Re: [EnergyPlus_Support] ASHRAE Compliant Fans and Pumps

Vinay

On Wed, Jul 7, 2010 at 9:25 PM, James V Dirkes II, PE <jvd2pe@xxxxxxx> wrote:

Dear Vinay,

ASHRAE 90.1-2007 specifies Baseline system fan power in Table G3.1.2.9. For VAV systems, also use Table G3.1.3.15 for part load performance. A sample object for the VAV fan is shown below.

For all baseline fans, I made a spreadsheet which, based on anticipated motor and fan efficiency, calculates the pressure rise which will result in the correct ASHRAE 90.1 fan power. Remember that E+, when asking for ?fan efficiency?, really wants (Fan mechanical efficiency x Motor efficiency). For example, if the fan mechanical efficiency = .60 and motor efficiency = .90, the E+ ?fan efficiency? = .54.

Fan:VariableVolume

Name

SFan_MainBldg

Availability Schedule Name

SchCpct_FanOpern

Fan Efficiency (incl. motor)

0.6

Pressure Rise (Pa)

498

Maximum Flow Rate

Autosize

Minimum Flow Rate

0

Motor Efficiency

MT

Motor In Airstream Fraction

1

Fan Coefficient 1

0.0013

Fan Coefficient 2

0.147

Fan Coefficient 3

0.9506

Fan Coefficient 4

-0.0988

Fan Coefficient 5

0

Air Inlet Node Name

NodeOut_ClgCoilAir_MainBldg

Air Outlet Node Name

NodeOut_SFan_MainBldg

End-Use Subcategory

The Building Performance Team
James V. Dirkes II, P.E., LEED AP
1631 Acacia Drive NW
Grand Rapids, MI 49504
616 450 8653

From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Vinay Devanathan
Sent: Wednesday, July 07, 2010 5:53 PM

To: EnergyPlus_Support@xxxxxxxxxxxxxxx

Subject: Re: [EnergyPlus_Support] ASHRAE Compliant Fans and Pumps

Alan,

In regards to your reply,

Does ASHRAE specify any efficiency value for the fans? If yes, could you please direct me to the same.

Thank you.

Regards,
Vinay

On Tue, Jun 29, 2010 at 11:33 AM, Jackson, Alan <ajackson@xxxxxxxxxxxxxxxxx> wrote:

You're going to want to adjust your Static Pressure DeltaP. Once you
have your Watts for the Baseline from auto sizing the flow you can use
DeltaP[Pa] = Power[W]*Eff/Flow[m3/s]

Since ASHRAE is telling you Flow and Power you have to solve for static.

Alan Jackson, LEED AP
KlingStubbins

-----Original Message-----
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of eddiecorwin
Sent: Tuesday, June 29, 2010 11:13 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] ASHRAE Compliant Fans and Pumps

I am curious as to how people have gone about modeling ASHRAE compliant
pumps and fans.

The pumps seem relatively strait forward, run the model, see what the
flow is, then enter in a wattage that equates to 22W/GPM. The fans,
however, do not have an input for the rated wattage. The only option I
see is to alter the fan's Motor Efficiency until you get close to the
correct W/CFM.

Are these the same methods people have applied in the past, or is there
a better way to the the correct W/GPM and W/CFM?

------------------------------------

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to
energyplus-support@xxxxxxxx

The primary EnergyPlus web site is found at:
http://www.energyplus.gov

The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/

Attachments are currently allowed but be mindful that not everyone has a
high speed connection. Limit attachments to small files.

EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under
the Documentation link and press the "search" button.

Yahoo! Groups Links

	Fan:VariableVolume
Name	SFan_MainBldg
Availability Schedule Name	SchCpct_FanOpern
Fan Efficiency (incl. motor)	0.6
Pressure Rise (Pa)	498
Maximum Flow Rate	Autosize
Minimum Flow Rate	0
Motor Efficiency	MT
Motor In Airstream Fraction	1
Fan Coefficient 1	0.0013
Fan Coefficient 2	0.147
Fan Coefficient 3	0.9506
Fan Coefficient 4	-0.0988
Fan Coefficient 5	0
Air Inlet Node Name	NodeOut_ClgCoilAir_MainBldg
Air Outlet Node Name	NodeOut_SFan_MainBldg
End-Use Subcategory