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He is a big shot trainer with Danfoss in North America and Jamie's actually from Canada. So you'll hear a little bit of that Canadia in his voice, but today we talk about electronic expansion valves. We talked about TTS in the past, we kind of first start the conversation by setting up different types of metering devices and just going through the different reasons for the different types of metering devices. But then Jamie gets specifically into electronic expansion valves, EE vs and how they work.

So here we go Jamie kitchen with Dan Voss talking about electronic expansion valves thanks for coming back on the podcast Jamie, absolutely great to be back, and so Jamie is a big shot. I think that actually is what your business cards say. I think it says big shot at Danfoss. If I'm not mistaken, yeah bs man, that's what we thought Jamie's in the training division, but he's also been given his toe and more of the grocery store refrigeration.

We were just talking about that which was interesting stuff and we're gon na talk a little bit today about metering devices in general. We've already talked about experiment, an expansion valves TXV these TVs, but today I want to talk a little bit more about electronic expansion valves and, as it turns out, that's actually something that you've been thinking a little bit more about recently right, yeah, there's. Definitely the idea in people's heads now to start migrating towards there. People have a lot of questions so usually, when I'm doing a class on metering devices or refrigeration, now you're almost guaranteed to get a question on a v's it used to be.

You know variable speed, whereas variable speed going now, there's a lot of focus on EVs, especially in the aftermarket, because we're starting to actually see TVs in equipment that typically would have had a TXV or even fixed, or if it's like a piston for that matter. So people are starting to be aware, they're starting to be concerned. If you want to use that word, they don't want to be caught off guard, be prepared as much as they possibly can so that when the opportunity arises, they're comfortable in either installing these things or servicing them, or at least explaining to other customers or to others. How they work and obviously the benefit, is the big part.

What are the benefits I could expect by installing an EEV electronic expansion belt got it so before we jump into that? Let's just do a quick review of metering devices and I'll kind of start off here. There's a couple different ways that metering device purpose can be stated, but one of its jobs or its primary job. If you will is to create a pressure drop, you have pressure in the liquid line. You have liquid high pressure refrigerant, relatively high pressure, refrigerant and the metering device.

The job of the media device is to create a pressure drop right. Absolutely building on that. I think that's a concept that most people think they understand the relationship between pressure and temperature, but when it comes to practice, I've seen people stumble over the fact that the reason we drop, that pressure is so that we can control the actual temperature of the refrigerant Boils that that's the absolute difference between low temperature in high temperatures? Yes, what pressures are they operating at? So when you pick a meter device, you have to establish what pressure drop. What is the operating conditions that I want the system to operate at everything from a wine cooler? That's operating with a very high evaporator temperature, say: 50 degrees through air conditioning, medium, temp, refrigeration and then low temp, refrigeration down to minus 10 minus 20.

That's all determined essentially by the pressure drop that occurs across the metering device and that's a interesting distinction to make, because in most cases we are transferring the heat out of the refrigerant, so we're condensing the refrigerant to outdoor ambient air. That's typically, what we're using as the medium, so our condensing temperatures stay fairly consistent, there's some variability but fairly consistently tied to the outdoor air temperature. Unless you start to go to some form of head pressure control in so application application, there's not as much variability if you're using outdoor air, it obviously there's cascade systems and there's water source systems and all that. But the bulk of what we work on is transferring that heat to the outdoor air and so that side of the system is fairly consistent across applications.

But the pressure drop side of the equation is not consistent across applications, because you have very low temperature, a ssin or low temperature, a ssin, and then you all the way up to high temperature air conditioning. You mentioned wine coolers, where you have a much lower pressure drop and so depending on the application that metering device needs to have more or less pressure drop. Absolutely again how stable that high side pressure is her? Temperature really has a big impact on the metering device that you can choose, and this real beginning with a basic orifice fixed piston, take a wine cooler where's a wine cooler located. Well, it's not stuck outside generally, it's usually inside in a conditioned space.

Most of the time in people's basement, so what you got a four degree: temperature gradient between high and low temperatures in your basement, maybe and you're keeping your evaporator temperature relatively constant, especially in a wine cooler, because you're, not loading tons of hot product in there at Any given time, that's probably the pinnacle of straight as a board high pressure, low pressure being stable so with a stable pressure differential you put a fixed or in there and you're gon na get very close feed 24/7 when the system is operate. In other words, if you're getting a pound a minute today, you'll get a pound a minute tomorrow or in whatever time of day it is you don't get that swinging temperature that occurs outdoors so there's a great example of where a fixed orifice is probably the best Forced scenario like that, because you pick a point that you want to maintain an optimal point and it will keep it that way: 24/7 365 days a year. There's an example where I wouldn't probably recommend going to anything more complicated than a cap tube or a piston. Because, to be honest with you, there would be absolutely no advantage in them.

