7 ms·

Just a personal anecdote to provide some context of how hot it really is. I'm from the south of India and now live in Europe. My body tolerates heat quite wel

Just a personal anecdote to provide some context of how hot it really is. I'm from the south of India and now live in Europe. My body tolerates heat quite well compared to my European friends. I remember tolerating 38-40C indoor temperatures and sleeping through it with heavy sweating. But air temperature of 42C is where I draw the line. It is almost biologically impossible to survive this. So this story isn't just about record high temperatures, it's about record high temperatures that coincide with biological limits. If air temperature reaches 44C, it's impossible to survive this without artificial cooling and I predict a state of emergency will be declared every summer starting 2030. There's one additional factor. The hottest months in the equator are June to August. This happens to coincide with the monsoon season in India. So I remember dreading May but looking forward to the monsoon in June. If climate change messes with the monsoon season, the Indian subcontinent is f'ed.

mensetmanusman 4y ago
This is also known as the wet bulb temperature, and it is a function of the humidity. https://en.m.wikipedia.org/wiki/Wet-bulb_temperature https://en.m.wikipedia.org/wiki/Wet-bulb_temperature If I were in a position of decision making in India, I would invest in large deployments of passive radiative cooling films: https://www.3m.com/3M/en_US/energy-conservation-us/applications/passive-radiative-cooling/ https://www.3m.com/3M/en_US/energy-conservation-us/applicati... These reflect nearly all the sunlight energy and cool their surroundings night and day by controlled black body emmisive radiation. (interestingly, for cooling applications, per unit area they are more power efficient than solar panels + AC, because solar only is working during the day, whereas passive cooling films also work at night)
- Retric 4y ago
  That doesn’t seem to line up with the marketing you linked. “10-20% energy savings when integrated with building refrigeration and HVAC systems.” PV on the roof can normally provide 100% of the energy needed for AC.
  - mensetmanusman 4y ago
    It’s a per-unit-area comparison: https://www.betonconsultingeng.com/passive-radiative-cooling-saves-energy/ https://www.betonconsultingeng.com/passive-radiative-cooling... “”SkyCool arrays work by cooling a fluid that moves below the panels and is pumped through refrigeration systems. The cooling helps reduce the run time of motors in the refrigeration system to reduce electricity consumption. All told, the SkyCool system can reject heat at about 100 watts per square meter, saving between 450 and 550 kilowatt-hours per square meter every year—twice the average production of a solar panel.—Brooks Johnson, Star Tribune, 12 March 2022“”
    - Retric 4y ago
      Ok, that’s your problem it’s about 2400Wh of heat moved per day per m2. A solar panel should be collecting ~1600Wh/day of electricity/m2, but an AC can then use that electricity to remove ~4,800Wh of heat. And that’s assuming you need to remove heat 24/7/365. A solar panel can also provide electricity when cooling is unnecessary. Things get even worse if you need pumps etc to circulate a fluid under the film, which is presumably why that 10-20% cost savings figure was suggested.
      - mensetmanusman 4y ago
        Don’t necessarily need pumps, depending on what you are trying to do: https://www.abc15.com/weather/impact-earth/asu-testing-new-material-to-make-tempe-bus-stops-cooler?_amp=true https://www.abc15.com/weather/impact-earth/asu-testing-new-m... This is what I was thinking of in the case of India :) Edit: wanted to add, application of this technology might require government level systems thinking. With an air conditioner, that heat being moved is being pushed to your neighbor, passive cooling technology rejects much of the heat out of the earth. I.e., AC contributes to the urban heat island effect, the situation snowballs and makes everyone’s AC have to run even harder. Passive cooling films are a mitigation for the urban heat island effect.
