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Ever since our ancestors mastered fire, humans have been able to warm themselves. Cooling down when it's hot has been more challenging.
The eccentric Roman emperor Elagabulus sent slaves to bring snow down from the mountains and pile it in his garden, where breezes would carry the cooler air inside.
[...] Needless to say, this was not a scalable solution. At least, not until the 19th century, when Boston entrepreneur Frederic Tudor amassed an unlikely fortune doing something similar.
He took blocks of ice from frozen New England lakes in winter, insulated them in sawdust, and shipped them to warmer climes for summer.
Until artificial ice-making took off, mild New England winters caused panic about an "ice famine".
Air conditioning as we know it began in 1902, but it had nothing to do with human comfort.
New York's Sackett & Wilhelms Lithographing and Printing Company became frustrated with varying humidity levels when trying to print in colour.
The same paper had to be printed four times in four colours, and if the humidity changed between print runs, the paper would slightly expand or contract. Even a millimetre's misalignment looked awful.
(Score: 2, Funny) by Anonymous Coward on Tuesday June 06 2017, @09:53PM (6 children)
I can think of other things 100 times more important. Why the hard-on for AC? Oh that's me... *blush* :)
(Score: 2) by JNCF on Tuesday June 06 2017, @09:56PM (4 children)
Fridges are just air conditioners in a smaller box.
(Score: 3, Interesting) by Grishnakh on Tuesday June 06 2017, @10:16PM (3 children)
Yes, but what's interesting is that refrigerators came before air conditioning. See Wikipedia [wikipedia.org]. Fridges (the vapor-compression type we use now, not simple iceboxes) were invented in the 1830s, and the first practical ones in the 1850s, with commercial ice-making machines being in use in the early 1850s.
Basically we have this backwards: all Carrier did was take existing refrigeration technology, which generally used ammonia, and apply it to rooms for controlling humidity, with the side effect of keeping people cool. And of course the big thing that probably made this feasible was the availability of electricity cheap enough to do so, something that didn't exist in the 1850s when they probably had to use mechanical means to drive the compressors, such as water wheels.
(Score: 2) by captain normal on Tuesday June 06 2017, @10:56PM (2 children)
Steam engines were well developed by 1850. It was used in 1837 to drive ventilation fans.
https://en.wikipedia.org/wiki/Fan_(machine) [wikipedia.org]
Having spent a good portion of my adult life in tropical climes I've found that lacking shade and a cooling ocean breeze, a ceiling fan works wonders. Also drives the mosquitoes away at night.
Aside note: to me it seems it would have been easier to send the Roman Emperor to the snow rather than bringing the snow to him. But I guess despots are unable to think like that.
Everyone is entitled to his own opinion, but not to his own facts"- --Daniel Patrick Moynihan--
(Score: 0) by Anonymous Coward on Wednesday June 07 2017, @01:03PM
You have it backwards: being able to make everyone else do irrational things for your enjoyment is one of the biggest perks of being a despot.
(Score: 2) by Grishnakh on Wednesday June 07 2017, @03:03PM
Ok, but even with steam engines now you're looking at having to have a big, noisy steam engine and all the associated overhead (giant pile of coal, big smoke-belching smokestack) located right next to your A/C unit to make it work. Installing this at the White House means it won't be white much longer.
This is one of the reasons we use electricity; we can move the power sources somewhere far away from the places we utilize the energy.
(Score: 2) by kaszz on Wednesday June 07 2017, @03:04AM
I heard "Anonymous Conditioner" is a thing :p
(Score: 2) by edIII on Tuesday June 06 2017, @10:04PM (6 children)
The Peltier effect was understood in 1834. With the application of electricity to it you have a solid state air condition circuit in 1834.
Probably horribly inefficient and way too expensive, and I think material sciences needed 100 years or more to catch up and make efficient Peltier/Seebeck devices. I know they use the Seebeck effect to generate electricity on some offshore drilling platforms now because they've become that efficient.
