Solar PV water pumping study - FINAL REPORT ... - UNDP, Namibia

Feasibility Assessment for the Replacement of Diesel Pumps with Solar Pumps
FINAL REPORT: September 2006
The PVPs used for analysis in this study are listed in Table 2.1 with their particular
performance information.
Table 2.1: PVP performance overview
Grundfos SQ
Flex 2)
Lorenz PS
Total Energie
TSP 1000
Total Energie
TSP 2000+
Pump type
used
Centrifugal &
helical rotor
Centrifugal &
helical rotor
Maximum
array size
[Wpeak]
Maximum
head
[m]
Hydraulic
load 1)
[m 4 /day]
Maintenance
interval
[years]
1,400 200 1,100 5
1,200 230 1,000 3
Helical rotor 1,280 130 900 5
Centrifugal 5,600 120 ~ 4,000 5
Watermax Diapraghm 300 100 3) 300 1
1) The hydraulic load is calculated by multiplying the daily delivery [m 3 /day] by the head [m] at a fixed array
size. This is fairly constant value and a measure of the PVPs performance and operating range. Here the
hydraulic load is calculated at an irradiance level of 6kWh/m2/day at the maximum array power of the PVP
system.
2) The Grundfos performance is based on the 900W motor. A new motor has been released but the manual
sizing information has not been updated by Grundfos yet. The only pump unit added to the Grundfos
range is the unit able to pump over a 200m head.
3) The Watermax is supplied in four models: WA: Up to 80m, WB up to 100m, WC up to 150m and WD up to
40m. Only the models up to 100m are considered for this study.
The hydraulic load curves of the above pumps are shown in Figure 2.1. The figures are
based in the technical specifications of the PVPs.
Daily Flow [m 3 /day]
120
100
80
60
40
20
0
0 30 60 90 120 150 180 210
Head [m]
Grundfos 1000
Lorentz 1200
Lorentz 840
Total TSP 5600
Watermax 300
Figure 2.1: Hydraulic load curve of four PVP systems at maximum Watt peak
The operating range of each pump is the area below each of the data series. The Grundfos
and the Lorentz pump cover a similar area. These PVPs are suitable for water needs at
villages, for homesteads and lodges, and for livestock and game watering. The low
maintenance requirements make these pumps attractive for remote water supply solutions.
PVPs are not a cost effective solution for highly seasonal irrigation needs. A PVP achieves
cost effectiveness through full use of the PVP modules. For example, using a PVP for half a
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