PROJECT
THE PROJECT
The project was executed by Rivers Projects and Plumbing
Services together with Grundfos. Rivers was primarily
involved in the assembling of the project, while Grundfos
supplied most of the materials used in the project.
The initial planning of the project began in May 2017.
The physical labour on the project started in mid-August,
completed in less than a month, and handed over on 10
September 2017.
Nedbank requested a system that would allow them
to use borehole water without consuming electricity
— which would enable non-reliance on the municipal
water and electricity grid. In addition, Nedbank
requested that the system provide 30m³ (30 000 litres)
of water over an eight-hour period daily. The eight-hour
window period took into consideration overcast weather
conditions that may not be conducive for the solar
system. The borehole water would be used for both
irrigation and domestic purposes.
Rivers did not have to worry about drilling the 80m-deep
borehole or installing tanks and water storage, as they
had already been installed on the property. The borehole
pump was an old one and had burnt out, therefore
needing to be replaced. It was replaced with a new
SQFlex 14-3 Grundfos borehole pump. The bulk of the
www.plumbingafrica.co.za
project involved supplying and installing solar panels that
would generate enough electricity to supply the borehole
pump, which in turn can produce 30m³ of water within
an eight-hour period.
39
Solar panels
generating over
2kW direct power
to the pump.
The project was very straightforward and had minor
challenges. Hoisting the eight panels to the roof of the
three-storey building was one of the few challenges
Rivers experienced during the project, because it was not
close to the borehole. If the distance between the panels
and the borehole had been shorter, then less panels
would have been required. Solar panels determine the
head and flow of the pump; more panels increase the
volume and pressure of the water from the pumps.
HOW IT WORKS
The borehole pump is connected to a 200m-long cable
that goes up to the solar controller at the solar panels.
The panels rely on a controller at the pumps to control
the water level when the tanks are full. The controller
is able to cut power to the pumps. The system also has
a level control float switch to stop the pumps when the
tanks are full. The pumps will only start pumping water
again once the water from the tank has been drawn.
The system supplies both treated and untreated water.
Through a 50mm HDPE pipe, untreated water is supplied
into two 10m³ tanks, each with a capacity to hold
Continued on page 41 >>
November 2017 Volume 23 I Number 9