        Retric 4y ago
- jillesvangurp 4y ago
  A wet bulb related crisis in India is used as a plot point in Kim Stanley Robinson's latest novel Ministry for the Future. The way he describes the wet bulb event is quite scary. (edit: corrected author and title, I confused this with Neal Stephenson's latest Termination Shock). Imagine something like that happening in a slum. It's the combination of humidity, temperature and poverty that is deadly. Think mass casualties (millions of people). No air conditioned environments to escape the heat. Limited access to clean water. Flaky electricity systems that cause what little capacity there is to cool anything to fail. Temperatures at night drop a little but not by enough to provide much relief. Robinson does a great job of making you believe how real this would be and what it would look like. The human body loses the ability to cool it self with 100% humidity. Sweat no longer evaporates. Basically, people start dropping like flies once that gets out of control. It's not survivable for more than a few hours. Any water you'd use for cooling no longer evaporates and would in any case have an ambient temperature that is close to or higher than your body temperature. Instead of cooling your body, it would just heat it up quicker. This is a very near future science fiction novel that describes a very scary reality that we might be dealing with on a regular basis pretty soon. North West US and Canada actually got a sneak preview when temperatures in the US and Canada hit record highs last summer.
  - germinalphrase 4y ago
    He did a talk at the Long Now Foundation recently: https://longnow.org/ideas/02021/11/10/climate-futures-beyond-02022/ https://longnow.org/ideas/02021/11/10/climate-futures-beyond...
    - germinalphrase 4y ago
      FWIW: he calls himself out in the talk on the lack of clarity between sabotage and murder.
  - ch4s3 4y ago
    I thought the setup for that book was interesting, but it's probably his worst book IMHO (though I haven't read all of them). Normally I'm careful about attributing the actions of characters to novelists, but Robinson seems to be increasingly advocating terrorism in his books and it's getting really off-putting.
akrain 4y ago
I live in a suburb of Delhi and to be honest it is not just the occasional days that it stays that high. This year it has consistently been above 40C since late March. Summer has just started and the hottest months are generally May and June. So, it is going stay like this for more than three months this year in all. Even worse is that unlike desert regions, even the night temperatures here stay above 30C many times during this part of the year. Sometimes you open the window at night expecting it to be better only to realize that a hot "breeze" is blowing. Owing to the pandemic, I had spent the last couple of years in the foothills of the Himalaya where the temperature rarely went beyond 30C. It has been really hard coping up with the heat as it literally sucks the life out of you. Ref: https://www.accuweather.com/en/in/delhi/202396/april-weather/202396?year=2022 https://www.accuweather.com/en/in/delhi/202396/april-weather...
jjav 4y ago
> If air temperature reaches 44C, it's impossible to survive this without artificial cooling Humidity is the other key factor though. When younger I remember a day of walking all around Phoenix for many hours on a day where it was 122F (50C) and while it felt like being inside an oven, it was ok because humidity was close to 0%. But high humidity with high temperatures is what makes it unsurvivable.
bigboy12 4y ago
I grew up in Las Vegas where summer would hit 120-124 F. Very dry heat. Sometimes in August it would rain for a day. Then moved to Arizona where it would hit 125 F once in awhile. Melt your brain.

