These notes are about a building design course for tech college students. The design program calls for sustainable-green renovation of an existing building, Fire Station No. 1 in Apple Valley Minnesota. Software tools include Revit Building Information Modeling (BIM), Autodesk Green Building Studio (GBS) energy analysis, and other software. A framework for organizing and evaluating information will be provided by Leadership in Energy and Environmental Design (LEED) Green Building Rating System (www.usgbc.org).
Teaching this course involves Green Building Studio plugin for Revit Architecture. We may use Sketchup with IES plugin as well. Our efforts will be outlined in posts below.
View from Southwest Corner
Model by Dan Starr, Rendering by Ben Poythress
Winter quarter students developed the initial design for Apple Valley Fire Station #1. They modified envelope insulation assumptions, increasing roof insulation for the entire building and not adding insulation to existing walls. The addition is masonry and steel frame clad with insulated metal panels. Curtainwall is a high-performance system with low U-Factor. HVAC systems for occupied areas are proposed to be geothermal heat pumps connected to the adjacent storm water retention pond. Initial envelope assumptions were established using Revit with Green Building Studio plug-in. Additional modeling of envelope and HVAC will be pursued in this course by the next quarter class.
Proposed Accessible Addition at South End
Revit model by Daniel Starr.
Daniel Starr produced a Revit model of the addition our class designed. We are currently developing the design and prepping the model to run Green Building Studio.
Proposed Entrance Addition to AVFS
Revit MEP New Features are worth a quick look if only to compare to Revit Architecture. After endless download (not complaining Owen), I pulled out a few New Features screens to peek at MEP Spaces and Zones. Some screens show that MEP also includes rooms. Sorting out exactly how spaces, zones, and rooms are used for GBS analysis will take trial runs.
Heating and Cooling Loads Based on Building Area and Volume
The paragraph above refers to loads for spaces, zones, and levels; it does not mention rooms.
Spaces shown above look the same as rooms only green instead of blue.
Spaces and Zones coordinate with Green Building Studio template tabs.
This illustration of room volume matches rooms in Revit Architecture. I wonder if MEP Spaces are interdependent MEP Rooms? My guess is no. Rereading the pdf with MEP instructions for Green Building Studio would probably answer this question.
Room definitions and tags are needed for equipment schedules and coordination with architectural documents, so it seems logical to define rooms and spaces separately. Rooms are for organizing equipment information; spaces, for energy analysis.
Next: Create a generic box in Revit MEP, export to Green Building Studio, and run analysis; then try importing a fire station model. I wonder what Nick Schorr is doing next week?
Nick Schorr and his group successfully ran Green Building Studio analysis on an updated model of the Apple Valley Fire Station yesterday. Encountering problems with their original model, they repeatedly stripped out complex elements and tried to export to GBS. After at least a half-dozen tries the model still returned error messages. They started from scratch with a new, simpler model adding complexity with each successive run of GBS. This approach worked. Details of Schorr Group efforts as well as daring exploits of Ryan Group and The Owenites deserve separate pages on this site. I await postable images.
I have been wondering if a series of short instructional videos might jump-start people new to Green Building Studio. With my new headset mic I feel ready — sorry no hip-hop.
Green Building Studio uses templates to analyze Revit models. You can define multiple templates describing different combinations of enclosure and substructure R-values and U-factors. Then you run GBS analysis using a different template for each run. Finally, you view reports showing how many SUVs of energy each version of your model consumes. It sounds simple and it is — once you get past somewhat confusing screens that define templates. When you have defined one or more templates appropriate to your model, you can quickly run GBS analysis and fine-tune your design concept by adding alternatives to the default template on-the-fly.
Project Screen: Click on Tool symbol (blue circle on left side)
Templates Screen: From here it gets complicated
Using templates you can control separately roof, wall, and floor R-values as well as door, window, and skylight U-factors. You are limited to defining one space type for the entire building. My runs show that different space type definitions have significantly less impact on SUVs than envelope R-values and U-factors. Maybe it is not so important to define different space types for this quick analysis.
Next: update the AVFS existing model (office addition), run GBS on the existing model to establish a baseline.
