Air Conditioners

A little love and spoonful for you guys out there. All right. Then, we actually have a little bit of business to get to before we jump right into the topic, and that is some listener mail. This listener mail comes from Ted, and Ted says, I'm a regular listener of the podcast and it's been great to listen to on my commute to and from my co op this summer. I'd like to hear about how air conditioning HVAC units work.

We design and build them, among other things that my co op company, and after helping to put one together and tested, I'm still not clear on how it works. I would also appreciate an episode about how capacitors work in circuits. As a supplement to the article on the How Stuff Works site. Lastly, could you talk about Google Plus as well as Windows eight. Thanks a lot, keep up the good work and good jokes. Ted, Well, Ted,

We're gonna talk about air conditioners today. But stick around because right after we record this, we're recording our episode about Google Plus. Yeah, because you know, a couple of people have asked for that. Yeah, you'll like a couple, I mean, you know. And I plan on scheduling the Google Plus episode to publish immediately after this one. So if this published on a Monday, look for it on Wednesday. If it published on Wednesday, look for it next Monday.

All right then, because I don't have the calendar in front of me. But we're gonna talk about air conditioning units. We're not actually gonna talk about h VAC units today. We're just gonna talk about air conditioners because there's a bit to them. Yeah, there's a bit to them. And it's also we in Atlanta right now are in the middle of a pretty nasty heat wave. It actually kind of broke a little bit. We we have a little

bit of a break in it right now. It's today, Yeah, it's in the it's just it's only in the upper eighties with a heat index in the mid nineties today. Yeah, but recently we had a heat index over a hundred and seven degrees and really high humidity. So in Atlanta that was pretty miserable, and a lot of the United States has been going through the same thing. This is, of course the summer of two thousand eleven from for

all of you people who are from the future. Uh So we thought, you know what, we really appreciate air conditioning, So let's talk about how air conditioners work. Yeah, I actually, uh, I actually am very grateful for the air conditioning, especially this last week. But um. The the answer to to the question though, how air conditioners work is sort of It's not an easy one because there are different kinds

of air conditioning. Yeah. Yeah, it's all based on heat exchange, but the method of heat exchange differs from one to the other, although I would say the majority of them use the refrigerant method of heat exchange, where you're compressing a liquid and then you are allowing it to boil off. Um. But that's a pretty complex issue. Did you want to talk about the other types really quickly or should I

just launch into a science lesson. Well, I think it might be a good idea to go ahead and talk about the type of air conditioning that most of us use, and then maybe look at some of the others. Um. I do want to mention a name that is familiar to a lot of us, at least here in the United States. That would be Willis Carrier. You might say, you know, I don't know who that is, Like, oh, wait,

Carrier made air conditioners. Well he Uh, this was in the early twentieth century, so really the modern electrical air conditioner. Of course, electricity not being that prevalent until um, you know,

the late eight hundreds, early nineteen hundreds. UM. Carrier lived in Buffalo, New York in the United States, and UM he came up with the idea of the do point control, which is an air conditioning UH system that basically the UH had to do with UH the saturation of cool air and UH which you know loses moisture through condensation.

And that's your science lesson, isn't it. Yeah. Yeah, we're gonna have to talk about the relationship between pressure, temperature, liquids, gases, UH, and and the It's important to understand this this basic level of science in order to really get a grip on what an air conditioner is doing, because otherwise I could talk about what an air conditioner is doing, but you would say, well, why does that work? I know how it works, but why does it work? Yeah, we

do have an article on the side about that, of course. Yeah. Actually we have a great article on how air conditioners work, and that one was written by Marshall Brain, who was the founder of how stuff works dot com. So this is it's one of our flagship articles. If you really want to see some good animations and illustrations about it, I recommend checking that out. But we're gonna talk first about well, some basic matter. So we know that matter is made up of teeny tiny particles, Yes, you know,

atoms and molecules. Right, So with solids, this these particles are they're not really truly stationary. Okay, these are particles are always moving, but in in solids, they're not moving a lot, right, Yeah, they're packed closely together. Yeah, they're very very dense, and that's why we think of them as solid and liquids, not that dense and liquids. Uh, they are these particles are allowed to move around, and they move around in a more or less random fashion.

