[Bldg-sim] FW:

[Andrew Craig]

Chien---

 

Section G3.1.3.14 of Appendix G hit on requirements for fan powered
boxes.  They are:

 

1.)     FTUs shall be sized for 50% of the peak design flow rate 

2.)     FTUs shall be modeled with 0.35 W/cfm fan power.

3.)     Minimum volume setpoints for FTUs shall be equal to 30% of the
peak design flow rate or the rate required to meet minimum OSA
ventilation, whichever is larger.

4.)     The supply air temperature setpoint shall be constant at the
design condition.

 

Hope that helps.  Good luck.


Regards,

 

Andrew Craig, EIT,LEED AP/ Mechanical Designer 
INTERFACE ENGINEERING 
direct 503.382.2696 

________________________________

From: bldg-sim-bounces at lists.onebuilding.org
[mailto:bldg-sim-bounces at lists.onebuilding.org] On Behalf Of Chien Si
Harriman
Sent: Thursday, February 21, 2008 2:07 PM
To: bldg-sim at lists.onebuilding.org
Subject: [Bldg-sim] FW:

 

 

 

________________________________

From: Chien Si Harriman
Sent: Thu 21/02/2008 21:46
To: bldg-sim at lists.onebuilding.org
Subject: 

Hi there-

 

I've been tasked with modeling a parallel fan powered box as my baseline
system for ASHRAE 90.1 Appendix G, and basically I am wondering if there
is anyone who knows of modeling guidelines for that FPB?  I have the
capability of modeling any sort of conditions I would like, so I can
vary the flow rate of the recirc air, the control sequencing of the
fan-assist, and even whether that fan is variable volume or constant
volume.

 

I can't find any guidelines that exist anywhere on this topic in ASHRAE
90.1, and this is the first time I've had to model it (I've never
designed an electrically-heated building before).  Does anyone know
whether:

 

1.)  There is a specific ratio for the amount of recirc air to minimum
primary air?

2.)  Whether the amount of recirc air should vary (ie-a variable speed
fan)?

3.)  You can just use a real FPB with data from a company like Carrier,
and just call it a day on the simultion effort?

 

 

 

Any guidance would be really helpful.

 

 

Thanks in advance,

Chien Harriman

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