Upload
komkit-srimanta
View
17
Download
0
Embed Size (px)
DESCRIPTION
Not
Citation preview
Page | 1
Building Energy Modeling with OpenStudio – Attendee Handout
SimBuild 2012 Madison, Wisconsin
July 30th, 2012 8am – 5pm
What’s OpenStudio?
A building energy modeling application suite
Software for rapidly creating new analysis and design tools
Exercise Instructions
Section 1 – Model the Building Envelope
Choose the “Large Hotel” building type template using the “New OpenStudio Model from
Template” button.
Draw a rectangle to represent the building envelope (see figure on next page)
o Select the rectangle tool and click somewhere on your screen to set starting point.
o Move the mouse up and to the right, then type 100’, 50’ and then press enter.
o This text will show in the measurements box at the bottom right of your screen and will
precisely size your rectangle.
Tip: The main SketchUp tools you need are the rectangle, pencil, select
tool, orbit, pan, and zoom
Tip: Templates do not contain any geometry. They are data sets for specific building
types. They contain data for constructions, loads and schedules for four different
vintages across the US climate zones.
Page | 2
Use the pencil tool to split up footprint to represent spaces shown above.
o SketchUp has an inference engine to help find midpoints.
Extrude the footprint into a two story building.
o Select all of the surfaces in your footprint by drawing a window with the
“Select” tool.
o Click the “Create Spaces from Diagram” button.
o Keep the default floor to floor height of 10’ and set number of floors to “2” and click
“OK”.
Set surface boundary conditions.
o Change to “Render by Boundary Condition” render mode.
o Click the “Surface Matching” tool and choose “Match in Entire Model”.
o Use the x‐ray mode or section cut to confirm green interior surfaces inside the model.
o Blue represents outdoor, tan is ground, and green is surface.
Apply a window to wall ratio to the building.
o Switch the render mode back to “Render by Surface Type”.
o Select all spaces by drawing a window with “Select” tool.
o Run the “Set Window to Wall Ratio” user script with the default values.
This is under the “Plugins/OpenStudio User Scripts/ Add or Alter Model
Elements” menu.
Tip: You can draw discrete windows and project them onto the model instead
of using the window to wall ratio.
Tip: The window to wall ratio script will remove existing windows but it leaves
doors alone. If it can’t meet the requested ratio then it won’t add a window.
Tip: Matched surfaces should be the same size and in the same position. The “Intersect
Entire Model” button will split surfaces that span over multiple base surfaces in adjacent
space.
Tip: You can double click to enter into a space, at which point you can alter
existing geometry or create new geometry. New geometry will be classified.
Page | 3
Search for south facing windows.
o Click “Surface Search” tool.
o Choose “OS:SubSurface” for class, and 180 to 180 for orientation, then click “Search
Entire Model”.
o These surfaces that pass the test are visible and selected, everything else is hidden.
o Clicking “View Hidden Geometry” will shows the rest of the model in hatched mode.
Use overhang script on results of search to add overhangs based on projection factor.
o Run the “Add Overhangs by Projection Factor” user script with the default values.
This is under the “Plugins/OpenStudio User Scripts/ Add or Alter Model
Elements” menu.
o Click “Unhide All” in the Surface Search dialog to cancel the filter and show the rest of
the model.
Save the OpenStudio model as “Exercise_01.osm”.
Tip: Interior partition surfaces can be added to represent surfaces that exist in a space but are not
a space boundary. An air wall construction can be used for space boundaries that don’t represent
physical walls. Both of these objects are in support of Radiance simulations; however they can
provide benefit for EnergyPlus simulations as well. You can set the interior partition surfaces to act
as an internal mass objects.
Page | 4
Section 2 – Assign Building Activity and Thermal Zones
Change to “Render by Space Type” render mode.
Use the context aware “Info Tool” to inspect the default space type for this template. It should
say “ASHRAE_189.1‐2009_ClimateZone 4‐8_LargeHotel_GuestRoom”.
Using the image below as a guide and the “Space Attributes” tool, assign space types to your
model.
o The four guest rooms don’t need any changes since they are going to use the building
default space type.
o Select the two spaces that are going to be a corridor. Drawing a window with the
“Select” tool may be tough; an alternative approach is to shift/click while using the
select tool to select multiple objects.
o Click the “Space Attributes” tool, choose the appropriate value from the “Space Type”
pull‐down menu, and click “OK”. We will use some of the other fields later on.
o Repeat the last two steps for the lobby and banquet spaces.
