Bureaucratic Affairs Building Heating Hot Water System Logic Modification Exercise
Optimize the Logic Controlling This System and Learn Something About Finned Tube Radiation and Reheat Coil Performance While Doing It
This exercise is built around the Heating Hot Water system serving the Bureaucratic Affairs Building associated with Center of the State University (COStU) located in the beautiful, quiet country town of Golden Girl, Missouri.
Eventually, the model will support EBCx exercises for the systems types you might find in a 20,0000 square foot or so building like this. For now, I have enough done to use it to support this exercise. Its also a good one to start with to simply learn how to get around in SketchUp because I have not drawn the partitions and other things that make it more challenging to navigate around when you are using SketchUp. And even if you don't do the logic exercise, there are a few "Easter eggs" to find, as indicated in the header picture. If you want to go that route, then give the Bureaucratic Affairs Building Scavenger Hunt exercise a try.
To do the logic diagram exercise, just keep reading on to get the background behind the exercise and the files you need to do it. Once you are done, you will find a copy of the Logic Diagram Tool with the "answer" in it here.
Eventually, the model will support EBCx exercises for the systems types you might find in a 20,0000 square foot or so building like this. For now, I have enough done to use it to support this exercise. Its also a good one to start with to simply learn how to get around in SketchUp because I have not drawn the partitions and other things that make it more challenging to navigate around when you are using SketchUp. And even if you don't do the logic exercise, there are a few "Easter eggs" to find, as indicated in the header picture. If you want to go that route, then give the Bureaucratic Affairs Building Scavenger Hunt exercise a try.
To do the logic diagram exercise, just keep reading on to get the background behind the exercise and the files you need to do it. Once you are done, you will find a copy of the Logic Diagram Tool with the "answer" in it here.
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The building has a long, storied history, having started life as the campus Administration Building back in 1946. It was renovated in 1984 to serve the ever-growing COStU Department of Bureaucratic Affairs following the construction of a new Administration Building. There have also been a number of renovations to the building systems over the years.
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In the scenario behind the exercise, you are the team lead for an existing building commissioning project that is focused on the facility. During your scoping visit, you interviewed the staff and discovered there was quite a bit of dissatisfaction with the performance of the heating system. Because of those complaints, along with the fact that the thermal benchmark for the facility was high relative to its peers and the average daily gas consumption showed a high thermal base load, you started taking a closer look at the heating hot water system.
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One of the things you discovered was that there is a comfort and energy savings opportunity that could be captured by modifying the logic controlling the hot water system supply temperature so that it is reset based on outdoor temperature instead of held at a fixed temperature.
The focus of the exercise is to take the existing logic diagram, point list and narrative sequence and modify them to add a reset schedule with set points that are appropriate for the building and the climate it is located in. Doing that will require that you understand how the equipment served by the hot water system works and how the building will interact with the Golden Girl, Missouri climate. To support doing the exercise, there are a number of files provided at the bottom of the page. A brief description of each one follows: 00 - Heat Exchanger Logic Modification Assignment v2.pdf
This is the guiding document for the exercise and includes a statement of the problem, detailed descriptions of the other resource files, and guidance regarding how you go about coming up with the set points you need for the reset schedule.
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A Portion of the Heating Hot Water System Diagram
Existing Heat Exchanger Control Logic
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01 - Bureaucratic Affairs Building v10 SUv8.zip
This is the model behind the exercise. Because this exercise is focused on logic, working with the model is not a critical part of it. But the model will give you some insight into what a pumping system serving finned tube radiation loads and reheat loads might look like. In my experience, that is important because if you are going to properly control something, you need to understand it. In addition, there is at least one "obvious indicator" type of clue in the model that might be a contributing factor to some of the comfort problems. For your new logic to be fully effective, it would need to be addressed, so you may want to try to find it. There could even be a few other "Easter Eggs" out there given my plans for the model.
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Hint: The "obvious indicator opportunity" has something to do with preventing a problem with deadheading the pumps.
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02 - Bureaucratic Affairs Building Description v2.pdf
This file describes the history of the Bureaucratic Affairs Building from its original construction in 1946 through the various equipment upgrades and replacements and the renovation in 1984. Basically everything that has happened prior to the current EBCx study. As is the case with most existing buildings, there are things about that evolution that will provide insight into some of the current issues in the facility. So understanding the history of the building can be helpful.
