Lesson summary: This transcript covers practical DOE 2.3, eQUEST, Chiller Plant Modeling, Temperature Controls workflows for eQUEST energy modeling. The transcript has been organized with SEO-friendly headings and readable paragraph breaks so it can be posted with the corresponding training video.
This is just the basic setup of the file of course and in order to enable chilled water equipment we have to edit the system. So we're going to edit the system and the first thing is we have to set the cooling source to chilled water coils. This will default the heating source to hot water coils and the hot water source will be a hot water loop. The default system type standard VAV with reheat, just a very typical chilled water system that this is going to make.
We're going to get one system per floor so that means we're going to get kind of the default for lead and 90.1 air handling unit per floor. We can change that. We could change it for the entire shell, but this is fine. We're not even going to be looking at anything airside.
So we're just leaving the defaults. Don't really care about any of this. What I wanted to be sure that we did was enable the chilled water plant and along with that we're enabled the hot water plant, but I'm not going to even look at that. I just want to show you some changes and chillers.
We don't see any changes here. I just want to set up so that we have two chillers. Let's go to an electric centrifugal open shiller. Another electric centrifugal open shiller.
We'll go make sure that it's water cooled actually we need to have it water cooled. The compressor, it doesn't matter. We're not doing an energy analysis. I'll just leave the defaults here.
We could change them totally irrelevant to what we're doing. So I'm just setting up a model so that all the loops are in place and that we have more than one shiller. We're going to finish that. This is going to put that all into a .imp model.
That way we can switch it back to detailed mode. Here we have two chillers going to our multiple coils in the VAV units attached to a cooling tower. One of the features, and this is really simple, but it's really important, is if we click the chillers. Actually, I'm going to come back to that.
If we click the chillers, there's, I think there's some new fields, but we can set the chillers to be in parallel or series directly now in DOE 2.3. And you would think that you specify that directly from the chiller. However, that's done at the chilled water loop. We can specify whether these are in parallel or series.
And that's kind of a big deal that we can automatically do that because parallel or series can have a large impact on the way that these operate. So we can't set up complicated chiller setups, but we can at least now define from the chilled water loop, whether they're in parallel or series. I'm going to copy one of these chillers again. I highlighted that, create another chiller, copy an existing chiller, copy chiller one.
And I just wanted to add another chiller. There's nothing really important about that. One of the new additions to eQUEST here is it doesn't seem new. We can add a water economizer.
Now, this is something that was always there, but it operates much differently now. The best way to understand this is to go to the help file, as is most things. Similar to this version, it was an either or mode. So if the water side economizer could model the entire cooling load, then, then and only then would the water side economizer operate.
Now, the water side economizer can operate simultaneously with the chillers so you can get some free cooling without having to get all of the cooling free. So here's the drift water side economizer and there's a, there's actually not a lot that you have to define to start at defaults to 2.4 GPM per ton, which is a number that probably all acquainted with if you do much modeling or design work 2.4 GPM per ton. So this is the standard. I don't need to say more because it's actually going to say so in the help file.
So the other items that we can define for, for defining the approach, the minimum approach, defaults to two degrees, which is probably a good idea because you don't want to waste more energy pumping, and then you save through your heat exchanger for free cooling. We go to item help. It gives us some reasonable rated water side economizer temperature differentials. That's 12 through 15.
The 2.4 GPM per ton corresponds to a 10 degree temperature drop. So this is basically what size is that. And this number is as to what approach it will no longer, it will no longer operate because the number of things could happen. You could, you could make water that was the wrong temperature.
And you could also use more pumping energy than you're saving. So this number is a designer's number. It's not something that you should just be guessing, although two degrees is a suggested default. We don't even need to run this file since there's nothing specific that I was running.
I just wanted to show you what was new in chillers. And that was the series in parallel field is new. If you ever have any doubt of these, you can open two versions of eQUEST at the same time. So, as I said in the beginning, I have eQUEST 7173, and I open that and go 2.2 mode and using two monitors.
I can look at these and then validate or verify exactly what's different on those screens and, and this is new and useful. Another thing is the water side economizer has become much more, much more useful to model and and can show a lot more energy savings than than it used to show. In fact, there's this goes back a long way, but water side economizers supposedly there's there's not a lot of data on them for the makers of simulation energy simulation software to to enter in basically when you get cold enough the the temperature to which the cooling tower can drop water to is, I guess, harder to predict because it's based off of dry bulb as opposed to wet bulb.