We were close though. An air conditioned White House in the 19th century :)
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 5, Interesting) by Grishnakh on Tuesday June 06 2017, @10:22PM (5 children)
You don't need the crappy Peltier effect for cooling air, you can use vapor-compression refrigeration just like we do now and like they did with the first A/C systems. Vapor-compression refrigeration goes back to the 1830s too [wikipedia.org], though it wasn't really used practically for another 15 years or so. So they could have had actual air-conditioning in the White House back then too. The problem was electricity; they didn't have a practical way of powering a large refrigeration system back then, and they probably hadn't come up with the idea of blowing air over the chilled coils either. A lot of technologies are like this: the fundamentals are discovered or invented decades or centuries before they become practical and commonplace. Look what happened with electric cars for instance; we had those back in the early 1900s, and only now are we getting them back, mainly because of limitations in battery technology.
(Score: 2) by edIII on Tuesday June 06 2017, @10:29PM (4 children)
Why do you think the Peltier effect is crappy? The efficiencies they have now make it work. I'm just curious what you think is wrong with it.
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 2) by The Mighty Buzzard on Tuesday June 06 2017, @11:10PM
There's nothing wrong with it but unless there have been massive improvements in efficiency in the past twenty years, phase-change cooling is more efficient.
My rights don't end where your fear begins.
(Score: 2) by bd on Tuesday June 06 2017, @11:59PM (2 children)
The peltier elements I worked with had something on the order of 0.6 W thermal for every 1 W electrical you put in, so the efficiency P_thermal/P_electrical would be something below 1. I think there was some fundamental physical reason for that efficiency being below 1, but not sure anymore.
That efficiency is not too bad. The problem is, even crappy chillers will move more thermal power than the amount of electrical power you put in. For a good one, the efficiency should be more like 3 or 5, I think. Add the price of high-power peltier modules and it quickly becomes non-economical.
I would rather use peltiers when you can't afford vibrations and complex plumbing. Even though, the nasty bit is that you have to keep the warm side of the peltier cool or P_thermal goes down and at some point it will suddenly start heating the cold side. In the application I used it for, that cooling was ironically done with a chiller.
If you know about higher efficiency modules, could you provide a link? I would actually be interested.
(Score: 2) by edIII on Wednesday June 07 2017, @01:20AM (1 child)
You know, I honestly just thought if they were capable of cooling a modern CPU, that at scale that must be capable of cooling a room. I really thought that they were more efficient than that these days. Perhaps I was confused with the Seebeck effect instead where you generate electricity.
Thanks for the technical descriptions. I think I may have learned something today...
Technically, lunchtime is at any moment. It's just a wave function.
(Score: 2) by bd on Wednesday June 07 2017, @09:03AM
They are totally capable of cooling a room or being used as A/C in a car. Peltiers do not have particularily bad efficiency, the problem is just that closed cycle chillers are _much_ better.
Actually, disregard the thing about the coefficient of power for the peltier always being below 1. I read up a little bit and you can achieve something like 1.2. The problem is: that is generally only possible with a thermal load far lower than the maximum of the peltier. If you want to use it at its rated specs, prepare for inefficiency. And 1.2 is still less than chillers with up to 7, if you take an extremely good one. There are also peltier stacks, but that is a different can of worms.
Another drawback of peltiers is that they get less efficient the higher the temperature difference. The optimal application of a peltier is therefore to keep something that generates heat temperature stabilized close to room (or rather heatsink) temperature.
(Score: 2, Informative) by amlu on Tuesday June 06 2017, @10:09PM (1 child)
https://en.wikipedia.org/wiki/Windcatcher [wikipedia.org]
(Score: 0) by Anonymous Coward on Wednesday June 07 2017, @07:58AM
Yeah. The Persians even had ice making and storage tech: https://en.wikipedia.org/wiki/Yakhch%C4%81l [wikipedia.org]
See also: http://www.cais-soas.com/CAIS/Architecture/wind.htm [cais-soas.com]
(Score: 2, Informative) by Anonymous Coward on Tuesday June 06 2017, @10:11PM (3 children)
That's pretty cool. Most people who haven't studied HVAC (which, lets face it is "most people") don't know that air conditioning is really two seperate things: temperature and humidity control. The HVAC industry even breaks them out in "sensible heat" [wikipedia.org] and "latent heat." [wikipedia.org] Sensible heat is what the thermometer measures and is unaffected by humidity. But latent heat is the energy held by moisture in the air and is the difference between muggy and dry heat. If you live in a humid environment you want to make sure your hvac system has high latent efficiency because keeping the humidity down can make it feel lot cooler, especially if you can combine it with a breeze like from a ceiling fan. As a rule of thumb you turn the temperature up about 5 extra degrees if you can keep the humidity down and keep the air moving. You can't rely on the those SEER ratings [wikipedia.org] to tell you the whole story, they are calculated by combining both sensible and latent efficiencies so two systems with identical SEER and BTU numbers might have vastly different levels of humidity control.
