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Zum lot comm for more information, and now the man who uses they don't make them like they used to as a universal verb, Brian. Or why hello? There? It seems you found the HVAC school podcast, the podcast. That reminds you of all the things that you forgot about, HVAC our or maybe reminds you about a few things that you forgot to know. In the first place, my name is Brian war, and I am your pretend Internet, professor of HVAC, our ology, and today on the podcast.

We have Jamie kitchen and Jamie is a multiple time return contributor to the podcast he's a very smart guy. He is a training manager at dan Foss, as well as an Account Manager, and we wanted to just talk about variable, speed technology, sort of a 20,000 foot view - and I quote a 50,000 foot view. But a 20,000 foot view of variable speed technology and the kind of the why, behind it variable speed gets a bad rap, sometimes, and sometimes it may be deserved. But in this podcast we're gon na talk about it broadly and then in the future.

We were gon na, do a podcast, maybe talking about some of the specific diagnostic elements, there's something I want to say just as a kind of overarching statement about diagnosis when it comes to diagnosing very complex systems, your best bet for learning how to diagnose them and Learning about them is just reading the manufacturer's information about that particular product. So, like you have to know generally how things work and why they are the way they are sequence of operation, how it's supposed to work and why it does what it does and what the objectives are. But once you know that, then your specific manufacturer is gon na, do it in a different way and they're gon na have different codes and so on and so forth. You know different error codes there and pop up on screens and how you get into different interfaces and all that sort of thing it's going to be very specific to the manufacturer.

So in those sorts of circumstances, it's best for you to go and get factory training or ready to manual. So today's episode is all about variable technology. We kind of start talking about blowers, but then we go into talking about all the different elements of variable speed technology, and here we go Jamie kitchen. I think at this point it's been like four or five time returning guests on HVAC school podcast and today we're going to talk a variable-speed blower technology.

So thanks for coming on the podcast Jamie, oh thank you for having me. Let's start here because you've done a lot of training on variable, speed, technology and obviously Jamie's with Danfoss and frankly. This is a weird place to start here, but I'd like to understand like what types of products does Danfoss have that relate to this whole world of variable speed motors. There's a couple things I mean you have the direct ones which are the piece of equipment.

That's actually being manipulated or driven by a variable, speed, drive and that usually comes down to fluid pumps, gas pumps such as compressors and, of course, air side. So the control of family blower motors things like that, so those are the ones that are actually actively being driven. The other side of that, of course, is the controllers, which need to react quick enough to get information back so that you can kind of do. Real-Time modulation, based on inputs coming in your sensor, so part of that is going to be your electronic expansion valves, the sensors and all that kind of stuff that go along and to feed the information back.

Because if you change the speed of something and you do that, based on either outdated old information - in other words, it's more than a few seconds old or your equipment can't respond properly to the reaction and the change in air say you're using a slow-acting TXV, then You're, actually gon na hurt more than you're gon na help. So all that kind of comes together is one package, so we just don't offer somebody a terrible speed compressor unless they can back up that compressor with the controls and the adaptive media devices that support it. Along the way, yeah, and so I think, a lot of technicians, they think in terms of like a particular brand, like I think, a carrier Trane or Lennox or whatever, but obviously Danfoss, is providing solutions to the actual manufacturer. So you'll see danfoss valves and danfoss compressors in certain OEM packages and then you'll also see them on the shelf for replacement components.

I mean the other day I worked on a danfoss variable frequency drive on a Walmart, and so there was the Danfoss component that then interfaced with the other controls and the variable frequency drive in that particular application was working with a hill Phoenix RAC. So you have these different OEMs, but then you have the in that case the variable frequency drive outside of that. But then you also have some particular solutions that OEMs also use. But I think the first thing that I want to address here is that most technicians, when they think a variable frequency or when they think of variable, speed, they're generally gon na start by thinking about typical residential blower technology, so they're gon na think about a variable Speed, well, that's a ECM blower or variable speed, blower or maybe even think about an X 13.

So, do you have much experience with that, where you can kind of Segway between what those products do and what some of the more advanced, especially in the commercial side, of how those function well, yeah sure it's not so easy, because they all do essentially the same Thing, first of all, you have to ask yourself: what are you trying to accomplish? What do I need? What are my goals that I can't achieve with a constant or fixed speed setup? So I guess we need to kind of start with. Let's take a couple scenarios and look at what the challenges are with a fixed speed and then we can kind of contrast that with variable speed and where we can kind of have our cake and eat it too. So to speak, I mean you addressed residential HVAC. Let's take a look at that, so you know you're down in the Florida area where dehumidification is key.

Yes, you have high ambient temperatures. Such you have high dry, bulb temperatures, but the same time, along with those you have high moisture levels, high relative humidity and our range is kind of, as it says, relative humidity and, as we talked about earlier on, our earlier podcast deal with humidity. How much moisture the airholes is relative to its temperature, so on a 90 or 95 degree day, the air can hold so much moisture that the latent component, the latent heat of the air, is like off the scale. You can't even plot it on a standard psychometric chart unless you use a high temperature version of one, because the energy levels are just too high.

