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Wet-bulb temperature

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Re: Wet-bulb temperature

#141

Post by generic92034 »

jncfhnb wrote: post #126
generic92034 wrote: post #111

Earlier quoted context omitted.

I think that point was well understood, by falcolas, to whom I was replying. But your assumption that it is not that hard to cool down seems a bit strong to me. In some countries electricity becomes unavailable quite regularly, so relying on A/C during a crisis like that might fail. And that is assuming that A/Cs are common (they are not, in large parts of the world). Cooling yourself down by using water from a tap m…

You don’t need much water. It doesn’t need to be that cool either. If you lack access to the water required to do this, which does not even need to be clean, then the lack of water is probably the bigger crisis. Heatwaves and infrastructure failures can undoubtedly be serious threats. But the vast, vast majority of people survive wet bulb events when they encounter them.

So you are saying a small amount of water would be enough to cool you down when it is (for example) 35° C at 90% humidity? How would that work? Evaporative cooling is out, for the most part and a small amount of water would be heated up to 35° C in no time.

Re: Wet-bulb temperature

#143

Post by sokoloff »

gorbypark wrote: post #17

I worked as a snowmaker at ski resorts for most my my adult life before getting into tech. We always use wet bulb temperatures because it’s a representation of temperature and humidity. With extremely low humidity, you can actually make manmade snow at about +3 degrees Celsius. That was always fun but scary, because a small change in humidity can turn snowguns into water guns in the blink of an eye.

I’ve occasionally wanted to try snowmaking at home on brutally cold days.

Any tips for someone wanting to try this at home? Let’s assume that I have access to tap water at 60psi dynamic pressure and air at 90psi and 10 SCFM continuous (more for short bursts if needed).

Re: Wet-bulb temperature

#145

Post by sokoloff »

aidenn0 wrote: post #124
NotMichaelBay wrote: post #119

Earlier quoted context omitted.

> Anybody without AC would die Couldn't you just eat ice to keep cool? Heat from blood transfers to the ice as it melts and warms in the stomach, then it leaves the body completely through urination.

Yes, consuming below-ambient liquids can cool you off. This will likely involve some form of refrigeration. Similarly you could put a giant block of ice in front of a fan and sit there; most people would call this a from of AC though.

Indeed, we even still colloquially quote/measure the cooling capacity of air conditioning in "tons".

A ton of cooling being defined as 12000 BTU/hr, or the rate implied by the latent heat of fusion of 1 ton of ice at 0°C being consumed via melting over 24 hours.

Re: Wet-bulb temperature

#146

Post by dahwolf »

hkpack wrote: post #14
studmuffin650 wrote: post #2

in my opinion, a lot of folks won't take climate change seriously until it adversely affects their way of life in such a dramatic way that they cannot deny it any longer. A wet bulb event, occuring over multiple hours, would be that signal. Piles of dead bodies from folks who either were misinformed or weren't able to move to safety would be quite the wake up call.

> in my opinion, a lot of folks won't take climate change seriously until it adversely affects their way of life in such a dramatic way that they cannot deny it any longer. It won't. People you are talking about have access to air conditioning. They will not care about people dying in distant places, whom become an annoyance after a while. They will just wish people die silently without complaining.

As is the case with the new social media meme where "Europoors" don't have ACs and should be ridiculed for it.

Re: Wet-bulb temperature

#147

Post by dahwolf »

I personally believe that I've been in a short-lived "wet bulb" situation twice in my life. In both cases, in the Amazon, pretty much at the equator, at some of the hottest days of the year. 40-45C, humidity near a 100.

A cold shower does nothing, it actually makes it worse as it activates your body to warm up. Stripping naked does nothing. Sweat just streams down the entire body as if a tap is open. It's near impossible to keep up with drinking water.

It was short-lived as the weather was extremely variable, but the feeling of being completely unable to cool down despite throwing everything and the kitchen sink at it, is memorable.

Re: Wet-bulb temperature

#148

Post by Tiktaalik »

jabradoodle wrote: post #105
alangibson wrote: post #54

Earlier quoted context omitted.

A massive failure judging by the numbers. Which is my point. We will continue to feel bad, maybe drop in some metaphorical traffic circles, but do nothing to actually solve the issue.

How is a ~24x reduction in deaths per mile driven a massive failure? What would you call a success? No death, total ban on driving?

Success would be the number in the USA moving in the right direction (down) which it is not as it is currently rising versus other wealthy nations such as France.

Success could have USA/Canada/[insert other poorly faring nation] looking more like the low casualty numbers of other wealthy nations (eg. Norway) as well.

Honestly no death is a pretty good goal. Cynically one could say it's not achievable but trying is nonetheless worth while. In my jurisdiction in Canada I don't see the government even lifting a finger to implement the lowest hanging fruit of policies that would move the needle in the right direction, such is the status quo and politicization of the traffic safety issue. They're not even trying.

Efforts to implement various traffic safety concepts well used elsewhere in safer jurisdictions would be politically attacked here I'm quite sure.

Re: Wet-bulb temperature

#149

Post by ryandrake »

jmcqk6 wrote: post #101
thworp wrote: post #24

Earlier quoted context omitted.

In my experience the issue is not about taking it seriously, I've rarely met someone totally unconcerned in real life. The real issue is what to do about it, how to do it and in what timeframe. With these wet bulb events and the breathless death counts in the media people get the impression that heat waves are bigger killers than cold winters, when it's the opposite (and if you include indirect and long-term deaths b…

> In my experience the issue is not about taking it seriously, I've rarely met someone totally unconcerned in real life. The Republican Party just held their first primary debate among the presidential candidates. They were asked about climate change and only one of them was willing to recognize it as a problem, and my understanding is that she directed action towards China and India. The candidate leading the pack,…

Anecdote: None of my conservative-leaning acquaintances believe that Climate Change is even a top-20 problem, let alone something that requires urgent nationwide or worldwide action. I believe the filter bubble is real.

Re: Wet-bulb temperature

#150

Post by jncfhnb »

generic92034 wrote: post #141
jncfhnb wrote: post #126

Earlier quoted context omitted.

You don’t need much water. It doesn’t need to be that cool either. If you lack access to the water required to do this, which does not even need to be clean, then the lack of water is probably the bigger crisis. Heatwaves and infrastructure failures can undoubtedly be serious threats. But the vast, vast majority of people survive wet bulb events when they encounter them.

So you are saying a small amount of water would be enough to cool you down when it is (for example) 35° C at 90% humidity? How would that work? Evaporative cooling is out, for the most part and a small amount of water would be heated up to 35° C in no time.

You just put your feet in the water and transfer heat to the water. It would not heat up to 35 in no time.
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