[BLDG-SIM] Ventilation Fans

Gavin Gui ggui at ers-inc.com
Fri Nov 9 08:03:06 PST 2007


Jim,

 

The fan static pressure has been set to the maximum of 8.0 WG (any higher and
the model will not run) despite the equipment schedule is stated as 10 WG.

 

As for the CFM, it is input at 250,000 cfm (according to the equipment data).

 

As for logger inaccuracy, we logged both supply fans and they checked out
against one another.

 

I have tried looking at all the parameters in the simulation that might affect
the vent fans energy and demand, including operating schedules, but were
unable to find any that might justify the differences.

 

 

With regards

Gavin Gui

 

________________________________

From: Zarske, Jim [mailto:jzarske at nexant.com] 
Sent: Friday, November 09, 2007 10:52 AM
To: Gavin Gui
Subject: RE: [BLDG-SIM] Ventilation Fans

 

It sounds like you need increase the fan static pressure or kW/CFM in eQUEST
(you stated these are high pressure fans, so I assume the power use is higher
than a typical fan), confirm you have the correct CFM inputted into the model,
or double check the accuracy of the logger data.

 

Jim

 

________________________________

From: BLDG-SIM at gard.com [mailto:BLDG-SIM at gard.com] On Behalf Of Gavin Gui
Sent: Friday, November 09, 2007 8:03 AM
To: BLDG-SIM at gard.com
Subject: [BLDG-SIM] Ventilation Fans

Hi, I am using eQuest to simulate a mid-rise commercial building. The HVAC
system is a simple setup whereby huge axial vane supply fans provide 55F cold
air, under high pressure, to the VAV boxes located at the respective floors.
The air is returned via ducts using similar fans located near the system.
However the modeled results obtained for the vent fans electric demand and
consumption differ greatly from the logged data obtained from the site. The
actual data shows about 75% higher than the model results, both in demand and
consumption.

 

I would greatly appreciate if anyone can advise me on where the problem is or
if there is any way I can fine tune the model to be closer to the actual data.
Thank you. 

 

With regards,

Gavin Gui

 

 
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