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.
Jason2011/6/14 José Ernesto Castillo Peralta <joercape@xxxxxxxxx>
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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