4 ms·

I was in Phoenix last summer in what (to my poor Canadian body) was the hottest day ever, anywhere. I think it was like 111F / 44C. While my friends and I were

by mabbo 7y ago

I was in Phoenix last summer in what (to my poor Canadian body) was the hottest day ever, anywhere. I think it was like 111F / 44C. While my friends and I were over at an outdoor mall looking for dinner, we entered a spot that was more than 10C lower than the ambient temperature. Just instantly colder. I honestly stopped in my tracks. Above us, a mister was spraying water. None of the water was coming within 10 feet of the ground as it all instantly evaporated- Phoenix is a desert- but in doing so, the air was chilled. The cold air dropped, cooling this small area. I cannot believe just how effective this means was. Now, granted, to do this they had to waste clean fresh water in the middle of a desert, which isn't great. But it does go to show the potential of some of these tricks. May not work in 99% humidity, mind you, but there are other tricks up the sleeve of the clever engineer.

ebiester 7y ago
It's called evaporative cooling, and until recently the principle was the way the vast majority of Arizonans cooled their houses. (They are called swamp coolers down there.) It only works in dry climates, but it makes such a difference.
- JustSomeNobody 7y ago
  Yeah, I'm from FL. Swamp coolers don't work most days. Just makes ya wetter. I was in Az a couple months ago and it was pretty neat figuring out that sweat truly does work.
- cr0sh 7y ago
  Also - it only works for part of the summer; we're in our so-called "monsoon season" right now, and humidity is highly variable, but is generally above what most evap coolers will help with. However, if there is some evaporation that can takes place (that is, the evap gradient is large enough to let it happen, but directly using that cooler air would make it uncomfortably humid), you can instead do what is called "evaporative chilling" (or something like that), where you run the water over a radiator, and the water evaporates, cooling the radiator (actually, removing the heat), and inside the radiator, you run coolant/water mix - that's your outdoor side. Inside you have another radiator, with a fan circulating air over it. It's something like an A/C system, with water/coolant as the "working fluid" and no compressor, just a pump. Think of it like a "dry evaporative cooler". This kind of system does work - it's actually used for industrial A/C systems as some kind of "pre-chiller" or something, but it isn't something you can buy for a home that I know of - but you can build it. But like all evap systems, once the humidity gets too high, it stops working. Another kind of system that can be used here in Arizona, but few do because it is ugly, big, and works only so well - are something called "solar chimneys". The simplest is just a large 2-3 story structure painted mostly white at the bottom and mostly black toward the top; the idea is that the sun warms it, sucking air thru it and out the top - the bottom end is connected to the house, to make a "forced draft" through the house. The better way is to make a similar "chimney" on the opposite side of the house and add cooling pads and a fan at the top (basically a large diy swamp cooler). Misting can also be used. So you evap cool the air, which falls, enters the house, then is sucked up and out the other side by the "hot" chimney. Another "hot climate" design for cooling is something that used to be found all over the middle east: https://en.wikipedia.org/wiki/Windcatcher https://en.wikipedia.org/wiki/Windcatcher Sometimes used in combination with: https://en.wikipedia.org/wiki/Qanat https://en.wikipedia.org/wiki/Qanat As you can see, this is basically the ancient form of "solar chimneys" - if we instead used these in Arizona, coupled with either monolithic dome construction and/or rammed earth, and below-grade construction (to take advantage of earth insulation and cooling) - it'd be so much better for energy use here in Arizona.
  - ebiester 7y ago
    Oh, this irritated me so much growing up in Tucson. I would read about something like passive water heating, or all of the ways we could reduce our need for AC (even back growing up where climate change was more theoretical) and saw that people didn't care.
Ididntdothis 7y ago
In Southern California the dry air often gives me breathing problems so this may offer another benefit besides cooling .
cr0sh 7y ago
> I think it was like 111F / 44C. HA! That's like a cool summer day - stay a while here in Phoenix, and you can easily experience 120+F days at times. Nothing like it being 2am and 100+F degrees outside... On the flipside - shorts at Christmas-time!
- scruple 7y ago
  I was living in Riverside county in 2016. In late June, I remember one day in particular the thermometer on the back porch read 119F in partial shade. I had to drive to Phoenix later that day to help a family member (one of my wifes aunts, her daughter had recently and unexpectedly passed and she was elderly, alone, was having issues with her AC and couldn't get things sorted out on her own). I left Murrieta around 10PM and while passing through the desert around midnight, close to the AZ/CA border, I had to stop and take a picture of the temperature gauge on my car. Midnight and 102F. It blew my mind. I knew that it was going to stay hot but I'd have never thought that it'd be > 100F at midnight. It gave me a renewed respect for this desert that we live near (and that you live in...).
- novok 7y ago
  My question is, why did somewhere so inhospitiable grow so large? There is no stand out industry like las vegas.

