Error - System Type 8 - VAV or PIUs.

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Dear all,

There is an error that has come up while simulating a 6 lakh sq. ft. bldg.

"cooling coil leaving temperature must be at least 6F higher than entering
water temp."

The CHW temp is 44 F and I have tried varying the zone supply temperature
from 52 to 60 F. But no luck. The air side system here was PIU or VAV.

However, when I model the same with an FCU at the air side. No error
appears.

Any clues why such strange behavior and how to resolve it?

Thanks in advance

Kushagra

Kushagra Juneja's picture
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Joined: 2013-02-21
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Take your fan out of the air stream - it is included in the temperature
difference and if you have large fan energy it can represent another couple
of degrees F.

bfountain's picture
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Joined: 2011-09-30
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Hi Kushagra,
I think it is because a PIU or VAV has a higher fan temperature rise than fancoil.
Could you send a screen cut of the air side system cooling setting.
We could know detail about this error.

JIE

Jenny Zhang's picture
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Joined: 2011-09-30
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Dear Jenny, Brian,

It was indeed because of the fan air stream temperature rise. I forced fed
it to zero, and its up and running.

Thank You so much.

Thanks Again

Kushagra

Kushagra Juneja's picture
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Joined: 2013-02-21
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