Anyway, that's the short story. So the nature of the calculation itself was conservative. And then it was all or nothing. And now we can at least do do a part of the load.
The calculation is conservative, at least it can operate anytime that there's some free cooling, and it's going to show a lot more energy savings when you have a water side economizer, and hopefully that that makes them easier to pitch in your design. Okay, there's that question. Oh man, I don't have an answer for this question about counterflow chillers off the top of my head. It's definitely a workaround and I will have to file that one away and and see if I can get back to you on it.
I've done that another software but but not any quest. So, with that question being on hold. That's everything that I have to say about chillers. Any specific questions I'm looking for on on chillers before we switch topics.
Good, I'm going to cut you short because I don't want to answer any questions about chillers. As there was a saying as some people say, you know, it's not chiller science chillers are complicated. And they're not there. They're simplified and eQUEST but the main thing is the sequence and what happens in the unloading curves, and that can get extremely complicated.
And we'll talk about those in a moment when we're talking VRF, which is the next topic. So at long last eQUEST is added variable refrigerant flow, and they've done it in a way that similar to the way that the folks with energy plus model of VRF. And break about their superiority. I'm sure at least several of you.
And several of you have made that comment yourself. No, it's okay. Obviously, equals is trying to emulate what energy plus has done with VRF. Let's go to the systems.
If we open any system, it doesn't matter what system, the VRF coil tab is available. If we click that tab though, you can see that all these fields are inactive that we cannot select them the tabs there because it's built into the backbone of the program, but we can't enable VRF for any particular system. We can only enable VRF for two types of systems. And one of these is the dedicated outdoor air system can be run off of the VRF.
And the other system is the packaged variable volume variable temperature system, which is the system operation for variable refrigerant flow. Usually when you have a PVVT system, you may have a system for for each zone. So I'm going to switch back to the previous file. So I don't have to recreate the systems, and I don't have to recreate the DOAS.
Okay, so this is just a package single zone. With this, we have to define the reheat delta T for some reason. However, sometimes I've noticed that it makes you to find that the reheat delta T and and then you restore the default and it goes blank. I'm just going to add another one here.
Okay, so we add two PVVT systems, and then we have our, our DOAS system here. So we want to set the DOAS unit to a VRF. One would think that we just go to the VRF coil, just like anything else, and then set this up, but there's a step we have to take first. And this is this is kind of, it's, it's unique.
And it's not explained well in the help file. The help file does explain how this works quite well. But not exactly what to do step by step. The only thing we have to do here.
Someone asked a question about a dyke and workaround. And I'm going to talk about that in a moment. Okay, so first thing is we just go, we have to create a condensing unit. If we don't do this.
We can't model the VRF. There are two choices. The first one. And this, the help file explains this is under a VRF heat pump is this will model, this will simulate cooling all at once or heating all at once, but not both.
VRF heat recovery mode or type will allow simultaneous heating and cooling and therefore the VRF temperatures can balance each other a bit and you save on that end. All right, now we get into this really, really interesting topic on on the header pipe. So when we have VRF and that the help file talks about this quite a bit. So someone who wrote that must have really had some strong feelings about this and after you read it is kind of kind of rightly so.
There's pipes. People think that with VRF that there's, there's not much pumping because there's no water to move but there is some refrigerant. And there's also heat exchange with that refrigerant. So this is the main pipe.
This is coming off of off directly off of the condensing unit bringing refrigerant to the building. So typically we're going to call that outdoor. That's probably outside. We click done.
And it brings up our condensing unit. And there's a lot more variable here variables here than we can probably understand. One of the variables that the help file mentions that that we should be defining are these pipes. And I did speaking correctly there.
I don't have the diagram in front of me. The leader pipe is the outdoor unit to the first branch. And then the header pipe is the first branch to the last branch. So if maybe the header pipe, it goes down a hallway or something like that.
It could go along the side of a building and then it would be outdoor. If I selected a zone, then I would have to assign it to a zone. So I'm leaving it outdoor. But this, the header pipe is not the one that's almost always outside.
It could be the refrigerant pipe. The main branch that goes down a hallway or somewhere through the the plan on something like that. If anyone's familiar with pipe sizing. If you have a pipe length, and then for whatever fittings you have on there, fittings are typically converted into equivalent length.
And so an elbow of a certain size is going to be considered so many additional feet. And that's how how pipe pressure drops are typically simplified. And that's how it's done in eQUEST here. We also have our diameters.