So what do you do? Well, you set up your air flow at say, 350 or 320 CFM a ton. You drop your evaporator temperature and you have a highly latent focused process. Unfortunately, this is a necessity because it is not efficient. If you were to take your unit, that's operating with, say a 38 or 36 degree evaporator temperature and you compared it to a 45 or 46 degree.

Evaporator temperature, you're, gon na use, probably fifteen or twenty percent more energy. Doing your cooling. Now, because it's an absolute requirement, we need to go that route, but here's the thing how many days of the year is that low CFM, low evaporator temperature ideal for the conditions, I'm just gon na go out on a limb here and say: maybe 50 % of The time or 40 % of the time and the other times of the year, you could get by with a higher evaporator temperature, higher CFM, achieve more energy efficiency through higher CEO P's and save energy and get better comfort, cooling where you're not over drying the air. When it's not really necessary, so that's kind of one side of it, the variable speed it allows you to measure the outdoor conditions, measure the indoor conditions and essentially measure what your system is doing almost live in real time and it'll say: ok right now we have Relatively low ambient temperatures but high moisture levels, so we can treat the air this way later on the day when the sensible heat portion climbs up - and it may not be a highly wet day with high RH, we can bump off the CFM a little bit increase.

Our coil temperature and away we go so we either spool the compressor down we spool the fan up. Our electronic expansion valve is always looking for the optimal superheat anyway, so it's just gon na do whatever the requirements tell it to do, and now you're running the system in a far more ideal situation, then, as the night time goes by, and your sensible load drops Off again, it can tailor the system to run. So it's really this smart way of doing it rather than taking one profile and applying it 365 days of the year. Let's look at another analogy, looks like a defrost.

You you have timed defrost, it's not bad. I mean you run your defrost for three or four hours at defrost, the evaporator, coil and refrigeration, say and you're good to go, but that time defrost in the summer time, if you set it when it's cool outside and there's not as much moisture you're gon na Under defrost in the summer time, if you set it up when it's cooler, if you set up in the summer time, so you have long defrost times to handle all the ice buildup in the summer time during the winter months or the cooler months, you're gon na Over defrost and you're gon na waste, a ton of energy, so it's not ideal! You pick a certain one and you stick with it unless you physically change it, it's gon na stay that way so like as a general overarching principle here. What we're doing when we're talking about variable speed in general, we can vary the speeds of lots of different things. We can vary the speeds if compressors condenser fans lowers in the case of the Walmart I was mentioning earlier.

I was working on the condensing fans, and so that has to do with outdoor ambient conditions. So, there's a lot of different things you can affect with variable speed technology and really what we're doing here is we're making sense of non optimal conditions where, when you have a fixed speed situation, you're not optimizing for varying conditions, and so, as a general rule, I Guess, let's just pin this down and see if you agree with this - that variable speed technology as a whole is designed to handle situations in which the conditions vary in one way or another. Is that fair? Yes, absolutely! There's two sides of this: one is the flexibility that you just mentioned and I was driving around earlier, but there's also the capacity factor, one of the things that we learned early on that to be honest, we they surprised the heck out of all of us, was When you look at the load on a building - and you do with your degree days - you do it very accurately, and you think you have this accurate heat profile for your building. What we found was that, when we put a variable speed system in that had a similar capacity to the fixed speed unit, it only ran at the rated capacity of the fixed speed unit.

In other words, let's say you had a 20 ton fixed speed unit. It only ran at 20 tons your for this for three percent of the time. You know three percent of the time, so we have these drastically oversized units, and not only are you compromising proper air treatment when you very away from the optimal conditions, but at the same time you're cycling these units far more often than what you should be to Give yourself effective cooling when all the energy extra energy use that comes from starting and stopping these units. It's incredible! So it's a two pronged approach, number one.

If you're gon na have a fixed speed unit, you got to oversize it so stupidly, big, because you got ta be prepared for that day and a half or two days in early August when it hits a hundred and five degrees, and you have high humidity on The rest of the days when it's a hundred and two degrees and slightly lower humidity, you may think of what's the difference. Well, the difference could be fifteen percent difference in energy requirements or cooling requirements. That's a lot because that means you've got about a five or six percent difference in energy usage to cool that air that you're just thrown out the window so to a residential person. What we're looking at is obviously better control, but also a greater savings on energy efficiency, and this goal is not just for the homeowner, but for the utilities and everybody else, that's providing this energy.

We all know about brownouts and probably the best way to avoid a brownout. To be honest with, you is a variable-speed HVAC system, because you don't have those instantaneous loads of equipment going on instantaneous loads of starting and stopping. You may think, okay! Well, my unit only draws high current for a couple of seconds. Well, when you multiply that by hundreds of thousands of Units starting and stopping, it adds a much higher percentage of energy requirements to the grid over those peak hours - and I mean we're talking twenty or thirty percent increase in electrical demand.

