ASHRAE Standard 183 Building Load Calculations Using SketchUp / OpenStudio
October 8th, 2019
In this YouTube video we discuss the steps needed to create building geometry using SketchUp with OpenStudio Plugin. Building heating and cooling loads are then calculated according to ASHRAE Standard 183 using the U.S. Department of Energy, EnergyPlus simulation engine via OpenStudio.
All software used for these calculations (SketchUp, OpenStudio, and EnergyPlus) are open-source and free to download.
Open Studio Modeling Steps:
1. create new OSM from Wizard
2. Window->Preferences->General Set Auto-Save time step
3. Extensions->Open Studio->Preferences Set Unit System to IP
4. Window->Model Info->Geo-Location->Add Location
5. Window->Preferences->OpenGL-> check: Use maximum texture size. You can uncheck this later if it bogs the model down.
6. Extensions->User Scripts->Template Generators->Space Type Construction Set Wizard and add additional space types. Uncheck create const set. Uncheck set building defaults.
7. Draw scaling line to exact dimensions
8. File->Import and locate project site plan or floor plan. Drop into model and scale to the scaling line. Do not rotate to true north until you are finished modeling.
9.Trace lines over floor plan using sketchup drawing tools. Select floor plan, Right click, and use hide/unhide as necessary. (Window->Preferences->Shortcuts to modify keyboard shortcuts)
10.Once floor plan is completed, select all the floor plan line elements and use Create Spaces from Diagram button
11.Double click the spaces to edit their height, draw additional features or plenums, and add windows and doors.
12.Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Intersect Space Geometry
13.Click the Surfacematching button -> Match Entire Model
14.Select a space and click Set Attributes for Selected Spaces button. Assign space types to all spaces. At this time you may open the OpenStudio Inspector and rename the spaces according to your preference.
15.Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Add New Thermal Zone for Spaces with No Thermal Zone
16.Select spaces one-by-one and rename them per the project floor plans.
17.Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Rename Thermal Zones Based on Space Names
18.Select spaces in groups by type. Click Set Attributes for Selected Spaces button. Fill in info for space type and thermostat type. You may also use this dalog to combine thermal zones into one.
19.Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Remove Unused Thermal Zones
20.Select specific windows and then Extensions->OpenStudio User Scripts->Alter or Add Model Elements->Add Overhangs by Projection Factor
21.For vertical or custom shading, click New Shading Surface Group button.
22.Rotate model to account for true north.
23.If Geo-Location has been lost, reinsert it for reference to existing buildings.
24.Create adjacent shading (buildings, trees, etc) by clicking New Shading Surface Group and use Geo-Location as reference. You may have to trace Geo-Location image prior to editing the shading group, then use those tracings as reference.
25.Click Window->Default Tray->Shadows to see and simulate the shadows. Delete any unnecessary surfaces from the shading group to minimize calculation time.
26.Open Open Studio Inspector and Purge Unused Objects from OpenStudio Resources to reduce calculation time. Select "OS:Building" and type in the project name.
27.Click Launch OpenStudio button.
29.Select the appropriate weather file and design day files.
30.Select Schedules tab->Schedules. Add on/off schedule for exhaust fans.
31.Select Thermal Zones tab->HVAC Systems. Review to ensure all spaces have thermostat schedules applied. Add exhaust fans to zones.
32.Select Thermal Zones tab->Cooling Sizing Parameters. Change all Zone Cooling Supply Air Temperatures to 55°F. Change air distribution effectiveness if applicable.
33.Do the same thing for Heating Sizing Parameters.
34.Select Measures tab and select Reporting drop-down. Drag the BCL Open Studio Results measure to the Reporting Measures.
36.Go to the model directory and open the html file using your web browser. Print to pdf file for record/reference.
To see E+ results in IP units: Select Measures tab. Click Find Measure on BCL button. Use the search box and type: IP Units. Select and download the "Set Output Table to IP Units". Close the BCL. Drag the downloaded e+ report measure to the e+ measures.
Okay, so today we're going to talk about doing load calculations according to ASHRAE standard 183.
We will be doing the load calculations with open studio.
This program kind of assumes that you already have open studio installed.
And the Associated Sketchup.
Sketchup should come with open studio when you download it.
I don't think you have to.
You shouldn't have to install them separately. Sso this assumes that you've already got that done.
So what we're going to be doing here is.
First thing that we'll do is create a new OSM from wizard. An OSM is just the dot OSM file.
That's the file extension for an open studio model.
And so first we need to open up Sketchup.
We will delete Steve, we don't need him there. If we go to open new open studio model from wizard.
