Personal "air conditioners" aren't what they seem

You may be seeing a lot of advertising content from internet influencers that you won't believe

they

don't want you to see! lately about these so-called

personal

air

conditioners

. You may have wondered if these might be too good to be true. And today I am here to tell you that you are right to wonder, and that the answer to your question is an absolute, unequivocal, indisputable and irrefutable probability. This thing, as well as most devices that emulate its design, including the Blaux?…Blaugh? Bloerp?...it's a miniature swamp refrigerator. Note; No air conditioning! Despite

what

it may say on the box.

Swamp cooler. By the way, swamp cooler

seem

s to be a rather US-specific term; Evaporative cooler is the more technical and also less crude term. But swamp is only one syllable, so I say it. It's also more fun! Swamp. Swamp. Swamp. See? Deal with it. Swamp coolers work; In fact, in some parts of the world

they

are actually wonderful and can sometimes eliminate the need for air conditioning altogether. But these are not substitutes for air conditioning. If you live in a region of the world where the function of air conditioning is not just to cool, but to dehumidify, then these things are nonsense!

You see, these are not air

conditioners

at all. However, in something of a strange twist, swamp coolers actually use the same general principle as a conventional air conditioner. They take advantage of the fact that when water evaporates, it needs energy from the air to do so. I talked a little about latent heat in my video on rice cookers. At a very basic level, it is simply that for a substance to change phase from liquid to gas, it requires a lot of energy. Water is, believe it or not, a substance and you can see it in action when you boil it.

It doesn't just disappear when it reaches the boiling point because it takes *more* energy to vaporize it. The same thing happens when water evaporates. It is not necessary for water to reach the boiling point for it to change phase. You probably already knew, the water cycle exists and we have rain and stuff and the oceans are not boiling. In any mass of water, water molecules near the surface can, depending on conditions, have enough kinetic energy to break free from the liquid phase quite easily. Of course, additional energy, for example from the sun, will help, but the key is that no matter how the water changes phases, it needs some energy for itself.

A device like this simply uses that concept to provide *some* cooling. All it is is a fan that blows air through some sort of absorbent material that holds water. The forced airflow and large surface area these paper flutes provide help water evaporate quickly. By doing so, it takes some of the heat energy from the air with it, and the effect is that... well, it cools down a little. By the way, this is exactly how sweat cools you down. Made of fun! The name swamp chiller is thought to have originated from the musty odor they often develop when algae and other fun life forms take refuge in their powerfully moist wombs.

If you've never encountered a swamp cooler before, we'll see why in a bit, but you've probably experienced the concept at work in one form or another. Those misting fans that not only blow air but also a fine mist of water? Their goal is not just to get you annoyingly wet, in fact, the hope is that you won't get wet at all. Instead, spray nozzles atomize water into a very fine mist, which will evaporate quickly and cool the air, sometimes by a dramatic amount. Even without the fan, if you've seen those gentlemen in a garden or

what

ever, that's usually the goal.

Cooling. And that's the same thing these devices do. But there is a big, big, big, big, big, huge warning. Look, where I live, air conditioning isn't there just to cool a space. It is also there to remove moisture from the air. In fact, that was the original purpose of air conditioning: to dehumidify the air in factories and other industrial buildings where humidity was causing problems on the production line. Human comfort was just a bonus. Air conditioners can remove humidity because the refrigeration cycle relocates thermal energy through a liquid refrigerant, creating a very cold surface on which water vapor from the air will condense.

Okay, time to take this guy out again. I'm going to explain what real air conditioners do and if you're not interested in this part, go ahead and skip over here. But I think it will help illustrate why these trendy devices are… trendy devices. This is a basic window air conditioner that works using the refrigeration cycle. This is as small as it gets, but for larger systems everything just scales up and sometimes moves around a bit. The refrigeration cycle is truly almost magical, so here's a brief overview. For now, the only thing we need to focus on is these pipes.