For all we know, it could be a very orderly fashion. But it's so orderly, it's like such a complex system that we're unable to understand it. So to us, we might as well say random. Yeah, well, there's one molecule on the side, going okay, keeping keeping mindone, if you if you look really closely, you'll see one with those little uh those little cones that air track, you know, the people on the tar mac use, and they're like, all right, coming in, go to the left. It's very

hard to hold those with your electrons. Yeah, and that's why that's why you hardly ever see them. Also, it's impossible to know where they are at any one time because the uncertainty principle. Uh wow, we're getting really kind of crazy with our humor today. So anyway, all right,

let's let's get serious. So in liquid, these particles move around more or less randomly, and some of these particles are moving around with with enough energy to break free of the surface of that liquid, so they will actually become a particle that is in a vapor above that liquid, right, all right, like water that evaporates and turns into water vapor sort of. But I mean more like water that's boiling off. But yes, um, yeah, so the I was trying to go for an image that people could Yes, yes,

very much, very much. So. So the way the way you would get one of these particles to do that, To get enough energy to break freeze, you have to add energy into the system, right. So you when you add energy into the system, these particles get more well, they get more energy, they start moving around more, and then they have they may have enough energy to break free from the surface. So if you add heat, that's

a form of energy, like the boiling water. Right, So if you start adding heat to a liquid, more of these particles will gain energy and be able to escape the surface of that liquid. If you get enough vapor so that it actually equals the atmospheric pressure that's on top of that liquid, that's when you hit the boiling point. Okay, all right, So let's say you've got a pot of water at sea level. All right, Now, boiling temperature for a pot of water at sea level is two d

and twelve degrees. Now, what that means is that when the water reaches two h twelve degrees, the particles in that water have enough energy to escape the surface of the water, and the vapor pressure is equal to atmospheric pressure, the water will boil and the water will not get any warmer than two twelve degrees. You could have that fire pumped up as high as it's gonna go, but the water temperature will be two hwelve degrees as it's

boiling off. Now, once the water is boiled off, if you have a thermometer in that pot, the thermometer is gonna skyrocket, you know, at that point. But the temperature the water itself will remain to her and twelve because it's actually converting from liquid into gas. So that boiling point is in is important to remember. It's it's when, like I said, when the pressure of that vapor has uh equaled the atmospheric pressure of the environment around it.

So if you change the atmospheric pressure around that liquid, you change the boiling point. So if if the pressure is if there's less pressure then it would be at sea level, then it's going to take a lower temperature to make that water boil. If there is more pressure then there is at sea level, then it's going to take a higher temperature to make that water boil. All right, So let's say that we have put a lid on

top of that pot. Okay, by putting the lid on top of that pot, we have decreased the air pressure or the atmospheric pressure on that liquid, so the water will boil faster. All right. If you take the lid off, then you have just increased the atmospheric pressure. Because now more air is actually pressing down that liquid. It's going to actually increase the boiling point to its normal boiling

point at that particular environment. So now we've talked about how you have increased pressure, you've increased the temperature of the boiling point. Now that's the basics for what we're going to talk about with air conditioners. Because air conditioners are at least the typical ones you find in houses and buildings, use pressure to use to create a pressurized liquid that then turns into a depressurized gas. And it's

a closed loop system. And the liquid in this case is a refrigerant, right, so it tends to be some sort of of of material that has a boiling point that is pretty low. Like it doesn't it's not a very high temperature in other words, in normal conditions, normal being like in everyday atmospheric conditions that would be a gas. Right. So in the one of the common ones we talked about is free on, which at this point is more or less a generic term, kind of like Xerox or Kleenex.

Would you know those companies would argue they are not generic terms. Yes, they would argue. Their lawyers would argue, yes, certainly. But but people use effectively use them, right right, So, like I said, I'm going to xerox this, you're you talk about, you're making a copy of it, or I'm going to Google this. In that case, you may be actually using Google, or you may just be using some

search engine. Kind of the same thing. When people talk about free on, unless they're spit talking about the specific uh refrigerant, it's more or less just refrigerants in general. Yeah, based on my experience recently, I haven't seen the actual product free on in quite some time. I think for concerns of cfcslora flora carbons. Yes, Um, so I that that these days, I don't think free on is used very much, if at all, at least not in the

United States. Um. Of course I could be wrong, but there are other refrigerants too, so right, so what an air cons what an air condissuer does, is it? It pressurizes this refrigerant in one section. Think of think of the air conditioner as a closed loop system that has

a low pressure section and a high pressure section. All right, the and the guardians of this, you know, the two elements that that separate the low pressure from the high pressure are a compressor on one end of the loop and a valve on the other end of the loop and expansion valve on the other end of the loop. These two act as the gateway that keep the pressure high on one side and low on the other. All right, And it's hot on one side and cool on the other, yes, exactly.