It will auto size these and whoever whoever wrote in the manual regarding this, see if I can find it right away. Here we go. There's this blurb here that I had mentioned is the pumping energy that it can be derated. The capacity can be derated down to 85% depending on these runs.
And so it's a solid point and it's one of the things that is easy enough to model. The vertical runs. And that comes into the pipe height. So the typical height of the outdoor unit above the indoor units, which will assist on one end and and cost pressure on the other.
So those are some numbers that we can control. That's the gist of that. The rest of these numbers, we could maybe get the outdoor fan numbers from the mechanical specs. Right now I only have one.
I only have one outdoor unit. We could define multiples and then we would have to. You can say if they're going to run together or they're going to run staged, that's going to change some efficiency and things like that. All right, so now to get to the, the inner core of this are these these unloading curves, and these curves are, most of them are by quadratics and they're really complicated, and it's virtually impossible to get the data from these curves.
It goes way beyond the scope of anything that that we're going to discuss here, and pretty much our choice is to accept these curves or read several hundred pages of white papers to find our own curves. In previous versions of eQUEST there in the previous version, there was a dyke and work around or dyke and published these curve or similar curves that you would use on a PVP T system. And it works, but it's, it's a, it's a very different thing, because the whole system operated differently. So those those equations were estimations of based on temperature and load and other things how efficient the units are going to be.
This is the same thing, but the part load rate is determined in a much more accurate fashion. The part load rate on any given unit, if it's operating at full load for 75% or 25% is going to change its efficiency. The other thing that is going to change its efficiency is the temperature of of the refrigerator entering it. Those numbers combined so how, how full it's operating and the temperature of the entry refrigerant is pretty obvious those numbers are going to change the efficiency from the design.
In fact, they, it may make it operate so that it barely needs to run at all. If it's the only zone and heat, if it's one zone and heating in the restaurant cooling, the refrigerant might be pretty warm, and it barely has to eat it. It's going to be really efficient. Well, these curves help to find that.
And yes, once I'll summarize VRF once once we go through it. So, the curves are virtually impossible to obtain in a very accurate fashion. There's, this is an old topic that I've worked on years and years ago to developing these curves from various data, and you're looking at 1314 pages of a spreadsheet where you you take different curves and then you have to generate the load. Other some companies have different ways of doing this and I don't want to say it's impossible because people do do this, but for the typical model or you're just, you're just better off using these, these curves then really messing with it.
So basically, that leaves us, you know, we can set up our pipe losses and a few things. We're kind of at this for that first screen. And we have the ability to set the number of outdoor units that will change some operating things. And we're going to set the total capacity, or we can leave it blank and let it auto size.
One of the main things that we enter here is the electric input ratio for cooling, the ER, that's the one divided by the COP. Like, whenever you enter that new quest is the ERR is the inverse of the COP. You'll notice, and it bothered me at first that it doesn't seem like we get to define the heating efficiency. We just defined the cooling efficiency.
Has this long equation here, but this isn't this some of these statements. Cooling includes both compressor and outdoor fan power but not indoor fan power. Some of that gets a little confusing. There is a part of the PDF somewhere that that says when you define this, this is how this is how this is done and there's a cooling performance number and the heating performance number is dependent on that, which should come from these curves.
So that is what it is. If you have one of these specified usually, at least from my experience, I see both the cooling performance and the heating performance. In general, I've noted that those two numbers are highly correlated. So it does make sense that as the cooling efficiency improves, so does the heating efficiency.
I can't say that that's always been the case, but that's generally the case. In fact, heating can sometimes be slightly more efficient depending on the unit, but it can be more efficient because you're getting the compressor heat that you get as a benefit in heating mode where in cooling mode it's an obstacle. All right, so we have this setup. And that was a lot of detail for basically all I told you is to add a condenser, but there's a lot.
You can consult with this PDF on new features. It's the first thing. And it's page 12. There's quite a few pages on it.
But I think we don't need to. We discussed most of this as I've read this a few times, but there, there was some place in here where we call it said something about that is how they're, they're sized. All right, we're going to look at this example in a second. All right, so we can leave the outdoor units.
And now we have these two fields and this is where this is very different than the previous method that I can work around an eQUEST. So we can enter the number of systems. This is the number of interior unit systems, or we can enter the maximum capacity per system, and then let this calculate to be the individual number of units. So if we said it was 240,000 BTUs per hour, some rooms might be some zones might require more than that.
