[BLDG-SIM] TEMP of air leaving cool coil in equest--A confusing result!

["Brian Fountain" <bfountain@xxxxxxxxxxxx>]

As for the chiller running year round – the default operating mode is standby – that should be changed to either demand or snap on OAT – otherwise your chiller runs whenever a system is running “just in case” it needs cooling.

 

 

-----Original Message-----
From: BLDG-SIM@xxxxxxxx [mailto:BLDG-SIM@xxxxxxxx] On Behalf Of Mingming Zuo
Sent: October 6, 2007 4:04 AM
To: BLDG-SIM@xxxxxxxx
Subject: [BLDG-SIM] TEMP of air leaving cool coil in equest--A confusing result!

 

Dear all:

 

Hi, I modeled a VAVs in eQUEST recently and the parameters related are summarized below:

 

 100% outside air for all the year

 for preheat coil, PREHEAT-T=48.2 F ;

 for central cool coil, COOL-SET-T=48.2 F and MIN-SUPPLY-T=60.8F;

 for chilled water loop, loop operation = demand only.

 no economizer and heat recovery.NO humidity control!

 

As in Shanghai, China, there are many hours when outside air dry bulb temp will go below 48.2F, So I think no cooling from chiller is needed.After simulation, I exmained hourly

 

results report and found out the CHW loop ran all the year and TEMP of air leaving cool coil is 46F. As no humidity control, in my opinion, there is no need to lower coil temp.

 

Why are temps of air leaving cool coil driven below 46 F while no cooling is needed?

 

Thanks&regards

 

Zuo Mingming

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