Thermal Storage Controls

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I am modelling the cost benefits of creating chilled water/ice at night
so I have added a thermal storage tank and set up a secondary chiller
and loop to serve the storage tank. I have assigned an on/off schedule
to the TES chiller so that it operates only at night, but I have also
added equipment controls so that it has first priority for cooling. This
was my initial thought on getting it to operate at night but not during
the day. I am getting an error "Ice Water Loop has zero design flow". At
first I figured this was because I had no size for the storage tank
selected so I started off small and through a 50 ton tank in the
capacity field. Still receiving the same error. Does this have to be
sized manually?

Here are the controls:

"Chiller Controls" = EQUIP-CTRL

TYPE = COOLING

CIRCULATION-LOOP = "Chilled Water Loop"

CHILLERS-1 = ( "Ice Chiller" )

CHILLERS-2 = ( "Air Cooled Chiller 1" )

..

and the tank

"Ice Storage" = THERMAL-STORAGE

TYPE = COLD-WATER-TANK

CAPACITY = 600

CHRG-LOOP = "Ice Water Loop"

CHRG-SCH = "Ice Making Schedule Annual"

DCHRG-LOOP = "Chilled Water Loop"

..

Thanks in advance

Alan Jackson, LEED(r) A.P.

Alan Jackson's picture
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Joined: 2011-10-02
Reputation: 0

I get that error when I do novel things, too, and it goes away when I change
the loop sizing type from secondary (the default) to primary. You may get a
warning afterwards that says that the loop is undersized for the connected
load. I ignore these warnings since the loop is sized based on the primary
equipment capacity (which should be sufficient).

I hope this is helpful!

Eric

Eric Studer's picture
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Joined: 2011-09-30
Reputation: 200

Eric

That did the trick. Thanks for the help. And it seems I had to introduce
different controls then I was at the time in order to get the storage
tank to provide capacity to the loop at the appropriate time. For
others, this is detailed in STORE-MAX-LOAD of DOE documentation. Example
below.

CHILLERS-1 = (CHLR-A,CHLR-B)
CHILLERS-SEQ-1 = ( 1, 2)
STORE-SEQ-1 = (3)

Thanks again

Alan Jackson, LEED(r) A.P.

Alan Jackson's picture
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Joined: 2011-10-02
Reputation: 0