(Score: 2, Interesting) by Anonymous Coward on Tuesday June 06 2017, @10:32PM
Does this explain why some AC environments are tolerable and some just strip the water from your eyes, throat and lungs? There's an interesting scene in a Leonard Bernstein documentary when he's brought in all these famous European opera singers to sing West Side Story in New York and they all fucking hate it because the AC (and Bernstein's smoking, to be fair) destroys their voices within the first session. By the end of the video they're all chewing gum and sipping water non-stop and wearing scarfs to try and be able to perform.
(Score: 5, Interesting) by AthanasiusKircher on Tuesday June 06 2017, @10:45PM
This is all true, though there's an even simpler summary metric: dew point [wikipedia.org], which is essentially a measure of absolute humidity.
I've never quite understood why modern air conditioning systems don't adopt a "constant dewpoint" setting, particularly in humid climates, which would actually correlate more closely with human comfort than temperature (or relative humidity, for that matter). 70 degrees F can be very uncomfortable at 100% humidity (particularly if you attempt to do anything), but 85 F might not be so bad at 30% humidity.
If you could just set your air conditioner for "dewpoint 55F" or whatever (some might be willing to go a bit higher or need a bit lower), you'd mostly be comfortable all the time in most climates. (Dewpoint isn't that precise, but it would be a better fit to subjective comfort level than temperature.)
Instead, people end up fiddling with the settings, particularly in humid climates where you might need an A/C setting of 70F or even lower to feel comfortable in spring or fall, but an A/C setting of 80F might be comfortable in the heat of summer (since the A/C will work more with hotter temperatures outside, thereby removing more humidity indoors and increasing comfort even without as much temperature drop). It would also do more to minimize the "transitions" that some people find uncomfortable, where you need to wear shorts and sleeveless shirts to feel comfortable outside, but end up putting on a sweater in your office building because they keep the A/C at a constant low temperature. With dewpoint as your metric, the indoor temperature will generally rise a bit as it gets hotter outside, thereby lessening the "shock" many people often feel going in or out in hot climates.
(Score: 0) by Anonymous Coward on Wednesday June 07 2017, @04:42AM
IDSHVAC (I did study HVAC, although I don't practice professionally). The one piece that pulls it all together is the ASHRAE comfort chart, here's one small link, http://pages.uoregon.edu/hof/f03ice/ashrae%2055.html [uoregon.edu] There are many others.
"Comfort" is defined as a combination of:
+ Air temperature
+ Radiant temperature
+ Humidity
+ Air speed
+ Metabolic rate (sitting at a computer vs. working out)
+ Clothing insulation
Within certain ranges that have been established by experiments, one or more of these can somewhat compensate for others.
For example, the house I grew up in had radiant heat (hot water circulated in the floor). This meant that somewhat low air temps were perfectly comfortable in the winter...as long as enough of your body could "see" the warm floor. If you leaned far over a table (working on a large drawing?), then you might start to notice the cool air temp.
(Score: 4, Insightful) by Unixnut on Tuesday June 06 2017, @10:26PM (11 children)
Am I the only one that finds AC just makes me feel ill? I end up with inflamed sinuses, headache and other cold-like symptoms whenever I am in an air conditioned room for more than a few minutes. It is absolutely awful!
Even in hot humid climes i found basic fans were good enough for comfortable temperature, as long as some airflow went across the body it was lovely. Not to mention a history of being able to keep ourselves cool in multiple ways, including the "windcatcher" mentioned above, and having nicely and cleverly designed houses to work with the climate rather than use brute force against it like we do now.
Also, with AC you can never get accustomed to high temperatures. If you are in a hot place and temps are constantly 25C+, then with time you learn to adjust, your fluid intake, what you wear, etc... and in a week or so it is all good, you don't even notice any discomfort.
However now, due to AC, you got a choice of dressing so you are comfortable in an AC area, and cooking outside, or comfortable outside, then freezing when you go into a mall or something.
