TRACE 700 Plant Unloading Example

Here we discuss the full details of cooling plants in Trace 700. We also walk through the calculations to determine the efficiency of a cooling plant at a given set of conditions, using the unloading curves to calculate the final efficiency.

In this example, we’ll create a new file based on an existing file. When we open trace, hit the close button as we need to go to the file menu, select new, and select new file based on. You can also hit control b to start this process. Once we select ‘new file based on’, we will be prompted with a window to open a project. It is tempting to select the file that we're going to create a new file based o here, but if you do that, you're probably going to erase that new file because we're actually saving the new project. So we want to give it a new name. For example, if we called it ‘Exercise One,’ we would be saving this file as exercise one and replacing the existing file, therefore destroying it. It’s very important to give it a new name here. I’m going to call it ‘New file based on.’ Select open. Once we have saved the new file, we will see if there’s the new file listed in the menu new file based on, and now we can select the file or files that we're going to base this file on. In this case, we're going to select exercises one and two. So we select exercise one, hold the control key, and select exercise two. Click open. If you select more than one file it will prompt you, ‘Multiple files have been selected. Do you wish to merge the plants?’ In other words, if the files have plants that have the same name and same structures, they're only going to be counted once. As an example, in exercise one and exercise two we have an air cooled chiller plant. If we selected no, the new file would have two air cooled chiller plants. We only want one, so we’ll select yes and it will merge the plants. Once we select yes, we're prompted to select the alternative. We can only bring one alternative per file. In this case, we only have one alternative so it's simple. Select the alternative from the first file, click okay. Then, select the alternative from the second file and click okay again. TRACE 700 will run through the process and tell you that the file transfer is finished. Note that we had 10 rooms in exercise one and 13 rooms in exercise two. The plants were the same, so we merged them and now have the same number of plants. If we look at the rooms, it tells us which rooms came from the second file and which rooms came from the first file. It does the same with systems. Having merged the plants but not merging the systems, we have to reassign some coils. Of course, that’s simple in this case. If we take a look at the plants, we will notice that there’s still one air cooled chiller like we said, and the heating plants are identical. The only difference is that the plants have a prefix of two on the front to indicate that they were brought in from the second file or merged from the second file. That’s all there is to creating a new file based on. The most important thing to remember is to enter a new file name when you create a file based on. It’s a common problem for most users. So creating a new file based on will solve the problem when you have alternatives two, three, or four, and you need to make it into alternative one, or when you have multiple buildings and you need to put them on one plant. You might wonder what happens if you want to compare two buildings and they're in separate files. While it's not documented in TRACE 700, the way to bring in a new file is to hit control alt b, and you can select an alternative from another file, which we’ll do now. We hit control alt b. In this case, it takes us straight to ‘based on what file.’ Again, we can select multiple files. In this case, we’ll just select exercise three, click open, and it will ask us which alternative, and we'll select alternative one and say okay. TRACE 700 will prompt us when the alternative has finished importing. And when we select okay, we’ll see that the rooms and systems have been imported. It's important to note that this process is not published because sometimes it can be a bit buggy. However, the problem is typically encountered when a user is importing alternative four. If you are importing alternatives two or alternatives three, there does not seem to be any bug. That concludes how to create a new file based on, and importing new alternatives.