Just due to that right. So, to be honest with you, you can shave a ton of energy requirements off of the grid just by switching to this technology, and the savings are incredible to be honest and that's kind of what I wanted to reveal like I'd spent a lot of time on This podcast in articles talking about the differences between x13 motors and variable, speed, motors and variable frequency drives, and that kind of thing I mean there's not that much to talk about. I mean really you're, just packaging variable speed in different ways. So when you think about an X 13 motor, we're really only solving one problem with an X 13 motor, and that is the issue of typical single speed, PSC motors of producing less airflow as the static pressure increases.

So, by putting in an X 13 motor, you help address that one problem and in the process you also help with energy efficiency, but you're not doing much else with that, because there's not variable it's just constant torque yeah, I mean it allows you to overcome certain Limitations in the system or certain challenges in the system, what dot work and things like that. And, of course no technology is over gon na, come back workmanship or bad, install or whatever, in duct work or on the air side. But there is definitely a value and it didn't making sure that something is constant in the system. The air side is probably one of the most ignored sides of our industry and it's really tragic, because I've heard multiple times.

People tell me that know. If you don't know your airflow than any other reading you take is going to be useless right, so it definitely addresses that one side of the equation, so I don't want to downplay it it. So whenever I say X, 13 is a good technology. People just start freaking out on me because there's been some technical problems with X, 13.

So of course, whenever you have a product that has a technical problem, a failure, I think largely they've gotten a hold of that, doesn't mean that it's a bad technology. It just means they had a few bugs to work out. I think X 13 is a great idea and it helps solve the problem that you just mentioned, which is air side output, making sure that you're actually producing the CFM that the system was designed for even in less than ideal conditions and it's a more efficient motor. It actually uses electrical energy more efficiently to produce airflow output.

So that's another advantage, 2x13, absolutely versa. And so then you move on to ECM and ECM just kind of ups. The ante, because now an ECM motor has the ability to on-the-fly make adjustments to air flow based on some sensor input. So if sensor input most commonly being dehumidification or equipment stage, so you have multiple stage equipment.

It can affect the inputs and tell the motor all right. This is the CFM that we need to produce and make those changes on the fly. So just like you mentioned. Instead of always producing 320 CFM per ton, it can produce 400 CFM per ton until there's a high latent load high relative humidity in the space, and then the thermosets drops in most cases and residential equipment.

It drops the d h, call or d call or d human ever the piece of equipment is and the equipment now knows. Okay, let's drop down the 320 CFM, because we know we have high latent load. That technology has been around for as long as I've been in the trade so almost 20 years, and that's a really nice feature unfortunately gets set up incorrectly in a lot of cases. But that's really the only extension of x13 in that particular application that I can think of.

Can you think of anything else, so you're using sensors but you're using like a sensor in the thermostat? That really is just an on-off. It's not really having granular communication with the equipment about real-time humidity readings. It's just saying all right: we have high latent load or we don't. We need to be humidifier or we don't need to dehumidifier and of course there are additional technologies that do a much better job of that, and you have some examples of that.

And this side is your air side outside inside and the before and after or you know, the return supply conditions so having something that actually gives you a wet bulb reading or some indication of humidity in the air is huge because, let's face it, we're in a Dry bulb driven world right. That's what your thermostat on the wall reads: it's dry bulb and if you have high humidity in the air, you better hope you have a dry ball below it as well. Like a warm ambient. That's gon na drive that system.

The dehumidifier wise you're, not gon na, get anything unless you over cool your space, so right down in there having that ability to measure wet bulb is huge. That's a big step up. On top of that. The next step is.

Some of this may deal a little bit more with the commercial side of stuff, but it's just having that before and after what is the condition leaving my coil, because that change in the air going over your coil is really gon na indicate what you're gon na Do to the space and if it says I don't have this need for this high latent heat removal, but right now I'm just garbage eating a tonne of moisture off my coil. I better do something about it. So it'll speed up the fan, it'll slow down the compressor a little bit it'll, do multiple different things and you're, really getting more of a dynamic response to what the coil is doing to the air compared to what the space needs. Let's take this typical situation.

You do a heat load on a house or any two Welling. You take the outside conditions, you take the inside conditions, you do a bunch of different things and then you says: here's my heat load. Well, we're doing that one step further, we're taking that heat load and we're breaking it down into sensible and latent. So, yes, you might have a certain amount of moisture inside the space, but if it detects that it's either dry or really wet outside and combine that with the temperature, if it's 20 or more outside than it is inside and it's at the same RH level outside That means the air probably holds 30 or 40 percent more moisture than it does inside.

So it takes that information and says okay. I need to make sure that I have a drying focus here, because I'm gon na be bringing in a whole bunch of moisture level and a whole bunch of moisture over the next few hours, and I need to deal with that. So it's almost like you're dealing with it on the fly you're actively setting your system up, so that it's gon na respond to certain conditions outside in anticipation of what's gon na happen. Okay - and I like that idea of it.

