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?
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