Well, even if you think about the traditional refrigerator with the capillary tube metering device, you make a really good point when you have a refrigerator, it's designed to be in a fairly fixed temperature environment. It's designed to be inside in controlled temperatures, and this is actually why, if you've ever noticed, you can take a refrigerator that you have inside your house and take that same refrigerator and put it in your garage in Florida in a dirty high temperature environment. The thing doesn't perform as well, because it wasn't designed to function in that type of an environment, because you are now changing the condensing temperature beyond what it was really designed for. So when you have that condenser, that's in a very fixed temperature environment - and you have a box temperature - that's fixed, you have your evaporator temperature, that's fairly fixed in a reach-in residential refrigerator, refrigerator, / freezer.

That's a perfect example where a cap tube makes perfect sense. You really don't need anything more than that. It's also why we don't recommend, unless you absolutely have to freeze product in your freezer, because it's not designed to increase refrigerant flow in the increased evaporator capacity to make up for that extra load you're putting in there. So if you want to freeze something fast in order to have the best preservation, the best quality of meats and things like that, when you thaw it out, it's best to buy it pre frozen and then place it in your freezer.

Can you freeze something in your freezer? Absolutely we do it with water all the time, but the fact is, it will take a lot longer and the ice crystals that form will be larger and there will be more tissue damage than if you flash froze it. That's why companies like McDonald's flash freeze their meat guy? No we're talking about McDonald's here, but the fact is you flash freezes so that when you thaw it out, it is almost identical to, but the consistency of the way it was before you actually froze it. When I was fresh so there's an aside to that, we are kind of bumping up against the limitations of a fixed orifice, but for 95 percent or whatever of the applications you want to use for that fridge works beautifully. You just identified the reason why, within commercial refrigeration, you are using TX, P's, largely and now we're moving to more and more electronic expansion valves which we're going to get to, which is that in that particular application.

Even if you have a reach-in, for example, something where the condenser is in the conditioned space, if you have variability in interior load, then you don't have any way to adjust the feeding of the evaporator coil to match that load. It's simply fixed, and so what Jamie saying there and then this is a really good point - is that if you take fresh, let's say you chop up a bunch of chicken and you throw it in your freezer at home, it's got to be a decent amount. Obviously it's just a little bit is probably not gon na make a huge difference, but when you add that additional load from that warm product into your freezer and it has to drop that product temperature, it's going to under feed, that of a protocol, a fixed orifice, Because it can't adjust and allow more flow into the evaporator coil to help compensate for that additional heat load when you're sizing equipment and, let's say you're, doing a walk-in box just to jump up a level. The rules state that, if you put fresh meat in here, you have to get it down to a certain temperature within a certain period of time.

So if you're gon na put hundred pounds of fresh pork or beef or something in there, the rules say you've only got six hours or whatever it is to get it down to this condition in order to limit bacterial growth. If you look at your load during that six hours, it is probably going to be substantially higher. To put it modestly, then what the load was previously when the door was shut, the system had pulled down, and the only thing you're really dealing with is a little bit of infiltration and heat coming through the walls of the box right then, and there, if you Look at a TX valve and you look at the opening curve of a TX valve. I can point to exactly where you're going to be during pulldown and I can also point exactly to where you're going to be six hours later, but just before the thermostat.

The system right anyway, Jamie says, pull down. I always like to redefine terms. If you don't know what that means: hot pull down as a term or pull down as a term. That's used to describe condition in refrigeration.

Where you have higher evaporator load, then the system is designed for a peak operation or a normal operation. I guess the be away on vacation and you've set your thermostat for 78 or 80 degrees in the house to save energy or turn the thing off altogether and you come back and you've got high humidity. You've got high air temperature, but more specifically everything inside that house, all tens of thousands of pounds of your house is a lot warmer than it would be if the air conditioning was running. So when you turn that air conditioning on not only have your cool in the air in the house, but you're also pulling the moisture and the heat out of everything, that's inside of that house.

So that would be your pulldown period and, as we all know that I can take a long time before we finally get all those conditions back to where it would normally be. If the system was running on a regular basis. And it's something that I think air conditioning technicians discount, at least in my market. You have a high humidity, high temperature market and so we'll go fix.

An air conditioner and the things been down three days over the weekend and had a bad compressor and we replace it and we get it functioning and it was 92 degrees in the house and then almost every single time. I mean no matter what we tell the customer four hours later, six hours later, they're calling us back and saying is still hot in here. It's not cooling down like it used to and what you have to realize, or what we wish the customers would realize in these circumstances is that everything in that house has mass and all the stuff inside that house has to also give up its heat. It's not just the air, it's not just changing the air temperature in refrigeration.

The refrigeration technicians know this very well that once you get a whole box full of product and a reach, an oriental walkin you've got all this product and all this product is down to temperature. Well that actually helps stabilize the fluctuations of the temperature in the box. So, even when that system goes into defrost or whatever the case may be all of that product in there is this gigantic heat sink, and so there's not going to be huge temperature fluctuations in those spaces. It's going to take a lot of time for temperature to change, which gives you the opportunity to do things that you need to do like defrost and evaporator coil.

