Actually, I just noticed that the Fan object uses the name “Fan Efficiency” to represent the product of mechanical efficiency * motor efficiency.
It also uses “Motor efficiency” for motor efficiency.
The pump object just uses “Motor efficiency”, which (help me here, Richard!) is the product of mechanical efficiency * motor efficiency.
So, it appears that the term “Motor efficiency” may be used to mean two different things……
(I’m getting dizzy thinking about it.)
The Building Performance Team
James V. Dirkes II, P.E., BEMP , 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: Thursday, June 16, 2011 10:43 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Re: how can I change the HOT WATER PLANT HW SUPPLY PUMP power in a HVAC Template
I think the Fan Efficiency field is Fan Total Efficiency, which is obtained by Fan Mech Ef. x Motor Eff.
Hope that's right. Someone can confirm!
On Thu, Jun 16, 2011 at 10:38 AM, Jean marais <jeannieboef@xxxxxxxxx> wrote:
Are you saying that for air fans, the field Motor Efficiency = motor eff. x fan mech eff. AND Fan Efficiency = fan mech eff. ?
This will explain why my powers are still off by a little bit.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jim Dirkes" <jim@...> wrote:
>
> Well……
>
> In order to calculate pump power, you must know flow, head, motor efficiency
> AND pump (mechanical) efficiency. Since there is no input field for pump
> efficiency in E+, I looked into this a while back and the documentation
> indicated that the pump efficiency was a constant 78%. Since you are
> indicating otherwise, I checked again and see that things appear to have
> changed!
>
> So, is it the case that pumps now follow the E+ fan convention and use a
> combined (motor efficiency * pump mechanical efficiency) as the "Motor"
> efficiency input field?
>
> p.s., I always thought that this was confusing, since it's not a normal
> engineering convention and the field label clearly says "Motor efficiency".
> It's workable, just confusing J.
>
>
>
> The Building Performance Team
> James V. Dirkes II, P.E., BEMP , LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
>
>
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Richard Raustad
> Sent: Thursday, June 16, 2011 8:56 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: Re: [EnergyPlus_Support] how can I change the HOT WATER PLANT HW
> SUPPLY PUMP power in a HVAC Template System VAV
>
>
>
>
>
> The pump efficiency is not actually used in the calculation but it is
> calculated internally to provide warnings for the user. The Engineering
> Reference shows the pertinent calculations for the pump (search for
> "Variable Speed Pump" or "Constant Speed Pump").
>
> The calculation for pump efficiency is:
>
> TotalEffic = PumpEquip(PumpNum)%NomVolFlowRate *
> PumpEquip(PumpNum)%NomPumpHead / PumpEquip(PumpNum)%NomPowerUse
>
> PumpEquip(PumpNum)%PumpEffic = TotalEffic / PumpEquip(PumpNum)%MotorEffic
>
>
> On 6/15/2011 7:31 PM, Jim Dirkes wrote:
>
>
>
> .. and E+ always assumes pump efficiency to be a constant value (78% I
> think.)
>
>
>
> The Building Performance Team
> James V. Dirkes II, P.E., BEMP , LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
>
>
>
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Jason Kirkpatrick
> Sent: Wednesday, June 15, 2011 6:57 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: Re: [EnergyPlus_Support] how can I change the HOT WATER PLANT HW
> SUPPLY PUMP power in a HVAC Template System VAV
>
>
>
>
>
> Jose,
>
> You can modify the pump power by changing the pump rated head in the
> HVACTemplate:Plant objects that you need to include to create the chilled
> water, hot water, and condenser water loops.
>
> Pump Electric Power = Pump Volume Flow Rate x Pump Head / Total Pump
> Efficiency
>
> Refer to the EngineeringReference.pdf documentation that came with your
> install of energyplus for more detail.
>
> Alternatively, once you have an expanded input data file that works, you
> could directly input the rated power consumption into the pump object and
> autosize the pump head.
>
> In order to accomplish this you will need to rename the file that end with
> .expidf to a file with name .idf and then you can edit and run the expanded
> idf like any other input file.
>
> Hope this is of help.
>
> Jason
>
> 2011/6/14 José Ernesto Castillo Peralta <joercape@...>
>
>
>
> Hi,
>
> how can I change the power of the HOT WATER PLANT HW SUPPLY PUMP, CHILLED
> WATER PLANT CHW SUPPLY PUMP and CHILLED WATER PLANT CNDW SUPPLY PUMP in a
> HVAC Template System VAV
>
> --
>
>
>
> Jose Ernesto Castillo Peralta
>
>
>
>
>
>
>
>
>
>
>
> --
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL 32922-5703
> Phone: (321) 638-1454
> Fax: (321) 638-1439 or 1010
> Visit our web site at: http://www.fsec.ucf.edu
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>
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