So, to be honest with you, it's just a little bit more smart than just reacting to what the current condition is size is when you use a variable technology, which again variable technology means that we can make changes based on changing conditions either in the system and The load and the space whatever it is that we're wanting to do and when you think about things like a variable speed or a multi speed compressor, for example, that's not necessarily what this podcast is about, but it's a similar concept. You also have to have a variable speed, blower that adapts to what the compressor is doing, because otherwise, you're not gon na, have a coil temperature that remains stable and so in the past, what we've done is we've done just the blower without the compressor, and so We don't have a stable, coil temperature in a lot of cases on purpose, because we're trying to drive down the coil temperature in order to remove more moisture. But when you affect that other side, you affect the compressor side. If you were not to properly change the variable speed blower, then it wouldn't be changing appropriately, and you would see this fluctuation in evaporator temperature, which ultimately on the evaporator and blower side, that's a lot of what we're wanting to do.

We're wanting to hit a target of CFM output for whatever the conditions are and then we're wanting to hit a target. Coil temperature, which means really a target flow of refrigerant target pounds of refrigerant being moved through that of a protocol at a given time. Just as the summary before we get started on sensible Leighton and all this, I want to just lay down what these things are. We talked about this in a past dehumidification episode with Jamie, so go back and listen to that for a full understanding.

But when we say latent load we're talking about moisture load, so we mean the moisture in the air we're talking about relative humidity of the air when it comes to comfort and when we talk about dry bulb. We're talking about the temperature that you see on the thermostat on the thermometer, that's sensible! That's what you see there and that's dry bulb temperature when we say relative humidity, we're talking about the humidity. That's in the air relative to its temperature, so air that is lower temperature can hold less humidity so air with the same grains of moisture in it. At a lower temperature would have a higher relative humidity higher humidity relative to how much it can actually hold and we're also gon na touch on sensible heat ratio.

We're gon na mention that, and whenever we say sensible heat ratio, you'll see that an equipment specs you'll, see it on plans, sometimes you'll see SH are sensible. Heat ratio means how much of the total capacity of this equipment under these conditions is sensible and how much is latent. So if you had a sensible heat ratio of 0.7 or 0.7 0, that means that 70 % of the capacity is going towards sensible. Changing the temperature of the air and 30 % of it is going to latent, which means changing the moisture content of the air.

Did I miss anything there on the summary? No, not at all, it's like a pivot point and you hit the nail on the head. It'd be interesting to know if most people know what their actual system is doing, because to be honest with you, we this back in school, sensible heat ratio and I'm just trying to think how many times I actually have applied that down the road. I know if I'm trying to figure out what a system is actually doing as far as cooling the air. You can't beat a sensible heat ratio, but you need to back that up with the manufacturer's literature, because there are the ones it's going to dictate.

What the unit should be doing, let's think of it, this way we were talking about humidity back in the day I actually mentioned. You know when we eventually get to cut the variable speed. I want to cover this if you happen to have a load on your evaporator and whether it's a TXV or an EEV, an EEV will give you a slightly lower superheat, but here's what's gon na happen. The meter device with a fixed fan, speed in a fixed compressor speed when you hits that late in the load, the EEV or txb doesn't give care whether it's laettner sensibly.

It sees that extra heat if the fan speed is constant. In other words, it's getting a certain amount of load across it. It's gon na need to open up to match that load. If you have a fixed speed compressor.

The first thing that's gon na happen is your suction pressure is gon na drift up, because that's the only way that fixed speed compressor can pump that extra refrigerant that the metering device is putting in as soon as you start to raise your evaporator temperature. You start to reduce your latent heat removal. So what happens? Is you find a balance point where the higher evaporator temperature has actually reduced the heat capability or heat absorbing capability of the evaporator, mostly in the latent side? You've compromised your dehumidification and you've balanced. At a point now, where you're not really accomplishing anything good on either side, sensible or latent right, you've got a higher evaporator temperature you're not pulling as much moisture out of the air.

The other thing you do now is to over cool the space to try and get that latent load out. Ideally, what would be better is why don't we just reduce our airflow a little bit? Let the TXV throttle closed or Evie throttle closed drop, our evaporator temperature a little bit and now we're running in much more of a latent focused load, so we might still have 80 % of the load we had before on the evaporator or even 90 %, but We've got a rid of a big chunk of that sensible load and we've replaced that with latent load. Now you may ask me well hold on a second. Our evaporator is actually colder compared to the space temperature, so why did we get rid of sensible load? Well, we never got rid of sensible load, but the latent load increases for every degree.

You drop your evaporator temperature compared to the air. The increase in latent heat removal is far greater than the increase in sensible heat load. So you're in sensible heat ratio is much smaller. In other words, you might go from 30 % latent load to 45 percent latent load, just by dropping your coil temperature, a few degrees and bump it down your CFM by 30 or 40 CFM.

