ago[deleted]
- athenot 3y agoIn Atlanta the tap water in summer is more like 22°C (72°F), which is coincidentally the average nighttime temperature. I could imagine that a place where the nighttime temperatures are in the mid 30s (°C) would not have any cooler water available.
- netsharc 3y agoLast summer there were reports of the water of Florida's beaches being bath-tub warm...
- Hikikomori 3y agoDo you believe everyone has that available on tap?
- jameshart 3y agoSo you have a supply of water at 50°F - that’s 10°C (an optimistic temperature in many places). And you are using it to try to maintain a body temperature around 37°C. Let’s assume you do so by transferring heat from your body into the water enough to raise its temperature by 25°C - that’s probably overly optimistic given that it will also be warmed by the environment and the rate of transfer will be reduced as the temperature increases, but it’s a working number. The specific heat capacity of water is about 4kJ/kg/°C so a liter of that cold water can absorb 100kJ of energy in the process of warming up. Once it’s warmed up it can’t do any more cooling. Your body, when not working hard, produces about 200W of heat. That’s 200J per second. So that liter of water can absorb your body’s heat output from about 500 seconds of being alive. That’s a little over eight minutes. So that means the cooling needs for one human for one day can be met by about 170 liters of cold, 50°F water. That’s about 44 US Gallons. If, however, that water can evaporate - well, the latent heat capacity of vaporization of water is over 2 thousand kJ per kg. That’s why the wet bulb temperature matters. If water can’t evaporate, that cold water can’t absorb body heat except by just warming up.
- saalweachter 3y ago> Your body, when not working hard, produces about 200W of heat. That’s 200J per second. Minor quibble, 2000 (kilo)calories / 1 day = ~100 Watts.
- jameshart 3y agoFair - I took a number for an active, awake human. You don’t produce that wattage all the time; resting and sleeping have much lower heat output; average power over a day is probably more like 100W (hence that being a reasonable average ‘healthy calorie intake’ number which I assume is where your 2000kCal comes from.)
- darkerside 3y agoFocused resting probably reduces it even further. You're not just "not working hard" in a situation like this, you are barely moving and probably slowing down your metabolism if anything.
- LeifCarrotson 3y agoBecause Minnesota is a cold place. Many of the places where 'wet bulb' events are most likely to happen have only hot water available. The tap water in Phoenix can exceed 100 degrees, people will fill a bathtub in the morning so their home A/C and evaporation will cool it off by the evening. Even river water in India or Southeast Asia can exceed 100 degrees. There is no cold water to wet the rag with unless you have a deep well or refrigeration.
- jijijijij 3y ago> The tap water in Phoenix can exceed 100 degrees, people will fill a bathtub in the morning so their home A/C and evaporation will cool it off by the evening. Eww! They probably have chlorine in their water, huh? I imagine, otherwise the microbial game would be out of control.
- dreamcompiler 3y agoWhat you describe is not universal. I recommend you visit Phoenix in July and open a "cold" water tap.