[Equest-users] Underfloor Modelling and Error Message.

[Nick Caton]

There's a large chapter in the EDR guidelines that pretty much details an overall "how-to" for UFAD in eQUEST... recommend downloading the PDF linked at the bottom and perusing!

http://www.energydesignresources.com/resources/publications/design-guidelines/design-guidelines-hvac-simulation-guidelines.aspx

IIRC - this is written in a fashion that does a good job of outlining the limitations of UFAD in eQUEST, and provides guidelines for DOE2 system selection by pointing out behaviors that might be desirable to include in the simulation.

~Nick



NICK CATON, P.E.
SENIOR ENGINEER

Smith & Boucher Engineers
25501 west valley parkway, suite 200
olathe, ks 66061
direct 913.344.0036
fax 913.345.0617
www.smithboucher.com 


-----Original Message-----
From: equest-users-bounces at lists.onebuilding.org [mailto:equest-users-bounces at lists.onebuilding.org] On Behalf Of Hall, Brendan
Sent: Tuesday, July 26, 2011 3:44 PM
To: Kazim Mirza; equest-users at lists.onebuilding.org
Subject: Re: [Equest-users] Underfloor Modelling and Error Message.

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
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