So we'll click this button, save the current model, no.
It's asking what type of construction we'll be creating for this example.
We'll do an office building. We will be using
ASHRAE 90.1 2010 Construction Set.
That's essentially saying that all the construction materials for the this construction template will comply with ASHRAE 2010.
For example, insulation on the walls and the windows and the doors and the roof and etc.
So for this location I believe the climate zone is 2A.
Yes, we want to create space types. Yes construction sets.
Set the building defaults using those construction sets.
So we will click OK.
It says the model has created 13 space types and 1 construction set.
That's based on an office template in compliance with ASHRAE 2010 90.1. Click ok.
It's saying if we want to add additional space types that we can do that later.
So for example if we don't have what we need for spaces in this construction set.
So we did office building but if we need, you know like a laboratory, or hospital room, or classrooms we can do that separately.
And then the next step says go to window, preferences, and then save time step.
And this sets the time step. I have it set for every 15 minutes.
You may want to reduce that number or increase it, however comfortable you feel.
Open Studio does have a tendency to crash sometimes, especially if you are doing complicated modeling.
And you don't do something properly.
So it's good to have that auto-save. I personally also do a lot manual saving in addition to auto-save.
So we'll click OK. The next step:
Extensions, open studio, preferences, set unit system to IP.
So, if you are working in the inch pound system you might want to go ahead and do that.
And that's in extensions, open studio, preferences.
I've already got it set to inch-pound. If you're going to be working in the SI system you can select that right there.
Click apply. Ok, the next step.
Go to window, model info, geolocation, add location.
And in this example we will be working on the city of Mader Washington, United States.
So, I've already got it typed in here.
You can set your location wherever you're working and zoom in and out using the map.
We'll select region and hit import.
Ok, and we'll close out of this window. And you can see that.
The location has been selected and imported into our open studio model.
The next step: window, preferences, OpenGL, check. Use maximum texture size.
You can uncheck this later if it bogs the model down.
I found that using maximum texture size allows you to.
It allows the images that you import into
Sketchup to be a lot more visible.
Sometimes if you have this texture size set to low then it's hard read the images.
You'll see how that works out later.
So we'll go windows, preferences, OpenGL, and then use maximum texture size, right here.
And it's saying that it'll slow the system down, but I haven't had a problem with that.
You know it kind of depends on your computer.
Click yes to continue, click OK.
Then go to extensions, user scripts, templategenerators space type construction set wizard.
And add it add additional space types.
For this example, you know look at this, we actually have a laboratory space here.
The rest of the building will be treated as an office.
But we have a small laboratory space here.
So we're going to have to import an example of a laboratory from a different construction set.
So we want to go to template generators, space type construction set wizard
So we go to extensions,open studio user scripts, add on-demand template generators space type and construction set wizard.
And this is where you go to add additional space types.
Like I said, if you want a classroom, or a laboratory, or a hospital room, etc. So we'll click on this.
And for this instance, I don't know if the other construction sets have a laboratory.
But I do you know that hospitals have laboratories, so we'll just add a hospital for now.
Obviously we want to comply with 2010. Our climate zone is 2A.
Yes, we do want to create space types. No, we don't want to create construction sets.
We've already got an office construction set in the model.
That's what we're going to use for our walls and our windows and our floors in our roof.
So we don't want to import construction sets from a hospital. Set building defaults using the new objects, no.
We don't want to set the defaults for this because we already have an office construction set as a default.
So, really all we're doing here is importing space types from a hospital.
We're not importing constructions from a hospital. So we'll click OK.
Alright, so it's added the hospital space types. I think that's all we all we need to do for importing space types.
So then, what we have to do is draw a scaling line to the exact dimensions that we have.
For this instance I've already I've already scaled the image.
You can see this down here, I've added a scale on the image to indicate just how wide the image is.
So for this instance it's 58 feet and approximately 8 inches.
So this is the image that we're going to import into open into open studio Sketchup.
What we're going to do is draw a line. We'll select the line tool up here and we're gonna draw the line at 58 feet 8 inches.
You can see down here, when
I'm typing, the the length of the line.
This is information that you should know. If you're not familiar with Sketchup you should do a small course.
Do a course to learn what all of the line tools and rectangle tools are.
We're going to do 58 feet 8 inches. That created our line down here.
That's our scaling line. The next step is to import the image file into Sketchup.
What we're gonna do here is go to file, import, and then we will select the floor plan.
And we will place the floor plan on the origin and scale it to our scaling line right here.
You can see that our our floor plan has been imported into SketchUp.
At this point I'll just click save, and go to desktop.
We'll label this example 1 version 001. Click Save.
