16 - 3 Zone HVAC systems: Part B

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Hi everyone. I ran this simulation and it worked successfully. If I click on this report section, here. And, go to EnergyPlus results, you can see I have some energy consumption for heating and cooling now, here, in electricity column. Idon't have any gas related equipment. Still my natural gas column is empty. But now, it makes sense that we have energy consumption, since we don't have any ideal air load systems in our project. We have package terminal heat pumps, now. Let's go back to the thermal zones, again. And, see what else can we do, here. Let's bring something else, maybe PTAC. Let's bring something which has DX cooling coil, it's written here. DX cooling and electric heating. DX,something like, DX cooling in gas heating. Gas heating means it has a gas furnace. Then your DX cooling and hot-water heating, it needs to have a plant loop. We won't work on plant loop for this class, so I won't like, you know, bring this one here.
But, let's bring something like, DX cooling and gas heating. Drag and drop, here. Click on this, PTAC DX, it's a yellow now so I know it's live. I'm going to click on this gear tool, here. And, you can see, you can make a lot of changes, here. You can change the schedule, like, when you want to make it available. Same thing, what we did for exhaust and package terminal heat pumps. You can provide this, supply air flow during cooling operation. There are a lot more information that you need to provide. Either you can just keep them auto size, or, in case you have information from your mechanical engineers, you can fill them out, okay. Like, for example, what is your gas furnace efficiency? It's very simple information that you can provide by just looking at these specs. Let's say my system, my gas furnace is 85% efficient. Do you have any hard sizing done for this gas furnace? Maybe, yes. Let's say it's 20,000 BTU per hour.

What else. Then you need to provide some values for constant value. There is always a default value for each and every input. But, you can always change them. Like, same thing what we did for exhaust in the fans, then you have a single speed DX cooling coil, here. You can, again, provide capacity, you can provide COP, coefficient of performance, you can provide a flow rate,then they're associated curves. I already explained to you curves in my last video. Then you have some information for, let's say, what else. Well that's it. You have all the rest of the information, associate two curves. Once you are happy with this, again, you can either provide it to some particular spaces, or thermal zones, or you can just apply to each and every thermal zone, okay. Then, here are some other systems. Something like, four pipe fan coil unit systems, they need to have some kind of plant loop associated to them, because they have water coils for heating and cooling.

I won't touch plant loop or anything related to water coils in this class, but we will cover them later. You can provide a dehumidifier. If you provide a humidifier or dehumidifier, for example,let's say, let's just bring it, here.You also need to provide a schedule for humidifier and dehumidifier, here. It's the set point schedule. I won't work on humidifier in this class. We won't, we don't cover it in this webinar session. But, let's just work on something else. What else do we have, here? Then you have baseboards. Again, they need to have some kind of plant loops, which we won't cover in this class, all right. Let's say, in one of the systems, we have multiple zone systems. One thing, like,let's say it has in this zone, one floor, one underscore Conference 104. You had two systems, PTAC DX, as well as, PTHP package terminal heat pump.

People ask me,hey, Harshul, which system will work first if they both are auto sized? Well, the thing is, in OpenStudio, we call it the sequential method. The way you place these systems,that's how they work. I mean, if, for example, if this system is first, then this system will always work before this. If both of them are auto sized, because this PTAC is number one in sequence, that will take care of all the heating and cooling loads, if they are auto sized, okay. This PTHP won't work ever. And so, again, if you have multiple systems, auto sizing is not the best way to provide these frequencies. You have to size them. You'll need to provide some kind of capacity for them. For example, if I provide a capacity of,let's say, PTACS, here. Let me just click on PTACS, again. Go to edit. Again, you need to be a bit patient with OpenStudio because it takes some time to jump from one tab to another tab, okay.
For example if I provide auto sizing,I'm sorry the size the capacity for this system. Let's say I want to provide a sizing for heating. Let's say it's hard size 2. 2000 BTU per hour, and, my next system package terminal heat pump. Let's say, now if I go too hard sizing, let's say for heating, it has a size of, let's say, 10,000 BTUs per hour. Let's say, for this zone, my total demand, the heating demand, is of 5000 BTUs per hour.

For initial 2000 BTUs, the PTAC will take care of it. And, for the rest of the thousand, that's when the PTHP will work, okay. But, if you auto size both of them, only PTAC, the first system, will take care of it. Again, don't get confused with ex1, that's an exhaust, it won't cover, or it won't take care of anything related to heating and cooling, okay. Again, very important. You need to understand this sequential method in OpenStudio.

