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Episode 299. Basic Refrigeration 101 · The Refrigeration Mentor Podcast

• 0:00
  What's up everyone? Thank you for coming back to the Refrigeration Mentor Podcast as I hang out. So glad you're here. This next episode was from the 2022 HVC Sym Training Symposium. I have a lot of fun every time I go down to this event. I've been there for over the last six years, training there. It's really.
• 0:01
  Leave a comment. Leave a review. If you enjoy this episode, as well as hit the refrigeration mentor.com/hub and find out about our refrigeration mentor community. This is a community where we're trying to uplift the industry uplift technicians to support them from technical support, professional support, and really get you to the next level by pushing yourself to your next limit.
• 0:02
  First off, for those who don't know me, my name's Trevor Matthews. I started a company about a year, year and a half ago called Refrigeration Mentor because I really want to help people like me in the field. I was a technician 6, 7, 8 years in the field. Didn't have a lot of confidence. Didn't always know what I was doing because I didn't have anyone to teach me or train me.
• 0:03
  It's so important, okay? And this is why I started my company. Some of the things we're gonna talk about today, we're gonna dive into key definitions. You guys know a lot of this, all of you know all these terms. I would need to get, you guys are gonna have to get pens and papers out because I'm gonna be asking you questions to take stuff down.
• 0:04
  And that's really where it changed for me. Is when I could really image and visualize what's going on in each component and it takes time. And Ty did a great job today. I really enjoy watching his visuals because he puts it in a way that you can see that relates to you. We're gonna get into system checkpoint review.
• 0:05
  I want you to take four to five minutes and write down what is sensible heat and all of you online as well. What is latent heat? What is saturated condition? What is soup, heat? What is dew point? This is very important. You need to understand these things at a, a fundamental level.
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  One of the big things as well is that we have a lot of key terms up here. There are many, many more and some of the TER terms that you'll see and learn of mean something different to other people, like temperature difference. We're gonna talk about that when you're talking to someone in hvac, talking to someone in refrigeration.
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  Has anybody ever seen a diagram that looked like this before? Show of hands. So we got one, two, oh. Almost half the people. That's, that's awesome. I love that. How many of you see it on a yearly basis? Let's see. Of hands. Well, half that amount. Okay. Okay. So we, you can call this many different things. Pressure, entropy, diagram, pressure, temperature diagram, a molar diagram I think it is.
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  You gotta be safe though. You don't just know start grabbing stuff that you don't know, right? 'cause you could grab a really hot discharge line, right? But before you start putting gauges on and temperature probes, you need to use your visual, your audio, I guess your ears, and, and then touching it. And then so where would we find this?
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  There's a ton of data in there so you can start plotting on how a system's running when you get more data. And this is three of the most important things that you need to get anytime you're installing, commissioning, servicing a system, even maintenance. Next one's latent. Heat tied. Did a great job explaining what is latent heat, again,
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  And it's very important to understand the different units. We here, we talk about PSI and we talk about Fahrenheit all the time. I'm from Canada. We, we say Celsius as a society, but in refrigeration, I say Fahrenheit. So I need to know both. If you want to travel the world and with refrigeration, you can travel all over the world.
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  Tim? 970 bts, or 2,250 joules per gram? So you gotta understand what is happening in the system and where is it happening. So you gotta visualize this stuff. And the, when this really started to click for me, when I really started understand refrigeration is when I seen all these different points all at the same time on a system.
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  exactly? Coexistent of liquid and gas. So you got vapor and you got liquid, but depending on where you're at on here. Okay, so if we're on this side right here, do we have more vapor or more liquid? Does anybody know? Or is it equal? 50 50? So we got more vapor 'cause this is our vapor line. There's a name for that.
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  See, that's something new, right? Because we're, we're used to being like, oh, at the compressor we need, we know the manufacturer says, what? What does Copeland, does? Anybody know what Copeland says? They're recommended superheat at the compressor because there's two different super heats. What's that? 15, 15, 25.
• 0:14
  You need to understand the compressor you're working on. Every component that you work on is different to that different manufacturer and they'll have a little bit different specs. We do need to get out of the rule of thumbs. We need to get out of this rule of thumb things because you will have a more efficient system on the way the manufacturer designed that system and you follow what they are talking what their specs are.
