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RE: [EnergyPlus_Support] Cooling coil overcools

The coils won't fight each if they each have their own set points (at their outlet nodes) rather than all referencing the same fan outlet node.  You can use a node list in the Set Point Manager: Mixed Air (or multiple manager objects) to put the mixed air set point on the outlet of the oa mixer, cooling coil, and heating coil.    Then change the control nodes in the heating coil and cooling coil controller to be the coil outlets. 

-----Original Message-----
From: EnergyPlus_Support@xxxxxxxxxxxxxxx on behalf of JV Dirkes II
Sent: Fri 4/18/2008 6:49 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Cooling coil overcools
 
Dear EPlus forum,

I've got a simple air loop with, in direction of airflow, an outdoor
air mixer, chilled water cooling coil, gas heating coil and fan.  The
report variables reveal that the air temperature leaving the fan is a
constant 12.8C, which is my intention and the setpoint of a set point
manager.  However, other variables reveal that the mixed air gets
cooled too much, then the heating coil warms it, and the fan heat
warms it further.
As an example:
Tma   Tcc  Thc   Tfan
19.2  9.2  10.4  12.8

I have another model set up identically except that the heating coil
is a hot water coil.  It works just fine;  Tcc = 10.4

This is a big problem because there is a LOT of excess energy used by
the sub-cooling.  Will someone please look at the file to determine
the cause of the sub-cooling?

Thanks!  (File uploaded very shortly)




[Non-text portions of this message have been removed]


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