And as a result, they're going to get two systems. So we could leave that at one and just if we had a list of our VRF interior units, we could leave the maximum capacity per system. And I'm just going to leave this here right now. So we set up the condenser.
And now we can add this to a system, your F like go wrong there. Let's go back to our OS system. Okay, wait, so we have the condensing unit. Before I can go to the VRF tab.
The first thing we have to do is go to the heating tab and it's, it's a little bit strange. We select condensing unit. And it's going to say which condensing unit. And then it's going to say, where's the pipe.
I'm going to have to say what zone that pipe is in. I can just pick, you know, whatever zone, it doesn't matter at this point, I'm just, this file has no real geometry. You have to select a zone though that's where the heat exchange is going to be. So we selected condensing unit for heating.
I'm going to walk through this all at once. And even though the cooling store still says electric DX, once we specify condensing unit for heating, it automatically assumes that we have the condensing unit is also doing cooling. And you can see now the VRF tab has the condensing unit automatically populated and has the pipe location in the zone that we set it, as well as this additional, this is the final leg of the pipe, I guess. Let's go add this again, just to repeat those steps, go to a new, it has to be a PVVT system for the heating.
Condensing unit one. I guess I'll put this in a zone. And now the VRF should be populated again. This should be auto populated.
It has just some rated default temperatures, these temperatures again. Your equipment could be rated at different temperatures and maybe you need to change these. These are pretty standard, standard defaults. For this particular system, I don't know why the DOAS system didn't gray out the cool source field.
Once we selected heating condensing unit, the cooling source is negated here. And it's assumed that the cooling is also provided by the condensing unit when it's in cooling mode. Okay, I'm looking at some questions here. Caleb mentioned that dyken uses package single zone.
I built several libraries from, I thought it was dyken, on various curves. I believe there were four of them, four sets that they used. And I implemented them with PVVT systems. Maybe they recommend package single zone on their website, but all the ones that I created were package volume variable temperature, because that's the nature of VRF.
So anyway, it's good to know. I didn't know that. I followed through something and I don't need to dig up those libraries because now I would definitely use this method. Um, the Okay.
Oh, as far as the question is, do we need to enter the cooling unitary power when we're modeling the condensing unit? And the answer is this is just a remnant of what we had in the previous model. If I restore the default there, since we had switched that, you can see the default switches to not available. And that the cooling is going to be determined at the condenser level.
I was looking for this field and just mind is drawn a blank on it. So there's this number of units. This is probably not super relevant to other systems. We can specify the individual number of units if we have a system with multiple VRF units here.
We don't need to get too crazy about that. But I do have the one example and this is where this ties it all back into this is a better method. And it's more similar to what energy plus does. So if we go back into the condensing unit.
We had the maximum capacity per system and we had the, the number of systems here. And let's just say, we have eight systems, let's say we have 24 systems. And that's going to give us an average of three per package single zone. It will probably it would distribute them based on the size of those systems, but more or less, we're going to get three per system.
And that will draw it will determine the hourly load for that hour, just like it always does any quest. So whatever the hourly average hourly load is for a zone. And then, in this case, there's really one condition zone on each system. And it will take the average hourly load for that.
And then it's going to assume that that's across three different units, and it does a statistical analysis to calculate the, the, what the part load ratio is, and there's an example in this help file that I want to walk through. So, for example, if an outdoor unit serves a single zone, and the zone has three indoor units, and the hourly load is 40% of the maximum. Typically, stopping right there, that would be our part load ratio is 40%. However, each indoor unit since there's three of them runs 40% of the hour but not necessarily simultaneously.
So the condensing unit will calculate the diversity of the indoor unit operation to be 78%. There is a black box to me, I haven't dug into the engineer's manual to figure out where that number comes from, where how we get three units, and at instead of at 40% each. 78% separately so the outdoor unit will then run 0.78 of the, the hour and a part load ratio of 0.4 divided by 0.78 equals 0.51 so that it changes the part load ratio, which changes the net efficiency. Based on that, and if we take that, and we take the sum of all the, the systems that can be assigned to that, we can, we can get a net effect, where we're looking at all the individual zones, taking their part loads, if those zones have more than one.
It's doing this calculation, and it should still take this statistical average of all the zones combined to and come up with this diversity ratio to come up with a more accurate number for the part load ratio. That's a lot of probably meaningless stuff to many of you and a gross oversimplification for many of you as well. The examples here to kind of read through that. But this short story there is it looks across the board at all of the individual zones, and it uses their individual loads to calculate a bottom line efficiency, the bottom line part load factor for the entire condensing unit.