Change to “Render by Thermal Zone” render mode. Since we don’t have any thermal zones the
model should appear white.
Tip: Space Types contain data related to building activity, internal loads, and
schedules. Optionally they can also contain construction specific data.
Page | 5
Using the image below as a guide use the “Space Attributes” tool to create and assign thermal
zones to your model.
o Select the two first floor guest rooms.
o Click the “Space Attributes” tool, choose “<new thermal zone>” from “Thermal Zone”
the pull‐down menu, and click “OK”.
o Repeat the two steps above for the four additional thermal zones. To keep your model
consistent with the one used for this exercise, add your zones numerically from low to
high. The zone names should then match what is shown below.
o Colors will not be the same, but that is ok. If you want to change thermal zone colors
you can use the paint bucket tool with an alt/click to edit the paint color.
Tip: You can rezone your building without having to alter any geometry. Just re‐
assign spaces to different thermal zones.
Tip: One or more spaces can be contained in a thermal zone. These spaces can have
different space types.
Tip: You can create a new zone and assign spaces to it, or you can choose from
existing thermal zones already in the model. For this exercise we will always make a
new thermal zone.
Page | 6
Assign thermostats and setup Ideal Air Loads System.
o Select all of the spaces in your model and click the “Space Attributes” tool.
o Moving towards the bottom of the dialog set “Ideal Air Loads Status” to “Yes” and set
“Thermostat” to “LargeHotel_Thermostat”.
Add a daylighting control point to your model.
o Double click on the banquet room to open up this space for editing.
o Click the “Hide rest of Model” button to hide all other spaces.
o Click the “X‐ray” button to make the space transparent.
o Orbit around and zoom as needed so you can view the space from a high vantage point.
o Click the “New Daylighting Control” button.
o To add the control point in the center of the room hover the mouse over one of the
edge midpoints of the floor, and then hover over the midpoint of an adjacent floor
edge, then as you move toward the center of the room and see inference lines, click to
place the sensor. (see image below)
o Vertically the senor should default to 30” above the floor. If instead it is positioned
below the floor by 30” inches, or if you want to locate the sensor at a height other than
30” you can move it with the move tool.
Tip: While we just used a single thermostat for this exercise, you can have a unique
one for each thermal zone.
Tip: The “Space Type Report” user script can summarize some of your input data. It
can also be customized to show different input data.
Page | 7
With the sensor still selected select the “Move” tool and click somewhere on
your screen to set a relative origin. Move the mouse vertically in 3d space
making sure you are on the “blue” axis. Then type 5’ to move the sensor to the
proper location.
Save the OpenStudio model as “Exercise_02.osm”, using the “Save OpenStudio
Model As” button.
Section 3 – Basic Simulation Run in OpenStudio Application
Click the “OpenStudio” button to launch your model in the OpenStudio Application.
Save the model as “Exercise_03.osm” using “SaveAs” under the file menu in the OpenStudio
Application.
The “Site” tab should be open by. Pick Chicago for both the EPW file and the DDY files.
o You can find these files in the EnergyPlus install folder under “WeatherData”
(e.g. C:\EnergyPlusV7‐1‐0\WeatherData)
Select the “Run Simulation” tab and click the green arrow to start a simulation.
o You can scroll down to view the progress of the simulation
o The tree sub‐tab shows you the behind the scenes workflow for running the simulation.
This workflow includes translating your OSM model to an IDF file which is passed off to
EnergyPlus. Results are then passed back to OpenStudio.
Select the “Results” tab to view the simulation results.
o Only lighting and equipment will show on the graphic charts. Heating and cooling for
Ideal Air Loads shows up under district heating and district cooling. You can scroll down
to see those tables.
o Once we add a full mechanical system then heating and cooling will show up under the
electricity and gas charts and tables, along with fans and pumps.
Section 4 – Adjust Internal Load Values
Save the model as “Exercise_04.osm”.
Investigate the model using the “Facility” tab.
o Select the “Facility” tab and sort by thermal zone.
o Expand out the tree by clicking on the arrows.
o Investigate Space Type.
Expand “OS:ThermalZone 1” and select one of the spaces
Look through the objects in the space type. The top contains spaces attributes,
internal loads are at the bottom.