Because as we pressurize the the refrigerant, the temperature of that refrigerant goes up, all right. So the refrigerant, normally at at room temperature, would be a gas. You use the compressor to compress this gas to a point where it's very very dense, and then you run it through a series of coils that allow the the this high temperature pressurized gas to give off a lot of heat. The heat escapes into the ambient. Uh well, that the environmental atmosphere. So what the atmosphere has to be of

a cooler temperature than the the pressurized gas. Right For, in order for heat to transfer, it has to go from high heat to low heat. You can't have something

go low heat to high heat. So, in other words, if I were to turn on my air conditioner and I happened to be in an incredibly hot environment, let's say that for argument's sake, it's a hundred and sixty degrees outside and my pressurized refrigerant only gets up to a temperature of a hundred and forty degrees, that air conditioner is not going to work because you are not going to have any heat exchange from the actually I'll have the wrong sort of heat exchange, but you're not

gonna have any heat released from the refrigerant into the atmosphere because the atmosphere is actually warmer than the refrigerant even at its pressurized state. All right, So you've got these coils that this heated gas, this compressed heated gas is moving through. As it moves through the coils and starts to release heat into the atmosphere, that means the gas cools. Well. As gas cools, it condenses, and this is the process where a gas converts back into a liquid.

Now it's going to be at a liquid at a higher temperature than normally would be because it's under pressure. You know, we talked about that the higher the pressure, the higher the boiling point. So once you get that temperature down below the boiling point of that pressurized substance, it condenses into a liquid. This is how we get

things like liquid liquid hydrogen, with oxygen liquid nitrogen. You compress these gases to a very condensed state, compressed state, i should say, and it condenses into a liquid, and as long as you keep it under pressure, it will stay a liquid. If you release that pressure, then it immediately starts to boil off and convert into a gas. Well,

that's the secret. That's the secret of the the valve at the end of this loop um the expansion valve, because once it the pressurized gas gets to the expansion valve, that's what allows it to move into the low pressure system and it immediately begins to boil off and essentially starts absorbing heat from the environment. Just as it was releasing heat when it was going through the condenser coils, now it's it's absorbing heat, which means that the surrounding

air loses heat. It transfers the heat from the air into this boiling liquid that's becoming gas very very quickly, and then the surrounding air is cooled. That's the basis of an air conditioner. Yes, we can actually walk through those phases and go into more detail now, but that that's basically how it works. It's all about, really you have two closed systems. You have the closed system of the refrigerant and then you have the closed system of

the air inside whatever it is you're you're cooling. Because you're not pulling air in from the outside environment and then cooling it and then pushing it into the building. You're recycling the air that's inside the building and it's cooling it through the bye bye this heat exchange method and just a little bit of h v A C. Some systems can reverse it works, and that's called a heat pump. I have one on my house, is a

matter of fact um, which is very convenient. Right In that case, you're you're doing the same system, except you're

you're reversing the process. Essentially, you're recycling the warm air inside your house and it's warming it instead of cool it YEA and injecting the cooler air outside from the process that actually takes place in the unit itself outside because if you've ever been outside and next to an air conditioner, you've felt you know, it blows hot air outside, So you know that, but that's not coming from inside the house. That is the result of the process, um,

and the the exchange of heat. Now, UM Carrier actually came up with a system for buildings. He installed one in at Grahman's Metropolitan Theater in l a Man's Chinese Theater. Yes, I've been there, UM saw the Matrix sequel. It was terrible. Theater was great. It was terrible. UM. Yeah. And at that point air conditioning was used to uh feed air or take air in the ceiling and put it out at the floor level, which would be you know, useful because the hotter air would be toward the top of

the room. Um. And the first fully air conditioned office building, according to Britannica, was the MILEM Building or MILAM. I don't know, it's like M I L A M in San Antonio in the United States, and that was built in the late nineteen twenties. UM. So again you know, this hasn't been forever and ever, but there uh you know, it's certainly something that we use and a lot of the buildings here down south, especially in these states. But there are many, many other types of air conditioning that