And that is what we have for what's new with VRF. It's extremely complicated to look at the part load curves. If you ever have plotted them. If you ever have plotted them.
It's not an x, a y equals x it's a, it's a bi quadratic curve meaning there's there's two variables, and they're both in quadratic so it's, you know, function equals x squared plus xy plus y squared, plus the standard number. And if you plot that you actually have to plot that over multiple regions. I'm going to spend too much time on it because the bottom line is that almost there's it's very hard to get these curves but they're there and they're they're more accurate than a standard curve and then on top of it it does the analysis so let's go from this to the top without worrying about any of the details. Step one, create a condensing unit.
We select whether it's cooling only or heating only or both do the heat recovery can put the pipe wherever there's a pipe diagram and follow that so we have this created just assume the defaults. Step one is creating the condensing unit. The next thing is we have to turn one of these systems into a VRF system, it only works on on two types. It's going to be a PVVT so we have that so can't select VRF we have to go to heating select the heat source as a condensing unit.
We just made and we're going to add the pipe to the zone in this case. We can't make them all outside or we're going to get inaccurate numbers. Add the condensing unit. The cooling should be grayed out at this point.
If there is a number we can restore the default just to be sure that that's not having any impact which it should end but for sanity's sake you can do that. And that's it. Create the condensing unit. Select the condensing unit.
Follow all the prompts. And then that system is running VRF. There's a lot of other variables to set just like systems with fan power and this and that fan power air flows. There's a lot of different temperatures and so on but the main steps are just there.
So that's everything that we can really cover on VRF in a in a three hour webinar here. There's there's a couple more topics that that we have. The next thing I wanted to mention. Not done any questions.
It's something that's invisible. I keep missing this. If we look at how we have the building loads. There's a few topics in here that we just can't cover.
Trying to cover all the popular ones. Let me cover you fed next. Where is the design sizing enhancements. Outlined here.
There was this this loads module. And it we don't need to cover all of us. I just want you to be aware of it because if you run something from the previous e-quest and you run it in this, we're going to get different loads and the loads should be more accurate. Given the same exact inputs, they should be more accurate in dot 2.3.
Naturally, there's no guarantee in any simulation, but they should the calculation is a more more natural sizing calculation. This line right here. This is the big line here. The size of the air ham there was set to the sum of the zonal air flows without taking any diversity into effect.
With some exceptions. So now it calculates the zone air flows, but then it does a another calculation. Accounting for the diversity at the air handler to finding to so that it can find the actual peak air flow that that's more realistic instead of just a sum of peaks it's looking at an actual simultaneous maximum. And previously, the design sizing run was made for HVAC equipment.
The results of this were ignored. This is the key line here. So the zones were sized that air handlers were sized based on the sum of the zonal air flows. And then the water side equipment was based on the sum of the attached coils.
This could lead to things being rather oversized. If we're not going to read through all of this, but the gist is that it does a load calculation. And it has to do the calculations more than once in order to do this accurately. And that's why you'll see this go to 200%.
It has to run the calculation, then it has to find the simultaneous air flows to properly size the next step. And then it has to run the simulation again, assuming everything that it learned to size the final plant equipment. And so you'll see this, it should be going to 200% now. And there's more detail on this, but the main thing is just understanding that it's very different, and that it should be more accurate.
I'm going to go back to the main page in this. Let me think here. There's also, and I'm not sure how I feel about this. I haven't had much success modeling this air distribution here.
So there's a uFed systems have been added. And there's a lot of pages here. It's actually a, I guess, I would call it a pretty good read, depending on how you view things, but it's relatively interesting. And it starts out saying that, oh, you know, uFed systems are great.
And then you keep reading and I get the impression that the author is just saying that uFed systems may not be so great. And they have a very solid point. Obviously just looking at the titles here. These are short circuiting, plenum short circuiting.
Short circuits are usually not good things. So they're kind of highlighting some of the things that don't work well in uFed systems. I don't have a personal opinion either way. These are just interesting tidbits that they saw as necessary to put this into the system.
So basically, the first paragraph summarizes this well. When we have uFed, we're supplying air to the floor of a spacer zone or what have you, and the occupied zone from zero to seven or eight feet is going to be a certain temperature, where the air, because of thermal plumes and the thermal plume is a lamp, a person, anything that gives off heat, and you have to have so many thermal plumes in order to make this stratification happen. But the air stratifies and this is a system where eQUEST does not assume that the air in the space is perfectly mixed. So we have this cooler air at the floor for, and it's like possibly, I don't know, it's like probably a couple inches or something.