It's important that you use this Save button right here. This is the save Open Studio model button.
You don't want to go up here and use save, because this is just saving a Sketchup model.
It's it's not the actual
Open Studio file. So, you'll never use this to save the information .
You'll always use this Save button. This is Open Studio Save button.
You want to make sure to use that button.
The next step is to trace the lines over the floor plan using the sketch of drawing tools.
You can select the floor plan, right click, and hide / unhide as necessary.
You may want to edit hotkey shortcuts in SketchUp. I did this for unhiding model elements.
Go to window, preferences, shortcuts to edit the keyboard shortcuts.
So, we'll go to window, preferences, shortcuts, and I've already created a hotkey for unhiding.
Unhide All. I've created the hotkey alt-u for unhiding.
That's how you create hotkeys or edit hotkeys.
Okay. The next step is to trace over your floor plan.
The reason I suggested that you use hide and unhide is because of what happens:
When you trace over the floor plan, the image covers up your tracings.
I'll show you we're just going to do a rectangle. We'll start the rectangle on the corner of the model.
We're going to drag it to this corner right here.
You can't see the rectangle, so what you have to do is:
Do a right-click on the image and hide the image. Now you can see the rectangle.
This is the rectangle we just created and you can see that the image covers up the rectangle.
It's a little bit cumbersome. I haven't figured out how to make it such that this image doesn't cover up your geometry.
It is what it is. You always do right click, and hide, to hide your geometry.
I've got a hotkey to unhide all geometry, so we can see what we've drawn.
We'll trace the next room. You can see that it automatically hones in on the corner of of the rectangle that we treat just traced.
We'll create a rectangle here and we'll trace it there.
You see we've traced the rectangle.
Unhide. Essentially you go through the model and you create tracings just like that.
I'm trying to line up these two walls. So what you do is hover over a point that you want to use as a reference.
See it turns gray.
It's homed in on that as a reference point. It's connected to the edge of the rectangle that we just created.
So you know that this point that it's locked in on is immediately adjacent to that corner.
We know that these two corners will line up and it will create another rectangle.
Oh, maybe that wasn't the best way to do it.
Some of this process is just learning how best to do Sketchup.
We'll hide this. You see that this wasn't created properly.
We will just delete this.
We will have to double click it to make sure that not only the surface but the edges have been selected.
Then we'll hit delete. We'll want to stretch this up to this line here to correct that again.
I just drew a line so that it knows to make this a surface again.
Maybe what we need to do is create a rectangle. We'll use this as a reference point.
Then we will do the rectangle from here to this endpoint.
Now you can see that it everything's lined up now. Do the same thing with this one.
Use this as a reference. It turns grey. You want to use this as a reference.
Perhaps the best solution is to draw a line: Go to this to this end point so it's lined up with that corner.
Then we'll draw another line to this corner here.
Then we'll draw this line to this corner here. Hide this real quick to see.
It looks like we've got our rooms drawn properly. Unhide.
The final thing that we have to draw is the garage.
Draw that from that corner. Then we'll use this as a reference. And all the way to this corner here.
We've got our storage / garage drawn.
Alright. We've got our floor plan drawn in two dimensional space.
The next step is to select all the floor plan line elements and then use the Create Spaces From Diagram Button.
We'll just hide the floor plan for now. We'll do control-a to select all.
Then we use this button right here create spaces from diagram.
It's asking what our floor height is. We'll just do a nine-foot ceiling. Number of floors.
We'll just do one. Click okay. There we go. It has created our building.
The next step:
Double click the spaces to edit their height and draw additional features of plenums and add windows and doors.
I'm not going to go into too much detail on how to modify these elements.
There's a bunch of other videos out there that show you how to use Sketchup for creating funky architecture.
We'll just add windows and doors for now.
We've got a door here. We've got a door here. Looks like we've got a garage door here.
Another garage door, window, window, door. Okay.
We'll just work on this window. We just need to draw a window. It's important to double-click that space that you're working on so that you will be adding the window to that particular space.
If you don't double click that, then the window won't attach to the space. It'll just be floating out here in the middle of nowhere.
You've got to double click that space. Then it's really easy to create a window.
Just click the rectangle button and: the window. There it is.
You can you can edit the windows.
We'll just delete the window. I'll show you again. Say we have a three foot by four foot window.
You can just click the rectangle button and then type in three foot comma four foot and hit enter.
Three foot comma four foot. There we go.
There's our three foot by foot window.
I don't usually get into that much detail. I kind of just approximate it.
For load calculations a couple of inches here and there is probably not going to make that big of a difference.
