 I'm going to start drawing the refrigeration cycle here. It doesn't matter where we start. I'm going to start with a compressor right there. Out of our compressor, we will come to our condenser. Right condenser on there. Condenser. Out of our condenser, we'll hit the expansion valve. And from our expansion valve, we will hit a very similar to the condenser. We'll hit the evaporator. Evaporator. And out of that, we'll come into our compressor. The direction we're going for our refrigeration cycle will be like this. Evaporator into condenser. Sorry, evaporator into compressor. Compressor into condenser. Condenser into the expansion valve. Expansion valve into the evaporator. And let's give these numbers. It really doesn't matter how we number it, but I'm going to want to match it on a graph, be able to use those later. Let's start with just calling this 0.1 down here. So between the evaporator and the compressor, I'll try to write compressor in here real small. Actually, I think I can fit it right here. I'll write compressor. The compressor is pretty easy to tell from the drawing. Come into the compressor. The compressor diagram kind of makes sense because you're coming in to this larger volume, to a smaller volume. Evaporator and condenser don't look exactly the same. So you need the labels. This is our expansion valve. Expansion valve. All right, this 0.1. So then we'll call this 0.2, this 0.3, and this 0.4. Let's talk about start with one. So here we have an evaporator. Out of the evaporator is coming a working fluid that is taken heat from a low temperature. So I'm going to call this QL. You could call this Q low. You call it Q in. You call it Q evaporator. This is taking in heat from a low temperature source to evaporate our working fluid. Out of this, we're going to have a working fluid that comes out as a saturated gas. I don't know much about the temperature and pressure yet, but I do know that it is a saturated gas. So saturated gas, or a saturated vapor. The saturated gas comes into the compressor. The compressor takes that gas. Compressors compress gas way better than they can compress liquid. Compresses that gas. And out of our compressor is coming a gas that has been put under pressure. So it's higher pressure. It's higher temperature. And now it's super heated because this compressor is a very special compressor. It is an isoentropic. Isoentropic compressor. So that isoentropic compressor is giving us out of this a high temperature, a high pressure super heated gas is what's coming out of that compressor. Then the condenser dumps its heat to the environment. We can call that QH or Q high or Q condenser. Dumps that heat to the environment. And out of that, it's dumping so much heat that we have this slightly lower temperature. I'll do this like it's a dial, slightly lower temperature. Equally as high pressure, but now it's coming out as a saturated liquid. So this condenser is acting in an isobaric way. Now some of you might be like, well, isn't there friction loss in the pipe? Yes, there is in a real refrigerator. It's not perfectly isobaric, but we're in this idealized version. It's isobaric. So same pressure coming out. And we've allowed all this heat to dump to give us this pretty high temperature, very high pressure saturated liquid. That saturated liquid comes through this expansion valve. And just like all nozzles and expansion valves, on this side of it, you're going to have high pressure. On this side of it, you're going to have low pressure. This is a pretty special expansion valve in that we've designed it to be iso enthalpy. Out of this, we're going to have a low temperature, low pressure mixture. And if you're like, well, why is it a mixture? Well, we'll come back to that when we graph it. And I think you'll see it as this saturated liquid expands, it's lowering in temperature, it's lowering in pressure and coming back down or coming up into a saturated mixture place. So somewhere between a saturated liquid and a saturated gas, it's a mixture. Then we dump Q into it to turn this low temperature, low pressure mixture into pure gas. So what we've done is designed a system where the temperature of QL, let's say that's your refrigerator box, let's say you want to be 40 degrees Fahrenheit, that at 40 degrees Fahrenheit, that's the temperature at which this low temperature, low pressure mixture will evaporate. It's the boiling point of our working fluid in these conditions. The boiling point is that temperature that we want our refrigerator box to be. So it'll take that heat evaporated into a low temperature, low pressure saturated gas that we then compress in an isoentropic way to make a high temperature, high pressure superheated gas, which we go through isobaric condensation, dumping its heat to the environment or your kitchen or your living room or your den. Do people still have dens? I'm not sure. Your cave. And that's going to give us a slightly lower temperature, high pressure saturated liquid, goes through an isoentropic expansion valve, gives us a low temperature, low pressure mixture. It goes through this evaporator, which will also be isobaric, isobaric, dumps in heat from a lower temperature environment, from a typically low temperature environment like a refrigerator box to give us this low temperature, low pressure saturated gas. The way that this looks on a, let's do a temperature entropy diagram here and I'll use blue. So point one, that's our saturated gas. That's an easy point to find. Here we have our saturated liquid line or saturated gas line. This is our mixture envelope. This is going to be straight up and down because this is entropy. So straight up and down. I promise that straight up and down. Just trust me. Then this is point two and this is point one. So here we are as this superheated high temperature, high pressure. And then we're going to go through the condenser and this thing is going to drop until it hits our saturated gas line. And then it's going to come straight across because now we're at phase change. And it's going to come all the way until it's a saturated liquid at point three. Now that we're at that point, we're going to come down, we're going to go through that expansion valve in an isoenthalpic way. This is a TS diagram, so I'm just going to just guess at what the enthalpic direction looks like, maybe something like that. This is, given my drawing ability, that's probably as good as it's going to get. And that will be point four. This is our mixture, point four. And then that's just going to come straight across because now we're in phase change. And there we go. These points here, this is QL jumping in its heat to get this mixture to become a gas. And then this is work in. I guess I should label that on here. This is work in. You can call this work compressor as well. Work in. That's work in working on that. That work is turning this into a high pressure, high temperature, superheated gas. Then we go through that condenser. It's this whole range here. We go through that condenser and we dump that heat out, which lowers its temperature until it hits this point. And then it just goes through phase change. So it became from superheated gas to saturated gas, dumping its heat all the way until it's 100% saturated liquid or x equals zero. Boom. And then we go through our expansion valve. I'll just go ahead and label this as iso enthalpic expansion. Iso enthalpic expansion. And just in case the numbers weren't obvious, I'm going to go ahead and put arrows on this, right? This is going this way. That's going that way. This is going this way. That's going that way. I'm going to come back to this and draw some equations and some maybe just equations. Draw some equations on here. Maybe put some numbers on here for fun. But this is in general the refrigeration cycle. Thanks.