The constant cycle of cooling/heating does more to give people "summer colds" than anything else, all thanks to AC. The "solution" for some people, is to just have AC everywhere, in their house, then their car, then whatever place they visit, and back again. People who inevitably moan incessantly the moment they are not in an AC area, and who become incapable of leaving their artificial environments. like little prison bubbles.
Air con, absolutely awful. and such large consumers of energy to boot. Bloody hate the things.
(I concede there are some places where they are useful, and some people really need help with temp regulation for medical reasons, but doesn't detract from its abuse everywhere else really)
(Score: 1, Funny) by Anonymous Coward on Tuesday June 06 2017, @10:36PM (1 child)
Why do you hate AC so much? Soldiers died for your right to have AC 24/7, indoors and out. Think of the soldiers, damnit!
(Score: 2) by jimtheowl on Wednesday June 07 2017, @05:30PM
(Score: 2) by AthanasiusKircher on Tuesday June 06 2017, @11:01PM (5 children)
25C isn't all that hot. Except when necessary to remove excess humidity, I rarely would put a home AC thermostat below ~25C.
If you live in a climate where summer days consistently have highs of 30-40C and dewpoint is above 20C for long stretches, you realize the necessity for A/C to do more than sit around and drink cold drinks all day.
But I agree with you about the often unnecessarily low temperature settings with AC that contribute to some of the effects you mention.
(Score: 0) by Anonymous Coward on Tuesday June 06 2017, @11:39PM (3 children)
You must live in a warm area... Most northerly-adapted people I know get uncomfortable above 70, southerners think below 60 is cold (and they're scared to drive in snow or rain but that's a whole 'nother story).
(Score: 2) by AthanasiusKircher on Wednesday June 07 2017, @03:04AM (1 child)
I think most people whine too much about temperature. I grew up in the North. I generally set my A/C around 80F at home in summer, and I set my heat around 60F in the winter. If it's hot, I wear fewer clothes; if it's cold, I put some more on. In the process, I save a lot in bills for heating/cooling energy. I don't see the need for keeping a house 70 degrees or whatever year-round when I can easily just wear a sweater or shorts.
That said, 70F can be very different things depending on humidity (as I explained about dewpoint above). In a humid climate at certain times of the year when it's not very hot out, I may need to set the AC as low as 70F just to bring the humidity down low enough to feel comfortable. But with low humidity and a fan, I generally don't find 80F to be bad at all.
(Score: 2) by Grishnakh on Wednesday June 07 2017, @03:12PM
I grew up in the North. I generally set my A/C around 80F at home in summer, and I set my heat around 60F in the winter. If it's hot, I wear fewer clothes; if it's cold, I put some more on. In the process, I save a lot in bills for heating/cooling energy.
You must not be married.
(Score: 2) by Azuma Hazuki on Wednesday June 07 2017, @03:05AM
Yup. Upper-midwest here. I haaaaaaaaate it when it's hotter than 70*F or so, especially with no breeze, and *especially* when it's humid. I can tolerate dry heat to 90*F or so but humidity is a killer.
I am "that girl" your mother warned you about...
(Score: 2) by Grishnakh on Wednesday June 07 2017, @03:14PM
But I agree with you about the often unnecessarily low temperature settings with AC that contribute to some of the effects you mention.
Those "unnecessarily low temperature settings" don't seem so unnecessary to millions of obese Americans....
Remember, we need to keep our offices chilled to 60F in the summer because otherwise fat Suzy will complain to HR.
(Score: 3, Informative) by The Mighty Buzzard on Tuesday June 06 2017, @11:17PM (1 child)
Beg to differ. Spend a summer in Oklahoma where the temperature gets up to 110-115F in the day and only cools down to 95F by the next morning. It is less than pleasant to sleep or work in.
My rights don't end where your fear begins.
(Score: 0) by Anonymous Coward on Wednesday June 07 2017, @07:17AM
O-O-O-O-O-kla0homa! Where the heat comes sweeping down the plain! (do we have music note emojis? But then again, I don't use emojis, anyway. Must the the heat, or not so much the humidity. Oklahoma! OK!)
(Score: 1) by oldmac31310 on Wednesday June 07 2017, @03:56PM
Totally agree. Moved office a few months ago and have had one cold after another. It's 60F outside and here I am wearing four layers just to be comfortable sitting at my desk. AC sucks.