have been going on for years. Do you want to get into those yet or do you want to go back and get more into the process. Let me, let me get more into the process of the typical air conditioner, because this is what's going to apply, I think to the majority of our listeners who have air conditioning. Yeah, so so, and then we can talk about the other kinds, including uh, my favorite, the swamp cooler. We'll get into that. So let's let's break this down further about the parts

of an air conditioner. So you've got usually typically of an electric motor, and the electric motor you turn earns a piston. This this is a very simple compressor. This is like the simplest form of a compressor. So not all air conditioner compressors are like this, but this, this demonstrates the principle. Uh you would call this a piston

compressor or a reciprocating compressor. So imagine that you have a chamber, all right, so a cylinder, let's say, and inside the cylinder you have a piston that can move up and down the chamber which is sealed, and you the electric motor makes the piston go up and down. Now at the bottom of this chamber, you have two valves.

You have a an intake or suction valve that will only allow fluid to flow into the chamber through and that's that's coming in from the low pressure side of this air conditioner system, so it's pulling the the refrigerant gas into the chamber. On the other side, you have the outtake or the the discharge valve. Is trying to think of the right word for it, This charge valve would be the right word. So now this valve only

allows fluid to pass out of the chamber. This pushes it into the high pressure side of the air conditioning system. So you're pulling from the low pressure pushing into the high pressure. And both of these valves are essentially spring loaded, okay, so there's a certain amount of pressure, that's a certain amount of force that's created by the spring that the system has to overcome in order for the valves to

open in either case. So you've got the piston down at the bottom of this chamber, so it's down against where the valves are. The piston starts to pull up, all right. This this creates an area of low pressure, which creates suction. Now, once that force of suction is strong enough to overcome the spring force of the intake valve, that valve will open. All right. So you're you're you're pulling hard enough to overcome the force of that spring. The valve opens, and that pulls the free on gas

in to that chamber. All right. Once the piston gets to the top, it stops for a moment that allows the spring to close on the intake valve. It is now there's no more fluid coming into the chamber, and the valve itself is closed. The piston then starts to move down. This starts to compress the gas inside the chamber eventually create you know, it starts to increase the pressure. Eventually that pressure is going to be strong enough to

open up the discharge valve. The discharge valve opens, and that means that the free on gets pushed into the high pressure system. You might ask, well, why is that high pressure on that system. It's because at the end of that side of the air condissuer system is that uh, that expansion valve alright, the expansion valve is sort of a bottleneck point. And because you keep pressing more and more gas into that side and the expansion valve only allows a little bit of that gas to escape at

a time, the pressure increases, right all right. Actually, and at that point it's not really gas, it's liquid. But we'll get there. So you've got the piston moving, and it's moving at an incredible speed. We're talking like a thousand rpm, so a thousand repetitions per minute. So when I'm talking about this process of the piston coming up, pausing, and coming back down, it's doing that multiple times a second,

something like between seventeen and twenty times a second. Uh. So, you're pulling that free on or other refrigerant through the low pressure system into that chamber into the high pressure system. The this this gas, once it gets pressurized this way, it starts to the temperature starts to climb. So now the temperature of the freon has increased, that's when it starts to move through the condenser coils, and that's when it starts to release heat to the environment. Now it

may release the heat directly to the environment. This is why if you were ever to look at an air conditioner outside and you see this this series of little tubes that are kind of criss crossing, a wiggling back and forth across a large surface area. Those are the condenser coils. I think of them as metal intestines. There you go, do not touch those. They are hot. And the reason they are hot just because they're releasing heat into that into the atmosphere. If this didn't work, then

air conditioners wouldn't work. So the heat starts to pull off into the atmosphere. Meanwhile, the gas inside those tubes that that temperature starts decrease because it's shedding the heat off into the atmosphere. The gas starts to condense into a liquid. Now, the liquid by the time it gets to the the the expansion valve at the end UM has reached sort of a moderate temperature. It's no longer as warm or as hot as the gas was in

the in the first part of this condenser coil series. Uh. Now, the expansion valve will only allow, like I said, a small amount of fluid through at a time, UM, and that's what's allowing this pressure to build behind it. Once it Once the liquid goes through and it is the low pressure system that it's immediately starts to boil, so it merely begins to convert into I guess that ends

up absorbing the heat from the air. And what you have is a fan right at that section of the air conditioner that blows this now cooled air into the building or room or whatever. Okay, So the fan provides the air movement so that this cold air can can make its way through the building and cool the entire environment. Yeah. Without that ability, it would be semi useless. I mean

it would be yeah, exactly exactly. So you also have an intake for to to pull air from the the building so that it can be cooled in this section, right. So you've got intakes and outakes. You've got the vents that are pulling air uh in, and you've got the vents that are pushing air out and uh you know, depending on you know, a lot of a lot of houses I've seen have the intake vents in the floor, right. So it's pulling the warm air or it's it's pulling air.