It's amazing how quickly that will change. Alternatively, if you do still have a high, sensible load, because it's you know, 95 degrees outside and a high latent load, just keep the TXV open the same amount or let it feed more in and then you can spool up your compressor, an extra 10 or 15 Hertz now you're, not necessarily gon na save energy. Doing this, but you're going to be able to ideally match the requirements when you have both a high, sensible and latent load. So you have this huge flexibility of how you can treat the air.

We have some limitations on the residential side because we don't use reheat and I'll talk on that in a second, because it's very important, but either way I still argue that you're almost over cooling, the air, if you have it, set up for latent heat. Well, because the air is coming out a lot colder than it would, if you had it, focused on sensible heat removal and people can still report it being drafty, but here's the catch. If you happen to have a smart thermostat, it should have algorithms that say: look if we drop our humidity in our space 10 %. We can bump our dry bulb temperature up a couple of degrees so that it still feels the same comfort level that it would have been if it was two or three degrees cooler, but had a higher humidity level.

You see what I'm saying here. The human experience is the same either way as far as your body is concerned, by keeping the space a few degrees higher and pulling more moisture and keeping the relative humidity lower. We achieved the same comfort level without really using more energy, which is an interesting thing when it comes to human comfort, because she's sort of there's a range of human comfort that you can affect by changing the dry bulb or changing the relative humidity side of it. And even changing the radiant heat of the space that affects human comfort.

Significantly, we've talked a little bit about that on this podcast and also on bills, bones building HVAC science podcast. I think they call mean radiant temperature, something like that. It was a new term. For me, but it basically means the temperature of the surfaces around you, whereas when you're talking about process, refrigeration or grocery store, refrigeration and refrigeration, where you're cooling food, those also have a range but they're more separate from each other.

You know, like you, have a range of relative humidities that are acceptable and you have a range of dry bulb temperatures that are acceptable and you really need to keep it in that range, whereas with human comfort we often think well, I want it to be 75 Degrees or 73 degrees or 72 degrees, but really do you need it to be that dry bulb temperature, or could you just affect the relative humidity down from say 58 percent relative humidity down to 54 and achieve the same level of human comfort? And the answer is that often you can absolutely but again there's so many factors in there that are going to affect it. It's gon na be hard to possibly find the right value for everybody. I know my wife and I are always arguing over the thermostat. All the time, because I'm always too hot she's, always too cool, but I don't think anything's gon na fix that to be honest with you, but from a ASHRAE standpoint or from what we're trying to accomplish.

As far as getting something that's going to be acceptable to the most people you're right on, if you control your humidity, you have a lot more leeway on the dry bulb side than what you normally would have you're, really handcuffed almost in keeping the space cooler. If you don't have good humidity control, if you have high humidity in your space, you almost always have to have at several degrees cooler inside in the summertime just to make people feel cool enough to be comfortable, but there's that fine line where, if it gets too Cold with high humidity now people feel cold and damp right and now they're really uncomfortable. So it's almost like you can't win either way without addressing that humidity level. This has a very broad subject here I mean this applies to refrigeration.

It replies to the commercial side. It applies to the residential side, talk about the differences between what's possible in most residential comfort, cooling applications versus what's possible and kind of the breadth and depth of commercial great question. We have a couple options here. Obviously, with residential were a little bit more restricted on what we can do, you may be bringing in fresh air.

You may have a rotary heat wheel or something that deals with that energy coming in and going out and making the exchange. But if you look at it, let's just take your normal system. Your average system you've got a compressor, a blower and evaporator all that stuff and you're running a constant amount of air across the evaporator. You've got a dry ball thermostat on the wall.

That measures dry bulb and if it gets hot enough in the space bang it brings on the cooling historically, in fact, not just historically currently we're relying on that dry bulb indication to bring the system on and run it long enough to do the dehumidification. So the dehumidification is kind of justa along for the ride. It's never really been a focus. So if you take your region down there, you tailor the system so that it operates with much lower evaporator temperatures.

So you have a latent focused compared to say up in the north central west, where you may have really hot days, but you only have probably half the humidity in the air that you have where you're located, so they would run a much higher evaporator temperature. So, ideally, for residential switch out that dry bulb thermostat to one this wet bulb, so in other words, it's almost like a total energy sensor, you're not just measuring wet ball, but you're determining both. Let's use that term relative unity again, you determine the relative humidity. How much moisture is in the air as well as how warm the air actually is? Dry bulb, temperature and it can say: okay, I have a dry bulb temperature, that's relatively high, but I also have this turn of moisture that I really need to deal with, and if I deal with it right, I can let that dry bulb temperature stay a few Degrees warmer than it normally would be, and what I'm going to do, instead of making sure the dry bulb temperature is low, I'm going to take more moisture out of the air, so what a variables system would do with that information from that sensor is it? Would fire the system up and it would make sure there's enough airflow going through just to scavenge all that moisture out of the year and it might run a certain amount of time dry, the air out without actually having to cool that space down to say 72 Degrees, it might maintain 74 degrees in that space instead of 72, but keep the relative humidity 10 % lower.