But if you were to put hot product in their product, that was at room temperature then takes rudd load of energy to get that down to the target temperature, because I probably weighs as much as all of the air inside of the restaurant, as opposed to inside Of the walk-in box right, if you won't look at and that's that point so there's a lot of thermal mass, we have a fancy term for that. It's called thermal inertia, in other words, how resistance something is to change in temperature. So if something weighs a lot, it's got a lot of inertia. It's gon na take a long time to change the temperature.

The opposite of that is, I can remember when we used to go snowmobile on this kids and you'd go into one of these cabins that you're rent and you go in there and inside is pretty much ambient temperature, thirty five or twenty five degrees or twenty degrees. Fahrenheit, so you fire up the wood stove and the baseboard heaters. The air temperature goes up to 75 degrees inside you turn that stuff off and that temperatures gon na plunge right back down to 45 degrees again because the rest of the house is still cold exactly. It's really interesting when you think about these things, because these are things that people who work in refrigeration they consider more often and air-conditioning technicians, maybe don't consider as much, we think very much in terms of air temperature and it isn't just air temperature.

It is the temperature of all of that mass, but one thing that you brought up in the last podcast where we talked about TX vs that I want to point out again here. Is it really does come down to the pounds of refrigerant moving through that evaporator coil and the temperature at which it's boiling? Those really are the two factors that control how much heat is being removed by that evaporator coil right yeah, the temperature difference between the air and the refrigerant, all else being the same and the mass flow through the other refrigerant through the evaporators. And if you take a coil design and you run refrigerant through it and you run more refrigerant at a higher delta T, a lower temperature difference. You're gon na have an issue boiling off of that refrigerant, without increasing air flow, for example.

Vice versa, you lower the amount of refrigerant through the evaporator. You increase the delta T across there. Now you got to reduce your air flow, so everything is in a balance there right now. The system itself, specifically with a TX V or an adaptive control, will always find a balance, and we see that, like we discussed last time as soon as your load starts to fall off the TX v throttles closed.

This drops the pressure in the evaporator, because the compressor is still pumping all about refrigerant there until it finds its balance. So the system will always find a balance between how much refrigerants going through the evaporator pressure and system capacity. So everything is going to find a balance depending on what we do and we can usually do this. You got these refrigeration trainers and schools and training classes, throw a piece of paper up against the evaporator coil cut back your airflow 50 percent or 40 percent and watch what happens if you have a cap tube.

The first thing you're gon na notice, is your super heat goes in the toilet and you start getting liquid out of your evaporator. Your pressure may drop a little bit, whereas with the TXV, your superheat might drop a couple of degrees, but your evaporator pressure is gon na drop substantially. In fact, if you're running at say 40 or 45 degrees in the classroom - and you cut your airflow you're, probably gon na drop below freezing and start to ice up, the TX valve is doing exactly what it's designed to do. It's not a TXV problem.

Another interesting thing this is a little bit of an aside, but it's something that I hadn't thought about as fully as I had recently was talking to Jim Bergman, and he was telling me that if you reduce the heat content of a fixed orifice system, so you Reduce the load on a fixed orifice system. What he was saying will happen is that your head pressure will start to draw pretty rapidly and I was like: why would that happen? I wasn't really getting any as I try it just do it, and so we shut off a blower on a fixed orifice system and watch what happened in the head. Pressure drop just as quick, almost proportional to how fast the suction pressure drops there you're not rejecting. As much heat, so you don't need as liability between the air and exactly because you're not absorbing as much heat you're rejecting as much heat.

So when you're compressing it that heats not being exposed, and so therefore you don't see the increase in pressure. It's just a really interesting effect because, generally speaking, while the super he does drop, there's a counter balancing effect because the head pressure is also dropping which then also affects it. So it's just a really interesting thing that I never fully considered. Oh, it's a good one, because again everybody has to realize you got to think about a system as a whole.

Get rid of this component focus. I know it's an easy thing to become fixed on a component, but if you're fixed on a component you're missing out pretty much everything else that can be going on into that system. What are the ambient conditions and what is your load? How dirty? What is my airflow, how much airflow do I have? Is there issue somewhere else in the system that can be causing problem a lot of times? You can come for one thing, but you'll notice that there's some other definite issues with the system that, if correct it would pay for themselves and energy cost savings in a very short period of time. Really you got to be open to how the whole system is operating.

You get rid of this component focus only. I think we'd be a lot better off if people were more comfortable understanding. How that whole system operates the pain on the load and your ambient conditions, but as you listening we're like 15 minutes into this thing, and we haven't even set a civil word about electronic expansion valves, but we're setting the stage for electronic expansion valve so be patient. If we have a perfect situation, especially when we have either varying ambient conditions outside so varying conditions that are affecting their condensing temperature and then also varying load conditions, we want to be able to still produce a proper amount of pounds of refrigerant mass flow rate.