It's putting cold air at the top to filter down into the the um the house, and then it's pulling air from the bottom. In order to cool it through the system. Right. Well, and if you uh, if you've ever stood it right in front of an air conditioner vent inside your house, you know that it can be quite cold. Um. And it's even colder. And I don't mean to say that it would be completely completely useless without fans, because my grandmother's house had a window mounted

air conditioning it um. And of course you know that would work just fine, but it wasn't circulating air through the house is vents. It actually was you know, sitting there in the window and working. Um. And let me tell you, standing in front of that thing, uh, it is a real blast of very cold air. It's kind of it's actually uncomfortably cold. And that's one of the reasons why you would want, uh the air to filter

down in the room like that. It's sort of diffuse it with uh the air otherwise in the room and sort of make it an it's comfortable a blast of cold air, um. You know. But but that's just you know, one of those things. And we also, I guess we need to add in the fact that air conditioners are really useful if you have a thermostat, yes, you don't

have to have a thermostat. You can have an air conditioner that's essentially on or off, but a thermostat what that will do is it's essentially a thermometers set with a switch. So when a thermometer hits a certain level or below, then the switch is turned off and the system is shut down. When the temperature creeps up, it activates the switch, turns the whole system on, and the

air conditioner kicks on. So that's that little clicking noise you hear is when the temperature and the thermometer inside your thermostat, like you've said it to say seventy two degrees, and it creeps up to seventy three, that's the thermometer

then activates the switch. There's you hear the clicking noise of the system turning on, and then shortly thereafter you should hear the fans system blowing, unless, of course, you have a really super quiet air conditioner, which is awesome, but then you would start to feel the effects of the a C and it happens pretty quickly. Like I said this, this is the piston itself is moving in, you know, an an incredible speed. So that's your basic

air conditioner. I skipped over a couple of little things, like on the high pressure end, you usually have a receiver tank holding tank for liquid refrigerant. That so, once it's been pressurized and condensed, it goes into this tank and then moves from the tank further into the system to eventually get to the valve um. And it can get a little more complicated depending upon the nature of the compressor. But that's the basic premise of an air conditioner.

Pretty awesome, really, Yeah, yeah, I know. It's it's an ingenious invention. So now that you want to talk about some of the alternatives, are you know, different types of

air conditioners, Well, yes, of course. Um building air conditioners work, uh, you know, whole buildings like we're we're actually in an office building, a very large office building with multiple floors, and you know, you'll often see multiple units, like if you fly over in an airplane you look at um, like a big box warehouse store or something like an office building like the one we're in, you'll see multiple air conditioning units on top and condenser towers as well, yes,

which you know condenser tower Essentially that's just an area that is specifically designated for condenser coils. It's to create more surface area so that you can have a hotter gas pump through those coils, and then the temperature will decrease as it goes as it releases a heat to the atmosphere. Remember that the temperature of that refrigerant is going to vary. It's all gonna depend upon the type of refrigerant that's being used, because different liquids boil off

and at different temperatures UM. And it's also going to depend upon the strength of the compressor because the more you pressurize that that fluid, the higher that temperature is going to be. So if you're using like an industrial strength air conditioner, it's probably going to be compressing that fluid and using a different type of refrigerant that's going to get in a much higher temperature than a home

unit would have. Therefore, you need more surface area to release that heat into the atmosphere and condense it into

a liquid. What's up home unit? Um? Now. According to our article on how stuff works dot com um, a lot of larger buildings do use a chilled water system, which basically, uh, well, you have a problem with see because if you have all those units on the roof, then what happens to the people on you know, and let's say a fifteen story building, Uh, what happens to all those people on the second floor, a third floor,

because that's a long way to go. So what they do is essentially they they uh and in a oversimplification as I'm want to do on this show, basically, they transfer the the cooling effect to water and then the chilled water is pumped through the building. UM and uh, you know that's just that's just the basics. Um. But um apparently takes water down to between around forty and forty five degrees fahrenheit, which is four point four and

seven point two degrees celsius. And it's just you know, connect they pump the chilled water through and it and it goes to those are connected to air handlers. Um. And these are closed systems. Yeah, and you have to you have to insulate those pipes too, because otherwise the uh you know, cold water inside the pipes, um, they will lose their coolant to you know, as they travel throughout the building around. So you can't really do that.

