chiller staging based on time

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Hello fellow eQuest modeller,

I am trying to model an existing building that stages chiller based on time
and not load. The building has a big chiller (~1000 ton) that runs during
day time and a small chiller (~200 ton) at night. I want to ensure the
model use the big chiller during day time even when the cooling load is low.

Is there any smart way in eQuest to model this? Or am I better off just
removing the small chiller completely and use spreadsheet to post-process
the efficiency during night time?


Edmund Wong's picture
Joined: 2012-04-25
Reputation: 0

Hello Edmund,

Yes, you can stage the chillers in eQUEST according to the described
building control strategy. To do this you will need to use both the
equipment controls and Load management controls in the detailed edit

The first step would be to set an Flag schedule that defines the hours
of operation of one of the chillers. Since it sounds like they do not
run at the same time you could get by with creating only one schedule.
Set the flag to 1 when your chosen chiller is operating and 0 when it is

Assign that schedule to the Equipment Control Schedule of the Load
management control.

Create a separate equipment control for each chiller

Set the equipment control you want to be on when the schedule is 0 in
Seq 1

Set the equipment control you want to be on when the schedule is 1 in
Seq 2

I hope that helps,

Byron D. Burns, EIT, BEMP

Byron Burns's picture
Joined: 2012-07-18
Reputation: 0