Through that evaporator coil to match the load on that evaporator coil, so we're fully optimizing that coil without running the potential of flooding back to the compressor. Is that the way that you think of that? Is there another way saying that absolutely man you want to maintain a minimum superheat, because superheat is removing capacity from an evaporator? It's also raising the average temperature of the evaporator by thinking along these terms, when I say raising the average temperature, that's a temperature above saturation. So that's not helping you, that's not saying I'm raising my saturation temperature, so my compression ratio is lower and I'm doing less work and saving energy that is basically cutting into your efficiency and your net. Refrigeration effect, your cooling and it's raising the average evaporator temperature.

So from an air conditioning standpoint that is the opposite of what we generally want to achieve. Ideally, you want an evaporator temperature, that's quite low. I remember being surprised. Last time we did.

This you've talked about how low the evaporator temperature you guys aim for in air conditioning, because you're focused on dehumidification and dehumidification for most of us, even up where I am, is a huge part of air conditioning. So if I increase in the average evaporator temperature by having too much superheat, we're really downgrading how well our system can operate and that's a huge thing you want just enough superheat, so the system is stable and your protect the compressor, but no more, how many watts You put in how many BTUs of heat moved you get out. You want to have minimum superheat, then the lowest superheat you can possibly have so for those of you who are listening. This is not what I'm telling you to do.

I'm just telling you from a strictly theoretical energy efficiency standpoint. You want the lowest possible superheat, so you're, using that entire of a protocol. In fact, even a flooded of a protocol is a great condition at the proper coil temperature to properly control humidity. Whatever that may be, that varies in some cases.

You want a higher coil temperature to actually keep the humidity higher. Like you mentioned in the case of a wine cooler in air conditioning where I am, we like to keep the coils cold, because we want to remove as much moisture as we possibly can, and we want to have as low of sub cool as we can have. Because the lower the liquid line temperature entering the metering device, the less refrigerant, is lost to flash gas initially, if you want to have a sub cool. So that way, your you don't have to drop temperature as far and you want to have as low a compression ratios as you can have so the difference between your section and your head pressure.

Those are the factors that play into efficiency, but there's more at play here than just efficiency. Is such a big deal and I talk about humidity a lot and I'm sure people probably get sick of hearing me talk about it, but you can save twenty bucks a month or ten bucks a month on your electricity bill. But if you're not dehumidified, properly, you're really not getting value for those energy savings, because if you have high humidity in your space, you're gon na feel uncomfortable and when people feel uncomfortable as it uncomfortably warm. What's the first thing they do with their thermostat yeah.

So you drop another two degrees. Well, there goes all your savings and more out the window. You can say well, yeah. You can use a programmable thermostat yeah right.

Do you not think, but also our spouses or whatever know how to override at an automatic thermostat? If we're uncomfortable, we're gon na do something about it, we're not gon na sit there and be uncomfortable all day, long just to save seventy five cents or a buck a day. You need to find that balance point and we can't do one and ignore the other and expect people to swallow it and be happy with it right. So there's a lot that goes into this, and this is where the intelligence behind a metering device can make a huge difference. The lowest liquid line temperatures possible.

It is going to reduce the amount of flash gas that you produce because, as you lower the end, the liquid, a high-pressure there's less of a difference between how much energy a liquid can hold right at high and low pressure. So you're going to produce less flash gas and we could talk about this for 20 minutes and kill the rest of this podcast, but suffice to say that's a good thing. Now we're gon na talk about electronic expansion valve. So we talked about th fees before.

If you don't know how to TX V, Werks go back and listen to that podcast, but let's talk about the emergence of electronic expansion valves and why they even exist in the first place. What's the purpose, why wasn't TX valve good enough to understand? Is that a TX valve - and this is where our humming up picture's worth a thousand words, but a TX valve pretty much opens linearly. So linear is a straight line. It's angled up! If you have on the left of the upper right axis, you've got percent opening and on the bottom horizontal you have super heat.

So as your superheat increases, it drives the valve open near top capacity. Let's say: you've got 12 or 14 degrees of operating superheat. That's what your measure at the bottom of the outlet of the evaporator, whereas when the valve is closed and is just about to start opening, you might have seven degrees and the seven degrees is what we call static or factory Supre. That's the value you're gon na see on the side of the box, so between seven and fourteen that valves gon na go from being closed to open that produces a straight line for given amount of superheat.

You've got a certain amount of opening, that's great except here's. The issue we have this value of the minimum superheat that evaporator requires it's called minimum stable superheat. So let's take a minute here and explain both this, because I really don't care if you remember minimum stable super-deep, but I want you understand that it's a minimum value that an evaporator has to have as refrigerant goes through liquid refrigerant goes through. An evaporator begins to boil: you've got more and more vapor being produced in that evaporator and what happens is as the amount of liquid drops.

It starts to form what we call a meniscus. That's the curve up the side of the evaporator wall. So you have this liquid being pushed up the wall by the boiling vapor. Eventually, when you're getting a small enough amount of liquid, it breaks off into droplets in that liquid because of surface tension.

What happens when you drip water off of something? It forms a ball right well that ball now travels down the center of the pipe. It is much harder to heat that drop of refrigerant, and there could be quite a bit of really liquid refrigerant here. We're talking about much harder to heat, that in the middle of the pipe than it was when it was actually sticking to the side of the pipe. Basically, what we're saying is if an evaporator has a minimum, stable superheat of 5 degrees or 4 degrees.

