[Equest-users] Underfloor Modelling and Error Message.

[Hall, Brendan]

A PIU system is fine, especially if you are using fan powered boxes to serve your perimeter. The more important part of trying to approximate an underfloor system is correctly appropriating the loads between the conditioned and unconditioned zones. 

As for the error, what is your supply temperature? It seems like the error would be related to a small dT between the room setpoint and the supply air temperature, which would require calling for a large volume of air to satisfy the loads in the conditioned zone. You might also try having different set points for your heating and cooling, there should be at least a 5F dead band per ASHRAE 90.1. 6.4.3.1.2. Hope that helps.

Brendan Hall, M.Sc., LEED AP BD+C
Mechanical Engineer
 
karpinski
ENGINEERING

3135 Euclid Avenue
Cleveland, OH  44115
P  216.391.3700
F  216.391.0108
E  bhall at karpinskieng.com
W www.karpinskieng.com
 

-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Kazim Mirza
Sent: Tuesday, July 26, 2011 4:18 PM
To: equest-users at lists.onebuilding.org
Subject: [Equest-users] Underfloor Modelling and Error Message.

Hello eQuesters,
                           I had two questions:

(1) Can underfloor modelling be done in eQUEST.? Does any body know
which 'system type' to consider? I have considered a powered induction
system type.


(2) I got a error message from one of my model  as follows. Can some
one help me understand this error?. i have attached my print screens
on the air side for this model.


*WARNING**********************************************************************

Zone: EL1 North Perim Zn (G.N1) has a design cooling

temperature differential of only 4.0F. This

may result in an extremely large design airflow.
***********************************************************************************

Thanks,

Kazim