(Score: 0) by Anonymous Coward on Tuesday June 06 2017, @10:50PM (2 children)
AC has also been shown to increase worker productivity and was supposedly responsible for boosting US economic growth.
https://link.springer.com/article/10.1007/s12273-010-0410-8 [springer.com]
https://www.washingtonpost.com/news/wonk/wp/2012/07/07/how-air-conditioning-transformed-the-u-s-economy/ [washingtonpost.com]
(Score: 0) by Anonymous Coward on Wednesday June 07 2017, @01:49AM (1 child)
It's also the most dangerous invention in the history of the world, responsible for slaughtering countless lives. More dangerous than ISIS.
No, really.
(Score: 0) by Anonymous Coward on Wednesday June 07 2017, @12:09PM
Countless?
I thought the threat of death by terrorism is on the order of lightning strikes or on the order of affecting a similar rate of the population as $100,000 lottery winners?
(Score: 2) by kaszz on Wednesday June 07 2017, @03:15AM (11 children)
Maybe it should been "How air conditioning increased the electrical power demand" ;) Mostly on daytime when the grid is heavily loaded. Not to mention all environmental issues.
Central cooling is a thing in some places.
(Score: 2) by jimtheowl on Wednesday June 07 2017, @05:20AM (10 children)
Assuming enough Sun, even if you only have enough solar cells to power your AC, that is where it counts the most.
(Score: 2) by kaszz on Wednesday June 07 2017, @07:27AM (9 children)
Photovoltic cells have issues with installation price and access to sun irradiated areas.
(Score: 0) by Anonymous Coward on Wednesday June 07 2017, @01:12PM
Installing solar on my house would require me to cut down most or all of my trees that give me enough shade to reduce how often my A/C runs.
(Score: 0) by Anonymous Coward on Wednesday June 07 2017, @02:31PM
Thank you captain obvious.
There is no such thing as a one-size-fits all solution to a complicated problem.
Any other deep thoughts you want to share with us?
(Score: 2) by jimtheowl on Wednesday June 07 2017, @05:29PM (6 children)
What I was trying to suggest is; one can reduce the installation cost with a closed system dedicated to run AC only, dispensing of a grid-tie inverter and most of the battery storage.
One can always choose to upgrade later.
(Score: 2) by kaszz on Wednesday June 07 2017, @06:19PM (5 children)
There's something called the Einstein fridge which is entirely heat driven. Maybe that could be used to build a sun driven AC with very few if any intermediate steps and thus losses?
(Score: 2) by jimtheowl on Monday June 12 2017, @08:04PM (4 children)
I can only guess that the main reason that this has remained in a niche market has to be because of efficiency, despite reports of improved design.
There is apparently one project making use of it for vaccine refrigeration where electricity is scarce, so I will assume that despite the efficiency issues, it is a more compact and sturdier design than the alternative.
That said, I would likely have to build one myself as it is not readily available.
(Score: 2) by kaszz on Monday June 12 2017, @09:30PM (3 children)
My thinking here is that the Einstein fridge may be inefficient. But.. when considering the alternative solar --> converter --> battery --> converter --> compressor vs solar --> compressor. It may still be more efficient. And daytime energy can be stored as a heat difference instead of electrical batteries.
(Score: 2) by jimtheowl on Tuesday June 13 2017, @02:57PM (2 children)
The reason a converter is normally used before going to an appliance is because most house appliances are AC. Nevertheless, DC Air Conditioners are available.
I googled this at random:
http://www.geinnovations.net/solar_air_conditioner.html [geinnovations.net]
(Score: 2) by kaszz on Tuesday June 13 2017, @04:13PM (1 child)
The general problem with solar panel is MPPT and varying power output during the day. And none at night.
(Score: 2) by jimtheowl on Wednesday June 14 2017, @05:51AM
The idea is to reduce the stress on the grid and your pocket book given a minimal initial investment.
Improvements can grow from there.
(Score: 0) by Anonymous Coward on Wednesday June 07 2017, @11:09AM (1 child)
Surely, a historical US company would be more likely to use foot pound punnets rather than millimetres.
(Score: 1) by oldmac31310 on Wednesday June 07 2017, @04:02PM
Yeah. Bushels and pecks.
(Score: 2) by wonkey_monkey on Wednesday June 07 2017, @04:51PM
It made it hotter, is what it did.
systemd is Roko's Basilisk