If you really want to do the actual window sizes you can do it that way. Okay.
Let's go to this side. Let's see. We've got a window right there. I'll just do a window right here.
We've got a door right there. Doors are a little bit different.
If you want to draw a door, you want to start at the bottom edge. That way OpenStudio knows that you're drawing doors.
Then we'll draw up like this.
We'll just make it three foot by seven feet.
There, it's a door!
If you want to draw doors you start at the bottom edge that way OpenStudio knows that you're drawing a door.
If you wanted to draw windows you draw it detached from the edges.
That way OpenStudio knows you're drawing windows.
The next step, we'll go to this space here.
Remember: click out and then click into this space.
Looks like we've got a window right there. We're gonna draw a window here.
The next one on the other side is a door. The door is right here, so we're gonna click this space.
Start on the bottom edge approximately like that.
Next, we've got two windows right here in this office space.
We'll just do a window right here. Window right here. You can use you can use SketchUps tools.
You can actually just copy that. Double click it to make sure you select the whole thing.
If you just click it once, you're only selecting the surface. You want to double click it so you select the surface and the edges.
So you're selecting the whole window component.
Now, just do a control C, control V, and that just copies the windows. Put them side-by-side.
The next one, we have a big garage door right here. Click it.
The garage door. And then we've got a window, window, door. Window, window, door.
Then, we've got another garage door right here.
And I believe that's it. Now we have all of our windows and doors in the model.
The next step is to alter or add model elements and intersect space geometry.
This is kind of important if you add spaces.
For this instance, we're just gonna do a simple roof.
We've already got our floor plan here, but we need to eat it we need to add a roof to it.
Unless your building is a flat roof then you can just skip ahead.
But, we will do we'll just add a simple roof to this model.
What we want to do is go up here, we'll click this button: Create New Space.
The new space will be essentially an attic space.
Then, double click to get into it and we're going to trace our rectangle here.
If you want to hide the other model elements you can click this button here.
That makes it so that you only see the spaces that you're working on at the moment.
If you click out of it, you can see that it unhides them.
So, we're going we're going to work on the roof at the moment.
One thing is kind of tricky. You'll notice what I did.
You'll notice that if you try to select this roof that we just created, you can't.
Because it's it's just a two-dimensional object and it's difficult to select.
You might have to hide some of these other spaces in order to be able to select that roof.
We'll select the roof. We're going to edit the roof.
We're just going to give this some depth.
We'll say, maybe, six inches.
Next we'll draw a line down the middle of this.
We're going to grab this and move it up. You'll notice that we're kind of off axis.
If you're trying to make this symmetrical it might be kind of hard to do.
If it's off axis like this you just hit the alt button.
And it's supposed to snap to the blue axis. Okay, now it says on blue axis.
So, we're on the blue axis and we're just going to make this go up nine feet.
There we go. Great. So, we're done with our roof.
Then, the next tool is to intersect space geometry.
You'll notice that if we look at our roof under here, it's just one area.
But in order for open studio to do calculations, it has to differentiate the heat transfer between this space and the roof.
It has to delineate the the edges of the walls where those spaces are.
I'll show you. You can see that this is just a full area right now.
So next we'll go up to this button here:
Surface Matching Tool. Select it.
Then we want to first: Intersect
Entire Model. So we'll click that. Click OK.
You'll notice what happened was; it transposed the walls from from the first floor on to the the Attic ceiling.
When Open Studio does heat transfer from those spaces it knows what surfaces will transfer heat to the next space.
At this point we're just going to save the model. We're going to create a new one just in case it crashes.
It's good to create additional versions so that you're always able to go back.
So you don't lose a whole lot of work. Click save.
So that's what we did on this step. The next step is to click the Surface Match Tool.
Same thing. We'll go to the Surface Matching Tool right here.
We've already intersected the geometry.
The next step is to match the entire model.
That is telling OpenStudio to match those two surfaces when doing heat transfer calculations.
Click Match Entire Model. Actually let's just cancel it. I have one more thing to explain.
We're going to select this: Render By Boundary Condition. You can see right here that these are all exterior walls.
And exterior roofs. And you can see exterior floor right here.
They're all color-coded based on what they are.
The walls are a little bit lighter blue, the the roof is a little bit darker blue.
We'll just select this. Right now, OpenStudio thinks that this is an exterior wall .
It thinks. I'm not sure what it thinks this one is. It thinks this one is an exterior, Sun exposed, wind exposed, outdoor ceiling.
It's all kind of messed up. We'll click these.
It still thinks that this surface is an outdoor roof or ceiling.
But, you see that OpenStudio thinks these walls are outdoor walls.
