First time here? Check our help page!

Ask Your Question

2

best way to evaluate plant sizing results in optimization process

I want to optimize chilled water loop sizing and configuration to meet the cooling load of a building. I have a detailed model that includes thermal zones and AHUs but I don't want to change them during the optimization process.

My concern is choosing a variable as the constraint for thermal comfort. I need this to evaluated whether my plant loop can meet the demand or not. I tried Unmet hours but I got weird results and I cannot work with that.

Is there any variable in energyplus that I can ensure it can evaluate my plant sizing results?

==========================================================================

Update: I'm using "Time Setpoint Not Met During Occupied Cooling" with 1 C tolerance. I get about 52 hours of unmet cooling hours. I don't the standard value but it seems a lot to me:

image description

By the way in this case I'm using two chillers with a sizing factor of 0.55 for each one.

asked 2020-11-01 03:21:35 -0500

updated 2020-11-09 09:45:39 -0500

edit flag offensive 0 remove flag close merge delete

Comments

1

You need to provide more information. First, which "unmet hours" you have tried, and where? Then, why did you find the results "weird"?

Yi Zhang (2020-11-01 03:58:09 -0500) edit

@Yi Zhang I provided some details. thanks.

Babak (2020-11-01 05:04:19 -0500) edit

add a comment see more comments

1 Answer

Sort by

2

It seems to me that either the system is under-sized, or there is too much inertia in the system/building and the cooling is not starting early enough. If you plot the hourly temperature profile, and the cooling schedule, you will be able to see when these unmet hours are, which will tell you what the problem is.

answered 2020-11-03 09:50:31 -0500

edit flag offensive 0 remove flag delete link

Comments

add a comment see more comments