A Control Logic Exercise and a Way to Get Comfortable With Navigating SketchUp Models

Plant V31 - Scenes Inside Bypass Answer 3

As many of you know, I have been experimenting with using SketchUp models as a way to teach EBCx techniques.  I frequently use them in my classes and also have started to post self-study exercises that are based on the models on our commissioning resources website.

The purpose of this post is two-fold.  One is to let you know that I just put up a new model and exercise that ties into the Control System Fundamentals slides I posted a while back.  In the exercise, you modify the control logic for the hot water system illustrated below to add a reset schedule, which will solve some comfort problems and also save some energy.

HW System Diagram

The model is also a good starter model for learning how to navigate in SketchUp since it is not as complex as some of the other models I use for existing building commissioning training.  Click here to jump to that part of the post.

Control Logic Exercise

If you are interested in giving that a try, I think you will find everything you need on the Bureaucratic Affairs Building Heating Hot Water System Logic Modification Exercise page, including the model, a description of the problem and the theory behind solving it, a description of the building, and other pertinent information.

SketchUp Scavenger Hunt

Once I posted the model I realized that it is also a good one for you to use to get comfortable navigating around in SketchUp in preparation for attending a class were I will be using models or if you want to try one of the self-study exercises.  The reason that this might be a good model to learn basic navigation in is that it is a relatively simple model.

If  you  use one of the scene tabs that turns off the walls of the building and/or other structural elements, there are not many things for you to collide with as you can see from this scene where the 2nd floor, as well as the walls, columns, and beams on the first floor have been turned off.

Tab 6 01

In SketchUp, you have super human powers and can pass right through a wall.  Once you are inside it, it can be very disorienting because there is nothing to focus your zooming and panning effort.

When that happens, remembering “Control” plus “Shift” plus “E”, which is the keyboard short-cut for “Zoom to Extents” is handy.  But you can totally avoid the problem if there is not much to run into in the first place, which is my point and why I say getting the hang of SketchUp navigation with this model might be a good way to go.

Once you get accustomed to things, you can work with more layers turned on to create a more realistic view of things, like this scene for instance, which is what it might look like if you had gone out to do some construction observation in the facility after the pipe and terminal units were hung but before the ductwork went in.

Construction Observation Scene

To make this all a bit more interesting, at the suggestion of Barry Estes, a friend of mine whom I work with at Marriott to provide technical training, I made an “Easter Egg” hunt out of it.  Meaning, I came up with a string of questions that require you to use basic SketchUp navigation skills like zooming, panning, orbiting and scene tabs to find the answers, along with some outside the box thinking and the ruler tool.

For this exercise, you won’t need all of the information provided on the web page to support the logic diagram exercise, just the model itself and the building description and history.  You can download those files individually at the link provided above, or you can just follow this link to get what you need in one zip file.

If you want to give it a try, here are the questions.

  1. What is the size of the inlet duct on a typical terminal unit?
  2. How many steps are there from the first to the second floor?
  3. What are the hours of operation for the Department of Bureaucratic Affairs?
  4. Who manufactured the ladders that are being used on the project?
  5. Will the ladders float?
  6. Does the hot water system have any balance valves in it and if it does, who is the  manufacturer?
  7. For the finned tube radiation serving the West perimeter zone (Scene 12), what would you estimate that the pressure drop was through the balance valve if the flow is 7.4 gpm?
  8. Can you propose a reason for the issue noted in the header picture on the web page.  In other words, can you find a problem in the piping network that could be causing people at the East end of the 1st floor to complain of being cold when the rest of the building is comfortable?
  9. Are all of the terminal units the same and if not, why do you think there is a difference between them?
  10. Did you find any other “Easter Eggs”?  If so, what did you find?

I will answer the questions for the first time in a class this week, so once I have done that, I will publish them here too so you can see how you did.

David-Signature1_thumb1_thumb

PowerPoint Generated White_thumb[2]David Sellers
Senior Engineer – Facility Dynamics Engineering     Visit Our Commissioning Resources Website at http://www.av8rdas.com/

This entry was posted in Controls, Retrocommissioning Findings, SketchUp Model Based Self Study. Bookmark the permalink.

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