I don't know what the program sizes that at. And then there's the space, the occupied space where cold air rises along something warm and makes it comfortable as at least, well, that's what I always thought until I read this. But, and then that rises and the warm air stratifies and goes to the ceiling. Okay, so that's the gist of the operation.
We don't need to cover the theory here beyond that. And what you have is you have two plenum. So you have in many buildings, you have a floor plenum and you have a ceiling plenum. And if there's just a slab in between those plenums, the floor plenum is really cold because that's where the suppliers coming from, from the floor.
It's probably, it's not always ducted. It's often not ducted. And so the floor plenum might be 65 degrees. And then the ceiling plenum is the return air, which, because of the stratification, the ceiling temperatures probably like 80 degrees, plus any heat that's gained directly to the plenum from from the lights, and the ceiling plenum can be 90 degrees or something like that.
And you have just a slab in between those spaces. And so the point there is that geometry is important in a you've had system where the plenums are. And this is where I can show you how to enable this. But as far as drawing this, and I tried a number of ways this past year to, to do that and I haven't found any great way to do this besides in detailed mode that is just difficult.
So you have to define your plenums and you used to be able to draw them in the wizard by selecting computer room units, which was the only system that allowed you fed. I can't get the geometry right. So, apart from just doing this manually to put the floor plenums in correctly. That's all I can tell you.
It appears you still have to do that. Any other way that I was able to try not been not been successful. So anyway, to set up a you've had system. All we have to do get to the questions that we had in a moment.
All we have to do to make a space into a you've had spaces we just go to that system. You have to, this would be any zones attached to the system. We have to go to the system, and we have to select an underfloor air distribution supply plenum. If the eQUEST geometry was able to set up an in floor plenum and above floor plenum.
This would be easy, but it doesn't. So we have to create a plenum. All we have to do is we have to create a space. So actually I'll just do this directly from you'll create So we have to have a space first go to I'm going to be at the set.
You can't switch this back it seems but anyway, I'll get to these questions in a moment. So we need to go into our spaces. And I'm just going to take a plenum space and it's a West plenum space. Create another space.
We set that. So we have to have a space that has no zones assigned to it. I just took the West perimeter space so that the geometry lines up. We're going to create a supply plenum.
It gives it its own thermal zone. I call this, sorry, we're going to call this, it's a plenum. This space is going to be the floor plenum. So we created a supply plenum.
And someone asked, can you use space polygons to copy as you've had plenums? Well, that's exactly what I did. I just I copied an existing space. I put that I copied the space which copies the polygon and makes this thermal zone 21 right here.
The issue is this is the space. The space copied the other plenum, but it's not located. There's no floor. It will work, but there's no, there's no adjacent heat transfer surface that it could transfer heat to the, the, an adjacent plenum.
And so we would have to shut that up. We would have to make like a ceiling on this and then make it next to the other plenum. And so that, that all gets, you can do it. It's just, it's confusing.
And it doesn't, it set it up in the wizards from anything I can tell. If I figure that out. Obviously I'll, I would, I would try to follow that up, but it's been, it's been a year. So I think you just started doing this manually.
If the heat transfer is not a big concern, let's say in your design, you're actually going to insulate it. Some people don't. Then, then we just make this plenum. And it's a, it's a space where air can go through.
And now we can use that, make a floor plenum, four plenum space. And we just have to give this a, a UFAD supply plenum. And that makes it a UFAD space. Usually these are VAV though.
So there's not a limit on what you can supply this to, but it's usually a VAV space. And the rest of the inputs are going to be based on just your design numbers, which, which tend to be different for UFAD than not. But to convert a system into UFAD, you just have to give it a supply plenum. And the issue is that maybe I'm being too picky, but according to the documentation, you're supposed to have the heat transfer across plenums, which, which makes sense.
But if it was well insulated, then you could probably skip that stuff. So the question on this is, do external equipment loads have an effect on this acting as heat plumes? The, anything that would make a heat plume would have to be inside the space. If it's coming in from like solar, I don't think that that has in reality, it would any, any space that was warmed up would create a plume.
