Energy consumption modelling - ADU-RES

3.9 Induction motors
Efficiency curves for induction motors are based on actual manufacturer’s
data, supplemented by data for very similar motors manufactured by Brook
Crompton 9 . Power factors of three-phase motors are similarly modelled as a
function of operating power. Power factors of single-phase motors are harder
to predict, because capacitor and winding arrangements differ between
manufacturers. They were treated as constants between 0.96 and 0.98. Any
errors have only a second-order effect on energy losses: reactive current will
cause small losses in power electronic converters.
3.10 Centrifugal pumps
The efficiency of centrifugal pumps is critically dependent on operating point.
This is modelled through application of the manufacturer’s head-flow and
power-flow curves. In some cases, data from very similar Grundfos pumps
was substituted.
3.11 Positive displacement pumps
The geometric displacement, taken from the manufacturer’s data, is used to
calculate ideal flow and torque. Volumetric and mechanical efficiency curves
are then applied to determine losses as a function of operation point.
3.12 DC motor-pumps
The DC motors in the selected systems are integrated with their respective
pumps and were modelled using manufacturer’s performance curves for the
complete units.
3.13 Membranes
The models of the RO elements in the Matlab/Simulink model are derived
from Dow FilmTec's ROSA 10 .
3.14 Clark pump
The Clark pump model is based on detailed in-house measurements made
over a broad range operation 11 .
9 www.brookcrompton.com
10 http://www.dow.com/liquidseps/design/rosa.htm
11 Thomson, Murray (2004). Reverse-Osmosis Desalination of Seawater Powered by
Photovoltaics Without Batteries, PhD, University of Loughborough, UK.
http://www-staff.lboro.ac.uk/~elmt/Thesis.htm Section 5.2
ADU–RES WP6 Deliverable 6.1 Page 14 of 69