How Your Air Conditioner Cools Your House

All righty, guys. Today we are going to jump into a quick video discussing how an air conditioner actually cools your house down, what are the four major components, and what in the world do they do when it comes to the refrigeration cycle and making you comfortable. By the way, I'm Tucker Yarbrough with Yarbrough & Sons Heating, Cooling, & Plumbing. We are a heating, cooling, and plumbing business in the Oklahoma City metro area. We're second generation. Keeping your home comfortable is what we do. So, let's get into it. Let's find out how your house is actually made comfortable via the means of refrigeration and what the components are. So, here we go. We're going to start outside at the condensing coil, or the condensing unit, as you'll often hear it called, is a condenser. And in the condenser, we've got two of the four major components of the refrigeration cycle, which is the compressor and the condensing coil. And the compressor is kind of the heart of the system, right? It's the the mechanism by which refrigeration gets to move through the house. And that compressor is going to be compressing a cool gaseous refrigerant into a high-pressure, warm refrigerant. And then as refrigeration, you know, as the refrigerant gets warmer in temperature, it condenses into a high-pressure liquid. Thus, condenser coil. HVAC people are pretty simple, guys. We we name things uh pretty much for what they do. So, the compressor, what does it do? It compresses a cool, low-pressure gas into a warm, high-pressure gas that then condenses into a high-pressure liquid. And as it goes through this coil, it's going to stack liquid, and it's going to slowly, you know, somewhere at the midpoint, it will turn into a high-pressure liquid solid liquid. It's not going to be any It's not going to be gaseous anymore. And then it goes through the liquid line all the way to your indoor unit. Whether that indoor unit is in a closet or for this example, you can see it's in a attic in a horizontal flow. Obviously, clearly, guys, everything here is to scale. This condenser is huge. It's half the size of an outdoor wall, and the furnace / air handler takes up the entire attic. Uh no, but this just gives us a clear representation as to what is actually happening. But, that liquid refrigerant travels all the way inside to the two other major components of the refrigeration cycle, which is first the TXV, or sometimes you'll hear them be called an EXV, which is an electronic expansion valve, but this is just a temperature uh expan- expansion valve. And so, what it's doing is it is constantly sensing the temperature of the suction line. And it's going to be sitting there saying, "Okay, yep, I'm getting too much, or I'm not getting enough, or I'm getting too much, or I'm not getting enough." And it's just constantly changing how much refrigerant is let through the expansion valve itself. Older systems have a piston. Pistons just release a set amount. It's really hard to uh to kind of get super high efficiencies with a piston because it's, you know, you're letting out the same amount no matter what. But, as it goes through the evaporator coil, it is going to be doing just that. Again, HVAC guys, pretty simple. We're naming it after the thing that it does. And so, we are taking a warm high-pressure liquid and just just spraying it into the evaporator coil. And as we spray it in the evaporator coil, somewhere around along the midpoint, you know, typically we want to see it towards the latter third uh of the evaporator coil, and it is going to be solid gas. It is going to have changed and transitioned into a gas again. It's no longer going to be no longer going to be liquid. And as refrigeration turns into a gas, it boils off at a really cold temperature. And so, the sensible temperature of your indoor coil might be gosh, might be 40°. Um and so, then what we're going to do is we're going to blow air across the coil, and as we blow air across the coil, what does it do? Well, one, it creates condensation. We're creating water. Uh we got a water-making machine as a byproduct of this thing. But, also it's going to cool that air down, and by cooling the air down, it then warms the refrigerant up. And so, now we have heat transfer happening at the evaporator coil of taking it from, you know, gosh, maybe a 40° uh uh refrigeration temperature up to 60° or up to, you know, 55° or whatever it is. But then now it is all gas and we're taking this gas at low pressure, cool gas all the way back to the condenser. And that's where you go outside and if you look at that line, the two lines, the copper lines going into the condensing unit itself, there's going to be a a small one that is your liquid line and that's going to be pretty warm and on hot days, especially when your air conditioner is working real hard, that can get pretty warm and toasty. So stay cautioned. You know, don't uh, don't don't touch that unless you absolutely have to. But then the suction line, the bigger of the two lines, is going to be nice and cool. And that's where like the old the adage of like the old heads in air conditioning is pop can cold. And pop can cold is, you know, you pull a a pop can out of the refrigerator, what happens to it? Well, it gets nice and nice and sweaty. It starts to condensate and starts to form some water because whenever you take a cool something and put it in a warm something, the atmosphere, well, we create condensation. And so now we have that cool gas back at the compressor, that cool gas, one, it helps cool the compressor down so it doesn't overheat, but then two, the compressor gets to start the whole process over again. It takes a cool gas and compresses it into a warm high pressure gas. And as we increase the temperature of the refrigerant, it turns back into a liquid, thus condenser coil, going from a gaseous state to a liquid state. And [snorts] it's a high pressure liquid as it goes all the way back to the evaporator coil >> [clears throat] >> and gets metered through the expansion valve, the TXV or the EXV, or on older systems, just a piston. And then it sprays into the evaporator coil and as air gets blown across it, well, we see that refrigerant take on heat, it evaporates, turns into a gas again and it goes back to the compressor. And that's the cycle, but you can see this warm air coming in here, cold air going out there. That is what creates condensation. And so that's where we got this little drip line happening right here. In a perfect world, that drip line is going outside or it's going into a mop closet or just a floor drain of some sort. And you should have, if you don't have one, you should have an emergency float switch on your system, especially if it's in the attic. And it should shut down the system if water ever gets backed up. So, if algae or debris or anything like that makes it to where this condensate line can't push water outside, well, it should shut that system down and not allow it to run so that you don't end up with a very wet and soggy ceiling and a very sad heart because you now have water damage. So, you should have an emergency drain pan cut off right there in the drain pan itself. But, that is the air conditioner in a nutshell. We have the compressor, the condenser coil, the expansion valve, and the evaporator coil, and both of them obviously driven by the blower motor, and by the condensing fan motor. But, guys, that's all I've got. I'm out. Do something nice for somebody. You never know, it might change your life. Hope this helped.