by mabbo 7y ago

ebiester 7y ago

It's called evaporative cooling, and until recently the principle was the way the vast majority of Arizonans cooled their houses. (They are called swamp coolers down there.) It only works in dry climates, but it makes such a difference.

JustSomeNobody 7y ago
Yeah, I'm from FL. Swamp coolers don't work most days. Just makes ya wetter. I was in Az a couple months ago and it was pretty neat figuring out that sweat truly does work.
cr0sh 7y ago
Also - it only works for part of the summer; we're in our so-called "monsoon season" right now, and humidity is highly variable, but is generally above what most evap coolers will help with. However, if there is some evaporation that can takes place (that is, the evap gradient is large enough to let it happen, but directly using that cooler air would make it uncomfortably humid), you can instead do what is called "evaporative chilling" (or something like that), where you run the water over a radiator, and the water evaporates, cooling the radiator (actually, removing the heat), and inside the radiator, you run coolant/water mix - that's your outdoor side. Inside you have another radiator, with a fan circulating air over it. It's something like an A/C system, with water/coolant as the "working fluid" and no compressor, just a pump. Think of it like a "dry evaporative cooler". This kind of system does work - it's actually used for industrial A/C systems as some kind of "pre-chiller" or something, but it isn't something you can buy for a home that I know of - but you can build it. But like all evap systems, once the humidity gets too high, it stops working. Another kind of system that can be used here in Arizona, but few do because it is ugly, big, and works only so well - are something called "solar chimneys". The simplest is just a large 2-3 story structure painted mostly white at the bottom and mostly black toward the top; the idea is that the sun warms it, sucking air thru it and out the top - the bottom end is connected to the house, to make a "forced draft" through the house. The better way is to make a similar "chimney" on the opposite side of the house and add cooling pads and a fan at the top (basically a large diy swamp cooler). Misting can also be used. So you evap cool the air, which falls, enters the house, then is sucked up and out the other side by the "hot" chimney. Another "hot climate" design for cooling is something that used to be found all over the middle east: https://en.wikipedia.org/wiki/Windcatcher https://en.wikipedia.org/wiki/Windcatcher Sometimes used in combination with: https://en.wikipedia.org/wiki/Qanat https://en.wikipedia.org/wiki/Qanat As you can see, this is basically the ancient form of "solar chimneys" - if we instead used these in Arizona, coupled with either monolithic dome construction and/or rammed earth, and below-grade construction (to take advantage of earth insulation and cooling) - it'd be so much better for energy use here in Arizona.
- ebiester 7y ago
  Oh, this irritated me so much growing up in Tucson. I would read about something like passive water heating, or all of the ways we could reduce our need for AC (even back growing up where climate change was more theoretical) and saw that people didn't care.

Ididntdothis 7y ago

In Southern California the dry air often gives me breathing problems so this may offer another benefit besides cooling .

cr0sh 7y ago

> I think it was like 111F / 44C. HA! That's like a cool summer day - stay a while here in Phoenix, and you can easily experience 120+F days at times. Nothing like it being 2am and 100+F degrees outside... On the flipside - shorts at Christmas-time!

scruple 7y ago
I was living in Riverside county in 2016. In late June, I remember one day in particular the thermometer on the back porch read 119F in partial shade. I had to drive to Phoenix later that day to help a family member (one of my wifes aunts, her daughter had recently and unexpectedly passed and she was elderly, alone, was having issues with her AC and couldn't get things sorted out on her own). I left Murrieta around 10PM and while passing through the desert around midnight, close to the AZ/CA border, I had to stop and take a picture of the temperature gauge on my car. Midnight and 102F. It blew my mind. I knew that it was going to stay hot but I'd have never thought that it'd be > 100F at midnight. It gave me a renewed respect for this desert that we live near (and that you live in...).
novok 7y ago
My question is, why did somewhere so inhospitiable grow so large? There is no stand out industry like las vegas.