Architecture Student's Guide to Energy Modeling

While I was an architecture student, I felt certain I was missing something in the world of energy modeling. Two courses on Environmental Control Systems taught us how to calculate simple heat gain and loss, shading, dew point position within a wall, bulk air flow, and so on. But these couldn't tell us how the earliest alternatives considered in design - massing and orientation - would compare annually in a particular climate. We were told, "Make it long and thin, and orient it east-west", but that was hardly satisfying for every site and every program!

I experimented with Ecotect, TAS, IES Virtual Environment, Demeter, Green Building Studio, eQUEST / DOE2.1, and everything else I could find at the time (2006-08). They all had their cool features - Ecotect's graphics were fabulous, even then, for example - but none delivered a simple, direct answer to the question: which form and orientation will give the lowest annual heating / cooling / lighting load on a particular site? And how much worse is the next-best option?

To be sure, several of the tools above can this question, if you have the time and inclination also to model the complete HVAC system and plant, and if you have a Windows operating system, and if you can afford the license (though student licenses are less than $100). Architecture students definitely do not have the time, even if they have the inclination and ability; they also tend to prefer Macs. The same is true for practicing architects.

So imagine my complete delight, last month, when I finally found the tool I'd been looking for all these years. It's EnergyPlus. Are you surprised? I sure was! One of the first building consultants I met, at SimBuild 2008 in Berkeley, was openly nervous about learning it. But for answering the massing-and-orientation question, it's easy. Here's what you do:

1. Download EnergyPlus (it's free)(and it works on Macs!).
2. Download some EnergyPlus weather files of interest.
3. Since you're an architecture student, you already have SketchUp. Good job.
4. Download OpenStudio (it's free too). Make sure it lands in the SketchUp plugins folder.
5. Download xEsoView (optional; also free).

Take a break. The next part might take a few tries, but it's worth it.

1. Open SketchUp. Look for the Plugins menu; if it's not there, OpenStudio didn't land in the Sketchup Plugins folder. But we'll assume it did.
2. Click on "OpenStudio" in the Plugins menu and go down to "New Zone Tool". Click there. The cursor will change to a little + sign.
3. With the + sign, click anywhere in the drawing field, placing the point, and then double-click on that point. A black dotted box will show up. This shows that you're drawing a thermal zone in OpenStudio. With the rectangle tool, draw a floor rectangle inside the black dotted box, and use the push-pull tool to extrude it into a box.
4. Draw a rectangle on one of the faces of the box - it should automatically become a transparent window. If it doesn't, you probably left the plugin - double-click on the thermal zone until the black dotted box shows up again, and keep trying.
5. Open the Outliner and watch as you create, reshape, and delete thermal zones. Practice until you can easily make, adjust, and delete thermal zones and their windows. Try right-clicking on a surface, selecting OpenStudio, and then selecting Object Info; notice that construction details appear, as well as the surface name.
6. Save a file with one thermal zone and perhaps a window as a *.idf file. Do this within the plugin, e.g. OpenStudio --> Save As --> Bauhaus.idf.
7. If you're curious, check out the Yahoo and OpenStudio support groups for their insights.

Great! Time for another break. Let's finish this up on the next post.