Pump Efficiency curves

[azein]

Dear,

In the help file, at section "Pump-Model Description, Pump model from Ip and FlowR as f(Head) with fixed voltage",

you state that you are using the strong hypothesis that Pump Efficiency is constant when varying the voltage, with measured variations of the order of 15% for a given voltage range.

Would you please let us know what mathematical model would you use for calculating the efficiency curves at different rotation speeds given only the efficiency curve at 50 or 60Hz??

Many Thanks,

[André Mermoud]

For a Centrifugal pump, when specified as Head as function of Flowrate, PVsyst uses a model called "similarity laws" (see the help "Physical models used > Pump - Model description > Pump model from Head (and P) as f(FR), fixed U or speed". This definition also requires to know the efficiency (or Power) as function of the flowrate.

For all other input parameter configurations, PVsyst doesn't use any model. It determines any operating conditions (I, U, H, F) or (P, H, F) by an interpolation between the specified operating conditions. This may represent a rather complex calculation. See the help "Physical models used > Pump - Model description".

You have a detailed description of the pump model in a document available on our web site:

"Technico-economical Optimization of Photovoltaic Pumping Systems Pedagogic and Simulation Tool Implementation in the PVsyst Software",

André Mermoud, 2006

Research report of the Institute for Environmental Sciences, University of Geneva.