Surface Matching determines what walls are exterior walls, what walls are interior walls, and what walls are adjacent to other spaces.
Then it tries to figure out what the heat transfer characteristics will be between those different spaces.
So let's Match Entire Model. Click ok. So we will see how we did. Ok.
Now you will notice that the ceilings are now interior ceilings.
There's no sun or wind exposure. This is showing it as a floor because it is the floor of the attic.
You can also see that the ceilings on the first floor are all interior now that they're green.
The next step is to select a space and set its attributes using the Set Attributes For Selected Spaces button.
With this we will assign space types to all the spaces.
Then you can rename the spaces.
We'll select this space first. This is going to be our garage 6.
So, we'll call it garage 6. Then we'll use the Set Attributes For Selected Spaces button.
And we're going to change the space type to office storage.
We're not changing the building story. We're not changing the construction set.
We're not changing thermal zones right now. We'll just leave all the rest of this on default.
No change. Click OK. Then we just go around and do the same thing for the rest of the spaces.
This is electrical 3. Change the space type to office, electrical / mechanical. Click OK.
This is the lab 1.
We had to bring in the hospital can space types because the hospital template has a lab.
We'll do the lab here. We'll click OK. Then this space is the rest room. Rest 2.
Set the attributes as an office rest room. Click OK.
This space right here is a hall. We'll name it hall 2. We'll set attribute as an office corridor.
Click OK. This is an office. We'll name it office 4.
We'll set the attribute as a closed office. Click OK.
We've already got the garage. The only other one we have left to do is the attic.
We'll name this attic. We'll assign this attic as office storage.
Now that we've we've reassigned all the spaces, we can check it.
We go into the open studio inspector and look at we've got.
Spaces: attic, electrical, garage, hall, lab, office, and restroom.
We've got all the spaces assigned. The next step in the process is to add thermal zones to those spaces.
To do that, we can use one of the extensions to add thermal zones to all the the spaces that have thermal zones.
Go into the inspector: you can click Thermal Zones and you'll see that we don't have any thermal zones assigned yet.
Go up to extensions, user scripts, alter or add elements, and Add New Thermal Zone for Spaces With No Thermal Zone.
So, we'll add a thermal zone for all those spaces and it's done.
You can now see that we have seven thermal zones assigned to the seven spaces.
This is says: rename the spaces according to the floor plans. We already did that.
The next task is to rename the thermal zones based on the space names.
That is another script that's already created for us.
OpenStudio user scripts, alter add model elements, and rename thermal zones based on space names. Right here.
That will rename all of our thermal zones from the default name.
Right now you'll see that all of our thermal zones just have a generic name.
It's easier, later on, to have those named according to the spaces.
That way, we can see what the thermal zone is serving. So, rename thermal zones based on space names.
Click OK. Then we'll select thermal zones over here.
You'll see that they all got renamed to include the space name in them.
The next task is to select spaces and groups by type. Then set the attributes for the selected spaces.
Fill in the info: space type and thermostat type.
You may also use this dialog to combine thermal zones into one.
We don't have any combined thermal zones at the moment.
We can use a filter up here to look at these spaces by thermal zone. It's this button right here.
Render by Thermal Zone. You can see that OpenStudio colors the thermal zones different colors based on how they're separated.
We'll hide the attic for now. You can see that the thermal zones are all different colors.
Now, we are going to combine this hallway and this office together into one thermal zone.
Just so I can show you how to combine thermal zones.
So, we'll select this, we'll hold down the control key, and add the hallway to this.
Then we'll select the Set Attributes For Selected Spaces button.
We'll change this thermal zone to office 4 so it is combined.
We already have the office on office 4. We're just going to add the hall to office 4.
We'll click OK.
You'll notice that now the hallway and the office are on they're on the same thermal zone.
Now that we have the hall and the office on the same thermal zone, we don't have any use for this hall thermal zone.
The hall was added to the office. We'll just delete this hall thermal zone.
Now we've got those two spaces on one thermal zone.
Let's see. Select spaces and groups by type, set attributes for...okay.
We already did that. We already removed any unused thermal zones.
Like I said, that hallway was an unused thermal zone. So, we just removed that.
Select specific windows and use: extensions, add overhangs or projections.
This is a script in a OpenStudio that you can use to add overhangs over the windows.
We'll just can't change back to construction here. OpenStudio user scripts, alter add model elements, add overhangs by projection factor.
This adds overhangs by projection factor over the windows.
You can change these values based on what your construction is.
We'll leave those as default right now. Click OK. Oh! We have to select the windows!