mensetmanusman 4y ago

This is also known as the wet bulb temperature, and it is a function of the humidity. https://en.m.wikipedia.org/wiki/Wet-bulb_temperature https://en.m.wikipedia.org/wiki/Wet-bulb_temperature If I were in a position of decision making in India, I would invest in large deployments of passive radiative cooling films: https://www.3m.com/3M/en_US/energy-conservation-us/applications/passive-radiative-cooling/ https://www.3m.com/3M/en_US/energy-conservation-us/applicati... These reflect nearly all the sunlight energy and cool their surroundings night and day by controlled black body emmisive radiation. (interestingly, for cooling applications, per unit area they are more power efficient than solar panels + AC, because solar only is working during the day, whereas passive cooling films also work at night)

Retric 4y ago
That doesn’t seem to line up with the marketing you linked. “10-20% energy savings when integrated with building refrigeration and HVAC systems.” PV on the roof can normally provide 100% of the energy needed for AC.
- mensetmanusman 4y ago
  It’s a per-unit-area comparison: https://www.betonconsultingeng.com/passive-radiative-cooling-saves-energy/ https://www.betonconsultingeng.com/passive-radiative-cooling... “”SkyCool arrays work by cooling a fluid that moves below the panels and is pumped through refrigeration systems. The cooling helps reduce the run time of motors in the refrigeration system to reduce electricity consumption. All told, the SkyCool system can reject heat at about 100 watts per square meter, saving between 450 and 550 kilowatt-hours per square meter every year—twice the average production of a solar panel.—Brooks Johnson, Star Tribune, 12 March 2022“”
  - Retric 4y ago
    Ok, that’s your problem it’s about 2400Wh of heat moved per day per m2. A solar panel should be collecting ~1600Wh/day of electricity/m2, but an AC can then use that electricity to remove ~4,800Wh of heat. And that’s assuming you need to remove heat 24/7/365. A solar panel can also provide electricity when cooling is unnecessary. Things get even worse if you need pumps etc to circulate a fluid under the film, which is presumably why that 10-20% cost savings figure was suggested.
    - mensetmanusman 4y ago
      Don’t necessarily need pumps, depending on what you are trying to do: https://www.abc15.com/weather/impact-earth/asu-testing-new-material-to-make-tempe-bus-stops-cooler?_amp=true https://www.abc15.com/weather/impact-earth/asu-testing-new-m... This is what I was thinking of in the case of India :) Edit: wanted to add, application of this technology might require government level systems thinking. With an air conditioner, that heat being moved is being pushed to your neighbor, passive cooling technology rejects much of the heat out of the earth. I.e., AC contributes to the urban heat island effect, the situation snowballs and makes everyone’s AC have to run even harder. Passive cooling films are a mitigation for the urban heat island effect.
      - Retric 4y ago
jillesvangurp 4y ago
A wet bulb related crisis in India is used as a plot point in Kim Stanley Robinson's latest novel Ministry for the Future. The way he describes the wet bulb event is quite scary. (edit: corrected author and title, I confused this with Neal Stephenson's latest Termination Shock). Imagine something like that happening in a slum. It's the combination of humidity, temperature and poverty that is deadly. Think mass casualties (millions of people). No air conditioned environments to escape the heat. Limited access to clean water. Flaky electricity systems that cause what little capacity there is to cool anything to fail. Temperatures at night drop a little but not by enough to provide much relief. Robinson does a great job of making you believe how real this would be and what it would look like. The human body loses the ability to cool it self with 100% humidity. Sweat no longer evaporates. Basically, people start dropping like flies once that gets out of control. It's not survivable for more than a few hours. Any water you'd use for cooling no longer evaporates and would in any case have an ambient temperature that is close to or higher than your body temperature. Instead of cooling your body, it would just heat it up quicker. This is a very near future science fiction novel that describes a very scary reality that we might be dealing with on a regular basis pretty soon. North West US and Canada actually got a sneak preview when temperatures in the US and Canada hit record highs last summer.
- germinalphrase 4y ago
  He did a talk at the Long Now Foundation recently: https://longnow.org/ideas/02021/11/10/climate-futures-beyond-02022/ https://longnow.org/ideas/02021/11/10/climate-futures-beyond...
  - germinalphrase 4y ago
    FWIW: he calls himself out in the talk on the lack of clarity between sabotage and murder.
- ch4s3 4y ago
  I thought the setup for that book was interesting, but it's probably his worst book IMHO (though I haven't read all of them). Normally I'm careful about attributing the actions of characters to novelists, but Robinson seems to be increasingly advocating terrorism in his books and it's getting really off-putting.

akrain 4y ago

I live in a suburb of Delhi and to be honest it is not just the occasional days that it stays that high. This year it has consistently been above 40C since late March. Summer has just started and the hottest months are generally May and June. So, it is going stay like this for more than three months this year in all. Even worse is that unlike desert regions, even the night temperatures here stay above 30C many times during this part of the year. Sometimes you open the window at night expecting it to be better only to realize that a hot "breeze" is blowing. Owing to the pandemic, I had spent the last couple of years in the foothills of the Himalaya where the temperature rarely went beyond 30C. It has been really hard coping up with the heat as it literally sucks the life out of you. Ref: https://www.accuweather.com/en/in/delhi/202396/april-weather/202396?year=2022 https://www.accuweather.com/en/in/delhi/202396/april-weather...

jjav 4y ago

> If air temperature reaches 44C, it's impossible to survive this without artificial cooling Humidity is the other key factor though. When younger I remember a day of walking all around Phoenix for many hours on a day where it was 122F (50C) and while it felt like being inside an oven, it was ok because humidity was close to 0%. But high humidity with high temperatures is what makes it unsurvivable.

bigboy12 4y ago

I grew up in Las Vegas where summer would hit 120-124 F. Very dry heat. Sometimes in August it would rain for a day. Then moved to Arizona where it would hit 125 F once in awhile. Melt your brain.