So it allows you to have this whole flexibility there, so by varying the compressor and varying the fan, it allows you to tailor exactly the condition to the air that you want. You don't have to over cool the space to maintain a property humidity level, which is what you almost absolutely have to do with a fixed speed system, unless you decide to dedicate it to latent heat removal, like you do in Florida, if you're in one of the States where you don't always have hot weather in the summertime, but you have wet weather. If you have a fixed speed system, what are you gon na? Do you either have to over cool the air to get rid of the humidity? Because you don't have this huge dry bulb load or you just treat the dry ball below it when required, and you leave this massive amount, immunity in the space and nobody's comfortable so either way you look at it. It's not a good solution with variable speed.

Take that dry bulb stat out of the picture, put one that measures both latent and sensible heat and run your system to focus on the air treatment, that's required and that's really about. As far as we can go with residential systems. All right, if you guys, have listened to this podcast for any amount of time. You know that I kind of have a little bit of a crush on the test of 6:05.

I it's just a stupendous, can I say stupendous and not have it seem like hyperbole? I'm gon na choose to say stupendous. It is a stupendous tool for the investment that you spend on, and it is a great than I'm a hygrometer, and for those of you who like what the heck is a thermo hygrometer well tell you a thermo. Hygrometer is basically a digital psychrometer, that's another term for it and it measures wet ball. Dry bulb relative humidity, the dew point.

You know it can extract all those. If you'll ever looked at a psych chart, you need a couple pieces of information and then you can extract the rest, but what the 6:05 eye does really well is that you can measure these readings in duct, so you can take wet, bulb, dry bulb relative humidity. In the return wet bulb, dry bulb relative humidity in the supply and right there in the smart probes app, it will actually calculate delivered capacity. As long as you enter the CFLs, which is pretty cool CFM, I always want to say CFM's CFM of air, so the 6:05 eye is a great tool.

But when you add in what Jim Bergman is doing with the measure, quick app, which you can find out more by going to measure quick, comm, four slash download now on that application, you know I'm excited about that product, but the tests have smart probes in this Test of 605, I work with Jim Bergman's measure, quick app, and so you can get the best of both worlds. A really really highly functional, app plus the test of 605 is that the actual smart probe app that you can use directly with a 605. I it works great, but you can extend its functionality by using it with the measure. Quick, app and so getting delivered.

Capacity is a huge thing. I mean you can actually show your customer right there in your phone. We've already done this in many occasions. Like look, this is how much capacity the system is actually delivering.

Here's what you paid for here's, what you got it's great product and it's also just a great way to get your indoor wet, bulb and dry bulb, which you need anyway, if you're gon na calculate super heat on a fixed orifice system. If you want to use it to calculate target delta, T your air temperature split, it's also great for that. It's just a good all-around temperature measurement device. Plus it gives you that additional data that you can only get from a thermo hygrometer and you have the ability to get it in the duct plus it's Bluetooth and, like I've mentioned a million times, you can get that particular product.

The test, Oh 605. I, by going to true tech tools, comm and a check out, use the offer code get schooled all one word: no caps, no spaces get schooled. Look at the bottom left-hand side of the screen when you're in the process of checking out there and there's a coupon code box and you type get schooled in there. And you will get a great discount in cases where you have high latent load.

And you don't have high sensible temperature, and I think a lot of my friends in Ohio will say that that's how it is in Ohio. Often you really left with the two options: you're left with the option of leaving it uncomfortable or making it uncomfortable. Yes, you leave it uncomfortable because of the moisture or you make it uncomfortable because you're over cooling, the space. Those are your options unless you have that additional control, where you can remove latent without adding significantly too sensible, which is a hard thing to do.

It is really hard to do because I hate to say you're almost taking the human element out of it, because you no longer can focus on that dry bulb temperature people look at that dry bulb temperature. They say it's too hot in here. That is no longer going to apply you're used to have in your house at 75 degrees, and you see it's 76 in there or 77 degrees. Your body isn't gon na.

Tell you oh wait a minute. It's you know 10 percent less humidity in here. I'm actually. Okay right, your brain is gon na.

Tell you oh it's too warm in here. I need to turn my thermostat down, but really physiologically your body is in the exact same environment as far as keeping itself comfortable as it was when the temperature was 2 or 3 degrees cooler. But the humidity was higher it'll, be interesting to see how that I hate to say it that human element plays out because we're so used to being accustomed to having control over and making that decision. We'll have to wait and see what happens there unless we can somehow trick people which, I don't think is gon na fly it'll be interesting.

How that turns out? What you're pointing out is what companies like Mitsubishi and their ductless line? They've done this for years, where they say too hot to cool, that's what the buttons say and that's kind of adjusting. I mean they still give you a number, but instead of saying I want it to be 72, you adjust it and say I'm too hot or you just up and say I'm too cool and that's interesting. We have to come up almost with a new language, because it's not just too hot or too cool I mean it is. I guess my body feels too hot or too cool, but it's not just the dry bulb temperature of the air.