We can double-click select on the windows: extensions, user scripts, alter add elements, and add overhangs.
Click ok. I just added an overhang over the window.
You can do that for all your windows and doors.
We're just going to delete this right now. This particular building actually has an overhanging roof.
I'm going to show you how to do custom shading for this. We'll just do a simple overhang around the entire building.
So, go up here to new shading surface group and click it.
Then locate it anywhere on the model.
It creates a new shading surface group. We'll double click to enter it.
Then, we'll just draw a rectangle from this corner to this corner.
We'll do an offset rectangle from the existing one we have.
It has a two foot overhang so we'll type in two feet here.
Click that. Then we're gonna select...Oops.
We'll select this interior surface. We'll just delete it. That way we just have shade on the outside edges of the building
So, there's our custom shading.
At this point we'll save the model and create a new version.
If anything goes wrong we can always step back to the previous work.
That's how you do custom shading.
At this point you can rotate the model to account for your true north.
You might have to reinsert the geo-location back into the model.
So, go to window, model info, geo-location, clear location, add location, and select region.
We'll just re-import it. You see it got re-imported into the model. Hummm.
It's backwards here. This is north. You'll notice that the green axis is pointed approximately towards the north
This building is rotated on the axis by 60 degrees. I think it's supposed to be facing these two streets.
We have to rotate it. We'll just do a ctrl-a to select the entire model.
Use the rotate button, use the origin as the pivot, use the red axis as the lever.
Then rotate it and we'll type in 6 0 for sixty degrees.
Click finish. Click enter. Now we've rotated our model by sixty degrees.
Now OpenStudio and EnergyPlus can do the correct solar exposure.
When you run the simulations it'll do the correct solar exposure. Click Save.
Save the model. We have rotated it and reinserted geo-location.
At this point you can create adjacent buildings, trees, etc. by clicking new shading surface group.
Just like we did with the the window shades. You can use the geo-location as a reference.
You can trace that location image prior to editing the shading group.
This image is not... Let's see...
This is just a street map. You should be able to use geo-location and insert a satellite image to trace over.
You should be able to change from a street map to a satellite view. Apparently I can't see that on there.
They must have changed map sources from the previous version.
Essentially, you're adding a shading surface group to create surrounding buildings that will affect shading.
These buildings are really large buildings and they're going to affect your daytime solar exposures.
For example: in the morning or in the afternoon. Just create a new shading surface group up here with this button.
You can click it anywhere on the surface. There double-click to edit.
Suppose we had a great big skyscraper here.
We'll say it's, maybe, 60 feet tall. In the late afternoons this building is going to be shaded by this larger building next to it.
You can do the same thing with trees.
Energy modelers suggest to delete some of these surfaces so it takes less time to run a calculation.
This way, EnergyPlus doesn't have to calculate all these extra surfaces.
So, you can delete some of these surfaces that won't affect the shading of the model.
For now, we'll just keep them.
If you wanted to see a simulation of that shading; click window, default tray, shadows.
This will let you see and simulate what those shadows would look like.
Window, default tray, shadows.
Window, default tray, shadows.
You can adjust the shadows based on date and time of day.
You can see what the shadows would look like. Let's take a look at this.
In the wintertime, maybe in the evening. Humm, the shadows don't seem to make a big difference....
Anyway, there is a lot more to it than I understand. There is more videos out there that describe what this shading effect is.
The gist of it is, you can create adjacent buildings and and other obstructions that create shading on your building.
This will affect your heating and cooling loads. Okay.
At this point, in OpenStudio inspector, we can purge any of the unused objects that we didn't use in in the model.
We're essentially done modeling.
So, we'll go into spaces...Oh, I'm sorry...
Okay, space types. We've got a lot of extra space types in here we didn't use.
Hospital corridors, dining, exam rooms, or any of that stuff. We don't need that.
It just clutters up the model. We'll just click this button: purge unused objects.
It erases everything that wasn't used in our model. Click Save.
One final thing. We need to name our building. We probably should have done this in the very first place.
That's okay. We'll just call this V--er WOWT building. And we'll save the model.
Okay. We're gonna save it. We'll save another version of it.
Say, version 5. Click Save. At this point we're going to open up OpenStudio.
You use the Launch OpenStudio button. This button right here.
It opens up OpenStudio. It automatically brings in the OpenStudio model that you created using Sketchup.
We'll set the Preferences, Units, to English IP. We'll go to OpenStudio.
Preferences, units. Make sure this is set to IP or if you're working in metric use SI.
We'll select the appropriate weather file and designed day files.
OpenStudio uses two different files for running calculations. The weather file is a full year weather file.
