Variable Speed Cooling Tower

asked 2016-03-21 01:08:10 -0600

Pranav
159 ●6

updated 2016-04-02 22:51:11 -0600

Hello,

I am trying to change a single speed cooling tower serving WSHPs to a variable speed cooling tower, but every time I make the change in OS, it stops working and I have to close it. No error file is generated, so it is not possible to understand the reason for the issue. I am keeping the design inputs same for the single speed and variable speed with the only change being the fan control. Even if I specify a fluid cooler instead of a cooling tower, the issue persists. Even if I change the type of setpoint manager, or delete one / all setpoint managers, the issue persists.

Here is the picture of the configuration:

image description

The heat exchanger exchanges heat with boilers. That's how the system is designed.

Looks like a similar problem was reported previously. https://unmethours.com/question/580/o.... However, answers to that thread don't help me. OS does not seem to model variable speed as readily as single speed.

Please share your thoughts on this.

Pranav

PS:Since I was not able to model the variable speed control in OS, I tried modeling it in E+. E+ simulated the IDF file, but (prima facie) the electrical energy increased instead decreasing.....so that's one more issue. I will write about this if I don't get any helpful tips on the OS issue above!!

Here is the picture of the issue C:\fakepath\OS-April3-1.png

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Comments

When you say "stops working" do you mean that the OpenStudio application stops responding, or the EnergyPlus simulation doesn't run? Could you post a link to the .osm?

aparker ( 2016-03-28 15:57:16 -0600 )edit

@aparker I edited the question. I included a file showing the issue. Hope that helps.

Pranav ( 2016-04-02 22:51:57 -0600 )edit

This looks like a software bug and should be reported in a github issue not on unmet hours.

Julien Marrec ( 2016-04-03 05:44:22 -0600 )edit

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answered 2016-04-05 08:43:13 -0600

980 ●1 ●8

updated 2016-04-05 08:43:41 -0600

I have a similar model and added several CTs for testing, but didn't see the issue. What is your version of OS ? Mine is 1.9.4. A possible solution can be: export idf from OS and edit the CT into variable speed in the IDF editor. It should be easy since you have every information such as node number in the IDF already. Hope this helps. image description

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Comments

@Bo_Lin I am using OS 1.10.0. At any rate, I think the software should give me an error if I am not modeling the components correctly, it shouldn't just stop working.

Pranav ( 2016-04-05 21:17:02 -0600 )edit

try edit the CT in IDF editor if you don't have a good solution for this.