On hold: eQUEST & instructional videos
Overview: Green Building Studio is an energy analysis tool suitable for schematic design; eQUEST is a similar tool for design development. Refer to this Autodesk document for more: revit_gbs_equest_workflow
Generic03, a Revit generic fire station model with doors and windows has successfully exported from Green Building Studio (GBS) to eQUEST. My goal at this point is simply to try export/import and see what comes out at the eQUEST end. Ultimately, it may be useful to export the actual Apple Valley Fire Station model into eQUEST for a more detailed energy analysis than GBS can provide. For now, I am attaching screen shots from eQUEST showing the imported generic model.
GBS exports a *.inp file imported to eQUEST *.pd2 file
GBS model geometry imported into eQUEST
GBS wall, roof, slab etc. imported to eQUEST
GBS rooms imported to eQUEST
Last Summer, before getting into Green Building Studio, I used eQUEST to create a building model from scratch. After working through 40+ screens of input, I wondered if there is a simpler way to model energy performance. GBS is the answer. Working with GBS and eQUEST is not an either/or proposition. They should be used in sequence: first GBS, then eQUEST. Read the Autodesk document linked at the beginning of this post for a fuller explanation.
Students following my exploration of Revit and Green Building Studio may find answers to technical questions at a new forum started at AUGI.
AUGI Forums>AUGI Technical (English)>Sustainable (Green) Design>
Autodesk Green Building Studio
Forum posts indicate others are working through issues similar to ones recorded here. Expert advice is available there, so I hope to have soon a firmer outline for how to use GBS for meaningful analysis of the Fire Station project.
Problems I encountered exporting from Revit to GBS could be avoided by following a video tutorial. None can be found, so I will make a series and upload at TeacherTube or YouTube and link here. Students frustrated by error messages can wait for the videos. They should be finished by the time this quarter resumes.
Comparing Green Building Studio (GBS) output for three base runs on different versions of the generic fire station model revealed default settings for walls, floor, and roof as well as HVAC system zones. Here is a summary of different models.
- Generic01: shell only, no interior partitions, no doors, no windows
- Generic02: shell with interior partitions and doors
- Generic03: shell with interior partitions, doors, and windows
GBS automatically used default values for shell and interior construction as well as HVAC zones. For Generic01 where no interior partitions occur, GBS assumed one zone. For Generic02 and Generic03, GBS assumed three zones. Images below illustrate GBS defaults for HVAC zones as well as other aspects of construction.
Generic01 Base Run Defaults
Generic02 Base Run Defaults
Comparing the base runs above it becomes clear that for this project GBS has consistently assumed particular roof, wall, and slab construction types. Addition of interior partitions in Generic02 prompts GBS to expand the number of zones to three. I divided the length of the building into five areas or zones, similar to the Apple Valley Fire Station (AVFS) project. I am guessing that GBS simplified this subdivision into three zones: north, middle, and south.
A next step might be to generate GBS runs using a model with multiple levels. In the meantime, the current Revit model of the AVFS needs to be updated with the most recent addition observed at a site visit last week.
Partial Plan Generic Fire Station Model
I drew interior partitions in the generic model, defining only the major space divisions between bays and other areas in the fire station. After spending most of yesterday afternoon trying figure out how rooms are analyzed by Green Building Studio, I have the following observations.
- Like the building shell, rooms in a Revit model are interpreted as geometry when exported to Green Building Studio
- Room names and properties other than dimensions are not interpreted as defining a use, in other words…
- GBS does not handle a room tagged “Office/Dorm” differently from a room tagged “Ambulance Bay”
- A close look at the VRML image of extracted geometry shows interior partitions
After running several trials of GBS, I dug into the GBS template screen, which has tabs for walls, roof, spaces, zones, and other basic features of the building. The check boxes on these tabs seem to offer options for predefining assumptions about the building for the base run. I am not finished trying this feature, but in the meantime here are my thoughts.
- The template screen is oriented toward Revit MEP (mechanical) which defines spaces and zones
- This is different from Revit Architecture which defines rooms
- It is not clear whether information entered on the template screens affects my GBS runs
- I received several error messages after trying to define a new template
- My guess is that GBS for Revit Architecture defines my building as a “fire station” and attaches a template
- Room definitions including detailed assumptions about use may not be possible with Revit Architecture
Reading the instructions for using Revit MEP with Greeen Building Studio suggests I am correct in my guesses about Revit Architecture rooms. Next, I will check the Revit City and AUGI forum posts and retry the template screen — after removing some snow.