You need to actually measure four or five degrees of Supre that the evaporator outlet, in order to ensure that all these droplets have actually evaporated and what ends up happening is if you try and operate a TX valve below this minimum stable superheat, because this liquid is In the center, but it's also moving around it's gon na slowly raise and lower the temperature of that puck, because you've got this mild mixing going on. It's rushing down the side, so the temperatures not stable, so you've literally got liquid surging up and down the bottom surface of your evaporator, and so this is gon na cause hunting in a TX valve, and we can show this on our refrigeration trainers by dialing down The superheat on the TX valve until it starts to hunt that is below that minimum stable soup reach setting for that evaporator. Now here's the thing: the minimum, stable superheat value for an evaporator changes with capacity. It starts with low capacity and gets higher as the capacity increases, but once you get about mid range, the change starts to drop off and the line becomes vertical.

So what ends up happening? Is you have a curve picture a curve for the minimum stable superheat? Now you take a straight line for a TX valve. What happens when you take a straight angled line and you put it against a curve. It touches in the middle, but then the curve moves away from the straight line at the top and moves away from the straight line at the bottom. So you have this huge gap at the bottom, at the top, where that TX valve is gon na, give you far more superheat than what is actually required.

So what we do is we aim the superheat about the TX valve, so that is always on the right side. It's always on the dry side of the stable side of that curve. That's why you can't just take your soup reset on a TX valve and say: oh man, I'm gon na drive this down to two degrees. Well, guess what move that straight line inside the curve so that the middle 75 or 60 % range of that evaporator we're in air-conditioning anyways? You spend 90 % of your time operating it's gon na be unstable.

So it's not just a matter of reducing superheat. On a TX valve, there is a minimum superheat you need with a TX valve in order for that system to operate. But the thing is it's not fixed that minimum stable Supre it actually changes with evaporator capacity and the course evaporator design. So there's the big difference and it all has to do with the velocity of the gas and the liquid change in the evaporator, and these droplets become and suspended.

Guess what an EEV does they paint on the design with a Danfoss, for example? This is what I work with ee-vie. It has built-in algorithms that search the superheat setting on that evaporator Inlet and when it detects a little bit of instability, it just bumps the superheat up a little bit until it becomes stable. So it's always pushing that edge and it will literally track that minimum stable superheat curve from high load to low load and always stay just to the right of it as small as possible. You don't have to have any particular algorithms for an evaporator.

It's just always tracking the superheat, so you put your refrigerant in there. What type of refrigerator you have and the control does the rest. This is simplified. There are many different superheat regimes that regiments that you can put in there.

You can have it. So it's a thick superheat, you can have it so that it tracks more, gives you more superheat at certain points, but think about what this does. If I have an evaporator being fed by a TX V - and let's say it gets very humid in my space - well, humidity is a load and that's gon na drive up my evaporator superheat. So, what's the TX valve gon na do Brian in response to that increased superheat? What's the only way that fixed feed compressor can pump that extra refrigerant, the TX valves putting in there it doesn't change anything.

The single stage, compressor is just literally tied to the mass of the refrigerant entering it right. The TX valve opens up the evaporator pressure starts to go up but and more importantly, the superheat setting or the superheat with the TX valve also increases and, as we know, under high load, as I said before, you've got far more superheat than what you actually need With the TX Vil, if you have a lot more superheat with a TX valve, combined with a higher pressure in your evaporator and higher saturation temperature, you end up with a much higher average evaporator temperature. And what does that? Average'High of average evaporator temperature due to your dehumidification, it decreases it so just at the time when you need more dehumidification, you're being penalised with it. This opens up two avenues.

I just basically foreshadow what our next podcast can be and that's a variable, speed, compressors and variable speed airflow by reducing the amount of super heat at high load. The EEV lowers the average evaporator temperature and will give you better dehumidification under high load when you most need it, but overall it lowers your average evaporator temperature. If I lower my average evaporator temperature. This allows me if dehumidification isn't a big deal like in refrigeration.

It allows me to increase my saturation temperature, my saturation pressure in my evaporator, so by increasing the saturation temperature by 2 or 3 or 4 degrees. This lowers my compression ratio and, if I lower my compression ratio that saves me energy, ok, I get less flash gas. I get more heat absorption in my evaporator, there's less energy being spent on compression. So overall my efficiency increases.

Now I mentioned food retail to you, food retail because they spend so much money on refrigeration and their margins are so low. They eat this stuff up. So you asked me: Yee V's are replacing TX V's and where that benefit is that's where the rubber hits the road right there, it allows them to optimize their systems to use less energy by increasing their evaporator pressure slightly and still getting the correct refrigeration. That's where those savings come from the automatic, superheat correction and optimization allows you to operate your evaporator slightly warmer and save a lot on energy and money.

