I'm modeling an ice storage system...the chilled water system has four
(4) chillers...from 8am to 8pm the four chillers work together to output
40*F leaving CHW after the ice tank is fully discharged...from 8pm to
8am only TWO of the chillers work together to output 24*F leaving CHW to
charge the ice tanks. Here's what I've done so far to model this
system...
* I've modeled SIX chillers even though there are only
four...the normal 40*F LCHWT operation chillers have an EER of 8.4,
whereas the 24*F LCHWT operation chillers during ice mode have an EER of
7.6, so 4 of the 6 chillers modeled are really just 2 chillers as they
are a 'normal mode' and 'ice mode' for two of the chillers as I have to
have those different EER values in there. The other 2 chillers are just
'normal mode' as they aren't on during ice charging.
* I have a charging schedule set up from 8pm to 8am with a value
of '1' and 8am to 8pm with a value of '0'.
* I have a loop setpoint schedule set up from 8pm to 8am to be
24*F and 8am to 8pm to be 40*F.
My question is, how can I schedule the chillers so that the two 'ice
mode' chillers are on from 8pm to 8am, and the four 'normal mode'
chillers are on from 8am to 8pm?? The 'Equipment Controls' only allow
LOAD defined management, and not Time-Of-Day defined management. And
there also aren't any "Availability" schedule options like there are for
air-side systems.
Any suggestions would be very helpful!
Josh Greenfield, PE