Note that it is a sealed circuit that begins and ends at the heart of the system, the compressor. All of these pipes are filled with a special chemical called refrigerant. What is special about refrigerants? Well, I'll show you! This is a can of R134a (also known as 1,1,1,2-tetrafluoroethane). It is normally used in automobiles, but is currently being phased out. Obviously you can't feel this through the screen, but this can is clearly full of liquid. You can shake it and realize there's definitely something sloshing around in there. Maybe you can hear it. Put it on a scale and you will see that it weighs what the can says more.

But here's the key: I would prefer this not be liquid right now. The boiling point of this chemical is -15° Fahrenheit or -26°C. That's really cold! So why is it still liquid? It is at room temperature but it is not a gas either. As? Well, because he's trapped in this can. It is under pressure, and when a gas is confined in a small space (and, therefore, the pressure at which it is found is increased), its boiling point is raised. Right now, at room temperature, the pressure in this can is about 70 psi. Not tremendously high. And as long as it's in this can, it will remain liquid.

It has no room to expand into gas. But, if I were to poke a hole in this can, which I'm not going to do because this chemical is problematic for the environment, it would instantly start to boil once the pressure is relieved. And the key is, in order for you to do that, you have to remove energy from the space you're in. The latent heat of vaporization doesn't simply disappear when the refrigerant is at a higher than boiling temperature: it still needs to get energy from somewhere to change phase or boil. Initially it will do this on its own, causing the liquid to cool very quickly, but then it will draw energy from its surroundings to continue boiling.

It becomes an area devoid of thermal energy, so ambient energy will naturally spill into it. That causes the air around it to cool. But, once everything expands to gas, we reach equilibrium and the energy transfer stops. The most important property of refrigerants is that they do not need to be under very high pressures so that we can raise their boiling point above ambient temperature. This can really isn't that strong and yet it is capable of holding liquid coolant. In fact, fun fact! Those cans of computer duster you can buy? They are filled with coolant. If you thought it was just compressed air, no!

It is a coolant. Very strong tanks are needed to contain the compressed air. Just look at this little three gallon air compressor. This tank is made of thick steel and when charged to its maximum 110 PSI, it barely contains enough air to fill a tire. Because selling a can of compressed air would require expensive steel cans that can barely do any dust removal work, these cans are filled with a liquid refrigerant that expands into a gas as it is vented through the spray nozzle. This allows much more dust to be produced. And that's precisely why these cans get cold when you use them!

It is a refrigerant that cools briefly. Spraying them upside down will release liquid coolant and you can watch it evaporate with your own eyes. Something a little scary about this is that many refrigerants are terrifyingly potent greenhouse gases, and the idea that we would simply sell cans of the stuff with the express intention of venting it directly into the atmosphere is more than a little disturbing. This particular can is filled with R152a or 1,1-difluoroethane. Now, as far as coolants go, it's not *that* bad. It has a global warming potential of 140, which sounds pretty bad, but it's about an order of magnitude smaller than R134a, plus its atmospheric life is only a little over a year (again, about an order of magnitude better that this).

So in all likelihood, it's probably not that bad. Still, I highly recommend that you look up what coolant is used in your preferred duster (if you have one) or, better yet, find alternative means of dusting your computer's junk. And by the way, this same chemical is often used as a propellant in products like spray paint and hairspray, and we used to use good old R-12, everyone's least favorite ozone-depleting chlorofluorocarbon (CFC). called Freon for that task. Yes, the ozone layer still hasn't forgiven us for that. But anyway, since terribly high pressures are not needed to keep refrigerants in liquid form, we can easily build a machine that forces them to condense and evaporate whenever and wherever we want.

And that is what an air conditioner or a refrigerator does. The compressor, which by the way is the same as any old air compressor but is sealed in this black cylinder so that it is surrounded by refrigerant and also does not leak, compresses it in the confined space of this first known heat exchanger. like the capacitor. That makes it quite hot but, more importantly, dramatically increases its boiling point as the pressure in the condenser increases. With the help of these fins and a fan that forces the air through them, the air will cool again as it travels through the pipes.