Tip: Generally you don’t need to save a SketchUp file. The OSM file contains all of the
OpenStudio model data. If you want to save scene, styles, or non OpenStudio
geometry then saving the SketchUp SKP file may be beneficial.
Page | 8
This space should have a guestroom space type in green text without an “X”.
This means that it is inherited. If you scroll to the bottom, you will see people,
lights, and equipment instances.
Go to the “My Model” tab and browse space types for any laundry or kitchen
space type, then drag the object over onto the “Space Type” drop zone for the
selected space.
The text on the “Space Type” drop zone should now be black and there will be
an “X” that lets you know it isn’t inherited.
If you scroll down you will notice that all of the loads have changed and a gas
load has been added.
Now go back to the “Space Type” drop zone, click the “X” and you will be back
to the large hotel guest room space type, the loads will return to their original
values.
o Investigate Thermal Zone assignment.
Select the same space in “OS:ThermalZone 1” that you were just using, and
scroll up to the top.
Now click on the “X” in the “Thermal Zone” drop zone.
You should see the selected space disappear in the tree from “OS:ThermalZone
1” and the text for “Unassigned Thermal Zone” should have turned red.
You can expand “Unassigned Thermal Zone” in the tree to find your space.
Select the space, go to “My Model”, look for the “Thermal Zones”, and drag
“OS:ThermalZone 1” to the “Thermal Zone” drop zone.
The space should now move in the tree back to “OS:ThermalZone 1”.
Adjust the lighting loads for the Banquet space type from 2009 to 2004.
o Select the “Space Type“ tab and click the icon to purge unused space objects.
o Select the Banquet space type and scroll down to the internal loads.
o In “My Model”, look for “Light Definitions” and search for “ASHRAE_90.1‐
2004_LargeHotel_Banquet_LightsDef”. Drag this object to the drop zone for the lighting
load. It will replace the original light.
Change the exterior wall construction.
Tip: You can grab the handle in at the end of the left pane to widen it. You can also
add an additional lighting object instead of replacing the existing one.
Tip: If a space isn’t part of a thermal zone, the internal and external loads from that
space won’t be part of the EnergyPlus simulation.
Tip: If you go back to the tree and look at “Large Hotel” you can see where the
default space type for the building is set, as well as the default construction set.
Tip: The “Add New Load” drop zone at the bottom of a space allows you to add loads
to a space beyond what it inherits from its space type.
Page | 9
o Select the “Constructions“ tab and click the icon to purge unused space objects. There
should just be one construction set left.
o In “My Model”, look for under “Constructions” for an object named “ASHRAE_189.1‐
2009_ExtWall_SteelFrame_ClimateZone 4‐8”. Drag this object the drop zone for the
Exterior Surface Constructions/Walls construction.
Re‐run the simulation and load ABUPS data to Excel file.
o Save your model.
o Click on “Run Simulation” tab and click the green arrow
o Click on the “Results” tab and then click “ResultsViewer”
o Copy the data from the “End Uses” table and paste it into the top half of the excel
spreadsheet named “ABUPS_Ideal_vs_HVAC.xlsx”.
o Save the spreadsheet and close ResultsViewer.
Section 5 – Add HVAC Systems
Save the model as “Exercise_05.osm” .
Click on the “Thermal Zones” tab.
Select “OS:ThermalZone 1” and then go to the “Library” tab in the right pane.
Expand the “PTHP” section and drag the object to the “Zone Equipment” drop zone.
Repeat the previous step for “OS”ThermalZone 2”.
Add air and plant loops to your model.
o Click the “HVAC Systems” tab, and then click the green “+” near the top right. This opens
a library of loop templates.
o Choose the one labeled “Packaged Rooftop VAV with Reheat” by clicking “Add to
Model”. The four icons represent they type of heating, cooling, fan, and terminal.
o Select the splitter or mixer object at the bottom of the loop to bring up a list of thermal
zones in the right pane. Check the boxes for thermal zones 3, 4, and 5.
o Inspect the air and plant loops.
Click on one of the two dots on the cooling coiling icon to navigate from the air
loop to the plant loop. In the plan loop the coil is a demand side object while the
pump and chiller are demand side.
Tip: Clicking on the object in the “Zone Equipment” drop zone will open up an
inspector for the PTHP system.
Tip: Adding Zone Equipment or other HVAC systems to a thermal zone will disable
ideal air loads.
Page | 10
Click on the dots by the cooling coil icon again to navigate back to the air loop.
