Dear Adrian,
Lacking actual data from the pump and VSD supplier, use the ASHRAE 90.1-recommended coefficients:
E+ Format | |
| 90.1 VSD |
C1 | 0.203671 |
C2 | -0.827077 |
C3 | 1.181191 |
C4 | 0.442055 |
James V Dirkes II, PE, BEMP, LEED AP
www.buildingperformanceteam.com
Energy Analysis, Commissioning & Training Services
1631 Acacia Drive, Grand Rapids, MI 49504 USA
616 450 8653
From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of adrianchong85@xxxxxxxxx
Sent: Wednesday, January 08, 2014 2:46 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Cubic Curve in variable speed pump
Dear EnergyPlus Users,
I'm trying to model a variable speed pump in eplus and one of the inputs required are coefficients to the cubic curve
FractionFullLoadPower =C1 + C2PLR + C3PLR2 + C4PLR3
where PLR = VolFlowRate / NomVolFlowRate
My question is how do we go about obtaining these coefficients? Is it correct to assume a constant head (maybe assume nameplate head) and using nameplate Power and Flow Rate as nominal data, obtain FractionFullLoadPower and PLR by reading off the Pump's performance curves (at different points with the same head) and then use least squares regression to get the coefficients.
__._,_.___
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.
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe
__,_._,___