03 - HW System Diagram.pptx
This is the system diagram for the hot water system in the model. The portion of the system that lies in the mechanical room has yet to be developed, but when I get that done, it will look like what is portrayed in the system diagram and for the purposes of the exercise, you can assume that the system diagram reflects the actual piping in place in the building.
04 - Logic.zip
This file contains a version of the logic diagram tool with the basic logic that is controlling the heat exchanger currently. This is the starting point for your work. In other words, the idea of the exercise is to modify this logic to include a reset schedule.
You should also note that there is an improvement that could be made to the logic - in addition to the reset schedule - that would save some energy and would require no additional hardware. See if you can identify the improvement and the reason it will save energy.
You should also note that there is an improvement that could be made to the logic - in addition to the reset schedule - that would save some energy and would require no additional hardware. See if you can identify the improvement and the reason it will save energy.
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Hint: It has something to do with what will happen when you add a schedule to turn the pumps off when they are not needed.
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The videos below are from informal web training sessions I did with some folks that are participating in the PEC EBCx Workshop that I help support. They agreed to let me share it for the greater good so if this ends up being helpful to you, remember to think a little "thank you" to them.
In the videos, I walk folks through how the basic logic controlling the heat exchanger serving the hot water system evolves. This is the logic that you will modify in the exercise to improve things and save energy. These are done in real time, stream of consciousness for me so each video is different. In this case, they kind of complement each other. So you may want to take a look at both of them.
That is not as awful a suggestion as you might think it is because if you hover over the video, you should get a table of contents list on the left side of the video that will let you skip some of the informal discussion and jump to a topic of interest. If you let the video play from the start, this is illustrated. But the point is that you can jump to a topic of interest in either video with out the burden of watching the entire thing.
In the videos, I walk folks through how the basic logic controlling the heat exchanger serving the hot water system evolves. This is the logic that you will modify in the exercise to improve things and save energy. These are done in real time, stream of consciousness for me so each video is different. In this case, they kind of complement each other. So you may want to take a look at both of them.
That is not as awful a suggestion as you might think it is because if you hover over the video, you should get a table of contents list on the left side of the video that will let you skip some of the informal discussion and jump to a topic of interest. If you let the video play from the start, this is illustrated. But the point is that you can jump to a topic of interest in either video with out the burden of watching the entire thing.
05 - Point List.zip
The point list associated with the basic heat exchanger control logic is included in this file. You will likely need to add points to the list to accommodate the logic you add to the logic diagram.
06 - Heat Exchanger Narrative Sequence - Basic v2.pdf
The narrative sequence for the existing heat exchanger control logic is included in this file. The narrative complements the logic and is something you would want to update to reflect the changes you make to add the reset schedule and any other improvements.
07 - Typical Reheat Coil Selection.zip
This is a coil model that allows you to use the Greenheck Coil Modeling program to play with the performance of a typical reheat coil in the building to see what happens as you lower the supply water temperature away from the design value.
08 - Bureaucracy Building Metrics v6.xlsx
This file contains all of the calculations behind the model and will give you a sense of where the performance metrics came from and illustrate how some of the equipment selections are made initially for a project.
It also includes the general floor plan for the model with the finned tube radiation and VAV terminal zones superimposed on it.
It also includes the general floor plan for the model with the finned tube radiation and VAV terminal zones superimposed on it.
Eventually, the model will have the partitions included in it, but for now, this will give you a sense of the internal arrangement of the facility.
09 - VAV System Slides.zip
These are slides from a class I teach that I use to explain how the cooling coil discharge temperature on an air handling system is set and how that leads to the maximum flow rate for the zones the unit serves. They also illustrate how the minimum flow rate are set for the zones. You will need to understand this because it impacts the low end temperature you will select for your reset schedule.
Bureaucratic Affairs Building Scene Guide v9.pdf
The model has preset views in it called "Scenes" that make it easier to navigate to different locations and perspectives. For instance, the image in the header is scene 7 in the model and I turned off all of walls, roof, second floor slab, beams, and columns to allow you to see the piping circuit with nothing in the way. Scene 1 (below) is that same perspective but with everything turned on.
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