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  That's, that's what Copeland said. And what do they recommend? Two 50 you said. What else? Two. Two 50. Anybody else? 2 25, 2 35. It depends. It depends. You gotta find out in that specific compressor manual what they recommend. Scroll could be a two 50. For an example, semi hermetic, they say 2 25. A hermetic may say, I can't remember, and Don may be able to correct me if it's two 60 in some hermetics.
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  And, sorry, I don't have all this in Celsius. I think it's two 40 Celsius and 1 0 7. Celsius for the Copeland 1, 2 20 fives. 1 0 7 Celsius, I think. But this is why it's so important to dive into those different manuals. Well, what we're talking about entropy diagram. Why are you talking about manuals? Because this all relates, it all relates.
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  Where we do start to condense. 'cause we get into what line, where, where do we get inside here when we cross this line? Saturation. Saturation. When we cross this line right here, we get into saturation. Great job. I love that. Thank you. Gonna have to get more of you up here to help me out. We'll get into two point a little bit later.
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  'cause I know a lot of you here will start to design systems and engineer systems at some point. I know for sure. 'cause you're here to learn and you want to grow and you're gonna continue to grow. And then the more we get outside that saturation curve, this is called the bubble point. The more we get out of there, the more sub cooling we're gonna have.
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  So when you get onto maybe supermarket system or larger systems, you actually have sometimes mechanical sub cooling or vapor injection compressors to make that liquid colder. So if I'm trying to get a minus 20 or a minus 20 fahr or minus 20 Celsius, it doesn't matter if I have that 75 degree liquid line or if I have a a 50 degree liquid line.
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  So these are things that you need to dive into more and learn more. Anybody ever run into that issue? Not yet. That's That's good Glide. Love This glide was something we never talked about years and years and years ago, but now it's a common thing. What is Glide the difference between dew point and bubble point. That's great. Okay. So I remember it was a spoiling little PT chart. I think it was all of a sudden I got two lines coming down.
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  So here's R 22, single blend refrigerant. Here's the pressure temperature, here's the pressure, temperature. This exact same both sides, but when you get a blend refrigerant, same pre, this pressure's running across, but there's a temperature here and a temperature here. Do you think this is a warmer or colder temperature on the bubble point?
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  There's a few in the refrigeration world, they've been around for a long time and a lot of them, you actually have someone driving behind you with a a bunch of different tanks because you never know what refrigerant you're gonna have in a system. Okay, but glide is so important. This is something that's been really hard on manufacturers over the last six to seven, eight years because they're designing evaporator coils with tds, which we'll talk about in a second.
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  So I'll give you a good little tip that I learned from a manufacturer friend of mine. If you're in a walk-in box. Take the SST of that coil and the room temperature. 'cause that room temperature should be all the same. So the return temperature, 'cause you're enclosed, if you're doing it on an open display case, that's where you do it from the discharge air.
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  Restroom, meter. Awesome. You got that compressor, you got the condenser, you got the metering device, and you got the evaporator coil. Fantastic. And I have it looking like this, but it could be a chiller. It could, it doesn't matter. Refrigeration's the same. We got high pressures or higher pressures and temperature and lower pressures than temperatures.
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  Is it a bit more complex? It? It could be, but this is why you're here, to learn to invest in yourself. So is it a higher pressure? Yes. We would still be using our 12 if we never had ever had a leak in a system, if that makes sense. It didn't matter if it was a lower pressure, you still figured it out. So you need to understand.
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  And then lo and behold, sometimes the receiver was low. Sometimes that TX valve screen is plugged. But I learned all this stuff before I even put any gauges on just listening. Okay. So, may be hard to see this, but we're gonna dive into the re refrigeration. Like anybody ever see a diagram like that before?
• 0:27
  Here's the enthalpy. Okay? Some charts, like I said, may have temperature, and there is temperatures right here. Over here is the pressures I got, PSI and I got BTUs. This is not to scale, so next time I'll have it more to scale. If you're looking at the exact numbers, this refrigerant is R 4 54 C. Okay? So it's a newer refrigerant, it's a blended refrigerant, and it's a glide refrigerant.
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  Okay, so here's the first step in a system. How many people here understand the systems that you install? The sequence of operations? Perfectly? Show of hands. One person, and that's okay. This is something that you need to understand if you want to be a top technician, the best technician at your company, understanding the sequence of operation and how you explain it to someone.