The guys with the highest energy costs are gon na jump on board first, and that's exactly what we've seen over the last 10 or 15 years. When you look at air conditioning, there's an opportunity now to better adapt your evaporator get better humidity control. You don't have to worry about people setting, T X, valves or a fixed superheat TX valve that set up the factory. Let's optimize for a specific point, these electronic expansion valves will figure out the superheat for you and do it automatically it's one of these things where we've taken an issue where people don't like to work with superheat, because they're not comfortable.

It's hard to understand. If you have the right value or not, and you have the electronics doing that for you, whether you like that or not that's kind of where the markets going at this pump, so I'm here with James Bowman from rector seal and real quick. I wanted to talk about the safety switch line of condensate switches and I actually just got a safety switch that has a clear body on it. So is that product gon na be hitting the market anytime soon James it's available.

Now we wanted to get it out to you first, just to get your input and see what you thought. So what do you think I approve? Let me reach over here and grab it real, quick you going to show it to everybody yeah! You can look right, I'll tap it against the mic, so everybody can hear it there. It is that's the safety switch. This is a Model S s1, which is a model that we use a lot of in my business.

We use ss1 ss2 s and SS threes in our business, and I like it because, with the clear body you don't have to go messing with the top to see if it's got anything in it and also, if you have an instance where you've got a homeowner And they're wondering if maybe it's the condensate switch, you can tell them to take a look at it without having a mess with wires and all that kind of thing cuz. You know it's, never a good idea to have a homeowner start yanking on things. So I think it's a really nice design and with it being still PVC, which is pretty cool, it says schedule 40 right on it. So I've never seen clear PVC like that before it's kind of amazing this, some of the things that we can do with plastics, but yeah you can make schedule 40 clear PVC.

What I like about the safety switches is: we've got a safety switch to cover a lot of. We got the inline, the SS won't be as to inline or as a secondary use. Ess, that is a secondary. The SS 3 goes into a sheet metal pan.

Those are our mechanical. Well, we also have an SS ap plenum-rated. We also have an SS 3 plenum rated. So if you've got a closet unit that they're requiring plenum rating because the switches are in the Airstream, we've got those - we have our SS 700 as a hockey puck type, the switch the hockey puck.

You can sit down in a return and on a floor and a pan electronic we've got the SS 500, which is a plenum rated designed for down flow rooftop packaged units. Then we have the SS 16 E, which is a mini split con estates which which yes is a code requirement not enforced everywhere, but it is a code requirement and what's the beauty of our electronic safety switches that they have diagnostic LEDs, so course green. No drain problem red drain problem. The third light yellow indicates that it's had a dream problem sometime in the last four days, so you got a slow drain.

It's such a unit off light light comes on the water slowly drains down the probes, get dry up. The red light goes off. The green light comes on along with the yellow light. So now, when you show up, oh it's had a drain problem sometime in the last four days.

Let me check for a slow drain. We also have an SS 103. The 103 is. A combination has two different sensors and three different combinations.

So it has the SS one inline body, the SS 3 metal pan clip and screw in adapter for the secondary port of your primary pan. So you can use two sensors with three different combinations. Well, very popular number, one selling line of switches in the country and very, very popular and reliable switches. Another thing, a lot of people don't know is that we test all of our mechanical and most of our electronic switches before they go into finished goods before they ship, because that's what we want, we want you to have a reliable switch.

That is the safety switch line of products from rector seal, probably the broadest line on the market. So look for safety switch products at your local supply house. Let me balance a few things here, so, especially in supermarket applications or in refrigeration applications. It's a good thing, because lower super heats and lower compression ratios are a huge factor in compressor longevity.

So you increase the cooling effect to the compressor because you have a lower superheat and you also simultaneously increase the compression ratio, which is also good on a compressor, because that's something you're fighting off in refrigeration, because the compression ratios are so much higher. Is that a fair statement? Absolutely now that you mentioned that I missed that point: yeah, a low temp, refrigeration, your biggest enemy isn't high load, because then you have lots of mass flow. Coming back to your compressor to cool it, your enemy is when you're running low load, with even lower evaporator pressures, low mass flow. Coming back to your compressors, how do you cool them? How do you get rid of that winding heat while you put head coolers on you put oil coolers on you, do all kinds of stuff.

The compressors look like a drone like they're gon na fly off and start filming people buy any little help you can get, thereby reducing your superheat by increasing or decrease in that compression ratio a little bit that all goes a long ways to increasing compressor longevity. So again, good point: it's not just a focus on the evaporator and the metering device. There's also the downstream benefits as well, and so the pitch for the residential market is more than by controlling your superheat more accurately, and so really, if you think, of a fixed metering device where you have essentially no control over superheat. And then you go one step down and you have a TX valve TeV that has decent control of superheat, but it has a range in which it starts to get outside of that zone.

