Cooling Tower Scoping Exercise
See if you can identify the 11 or so opportunities to save energy and improve the operation of this cooling tower
This exercise is similar in nature to the Chilled Water Plant Scoping Exercise and the Ballroom AHU Scoping Exercise. In fact, these are the cooling towers you observe as you arrive at the site as described in the narrative that sets up the Hijend Hotel exercises on the Chilled Water Plant Scoping Exercise page. It turns out that the Ballroom AHU is not the only system on site with some issues and thus, opportunities to save energy and improve operations.
As is the case for the Ballroom AHU Scoping Exercise, this exercise can stand on its own. Butt it was originally designed as a follow-on to the Chilled Water Plant Scoping Exercise. So, if you have not tried the Chilled Water Plant Scoping Exercise, then you should take a minute to read the Setting the Scene portion of that exercise because there are some pieces of information there that create context for this model, like the type of day it is outside and what's going on at the central chilled water plant at the time for instance. In addition, here are another few tidbits to add to that situational awareness.
As you are walking out to the tower with the Chief and her technician, they bring up a mysterious problem and hope that maybe you can find the root cause of it. Ever since the plant was brought on line, they have noticed that when the are operating one chiller, as the load increases, there frequently comes a point when even though the chiller is not fully loaded, the tower seems to be having trouble rejecting all of the load from the chiller. Its as if it is undersized.
But, if two machines are running, the two tower cells together seem to have not problem handling the heat rejection requirements of the plant, even when they are running at 100% occupancy and they are concurrently experiencing one of their extremely hot and humid design or near design days.
The operating team also mention that while they know it is not the ideal way to operate, they find that they need to keep the condenser water pump for the lead chiller in Hand because if the automation system shuts the plant down for any reason, then when the pump cycles off, the tower basins over-flow and they loose a bunch of water and water treatment chemical.
And, when that happens, the plant can not automatically restart because when the pump starts, it draws a vortex in the tower inlet and cavitates. In addition, the system is air bound and they have to go to a lot of effort manually to get all of the air out and the system back on line.
Unlike the other two scoping exercises, I am not giving you any leading questions on this one. I figured that way, you could apply what you learned from the other exercises and gain some confidence that way. The same concepts apply and who knows, there may even be some very similar opportunities that manifest themselves.
As is the case for the Ballroom AHU Scoping Exercise, this exercise can stand on its own. Butt it was originally designed as a follow-on to the Chilled Water Plant Scoping Exercise. So, if you have not tried the Chilled Water Plant Scoping Exercise, then you should take a minute to read the Setting the Scene portion of that exercise because there are some pieces of information there that create context for this model, like the type of day it is outside and what's going on at the central chilled water plant at the time for instance. In addition, here are another few tidbits to add to that situational awareness.
As you are walking out to the tower with the Chief and her technician, they bring up a mysterious problem and hope that maybe you can find the root cause of it. Ever since the plant was brought on line, they have noticed that when the are operating one chiller, as the load increases, there frequently comes a point when even though the chiller is not fully loaded, the tower seems to be having trouble rejecting all of the load from the chiller. Its as if it is undersized.
But, if two machines are running, the two tower cells together seem to have not problem handling the heat rejection requirements of the plant, even when they are running at 100% occupancy and they are concurrently experiencing one of their extremely hot and humid design or near design days.
The operating team also mention that while they know it is not the ideal way to operate, they find that they need to keep the condenser water pump for the lead chiller in Hand because if the automation system shuts the plant down for any reason, then when the pump cycles off, the tower basins over-flow and they loose a bunch of water and water treatment chemical.
And, when that happens, the plant can not automatically restart because when the pump starts, it draws a vortex in the tower inlet and cavitates. In addition, the system is air bound and they have to go to a lot of effort manually to get all of the air out and the system back on line.
Unlike the other two scoping exercises, I am not giving you any leading questions on this one. I figured that way, you could apply what you learned from the other exercises and gain some confidence that way. The same concepts apply and who knows, there may even be some very similar opportunities that manifest themselves.
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To do the exercise, you will need a version of SketchUp running on your computer as discussed on the SketchUp Resources page. Once you have SketchUp installed and running, you should be able to down load the file with the model in (the first file to the right) and begin working with it. You may also want to download a copy of the scene guide (the second file to the right).
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The model has been back-saved to SketchUp version 8, so as long as the version you are using is that one or newer, it should open up.
A few points that are particular to this model.
As was the case for the other scoping exercises, all of the opportunities you can discover in the model have what I call "obvious indicators" associated with them. You can take a look at the introduction to the chiller plant model for more information on what I mean by that if you are not familiar.
Once you have made your findings list, you can download my finding list (the third file called "Answers" in the group of files above) and compare it to yours. In addition to listing the findings, the answer file tells you:
As is the case for the other models, eventually, we hope to develop a track for each of the findings that will get into the details of how to assess it, how to do the math, now to implement the improvement, and how to verify that what you did is working. So check back occasionally to see how we are progressing on that lofty goal.
But meanwhile, try your hand at scoping out the cooling towers and condenser water system. In addition to saving pretend energy and making pretend improvements to the way the system works, you may find some other pretend resource savings you can quantify (hint, hint). Hopefully, you'll have some fun, learn a few things ,and be inspired to get out in the world and make it a better place for us and our kids.
A few points that are particular to this model.
- To completely understand the condenser water piping circuit, you actually need the chiller plant model in addition to this one because that is the model where the pump room below the towers shows up along with the utility tunnel where the piping runs from the tower location to the plant. If you don't already have it, you can download the model from the Chilled Water Plant Scoping Exercise page.
- One of the elements that is included in the over-all model is a fairly detailed model of a cooling tower. So, even if you do not want to do the scoping exercise, you may still find the model to be useful because you can see how an induced draft, cross-flow cooling tower is put together. A number of scenes have layers turned off so that you can see inside the tower, and others take you to specific locations inside the tower, like the motor and gear box.
As was the case for the other scoping exercises, all of the opportunities you can discover in the model have what I call "obvious indicators" associated with them. You can take a look at the introduction to the chiller plant model for more information on what I mean by that if you are not familiar.
Once you have made your findings list, you can download my finding list (the third file called "Answers" in the group of files above) and compare it to yours. In addition to listing the findings, the answer file tells you:
- What the obvious indicator is,
- What scene numbers are associated with the finding,
- What type of benefit is associated with the finding,
- What the next steps would be in terms of developing the finding, and
- What are the precautions and other considerations you should be thinking about as you move forward.
As is the case for the other models, eventually, we hope to develop a track for each of the findings that will get into the details of how to assess it, how to do the math, now to implement the improvement, and how to verify that what you did is working. So check back occasionally to see how we are progressing on that lofty goal.
But meanwhile, try your hand at scoping out the cooling towers and condenser water system. In addition to saving pretend energy and making pretend improvements to the way the system works, you may find some other pretend resource savings you can quantify (hint, hint). Hopefully, you'll have some fun, learn a few things ,and be inspired to get out in the world and make it a better place for us and our kids.