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  Why? Okay, why? It could be wide energizes. This is how you gotta think. So now you go right into, and then you said the solenoid. So the solenoid got a coil in it that energizes. When that energized, what happens? It normally close opens. It opens, and then what happens? As it opens, then what happens? The pressure control makes well, but before the pressure control can make, it opens what's happening inside the line.
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  Flashes. So it starts a flash you, and then it starts going through your evaporator and then it gets into your suction line. And then, then what happens? Pressure starts to rise. Then the pressure control makes, then the pressure control makes, that sends more energy to usually a what? To a contactor. That contactor energizes and it should pull in then.
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  We go from a low pressure to a higher pressure. We push our ourself up into really, should this be a higher zone, but we push ourself up. What is the next step when we leave there? Leave this compressor. Time to reject some heat. Reject some heat. Where's the hottest point in any compressor discharge? The discharge valve.
• 0:32
  So as we leave there, we're leaving B, we're going over to one. What is happening at this point? So we said the hottest point is right. When that last squish of gas happens, what's the next thing that, what happens when we start to go down B to one? DUP reading. Thank you. You start to dupre and you'll see in some applications.
• 0:33
  Then we get into the condenser and what that, what's the condenser doing, stacking, removing heat. We're moving, we're removing heat, we're rejecting that. We're wasting, actually we're wasting heat. There's new technology that we're using that, but we're really wasting energy. You are gonna see a lot of system changing over the next five to 10 years.
• 0:34
  Blades could be The fan blades are on backwards. There's so many things that you need to think of. Right. There's a lot of different things, but getting these temperature, these these units, I should say, and putting it down, you need to understand the sequence of vibration as well as have a checklist.
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  sub cooling, right? Depending on your system, may depend on how much sub cooling you need. Air condition, refrigeration, low temp, medium temp. If you're adding economizer on a system, if you're adding efficiency to a system. It is real important to understand that stuff because when you're way out, if I have, if the, say a condensing unit, the manufacturer says, I need 12 degrees sub cooling and I got 29 degrees sub cooling, what could that mean?
• 0:36
  Here's a straight line. This is a single blend. Refrigerant. Okay, bubble do. These are our temperatures. 60, 40, 20 0. We hit the pressure rate here, it's the example is 60 PSI and four and a half bar. Okay. That is the temperature right there. So we're between zero and 20. So say we're at 10 degrees Fahrenheit at that bubble point.
• 0:37
  So you need to understand what's happened to the dynamics of the systems. There's definitely gonna be changes that you need to make to a system. They could be minor, but there could be a lot when you do a gas retrofit. And it's very important to understand that. So then we have our meter life. We have that pressure drop.
• 0:38
  What if it's really cold? What if I got a cold liquid line? Too much heat, too much sub, too much sub cooling. What else could it be restriction? If you have a liquid line that's colder than your suction line, probably something you wanna look into. Okay. But these are the different things that you want to review and go back to over and over and over again.
• 0:39
  Doesn't matter if we talk about residential, commercial, industrial, we're trying to move energy, we're trying to move heat. We're trying to pull that heat out and reject it out the through the condenser or reuse that energy. And you're gonna see smart systems coming where we're gonna start using more energy properly and not waste so much.
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  Dirty. Dirty air, dirty coil, dirty honeycombs. Any, any one of you is doing supermarket work. It could be a dirty honeycomb. What's a honey cone? Look it up if you work in supermarket. Look what a honeycomb up, because I didn't know for many years. Okay? There could be multiple sets of fans when you're doing refrigeration on old systems, that'll trick you up and trick me up for many years.
• 0:41
  Be the technician to fix the problem. If it takes you longer, it takes you longer. Get the job done right the first time. And when your refrigerant is not boiling off in your evaporator, what does that lead to? Back, flood back. Okay. Mechanical wear. Mechanical wear. Yeah. Heavy mechanical way. And it looks different in different compressors.
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  So that's called a slug. Okay? But when we talk about a refrigerant, cool compressor, do we get a slug? When we get a flood back, you get di loaded oil, which is different. This is why it's so important. No, no, the differences. I used to just say, oh, it's liquid. It's liquid. What liquid? Is it oil? Is it refrigerant?