But um, yeah, there are also some ice systems where you essentially what you do is you have an enormous tank on the top of a building. This really works for for large buildings, not for houses. But you would have a a storage tank that would hold water. You would freeze that water at night when electricity rates are lower, so it's more it's not gonna cost as much to

UH to actually freeze it. But you freeze that water, and then in the daytime as the water as you've got this big old block of ice, you have fans blow air against the ice, which creates this chilled air, that conditioned air that you can then can circulate either through the building or you use it again to chill another water line that circulates through the building and thus cools the building. UM. This is a pretty inexpensive way to create air conditioning once you've got the system in place.

But putting the system in place is quite expensive, indeed, because you're talking about building a pretty enormous tank and it's it's it's not cheap to build, but once it's there, it tends to be less expensive than running a conventional

air conditioner. And of course, down at Turner Field here in Atlanta, which is where the Atlanta Braves baseball team plays, UM, there's a space outside where UM they spray water and the fans can walk through that area and it you know, you don't get I guess you get a little damp. But the effect is the cooling effect because it's you know, they atomized water feels you know, it's it's sort of like sweat actually when you know, when it evaporates, it

makes you feel better. Well that they used to, uh, they used to do that in the nineteenth century textile industry, um, because they were using it for humidification and cooling purposes. According to Britannica UM. But in India a long time ago, they used to hang wet grass mats over their windows, basically doing the same thing. It was the evaporating water would uh would cool down the room, it cools down the surrounding air. Um. Because again, the in order to evaporate,

the water needs energy. So the water is taking energy from the air around at the heat from the air around it, and then you have air that has it's cooler. It's the heat has been transferred to the water utter um. Yeah, Benjamin Franklin actually looked into this as a way of cooling systems and uh, he kind of figured it out as well. And you know, it's been. It's been in use for millennia. Ancient Egyptians have been doing this, you know,

Well ancient Egyptians aren't doing it anymore. They're not doing much of anything other than, you know, hanging out in museums. But anyway, the which I do too, but I'm actually a little more lively anyway, I'm getting off track again, thank you. So this actually brings us to what I had mentioned earlier, the swamp coolers. So swamp coolers work on this system. And you might wonder why they're called swamp coolers. Well, it's probably because they can smell a

little swampy if you don't maintain them properly. They actually do not work very well in humid environments, and I'll explain why in a minute. The process of a swamp cooler is kind of interesting. What essentially what you're doing is you're pulling warm air from outside. You're blowing that warm air through a a chamber that has usually moist pads in it. So you've got like some sort of padding material that has water. Um, it's soaked with water.

The warm air causes the water to evaporate. In that process, the air itself loses some of its heat and then uh a fan blows the cooler air into the environment, into the house or whatever. Now, this is different from an air conditioner in several ways. One of them is, like I said before, an air conditioned system and is a closed system, not just from the free on but

also the air inside the building. If you open up a window or open up a door inside an air conditioned house, you know, you'll you'll hear like your mom will yell, you're letting out all the air conditioning. Well, that's that's actually true because what it's doing, because it's recycling the air inside that system. So if you open up stuff, it's you're losing that that uh you're you're causing the air condition to work harder in order to try and get to the right uh temperature. Also, what

were you raised in the barn? Right? Do you think we're air conditioning the whole neighborhood. Uh So a swamp cooler though, it's pulling air from outside and pushing it into the environment, So you actually have to have a window or door open or to have air circulation, otherwise you're just pumping air into a house until it explodes. It's not entirely true. Not entirely. Yeah, it doesn't actually have it that way, but you have exactly. Man reminds

me of my house. But anyway, you have to you have to open up a window really to have this be effective. So it's pulling this hot air from the environment, pushing it through a chamber that has these moist uh padding things inside of It depends on, you know, the kind of swamp cooler exactly what form it makes, but pads moist pads um evaporates the air, cools, the evaporates the water cools the air, and then the cooler air polls is pushed in through by a fan into the

into the house or whatever. Now this only works in really dry and ironments, and the reason for that is that the temperature of the air is going to be different between the regular dry bulb air, which is the temperature of the air as it is, and the wet bulb air, which is the temperature of the air if it were a humidity all right. So the greater that difference, the more a swamp cooler will cool a building. So if you're in a very dry spot, let's say Las Vegas.