Even if you have like, five or six systems, you need to make sure that you either provide the proper sequence, or at least provide their sizing properly, okay. But again, a system whichever system is number one, it will always work first. It will always take care of that initial part of the heating or cooling demand, okay. Very important, all right.
Let's look for some otherstuff. What if,if you want to reduce your workload, can you still use something like OpenStudio measuremethod. Well, definitely,that's the beauty, here.

Got to components and measures, apply measure now, again. Same thing, save your model.
It will take some time, like, because we clicked on that, apply measure section, so it reboot itself. Like, it takes some time to collect all the information for background. Let's just wait for another five or ten seconds, andhere we are. If you go to HVAC, in whole system, again, I know all these things, so I know where my like, whole system lives.If I just want to make some changes only in cooling,that's where I need to go. For example, add chill beams, high efficiency chillers, set COP for two-speed DX cooling coil.That's where all found like,in cooling section. But, if I want to assign a whole system, I need to click on this whole system sub-tab. Let'ssay I want to bring a Sys 1 PTAC residential for each and every zone. Let's bring something else, well, most of things need to have some kind of plant loop, so let's just work with package terminal air conditioners, okay. Apply measure now, okay. It's,it's running the script for you. It's executing this script so it will take maybe five to ten seconds.
Once it's done it will show you the initial and final condition. Or, maybe not, because it depends how the measure is written. It's totally on your choice because I worked on this measure, so I thought maybe there is no need for me to provide final or initial condition. I know this measure works, it says successful. I'm going to accept changes. And, once it's done, I will show you how my systems look,now. You can see, it brought new PTACS for me. Say,like, you know, it renamed them properly. It did not, okay. They also are connected to the water coil, okay. Again, I don't want to confuse you for now. But, the idea is, how these, like, measures work even for HVAC systems. You can do it for PTHP, as well, package terminal heat pumps. For example, if I just, if I just like, bring ideal air load in this, in these spaces,let's say, let me just do it real quick for you guys. If I just click on ideal air loads,really quick. I mean, I'm just removing all these systems in my, from my spaces in. You can see, when I click on these ideal air loads, they also, it also deletes the zone equipment. Either you can run the OpenStudiomeasure to bring the air loads, ideal air loads, just within a clip, or you can just do this manual method. I mean, I don't have a lot more zone, so I'm just going to do this manual exercise. And now, you can see, I don't have any zone equipment. I'll go to my HVAC system tab, again.
Well, I know there's a plant loop. Again,don't get confused with this. We created a new system, and it also created the loop for us.I'm just going to delete it manually.I'm not going to explain this for now. Let's just assume that we never ran that, ran the measure, and it never created the plant loop for you. Let's start from scratch. Go to apply measures. Now, hit save. Again, it will take five to ten seconds to reboot itself. And, go to HVACs, go to whole system. And, this time, let's bring package terminal heat pumps, okay. Apply measure. Well it's a system 2 based on appendix G for 90.1. It says successful, so I'm going to accept the changes. And, once it's done, I will see all those package terminal heat pumps.

Well, again, that measure did not have any inputs to provide. I wasn't able to change the COP values or curve values. Well, it was my own measure, I have like, you know, created it for my own convenience. But, you can always create your own measure. There should be a measure definitely somewhere on BCL. Or, you can always ask us to provide you measures. You can provide a lot more feedback then just like, you know, clicking on accept changes.

If I click on package terminal heat pump, one of them, I can see all the properties which I already showed you earlier, same thing, okay. I won't go through each and every tab, again. But, you got the idea how those measures work. You can change the properties later. I have those package terminal heat pumps. Looks like there is no ideal air load system, so I can run this simulation now. And, yeah, save the model later. I'm going to run the simulation, here. But, before that, I want to like, make sure you understood everything, here. Please practice this HVAC thing as much as you can, because it will help you out, to understand how things work in OpenStudio. If you have any questions, you can always reach back to us. You can always go to EnergyPlus documentation. I gave you a lot more references, here. You can always go to unmet hours. If you like, search for any query, if,let's say, for PTHP, you will at least get some like, new questions.

For example, if you want to understand what is PTHP analysis, you can click on this, and it will give you more information. Or, you can always ask your own question, allright. You can always learn measures. These are like, very important things. I don't want to cover air loops, as well as plant loops in this class, because you'll be super confused. But, please make sure that you cover the zone equipment, get used to them, get familiar with the workflow. And, in next class, we will cover more stuff. We will cover air loops, plant loops, and the zonal equipment that are connected to some kind of plant loops, like water coils, all right. For this session,that's it for now. Thanks a lot everyone, for joining us. Have a good day. Bye