And this it is set to high. And then you go to an electronic expansion valve that not only controls it very accurately because, first of all, it's just a more precision device, but second of all, because it actually is using algorithms to do it and to actually adapt to the operation of that system. That you are controlling superheat in essentially the optimum possible way that seems to be sort of the purpose of it is you're really managing that superheat in the optimum possible way to feed that coil with as much refrigerant as you possibly can, while still ensuring that you Don't have hunting or flood back; let's just spend a minute down the road talking about this there's a couple: different types of electronic expansion bills, but on the other side for the listeners out there floating head pressure control. What it essentially does is it allows your head pressure to drop at night and during periods of lower ambient conditions so that it drops to the point where you just have enough pressure difference to feed your metering devices properly, because you're dropping your head pressure.

This allows you to lower your compression ratio less during favorable time. It's not like the economizer site for the air really is what it is and it allows you to save energy. Historically, what guys have done? You can achieve the same effect by putting an oversized TX valve in, and this allows you to drop your condensing pressures a little bit more, where, if you had a normally sized TX valve when that condensing pressure dropped, you wouldn't have enough feed through it by over Sizing your TX valve, believe it or not. It allows you to operate in this range of lower condensing temperatures.

/ sizing the valve works, but there's also the downside to it. You got to make sure everything in that system is working exactly as I supposed to do. It because if the system, honks or / feeds, or whatever it's only gon na, do that much worse. If the TX valve is oversized with an ex-con expansion valve, you can oversize, or you can size that electronic expansion valve based on the lowest pressure difference that you can expect or that you want.

You can let your condensing temperature drop to say 80 degrees outside or 75 degrees outside, and the electronic expansion valve is sized so that it will just open up more while still maintaining the minimum possible superheat, because it is only looking maintain that minimum possible superheat and As long as the valve has enough capacity, it will open closed, throttle open and close happily all day long, maintaining that minimum stable superheat. So this allows you to put variable speed fans on your condensers. It allows you to drop the condensing temperature substantially. Saving lots of energy and supermarkets once again led the way on this, because it is what we call low hanging fruit.

Well, you have one technology enabling another technology or another opportunity to be pursued, so the capability that I chronic expansion valve to fine-tune superheat, regardless of your load and other extraneous conditions, allows you to go into areas that you will not go into. So, as you mentioned, fixed orifice is the opposite of that right. You got a cool rainy day and air conditioning and you most need dehumidification. You don't have enough outdoor pressure to feed that piston, so your evaporator superheat goes through the roof under high wet bulb conditions.

Just look at a piston charging, shirt and you'll, see what I mean. Look at a 68 degree or 66 degree, indoor wet bulb, look at a 75 degree. Outdoor dry bulb and you've got like 20 degrees of superheat or 24 degrees of soup. Read on your evaporator that drives your average evaporator temperature way up so by doing one step and going to a TX valve, it can really help in that situation.

In fact, it will probably give you the biggest bang for the buck. To be honest with you - and I mentioned this last time, going to an Eevee - will give you even more of an incremental benefit, but I have to admit in at least in this situation. The TX V is probably gon na. Give you your biggest bang for the buck.

The Eevee will certainly be a benefit, but again just going to a adaptive. Control like a TX valve will give you a lot of improvement there getting back to a floating head pressure. You can see what I mean we're. Having something suddenly becomes available makes something else also available, as in good floating head pressure control to kind of summarize this portion of it, the more variability that you have, both in condensing temperature and in evaporator load, the more valuable a electronic expansion valve becomes because really What we're chasing, we kind of already mentioned these few things or chasing target evaporator temperature.

We talked about that a lot. You have a particular target, evaporator temperature that you're trying to hit in almost every application for a particular purpose. Colder evaporator coil means more humidity. Removal warmer of a prequel means less humidity removal, depending on the application.

It's gon na dictate that in refrigeration air conditioning whatever the case may be, we're also chasing low compression ratios and in refrigeration, especially they're, really chasing. That which is the reason for the floating head pressure, controls cuz back in the day, and we've all seen this in air conditioning and a lot of different applications. You have fan cycling switches, an old-school head pressure control. You just cycle a condenser fan, one of the condenser fans out of many on a large rtu or on a bank of condensers and refrigeration, and that keeps the head pressure at a set target.

But what they realized is well you're, artificially driving up this, this head pressure and it's not necessary to always drive it up that much and what's resulting is you have in some cases astronomical compression ratios, which is killing your compressors in one hand, it's they're not being Properly cooled and on the other hand, it's just driving down your efficiency unnecessarily. So there's all these factors and the more money that you're spending on these things, the more that becomes a consideration, whereas on the residential side, we're finding that we're less concerned. We are concerned about efficiency, but it's kind of diminishing returns at this point, we're more concerned now about dehumidification and when Jamie says average of a pert our temperature. I just want to hit on this real quick, because a lot of you and I've actually pushed for this.

I've been telling guys, let's start calling what we previously would call suction saturation. Let's start calling that evaporator temperature, because there's a lot of areas that they do that and so the evaporating temperature, the boiling temperature of the refrigerant in that coil, is going to be your suction saturation or your evaporator temperature. Until you hit the superheat range and the more superheat you have, the more of that coil is dedicated to superheat, and the less of that coil is dedicated to the boiling of refrigerant, which is why the average evaporator temperature is now less efficient. So you have a higher average of aperture temperature, so when you say it has a higher average evaporator temperature, we're not saying that thieves and the suction saturation changes.