It's a typical meteorological year for that location.
We'll use to Teldo Wind Lock. It's an EPW file.
That's what the weather file is. You can download those load those from the EnergyPlus website.
Click Open. Designed day file. You have to select the design day file from same place.
It is a ddy file. You can get those ddy files from the EnergyPlus website.
Celso. EnergyPlus didn't have a weather file for Kelso but they have designed days for Kelso.
Click open. The design days are the most important.
These are what will determine your peak loads for the purposes of load calculations.
So, it's important to have the correct designed day file. Since we are doing load calculations.
The next step is to select Schedule Tab, Schedules.
Go to schedules....
We can fill out this too. Climate zone is 2a. It's 2 I guess. Save it.
I'll save the model.
Next, go to the schedules tab. That's this tab right here. Click on it.
Add a typical on-off exhaust fan. Click Add. Oops. Oh, let's see. No, we don't want that.
We'll just delete this. Actually, go to the schedules tab up here.
Click Add. It's just going to be on/off for an exhaust fan. Click Apply.
Call this Exhaust Fan.
Double click where you want to make a break. It's going to be off during the night time and it'll run most of the day.
Then it will turn off at 5:00 in the afternoon.
That's how you create a schedule. It's pretty simple for on/off systems.
Next: select Thermal Zones tab, HVAC systems.
We'll go to Thermal Zones right here. It's this tab. Click on thermal zones.
Review to ensure that all spaces have thermostat schedules applied.
Add exhaust fans to zones. So, add zone...
We'll add zone equipment first. We have an exhaust fan in the restroom.
We'll add: zone exhaust. We'll go over here to the library tab, scroll down, fan zone exhaust.
Do zone exhaust fan. Just drag this over to the restroom and we'll just drop it right here.
Now the rest room has its own zone exhaust fan.
Click the zone exhaust fan. We'll input 80CFM and 1/8 inch of static pressure.
The rest of those zones don't have any equipment associated with them, but we do need to add some thermostats.
We have to find the office schedules...Schedule rule sets...Large office building.
We'll use small office building cooling set point.
We'll just drag this cooling set point here. Small office building heating set point.
Bring it here. The rest of it can get more complicated if you've got humidification or de-humidification.
For this project, for simple sensible load calculations, we'll just worry about these at the moment.
Next we have to apply these two set points to all of these spaces.
If the spaces have different set points it gets a little more complicated.
You'll have to add an additional schedule. But, for a small building like this we'll just keep it simple.
For now, we'll have the same set points for the space.
Select this. Then, select (with the checkmarks) all of the other ones that don't have the thermostat schedule.
Next, select small office cooling set point and hit Apply To Selected button. and then small
Then, small office heating point set point, hit Apply To Selected button.
You'll see it applied all of those set points to those other spaces.
We can save the file. Select thermal zone tabs, Cooling Sizing Parameters.
Adjust those as applicable. We'll go to this tab right here.
Cooling sizing parameters. Set all of our supply air temperature to 55 (if that's what your design conditions are).
Hit Apply To Selected button.
Then, you can adjust all of these other parameters if needed.
Supply air humidity ratio, and all of these...sizing factors...
One of the things that you might want to adjust is the air distribution effectiveness.
This is based on the ASHRAE ventilation rate procedure.
If you have overhead supply and return air distribution, the ventilation effectiveness is going to be 0.8.
Apply that to the rest of those...Let's see...For heating sizing parameters, we'll input 90 degrees.
I don't know why it defaults to such a high temperature. Residential equipment or something.
Apply to selected, 90 degrees supply air, ventilation 0.8, Apply To Selected. Okay.
Distribution effectiveness. Save the model. The next step is to select the measures tab.
Select reporting drop down. Drag in the OpenStudio results.
Select the measures tab, go over here to library, reporting, QA/QC.
You might not already have this. You might not have these files.
So you will have to use the Find Measures on BCL button down here.
You should have set up the BCL link when you set up your OpenStudio.
If you didn't, there's documentation and other videos out there.
Let's select this and it opens up the BCL online database.
We'll go to reporting, QA/QC, and search for OpenStudio.
You'll want to look for OpenStudio results. This one right here.
You can see (with the checkmark) I've already got it downloaded.
So, just check this and then click the download button.
You'll suddenly have OpenStudio results there.
Grab the OpenStudio results, drag it over here to the reporting measures, and there it is.
Then you can run the model. Run the simulation.
We'll just save first. Then go down to here: the run simulation tab and click run simulation.
It could take quite a while depending on how large your model is.
I forgot to mention: at this point you can also go back and purge some of the unused information that we have in in our model.