Las Vegas is pretty dry, the difference between the air's temperature at its normal state, and the air's temperature if it had a humidity will be pretty large. Yeah, then using a swamp cooler means that that difference in temperature will essentially result in a cooling effect. They can get a house down to around say seventy two degrees, which

is a comfortable temperature for most people. Now, if you were in a very high humid area like say, I don't know, Atlanta, Georgia, where the humidity can be or radar, the difference between the dry bulb air, which let's say it's at that eight percent humidity, and the wet bulb air, which is a percent humidity is small. The difference is not significant really, and so you are not going to

get a big cooling effect from a swamp cooler. You may just feel like, oh, the hot air in my house is being replaced by slightly less hot air coming from this cooling system. That's not not more comfortable, it's just not as hot. So swamp coolers can work great if you are in a very dry place, a dry, hot place, um, and if you're in a stifling hot, wet place like like most of the southeast most of

the Eastern seaboard. Really in the United States, I should say, yeah, there are many other places around the world that would have similar problems. Yes, yes, this is true. It's not just us. It's just easy for me to talk about because I have a lot of experience on the East Coast the United States of America. Um, swamp coolers are not the best choice for you, Yeah, they're there are problems with I mean, my father told me about someone he knew who tried to essentially a modernized version of

the grass matt technique. And you know, blowing air through your house in a high humidity climate when you've been you know, pumping water down this you know surface, basically you're just adding more humidity and it's closed off, which makes mold and mildew a problem. Yeah, and it's yeah, there's also that there isn't with regular air conditioning. My basement is the top floor of my house is you know, pretty decently comfortable, but downstairs is like a meat locker.

And uh, we actually run a d humidifier in the summer because it can get sort of musty down there. So yeah, and uh, really, when you when the air is saturated with water, I mean we're talking about a hundred percent humidity. When the air is saturate with water, then you're not going to add more water to that system. So that's why the swamp cooler won't be effective at

that point. It's also why if you are in the southeast of the unit It States and it's a very humid day, you might start sweating, but you don't feel any cooler because the sweat is not really evaporating off your skin. It's just accumulating because the air is already so saturated with moisture. That's that you can't you can't add to it. That makes me feel even warmer, right right. That's why you will often hear the phrase it's not the heat, it's the humidity, and then you immediately punched

that person out. It's uously followed by vio. I have been punched in the face many times. When I've talked to my friends out west. We're like, yeah, well, it's a hard or fifteen degrees out here in Texas, And I said, well, it's you know, only degrees here, But you know it's not the heat, it's the humidity in Texas. They like to punch yeah, yeah, cattle. Sometimes I end up sometimes Jonathan, It's it's terrible. I mean it's just

blood and barbecue sauce everywhere. It's it's a horrible thing. Anyway, that's all I have. Do you have anything else you wanted to add before we kind of wrap this up? Nope? Cool, Well, well I did not. Yeah, that was totally unintentional. Guys, that was well. First of all, Ted, thank you so much for that request. That was great. We had a fantastic discussion. We talked about one of our really cool

articles on the site. Like I said, if you guys want to learn more about this, go find how air conditioners work at how stuff works dot com because there's a great article on that, and and really this is one of those things that we a lot of us take for granted, but it is a pretty cool application of science and technology, and I thought it was a really nice topic to tackle. So thanks a lot. If you guys have any suggestions for topics that you would like us to talk about, you can let us know

an email. Our address is text stuff at how stuff works dot com, or contact us on Facebook or Twitter and the handle there is tech stuff h s W. Chris and I will talk to you again really soon. Be sure to check out our new video podcast, Stuff from the Future. Join how Stuffork staff as we explore the most promising and perplexing possibilities of tomorrow. The house. Stuff Work's iPhone app has arrived. Download it today on iTunes. Brought to you by the reinvented two thousand twelve Camray.

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