When it reaches the end, it has condensed into a liquid. Let's see it with a thermal camera. This was turned off overnight so everything was close to room temperature. It is surprising how quickly the condenser heats up and also how evenly. Almost instantly, the pressure is high enough that some of the refrigerant begins to condense on the inner walls of the pipes. And just as an evaporating refrigerant steals energy from its surroundings to boil, a condensing refrigerant releases energy when it turns back into a liquid. That's why the condenser gets hot: the refrigerant releases a ton of thermal energy as it changes phase.

The liquid refrigerant will eventually start to build up at the end of the condenser and will typically cool a bit more (which, by the way, is called subcooling in HVAC parlance) before reaching the metering device. This ensures that there is a decent volume of liquid refrigerant in the metering device in preparation for the next step, and is precisely why the amount of refrigerant within any given cooling system, known as charge, is so critical to its proper operation. . The restriction created by the metering device facilitates a dramatic pressure imbalance between the two sides of the system, because just as the compressor creates high pressure on its outlet side, its inlet side creates suction and therefore low pressure.

The metering device can be as simple as a capillary tube that restricts the volume of refrigerant that can pass through it, or it can be as complex as a thermal expansion valve that reacts to changes in thermal load to ensure performance of optimal cooling. That's deeper than we need, but once the liquid refrigerant passes into the next chamber, another heat exchanger called the evaporator, its boiling point plummets. Now that it is in a low pressure environment, it begins to boil like coolant released from a can of computer duster. And it needs energy to do it, so it draws in the air around the evaporator, which makes it very cold.

Again, let's take a look with a thermal camera. As soon as it is turned on, the evaporator becomes a cold sink, a place where the room's energy will naturally go. The refrigerant here NEEDS energy to evaporate, and it MUST evaporate because the pressure is too low for it to remain liquid. The evaporator fins help it absorb energy from the air, which ends up cooling the room. Once the coolant has reached the end, assumingIf the charge is correct, it will have absorbed all the energy it can. It will then re-enter the compressor and the cycle will repeat.

Now the energy you just collected from inside the room can be expelled to the condenser. The conditioning part of air conditioning happens because the evaporator gets very cold. Moisture in the air will condense on cold surfaces. You've seen it before when holding a glass of ice water on a humid day. This happens because the ability of air to retain moisture depends on its temperature. If the temperature drops, it won't be able to hold as much water, so the water it contains condenses and falls on the cold surface of the glass. Made of fun! This is how clouds, storms and dew occur.

Because the evaporator gets so cold and air rushes through its fins, that air will lose its ability to hold moisture, so it will lose water and the evaporator will get very wet as time goes on. Thanks to surface tension and gravity, accumulated water (called condensation) will travel down the fins to some type of drip tray or, in the case of many window units, simply to the bottom of the machine, where it can seep out. outward. Newer models like this will intentionally pool it around the condenser, and the condenser fan blades (or even, as is the case here, a specialized component thereof) splash water onto the condenser, increasing the efficiency and effectiveness of the air conditioner. through, somewhat ironically, evaporative cooling.

In fact, in this one, the condenser is actually shaped such that part of it sits in the collected condensate. And it's done quite cleverly at the end of the capacitor circuit. At this point, the coolant should already be liquid and pooling in the metering device, but the water will cool it down further, making doubly sure that this actually happens and also increasing the subcooling; again, that is the amount the refrigerant can cool further after it has condensed. That increases efficiency and effectiveness by allowing the evaporator to absorb a little more energy after the refrigerant boils. Remember that when it boils, it takes energy from itself first, so generally the colder you can make it before it goes back into the evaporator, the better (although there are some nuances).

Some people claim that this practice reduces the life of the capacitor by promoting corrosion, but those are just some people who didn't design this thing. Also, the evaporator, which is the exact same type of thing, made of the same material and everything, constantly gets wet while running, but I digress. So here's the key: the coolant here is trapped and forms a continuous loop. We force it to boil, then to condense, to boil, to condense, to boil, to condense, to boil and to condense again and again and again and again. And one more time. And most importantly, we control where those two things happen.