You can also navigate loops using the pull down near the top of the screen.
The hot water loops will show additional objects on the demand side for zone
terminals with reheat.
Re‐run the simulation following the steps outlined in section 4. This time add to the bottom half
of the spreadsheet to compare the Ideal Air Loads model against the HVAC model.
Section 6 – Refine Fidelity of Loads in Model
Save the model as “Exercise_06.osm”.
Change lobby lighting from LPD to discrete lights.
o Click on the “Loads” tab, expand the “Lights Definitions”, and purge unused objects.
o Select the lobby light, and change the value to “20 W” instead of “0.99 W/ft2”
This represents a specific fixture vs. a LPD.
o Now go back to the “Space Types” tab and choose the lobby space type
o Change the multiplier for the lighting instance to “20” to indicate the number of fixtures
in this specific space.
Make a new construction set to apply only to spaces on the first floor.
o Click on the “Constructions” tab and then the green “+” at the bottom to add a new
construction set.
o Go to “My Model” and find the Construction named “ASHRAE_189.1‐
2009_ExtWall_Mass_ClimateZone 5”. Drag this to the new construction set as the
Exterior Surface Construction for walls. Leave all other drop zones empty.
o Click on the “Facility” tab and select a space on the first story, then click the arrow by
the space object to expand it.
o Then expand the walls, and select one of the walls with an arrow next to it. You don’t
have to expand this, it just indicates that there are sub‐surfaces under it. Since all of our
windows are exterior we know this is an exterior wall.
o The construction for this wall should be a steel frame, which is the building default.
Tip: To add objects to the loop select them from the “Library” and drag them onto
the nodes between existing objects in the loop.
Tip: Clicking the “+” and “‐“ in the magnifying glass will adjust the zoom level of the
loop diagram.
Tip: If you inadvertently click thermal zones 1 or 2 and add them to the loop the
previously added zone equipment will be disconnected. You can go back to the
“Thermal Zones” tab to correct this.
Tip: Selecting any object on the loop will bring up an inspector in the right pane. In
some cases there are multiple sub‐tabs for an object.
Page | 11
o Now go back to the story object, find the new “Default Construction Set” and drag it
over to the “Default Construction Set” drop zone for the story.
o If you go back to the exterior wall it should now show the mass wall vs. the steel frame
wall.
Alter the lobby occupancy schedule.
o Click on the “Schedules tab, and then “Schedules” sub tab, and then find the schedule
named “LargeHotel_Lobby_Occ”.
o The schedule contains a number of rules. Each represents a 24 hour profile for specific
days of the week and days of the year.
o Select the run period profile named “Priority 2” This rule applies they entire year
Monday through Friday.
o There are two peaks in this profile. Hover over the flat top of the afternoon peak, and
type .6 and then enter. This will change the profile. You can also drag it.
o Next click/hold over the left side of the afternoon peak and drag it to the left so it is at
14:00 hours vs. 16:00 hours.
At this zoom level time step is 1 hours, but you can zoom down to 15 minute or
1 minute time steps.
o Alter the days of the week for the profiles
Check Saturday for priority 2. Looking at the color coded calendar at the right
you should that this didn’t make a difference. That is because priority 1 which
takes precedence also has Saturday checked.
Select the priority 1 rule and un‐check Saturday. You should now see the priority
2 color showing for Saturdays on the calendar at the right.
Optionally make additional changes and re‐run the simulation.
Tip: If you want to change a construction for a specific wall, you can drill down to the
wall and drop on the appropriate construction.
Page | 12
Tip: The OpenStudio SketchUp plugin and the OpenStudio application use the same
file format. As a result you can go back and forth between applications but you must
first save it in one app and then re‐load or open it in the other application. There
isn’t a live link. Making changes in both and then saving both will result in data from
one overwriting the other. For internal loads the schedules can be overridden at for a
specific space or instance.
Tip: The Schedule Set sub tab looks a lot like Construction sets. It is a holder for the
typical schedules to use for a space type or a number of space types. For internal
loads the schedules can be overridden at for a specific space or instance.
Tip: The default profile is a catch all. It doesn’t have an option to the day of week or
year.
Tip: Double clicking a horizontal profile section will split it. Double clicking a vertical
section will delete it.
Page | 13
Support Questions
Use the OpenStudio E‐mail or forum
o https://openstudio.nrel.gov/forum