Go back to schedules, schedule sets. You'll notice that you'll see all of these hospital schedules, corridor schedules, dining schedules.
Most of these schedule sets, we didn't use any of them.
You'll want to purge them using the Purge Unused Objects button.
We'll click this button Purge Unused
Notice that some of the things were retained like the lab schedule.
This is because we used lab space, closed office, corridor, and storage schedules.
Ok, we've got all those still remaining.
I did forget to assign the exhaust fan schedule for this zone exhaust.
So that it does turn on and off according to the schedule that we created.
Go over here to schedule, exhaust fans. Click Save.
We'll run the simulation again. It should go a little bit faster since we purged some of those items.
It's finished, completed, it was successful.
Go to results summary tab. It automatically opens up the OpenStudio results.
Go through all of this information and see what the peak loads are. Zone equipment detail.
One thing I forgot to do was set the ideal air loads for these thermal zones.
I have to go back to the thermal zones tab and turn on ideal air loads for all of these spaces.
This will...okay...that that got rid of our exhaust fan.
But, you can turn on ideal air loads for all the spaces.
EnergyPlus will run through a simulation to determine the ideal loads are for the spaces.
It will not take into account equipment performance or or combining zones or adjacent zones during different peak times of the day.
Ideal air loads will be a worst case scenario of design loads.
That's essentially what ideal air loads are.
Save it. Go down to run simulation. Run it.
Go to the reports, results summary, OpenStudio results.
Go to zone overview. This time you'll notice that it did come up with some loads for each of the zones.
Let's see. Okay. Right here. Sensible
Cooling and Heating sizing.
This is the calculated design load and here's the design load with your your sizing factor.
That's for cooling and heating for each of the zones.
This is worst case scenario. This is peak load for all of the zones at any particular time of the day or of the year.
It's not exactly representative of the total building peak load. You cannot just add these up to get building peak load.
Building peak load is based on solar exposure, occupancy, and all those other factors.
If you want to do a quick and dirty whole building design load calculation;
Just go back to thermal zones and we'll turn off ideal air loads for all of these.
Add a package terminal air conditioner PTAC for each of these zones.
We'll just add this as zone equipment.
Apply that to all of the other zones. Apply to selected. It created PTACs for each of the zones.
We might as well go back and add our zone exhaust fan to that restroom.
Here. Edit it. Schedule (that we created earlier) is exhaust fans.
1/4inch static. 80 CFM. Save the model.
Go back to run simulation.
It was successful. Go to reports. Zone overview. Design loads.
Calculated design loads. At this point it actually shows you zone equipment selections.
Zone equipment selections for each of the zones that we assigned PTACs.
Previously, we just did ideal air loads. There was no zone equipment.
This time, since we added PTACs to each zone, it shows equipment selection for each of these zones.
So... If you want to print out the report: go to the OpenStudio model file location.
We're working on version 5.
Open up the version 5 folder right here. It should be in the same location.
Go to reports. Open up OpenStudio results report in your web browser.
Hit print to print that out as a PDF or whatever file you want.
Or, it's an HTML file, so you may want to just keep it as HTML.
One of the things that I should point out: OpenStudio results are pretty good.
Almost comprehensive results about your model.
But the EnergyPlus results provide more detail.
Go up here into this corner and click EnergyPlus results.
It is more comprehensive than the OpenStudio results.
Unfortunately, it defaults to metric units. You can go to the table of contents over here and click that link.
It's got significantly more information than the OpenStudio results have; if you're trying to troubleshoot the model.
But, as I mentioned, the energy plus results comes out in metric system by default.
EnergyPlus does all of it's calculations in metric. Then at the very end they convert to English.
If you want to change your EnergyPlus results to the English system, you can't run the OpenStudio results at the same time.
You'll have to delete those, go to library, reporting, QA/QC, Set Output Table to IP Units.
You may have to search for this on the BCL. Select it and bring it over here.
This will print EnergyPlus results out in IP units.
Unfortunately, you can't add the OpenStudio results, because they are expecting an input of metric units but at this point the output is IP units.
Anyway. That's the short of it. Go ahead and run the model simulation again.
You'll get your energy plus measures in IP units.
We'll go ahead and run this simulation again and see what it looks like with the EnergyPlus output as IP units.
Successful. Now, you can see that the
EnergyPlus results are using the IP, English system.
Go to the table of contents. Look at any number of factors that affect your building loads.
Lighting, people, HVAC sizing, etc...
That pretty much concludes the simple load calculations using SketchUp/OpenStudio.
If you like this video, please give me a thumbs up. Thanks.