We are using the properties of latent heat to our advantage, in a deliberate and controlled way. We call this a heat pump. With it we can collect and concentrate thermal energy in one place, and transfer it to another to be released. In one direction, this will cool a room by moving heat outward, but the cycle can be reversed, which is becoming more common. Since the refrigerant actually does the work when it changes phase, it can move four or five times more energy than the heat pump consumes in the compressor (depending on conditions). It is the closest thing we have to releasing energy and it is very interesting.

Every real air conditioner, even the terrible single-hose portable air conditioners that you should avoid at all costs, as I explained here (feel free to skip that video as we're covering some of the same things again) has a hot side and a cold side The cold side collects energy and the hot side releases it. Take energy from a space and cool it, move it to space and heat it. This thing, however… you won't find it anywhere at all. It's basically just a wet sponge and a fan that has two giant flaws. The first is that there is no autonomous loop.

While you can certainly use water to cool the air, once it evaporates you must add more. Water generally isn't scarce (except where it is), so for the most part this is more of a hassle than anything else, but it's worth noting. And the second defect? Well, now it's time to answer the question at hand. Do these even work? Well, as a concept, technically they can work. In fact, you can even see a slight cooling effect here in the thermal camera. I'll emphasize the slight, but honestly, it's pretty interesting how it manages to achieve cooling with nothing more than room temperature tap water.

And it was more powerful than I expected, since the air coming out was about 2 or 3°F below room temperature. Yes, my expectations were really that low. But now comes the gigantic warning. The real deal breaker is that, if you haven't figured it out already, a swamp cooler doesn't dehumidify, it adds humidity! For a swamp cooler to do anything, it has to help the water inside it evaporate. And that causes the environmental humidity to rise. In case you thought, well, no big deal, at least it's cooler, here's the other thing: if the ambient humidity is already high, then swamp coolers just don't work.

They can't work. It literally becomes impossible. The air has to be able to absorb more moisture for the cooling effect to occur, and if you are at or near the saturation point, then you are simply SUNNY. The air coming out of this feels a little colder than the air coming out of a normal fan, but... not by much. In this test I aimed the vents to blow directly on this thermostat (because apparently I don't have a thermometer) so I could get a fairly accurate temperature reading. And, well, 64 degrees was the best he could muster. That's less than an ambient temperature of about 67 degrees, maybe 68.

So at best it produced a 4 degree temperature drop. This becomes even more damning when you consider that this was already in an air-conditioned space! The relative humidity was about 50% when I tested this. Abroad, however, it was around 80%. It totally wouldn't work if it was my only source of cooling. To really understand how much they are like air conditioners, I used the thermostat again to see what air was coming out of the air conditioner and… yes. That's really cold. In short, swamp coolers only work to a certain point. And, because we're dealing with relative humidity (which in turn affects how warm we feel at a given temperature), it's anything but simple.

As a rule of thumb, a swamp-type chiller could, assuming it's a good one, cool to within a few degrees of wet-bulb temperature. Now, what is the wet bulb temperature? Heh, well, it's annoying that it's the lowest temperature achievable through evaporative cooling. I know. He describes himself. Wait, I'll try that... Basically, the wet bulb temperature is what a thermometer that has the bulb wrapped in wet cotton or something similar will read. It is affected by how quickly the water evaporates from that cotton ball. It presents the theoretical minimum temperature that an evaporative cooler can expect to achieve, and as humidity increases, so does the wet bulb temperature.

When the humidity is 100%, the wet bulb temperature is the same as the dry bulb temperature (aka...normal) because the air cannot absorb any more moisture. Given my sense of humor, I'm sure I've been called a dry bulb several times. Honestly, all you need to know is that as humidity increases, performance decreases. I mean, that makes sense, given that they're basically little humidifiers, and explains why calling these air conditioners is super dumb. Now, are they worthless? Well, that depends. It would be nice to use it on my desk as a supplement to central air conditioning. Maybe I could run that a little less.

After all, a temperature drop of three degrees is definitely noticeable. But it certainly won't make a dramatic difference and it definitely won't cool the room. In arid places, swamp coolers work wonders! Many people have them to supplement traditional air conditioning and dramatically reduce energy needs (at the expense of increased water use). And, since you usually want a little more humidity in airy places anyway, everyone wins. Swamp coolers can also help the efficiency of split air conditioning systems by cooling the space around the condenser coils, thereby increasing their effectiveness. Something like this builds up the condensate around the condenser.

