Page 231 - Applied Photovoltaics

Four different physical configurations are identified by Barlow et al. (1993):
1. Submerged pump and motor. This arrangement is often used for medium
depth bores with centrifugal pumps, which are then automatically primed and
safer from damage and theft.

2. Submerged pump with surface motor. This allows easier motor
maintenance but introduces reliability and efficiency problems through the
mechanical drive down the bore. The reciprocating displacement (Jack) pump
uses a vertically-reciprocating shaft to transfer energy from the surface motor.
3. Floating pump/motor set. This design is unsuited to boreholes but attractive
for pumping from dams, canals and open wells.
4. Surface suction pump set. This setup is convenient for maintenance but can
be problematic for pump priming.

11.3 WATER PUMPS
There is an abundance of names and classifications for pumps but they may all be
separated into two categories (Thomas, 1987; Krutzch & Cooper, 2001):

1. Dynamic—in which the water velocity is continuously incremented, then
reduced at the output, leading to a pressure increase.

2. Displacement—including reciprocal and rotary types, in which energy is
added periodically by forcing volume changes of an enclosure.

Figure 11.3. Approximate ranges of application of photovoltaic water pumping
configurations (after Thomas, 1987, used with permission of Sandia National
Laboratories).

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