Just looking at here we go thermal plumes. Okay, so it gives us, there's a big range and it defaults to 10% of the zone heat canes bypass the space and flow directly to the return. What we need to, the takeaway on that is that we can't rely on external heat sources, such as a window or sunlight coming through to drive this, you need to have a consistent source of heat in order to make the space stratify. So you would need to have miscellaneous loads.
Or, and, and anytime there's people, the people also have a load that would drive the, that would drive the thermal plume. And it defaults to 0.1, but it can go anywhere up to 90% of the heat can be run that way. I'm looking here to see where we can enter. So we can enter that number in here.
And we can enter it, apparently we can enter a different for heating and for cooling, but it's going to default to 0.1, which is a conservative number. I mean, we can't assume, I think it would have to be a really hot source of heat to assume something as high as 90%, something that stratifies really quickly. Versus temperatures that are closer to room temperatures, they're probably not going to stratify as quickly, and that's where they get the 0.1 is the default. But, but we can enter those numbers here.
It's not necessary to model. The only thing that is necessary to model, you've had is creating a space plenum and then setting that as your underfloor plenum. And then of course, specifying your temperatures. Although it would still work if you had specified.
Supply air of 55 degrees or something like that. In general, the supplier is going to be something like 65 degrees for a UFET system. So that's, that's the main takeaway on UFETs that I have is that we can enable it. It gives a big long explanation in this PDF about what's good and what you should do.
And that those things are not easily implemented from the geometry in the wizard. One more feature that we can discuss here. That I think is pretty popular. There's quite a few.
You can look at this document. This document's all hyperlinked, which is useful. There's data center enhancements. This is nothing we're going to cover here.
And then enhancements to ground loop heat exchangers. There are some people that use eQUEST for ground loop sizing. But most, most of the people that I know that use a ground source sizing take the loads, the hourly loads from eQUEST. And they take those loads and export that the ton hours for the year and the ton hours by month.
And then the peak ton hours that goes into a program like GLAG pro. There's a few other ones and they size it from there. But I do know a few people that use eQUEST for that. And there are design enhancements to that.
I've worked with ground loop, I think, too closely. And it's always been in other software. So that was one where I got to explain it to the judge on the behalf of someone. And we definitely did not use eQUEST to do that, that calculation, though I tried to, on my own end, and I couldn't match it up exactly.
So long story short there is that some people use it successfully, but I think most people, most people would use the ground source software and the loads from eQUEST, which the loads should have been improved. But there is one, the fan assisted natural ventilation. Previously, this is right here. The natural ventilation options included a constant volume air change method and a wind temperature driven model.
The new options have been added to allow for fan assistance. So fan assisted ventilation may operate on its own or supplemental to the two methods. So this only applies to a list of systems. And then also a single duct system.
We had some PVVT systems in our model. See where they were. Is there any questions regarding any of the topics that we discuss about a dyke in a work around to model VRF? I want to accidentally go to their commercial site here.
I want to do a search on dyke in VRF work around or VRF eQUEST. You can get a modeling guide for dyke in VRV in eQUEST. And there's this whole setup. So this would take a while to cover.
Tells you where to get eQUEST things like that. Just trying to. It has some, you can download this file and it. It's how it explains like how to.
Replace your. Your dot file so that you can replace it with one that what they've given you that has a VRV library in it. What that does. Is it creates these cooling curves in your library.
And then you go through this, this whole step. For these curves. So you have to set up a system, load the component from the library. It's been a while since I went over this.
And then you set up this another curve that you also have to add. And they show these curves here, but those are built into that. And it has some specifics on what you can do to. Use these curves.
And then you can select them from. From from the wizard apparently. Actually, so my background on this is I. I don't want to go searching for these files either because I think I have them on energy models.com somewhere.
But this method is a nice one to stick to. For my as for myself. I took these files, these curves out and I broke them into four different. Individual.
And that way I could import them directly into into a model. But that is assuming you're in advanced mode. All this really does is it, it brings in these curves and it sets these curves up, which are a little bit more accurate for, for heat pumps to figure out the efficiency at various loads. I think heating and cooling at the same time.
But it's a completely different method. It doesn't use the statistical analysis, sending a list of individual heat pumps to a condenser. This workaround is for eQUEST though 2.2. Yeah, if you just Google search eQUEST VRF, you'll see that there's a bunch of different types of heat pumps that you can.
And they have this whole. This whole step by step guide. And I've gone through, I've gone through the dat file a long time ago. And I don't use it anymore, but I.
I think it must have been. Four of these two of them were identical besides you changed the. The two files. I can import them.