You can see this in practice in this video made by HVACR videos. You should check out that channel if you want a closer look at some of the various commercial refrigeration and air conditioning systems that exist, as well as the various ways they fail and how problems are diagnosed and repaired. It's a really great channel for that kind of thing. But here in the Midwest, where the humidity can often be oppressive, swamp coolers don't do much and, in fact, only make things worse. Now this little thing, to its credit, suggests that you put ice cubes in it.

Which is, well, kind of funny because you're actually using your refrigerator to cool off and you know what? I approve it! Not practically, of course. It's absolutely stupid. Your refrigerator produced that ice by extracting energy from water and pouring it into your kitchen. But technically it would work at least a little. But in general, these

personal

desktop refrigerators can only sometimes do something. It completely depends on where you live and also varies day to day. Now, just because I'm not a complete moron about this stuff, I've actually tried it in a few scenarios. And while I think it, of course, provides a cooling effect, it is not the miracle product that you HAVE TO BUY and that all the advertisements proclaim it to be.

And how the heck this little thing managed to get all these five star reviews is... Suspicious! And plus, right now, these are insanely expensive! It's literally a computer fan, a piece of cheap plastic and a piece of paper with a little control board for everything. It is powered via USB and they don't even give you the courtesy of providing you with a power source. These shouldn't cost more than $25 and even then, that's a lot for what it is. Additionally, the water-absorbing material must be replaced periodically. It gets gross over time and do any of these companies offer replacements?

Who knows! Also keep in mind that by adding humidity you are making your air conditioner work harder. Making water condense removes thermal energy that we cannot feel; that is the latent heat. So if you have a lot of moisture in the air, your air conditioner must run longer to provide the same amount of cooling thanks to all that water condensing on the evaporator. Using a mini swamp cooler in an already humid location makes your struggling air conditioner struggle even more (although admittedly not much, given the small amount of water this thing is capable of producing during a day) .

So... these things. Are they a scam? Well, they barely manage to say no on a technicality. I mean, calling it air conditioning is an absolute lie. But if they're sold as "personal cooling devices" then... well, yeah, I guess that's technically true. But they are only useful in certain places and certain situations. This is not a personal air conditioner and I wish it were as easy as just adding water! I regret to inform you that this is not the case. If you want to take this concept for a little test drive, I suggest making your own evaporative cooler to see if it could do anything for you.

You could probably just tape some kitchen sponges to a plate upright, with a little space between them, add a little water for the sponges to absorb, and place that contraption in front of a small desk fan and get a lot more. cooling than this thing could ever hope to produce. Any time you see a cooling device for sale that requires neither an exhaust hose nor actual installation, it is not an air conditioner. There hasn't yet been a device that you can drop on your desk and get air conditioning from. In fact, that is impossible. So while I can't say this is a useless device, it is alarmingly fake, horribly expensive, and almost always not worth your time.

Thanks for watching! I think this is the third time I've explained the refrigeration cycle without making a video specifically about it. It truly is a remarkable achievement of humanity, and heat pumps will become increasingly common and important as we move into the era of electrification. You'll probably see a video about this before long, and I think then we'll get into the nitty-gritty, like all thoseterrible coolants we used to use and how we can move forward gracefully. But for now, bloops. ♫ falsely smooth jazz ♫ But the swamp is just a syllabus... syllabus... But the swamp is just a syllabus... syllable!

I said “syllabus”…twice now. Now the energy obtained by cooling the process…. From the cooling process… uugghghhg But! I think it will help illustrate why these... oh, I need it here, ha! In fact, fun fact! The shot. And if you're not interested in this part, go ahead and jump here. But I think it will help... that's right in front of my face, that's a bad idea. The air coming out of this feels a little colder than the air coming out of a normal fan, but not by much. It's not much. It's not MY much, it's YOUR much!

The way these things are marketed? It's not cool. Oh, I'm sorry I didn't include that in the script somehow. But now it's the secret punchline, so yeah!