EcoDesigner STAR – Thermal Bridging Simulation Part 1

EcoDesigner STAR – Thermal Bridging Simulation Part 1

Now we really begin our EcoDesigner STAR adventure. I see three things that we need to tackle with Thermal Bridging Simulation to feel comfortable using it on a real project and adding it to our bag of design and analysis tricks.

  1. How to use this function with our existing details.
  2. How to create new details that will be ready to use without extra work.
  3. Understanding what the results mean.

Let’s explore the first issue in this post. To understand how Thermal Bridging Simulation works with one of my existing details, I  am going to examine a foundation detail for a townhouse in Houston for which I just finished the documentation. For now it seems best to go with a simple detail, one that has minimal materials and doesn’t involve a window or other more thermally complex elements. Not because EcoDesigner STAR can’t handle it. But because I’m the weaklink and this detail will be easier to dissect. Keep It Simple Sweetheart, right?

Here's the detail as it showed up in the Permit Set issued last month.

Here’s the detail as it showed up in the Permit Set issued last month.

I initially thought that this detail was in pretty good shape. However as I got into the simulation I needed to do more than I expected. Nothing complicated, and now that I know what’s going on, it’s all stuff that can be easily avoided in the future (looks like we’re starting to understand point 2 in my list above!). I needed to add the internal and external air, one piece of air space, tweak the ground (don’t know if that’s necessary, but I wanted to), and add a fill for the plywood. All of those changes (except the ground fill tweak) are shown in orange in the image below. I also had to delete a masking fill that was hiding part of the detail. The simulation window can’t ignore fills, so if I left that masking fill there, it’d get analyzed. Not good. (note: I’m hoping that eventually the simulation will ignore drafting fills, but that doesn’t seem to be the case in the Beta).

In its current iteration (don’t know if this will change), the Thermal Bridging Simulation only recognizes fills, so I had to delete some objects and replace them with fills. Which is too bad because I love the 2D lumber object (which was the object I had to delete). Of course if I was generating this detail directly from the model, this would be a non-issue. The objects in the section or plan would be turned into fills in the details. But more on that later. In the image below, the 2D objects I had to replace with fills are shown in green. Again, nothing complex or hard. And now that I know – we can skip this step in the future by doing everything right from scratch.

Here's the detail with the fills added that are needed to run the Thermal Bridging Simulation.

Here’s the detail with the fills added that are needed to run the Thermal Bridging Simulation.

One reminder, this is the process for scratch built details of someone teaching himself this new feature. As we’ll see in future posts, using the Detail Tool to construct the details will save a few steps (such as not having to draw internal and external air). It’s nice when following the logic of ArchiCAD makes using the program easier. But that’s for another post. First we have to work with our current work flows. Then we can learn how to work smarter.

One More Lesson Learned for My Revised Template

I’m going to talk about Templates A LOT as we demystify EcoDesigner STAR. Most of the challenges we will find will be tweaking how we model and construct a file so that EcoDesigner STAR will be seamless with our workflow. This is great news. Once we’ve learned these lessons, we can incorporate them into our template and then there’s nothing extra required of us to get more benefit out of our models. So here’s the last lesson for this post: Thermal Bridging Analysis works for Detail windows, but not Worksheets. For me that means changing my template and making sure that I am using detail windows for all my details.

Something to Think About Between Now and the Next Post

In the next post we’ll actually launch the Thermal Bridging Simulation. We’ll designate what’s air, what’s ground, and look more closely at the first three tabs of the Thermal Bridging Simulation. And since I haven’t finished writing that post, the exact scope might change, and I might have to make some addendum to this post. Before we do that, think about this: right now (and in the examples GRAPHISOFT is showing us) we’re looking at individual large scale details. There’s no reason we can’t run the Thermal Bridging Simulation on an entire 1/4″ wall section (assuming we’ve grabbed a detail of it and set up the fills). Let’s make sure we test that out before we look at another part of EcoDesigner STAR.

As a refresher here’s a link to my first EcoDesigner STAR post that has the intro video to the Thermal Bridging Simulation.