And then I would have the custom system made. And that's how, that's how I went with this data. But if you follow through these steps, it looks like you can add it to the, the wizard as well, though I would, I would have to walk through it to believe that for sure. So anyway, that's, that's that it's.
Lots of pictures though. That was a good question. The new method is supposedly quite superior to this. I'm just trying to.
Go through the windows here. I knew I saw a question. So the question is, if I have an idea when updates might occur in the future, whether it's annual or just when they feel like it, it's, it's just when the, they're funded by. Utility companies in California.
And they release updates. When they're told to release updates by the utility companies and paid to do it. And then they released the software for the rest of us for free. And all I know is that development is.
Has been, has been going on faster now there than in their. Gosh, I don't know what it is 30 year history, maybe longer than that. And, and, and that's all I can tell you. I don't know any more than that.
I don't know if the developers know any more than that. Developing is one of those things where you can say something is a month away and it turns into a year or you can say it's a month away. And it's really only two months away. I don't think it's ever early.
The next question is energy plus versus eQUEST, which is more widely accepted. Energy plus, if I were to teach a classroom full of people, just general practitioners on energy plus. Originally, it just showed them the energy plus. Things I would, I would lose half the classroom.
Like that just leave. And energy plus is it's intense and it's hard to learn. It's, it's more robust and the calculations are. Much more advanced for a lot of things.
It's open source software that ties into a number of other types of software and it's got this modulistic nature where you, you can write. Some software tied into energy plus and, and build on that and it can get very complicated. It has a much more power, but as far as learning it, that someone can start using eQUEST within a day in the schematic wizard in energy plus. There's really no sort of equivalents and anything for geometry requires a third party software.
There was a free option and open studio. It's still, it still works, but the graphical user portion of that is no longer funded by the federal government. It's still current and everything. And there's groups of people maintaining that.
There's just no promise on how long that will exist. So anything using energy plus, you're really kind of putting yourself into using another set of software. Then you move into energy plus and then you can make some advanced things, advanced changes. This is almost all in text or in this glorified spreadsheet.
Called the IDF editor. Not that I have anything against energy plus. It just takes a really long time to learn and it's overkill for probably 90% of projects that we're looking at. If you're doing something that requires any sort of computational fluid dynamics or advanced systems that require total customization, then you definitely need energy plus.
As far as modeling, simple ROI calculations, lead projects and so on. Those can all be done in energy plus, but whether eQUEST is better or not. I mean, I think it's easier to learn an eQUEST unless you're using something like design builder where, you know, it's a program that's built on top of energy plus and you don't even really notice that you're using the energy plus engine. So that program is probably easier to model for lead in that, but you are going to pay for the software.
And that's about all I should cover on that topic. I mean, there's lots of debates and things in that, but you can learn to use eQUEST very quickly and anything you learn in eQUEST, that's what I like about that. Anything you learn in eQUEST since it was the predecessor to energy plus, the knowledge of systems and how things work. Can be applied moving forward into energy plus anyway, it's all based on the same mathematical principles, even just the way schedules are set, zones are set, rooms are set, systems are set, plants are set.
It all works effectively in the same hierarchy. And so most of the things you learn in eQUEST, the principles apply to energy plus, but the engine where the math is computed is a lot more advanced and there's a lot more money being put into that. So I appreciate that question. And anyway, it's a three o'clock here and that was our end time.
My voice is barely hanging in. So I appreciate everyone. And if you have follow-up questions, you can let us know. I had a couple of questions in the chat log that I have to answer privately and I appreciate everyone attending.
I hope that this gets you up to speed. This took me a year to really feel comfortable with the topics that we talked about and running individual tests. So it should be pretty good on that. Beyond that, there's this whole PDF that you may want to read.
I like the digital version and I like the printed version. So the nice part with digital is that it's hyperlinked, but it's a little harder to write notes on. So I appreciate everyone's attendance. And there's some other announcements we'll have for follow-up.
This is recording and that's going to take some time to process for a 3R video. And there's some other videos that we have related to this that we'll have some announcements on. But that's everything. And yeah, I hope that you're ready to use the new eQUEST because it saved me literally in the last week on an ASHRAE certification where we could meet the savings.
All right, everyone, take care.
This lesson provides practical guidance for modelers working with DOE 2.3, eQUEST, Chiller Plant Modeling. Use this organized transcript as a reference while watching the video and applying the workflow inside eQUEST.