It's I'm uncomfortable on the low side or I'm uncomfortable on the high side is really what it is, because there are these three factors and we're talking about the humidity factor, primarily as it relates to variable speed and the dry bulb factor. But then there's also like a before the radiant temperature of the surfaces that are exposed to your body. That also affects human comfort as well as airflow. I mean airflow also affects human comfort.

So, there's all these different factors that you can change one and it changes the perception of comfort, even with that dry bulb temperature on the wall being exactly the same yeah and without getting off track here. If your diffusers are dumping, cooled air down the back of everybody, I don't care what you have for technology in the system. People aren't going to be comfortable and if you have a large window that sits outside your friend in Ohio is probably going to feel pretty darn cold because they're losing all this radiative heat to that window in the wintertime right. It doesn't really matter what the space temperature is the side this face, and that window is probably going to think it's about ten degrees colder in the room than the side.

That's not facing the window right, so you really have to address the whole thing to make people comfortable, but from a residential standpoint, where you kind of have a lot more control over that we ship you should, I think, you're right, that wall sensor that tells people The temperature I like that idea to warm to cold because now it's more of a hole, how I feel effect rather than just a number of value, so on the residential side you mentioned about over cooling the space. Your friends in Ohio would appreciate the fact that, when it's 75 degrees outside - and it's raining in other words, you know it's 98 percent or 100 percent humidity outside what really would help them out a lot. As this thing called reheat, you have your little dehumidifier and you take your dehumidifier. You put it in your basement where you have the real moisture problems and if you look at what does a dehumidifier, do it cools the air and then it runs the air through the condenser, which raises the temperature back up again, probably seven, eight even ten degrees.

Above what it was when it went in there, so the air is coming out have been warmer and a lot drier, and that really helps with the humidity, because you don't over cool that space to dry it out, and it really accomplishes that with keeping people comfortable Spot dehumidification: well, we can do the same thing with a air conditioning system, an AC system by taking some of that air running through an evaporator cooling it down more than we really need to right and then heat it back up again using heat from the condenser And this is a great way to maintain the comfort zone in a building or space where there isn't this large dry ball, bloat. Okay, so you use variable speed to slow the fan down or speed the compressor up or whatever you need to do to match the load, and then you over cool the air to pull the humidity out of it. And then you end up reheating that air back up again with free heat from that you're pulling off the condenser, and so when you take a step up to some of these more advanced systems, you don't really see that in residential too much now, I don't think, But you're definitely seen it on the commercial side and on the commercial side. This is really where it's starting to shine, because there is such a huge opportunity for energy savings, and there is this huge demand for fresh air outside, and I don't know how much you've covered the need for fresh air.

Now, where you have these hundred percent fresh air or makeup systems, but this is really where variable speed shines. So if you want to take a few minutes and touch on that, then let's do that. So we've talked a little bit about economizers and bringing in fresh air and some of the challenges, but I'm interested to hear about how variable speed technology is used in fresh air and especially as it relates to, like you said, 100 % fresh air machines. If you remember back in the day of the old economizers, I referred to a back as the day when you had three refrigerants in your truck.

Right generally, the economizer was set up so that it measured the outside air and there was this range of air conditions outside where, if it was the right condition, in other words, it was cool outside with not a lot of humidity. You said: hey free cooling, so you would bring this air in and you would exhaust the same amount of air outside or a similar amount of air, depending on whether you want to keep a negative, a positive pressure in the building, and this would remove a big Chunk of both your latent and sensible load, but the challenge is that the outside temperature doesn't really stay where you want to stay so economizers work great when the air is at the right condition, but that's really a narrow piece of time, depending on where you live. Someplace you'll you bill to you more than others, but it is still limited that is irregardless of the need for fresh air in a building. The need for fresh air and buildings is going up and up and up for multiple reasons.

You need to bring that air. In regardless of what the condition is, whether it's 95 degrees outside with high humidity or whether it's 10 degrees outside and bone-dry, you still need to bring that air in and treat it. So what you have is this huge range of treatment requirements even from starting the morning to the afternoon. You can have a completely different requirement for treating that air and it's not a small requirement.

The loads are enormous or can be enormous if they're not treated properly. So, with variable speed, what you're really doing is you're measuring the indoor conditions, you're measuring the outdoor conditions. There are some algorithms and the controllers that compare these tube and they say: okay, here's what I need to do to treat that air. So that's going to be exactly what I need to maintain my inside conditions.

This is what I want inside. This is my ideal conditions. This is what I need to do to that air to treat it so, in the case of a day where it's relatively cool outside, let's say 75 degrees, and it's pouring rain now you need almost a complete latent focus on that air coming in so you run A slow fan, speed, probably very similar what you would do in Florida. You don't even need to treat all of the air you may siphon off.