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  Scroll to a low pressure, a high pressure side scroll compared to a low pressure side scroll. There's a lot of differences out there. This is why you need to get to those manufacturers. And then our last point we talked about already is the superheat. You could call it system superheat, compressor superheat, and then you have evaporator superheat.
• 0:44
  So you need to take those measurements. But once again, first you need to look, you need to touch, you need to listen. Questions on this.
• 0:45
  Yeah. Take a super heat at the compressor, usually in fixed system to see if it's charge is correct. Yeah. Again, to protect the press. Yeah. So great point. He said it's to use it to properly troubleshoot what's going on in the system. Okay. And what you really want to do, because there was a good point there, if I have this suction line and Ty said at a great today talking about super, if I have that running through a really hot space, it's gonna absorb that heat.
• 0:46
  It's kind of like checking sub cooling. Where do you guys check sub cooling at? Where is it at? Liquid line? Leaving the condenser liquid line, leaving the condenser. Is that the only place you can check it? You can check it at the metering device, but if you don't have a port to check it at the metering device to be the most accurate, what else can you do?
• 0:47
  They can constantly do the work. If they did, at least I know they got the right checkpoints, and you're gonna learn this over time. The more points you have when you call a manufacturer up for help, and you can give them the more points they're gonna be able to help you so much faster instead of asking you, well, what's the pressure and temperature?
• 0:48
  But let's talk about some system checkpoints that you would do. And this doesn't matter what system you're on, maybe a little different if you're using plate heat exchange or, or a shell and tube system. But it doesn't matter. What are the system checkpoints you guys are taking? What, what? Some of the checkpoints you take just one six inches off the compressor, six inches off.
• 0:49
  I guess before you touch the refrigeration side, you can check your amp draws to see if you have Ah, there we go. Where else? My system. Yeah. You don't even need, when you first start troubleshooting any system, you should not be pulling out tools. You do not need tools. 'cause when you walk out to the condensing units residential and it's plugged up solid, you can think already, well we're tripping off on a high temp.
• 0:50
  But it's what we do to make that system run better. Or the customer, if they don't wanna pay for a maintenance plan and the condenser keeps getting plugged up or supper out, that's another reason for failure. But you, these things can be prevented, right? By getting these numbers. What else is there? So we talked about getting some temperature, visual looking amps.
• 0:51
  How many people have the Copeland mobile app? Show of hands, what? Copeland Mobile. Yeah. Yeah. Every, and you should have all the manufacturer, you work on it. If it's kin, you should have the kin tech hub app. If it's Tessy, you should have TE Tech tool. I don't know. I don't think spoiling has one. I keep looking for the spoiling output.
• 0:52
  And then you can also use it as to see if you've got liquid refrigerant in there, right? Do you have a charge in there? Then you could check potentially your sub cooling. At least get the temperature there. This is so important. Area and air out of the evaporator can help tell you if it's plugging up or not.
• 0:53
  What could it become? Pressure drop. It could be a drop capacity. Yeah. Pressure drop. Pressure drop capacity. That high compression ratio again. So you just change the failed compressor. You put in a filter dryer, you leave, everything's running at that time, but two days later this plugs up, then you come back for another failed compressor.
• 0:54
  Dew point. So dew point's, getting to the point where you're converting into that you're saturating, but you're, you're working your way there. Let's go back. So this point right here, B two one. So right here is the hottest point. So this is the hottest point in that system. That last point is everything leaving here to you till you get to this dew point, like you said. This is DUP heating.
• 0:55
  So is there like these super heating occurring for like the first third of the condenser coil or It depends. Depends. Yeah. It depends on the design. 'cause there's some coils that have natural sub cooling built in mechanical sub cooling added on. So, but there is a point that's something you can bring up with the manufacturer.
• 0:56
  That's not the way to do it. You don't roll the belts on. 'cause that's why I used to do it. I did it for many, many years. Oh, I can rip through this maintenance in this eight hour maintenance in two hours. You're doing it wrong. Like, like stretching it over. Yeah. Browning. Browning. You can put a belt on.
• 0:57
  We always love that. We love the support out there. This is how more people find out about the Refrigeration Mentor Podcast and we'll see it the next episode. Let's get a conversation going.