What we're saying is is that, because you have extra superheat, the coil is warmer at the end of the coil, and so when you average that all out you overall have a warmer coil. Well, let's take it to the extreme. You got an evaporator temperature right, a 45 degrees you're aiming for 42 degrees, 40 degrees. Depending on where you are for air conditioning.

You get a blocked, piston or metering device. Your evaporator temperature drops down to 20 degrees. You've got frost on your inlet, but you got like 3,000 degrees of superheat at the outlet of the evaporator right. I can guarantee you.

I put 20 bucks down that your average evaporator temperature with a twin degree, saturated suction and no refrigerant flow, is going to be a heck of a lot higher than your average temperature is when it's properly feeding refrigerant in your saturation. Temperature is 45 or 40 degrees. Otherwise, if it wasn't you'd continue to cool and you continue to de middle Phi right and that's not the case - it's how much refrigerant you have flowing through it. How much heat removal you can do that largely determines that average evaporator temperature, there's really two types of electronic expansion valve says: let's call a pulse width that is like a solenoid valve.

That's either open or closed. Oh there's a stepper motor and a stepper motor is kind of like a motor doing the same thing as you turning off a faucet right opening and closing it you're driving a spool down or the spindle down and open the stepper motor one. It pulses in the sense of is, maybe have a couple of hundred steps to be fully open and a couple of hundred steps be fully closed and you got a little motor that turns one way or the other depending on the signal. So the motor will drive the valve open or closed depending on the superheat, whereas a pulse-width valve in our case and danfoss this case it is either open or closed.

You run over a six second period of time, so if your load is 50 percent of the valves, capacity is gon na be open three seconds out of six. If you're in pulldown mode, it might momentarily very short period of time, be open five and a half or six seconds out of six and then, as your load drops off the amount of time it's open during that period of time, drops off. There's benefits and there's drawbacks to both the benefit of the pulse width is hey. You've got a built-in normally closed, solenoid valve when it goes in to pump down load.

It acts as a solid velve for you and eliminates that issue. Some people don't like the pulsations that a pulse-width valve does but again, the industry and Danfoss is working on a pulse width valve that eliminates that by having soft opening and closing so there's always an opportunity to improve on something a stepper motor design has the ability To pick a spot inside where it will open and close and modulate it's a lot quieter benefits to that. The other benefit to pulse width is when the valve is open. Your refrigerant velocity is high and you flush the oil out and move it along again.

It all depends, you can argue both technologies, both of them accomplish the same thing, and that is maintain that minimum stable superheat, not the blow danfoss, is horn, but we actually have that patent on minimum stable, Supre control. Everybody else has to do a fixed superheat. If you go to anybody elses valve, you got to pick the superheat you want to maintain, and then it maintains a straight vertical line for superheat. You can do that with our valves as well.

A lot of people opt for this minimum, stable, superheat design. You can go through and pick your control regiment that you want to follow, but the default one in this aftermarket kit is going to be minimum stable, Supre and it's probably gon na - be a stepper motor valve at this time. But things do change so stay tuned. It is interesting just as a general observation is that when you go from analog to digital, everything in digital is some form of like on and off some form of it even a separate motor.

It isn't really on and off, but it's still on and off of different steps like it's analog signal between voltage and polarity right. So it's driving it back and forth. But when you think of like - and this is true so many everything is digital photography versus analog photography - you have pixels and digital photography where it breaks it down to these. Ultimately, yes, no.10 true/false type of boolean equation type of thing in an analog you do you just have this kind of more smooth thing, which is a factor when you think about these technologies we're so everything being new.

Is digital? Look at the variable speed fan. What's the output on your controller, it's analog analog to a variable speed motor got a voltage ramp, you got a frequency ramp, that's the kind of but you're looking at. Digital is definitely on/off open and closed, and a solenoid valve is definitely a digital control. But even when you look at variable frequency drives, you look at PWM and variable frequency drive.

It's the same sort of challenges that you face where you're attempting to take a pulse with a signal and attempting to mimic a natural analog frequency, which is interesting. It's the same kind of thing: if you can imagine what this valve is doing, it's doing, essentially what a variable freak see drive is doing in the case of powers. Everybody has their preferred way of doing it, and both technologies are probably gon na be around for a long time and definitely depend on who you talk to you're gon na find one person on your efforts that one over the other - and there is some benefits to Some compared to the other, but again it all depends on the application. What you prefer, your piping runs.

How long are they? How big of an issue is oil return things like that again? There's solutions on both sides of these, but it all depends on what you prefer. We're, definitely looking forward to getting more the electronic expansion Mel's out there only because it will eliminate a lot of the issues of having to sit down and fine-tune to breed. So if you look at the time of tech, spins fine-tuning superheat, especially on certain evaporator designs, trying to find something that is as low as possible, but at the same time is stable. The electronic expansion bells will do all that work for you from a time-saving standpoint.

Labor's not cheap these days. There is a benefit to that too, as well that and also being able to tie back to track.