A portion of this air coming inside treat a certain amount of it and then inject it back into this fresh air space so that when it mixes that air is exactly at the condition it needs to be so there is no fixed treatment. It is changing all the time and if you don't have a high sensible load, you are going to over cool the air, even if you do have a latent focus. Even if you are running 320 CFM and a 36 degree evaporator temperature, the air coming out is going to have so much sensible heat removed from it. It's still going to over cool the space.

So what do you do? You run it through Arijit coil, using heat from the condenser that you would normally eject into the air. So you are really tailoring your fan speed and your compressor speed to maintain that evaporator condition to pull all that heat out of the air. The pull out moisture and then you use a certain amount of reheat gas to reheat that air back up again and in the end the variable speed make sure that all the conditions, the air, the compressor speed the amount of refrigerant the compressors pulled out of the Evaporator maintain the temperature, all that is completely aligned with what you're trying to accomplish in treating that air. So in the morning time we might reflect what we're just talking about in the afternoon when the temperature goes from 75 to 95 degrees outside, oh heck.

Now it's complete we're gon na run this system at 95 % of its capacity. We're gon na run it with a higher evaporator temperature. We're gon na run it with a higher airflow and we're gon na treat the air once again, exactly as it needs to be treated to treat this air coming in. And you can say the exact same thing about the indoor air as well.

But really this requirement for outside fresh air. If it's not done right, the cost becomes prohibitive to be able to do this effectively, because really I hate to say it is what you're really doing is bringing air in treating it and then ejecting it back out again. You can use heat pipes and Rohde reheat wheels to retrieve a lot of that heat that you're sending in and coming back out again and that's a whole other area. But in reality you really it's like you're taking heated water in and then you're, throwing it back out the door again is really what you're doing so.

You want to be able to do that as efficiently as possible. So you're, not basically flushing money outside, is along the way yeah. So the variable speed technology is a huge part of that, because it helps balance the equation so that you're not over cooling, so that you're not decreasing or increasing the sensible state inside the building. If it doesn't need to be another thing I wanted to mention is that you mentioned using the condenser for reheat, but that isn't the only form of radiative, and there are machines that use fossil fuels, gas.

You could potentially use hydraulics and another thing that we see a lot in grocery stores. Is they use reheat off of the refrigerator raishin condensers, the actual Racker system? That's the reheat that they use for the store air, which is another interesting way of doing it. Yeah, absolutely because again it's free heat that you would otherwise have to pay for or let you just flush outside to get rid of, so you actually find a use for that's great and it depends geography to geography. Obviously, down here in Florida, you're not gon na see much gas reheat because we don't have outdoor conditions that require it.

But one thing that I think is interesting. Just from a like a futuristic standpoint, 10, 20 years ago, we weren't talking about all of this different variable, speed technology that can be used in order to match conditions perfectly, and one thing that everybody feels is fixed right now. They feel the need for fresh air is completely fixed right. That's generally how people think about fresh air.

You have so many slated occupants. You have so much square footage. You know there's certain use case, and so you have to comply with this particular fresh air requirement, but a future is coming as sensor. Technology gets better where the fresh air that needs to be brought in or the outdoor air that needs to be brought in will be controlled based on co2 levels based on vo sea levels, things actual real-time indoor, space conditions that will then control and limit the amount Of unnecessary outdoor air that we would have to bring in based on the actual conditions in the space which I guarantee you in the next 5-10 years, we're gon na start doing a lot more of that makes absolute sense having better control over.

But you know from a technician standpoint: the challenge is obviously understanding these systems, understanding how they're supposed to work and, of course, understand how to service someone. They don't, and I always shake my head whenever you talk to people who are also in positions who should know better or at least understand, this is not a static field. This is continuously changing just as much or more so than any other technical field, because it's being driven by, as you said, the availability of new technology, which allows us to do things we couldn't do before combined with legislation and the technology allows us to meet these New legislative requirements and the catch is once they go out there. Somebody has to know how to install them correctly.

Commission it properly do proper preventative maintenance on it to make sure it remains doing what it's supposed to do and service it when something goes wrong in the biggest hole back to the adoption of variable-speed that we get like we go out to manufacturers when we go Out to people who could utilize this technology, you know what the biggest pushback we get is who's gon na service. It is there a technical body of people out there that understand this technology that can service it, because it doesn't matter how good Siemens or Danfoss or anybody else makes a technology if it's put out somewhere and it breaks and nobody can fix it or know how To maintain it, what ends up happening? It just gets jumpered out, or it becomes more of a drag on the system. More of a liability than it ever is a benefit. So there is this huge demand for education and training in these new technologies.

So if you work in the field, my recommendation or my advice to you - is to seek out places where you can receive training on this from the manufacturers. You know phone companies like carrier diking in that, because it's coming and any training or education that allows you to do something you couldn't do before is an opportunity, so jump on board as quick as you can, because this is something that's coming and it's gon na.