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Nedbank’s green future

By Dineo Phoshoko

The Nedbank Sunninghill Campus is one of the first corporate buildings in South Africa to install a solar-powered borehole system.

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For Nedbank, commitment to water and energy stewardship is a central, non-negotiable component of their ongoing environmental sustainability efforts. Nedbank believes that the only way for South Africa to effectively deal with the country’s water and energy challenges, and limit the impacts they create, is through a shared commitment to good resource management. In this regard, Nedbank is committed to managing their impact by example.

A prime illustration of Nedbank’s efforts to reduce their impacts is the Nedbank Sunninghill Campus building. This building is one of the first corporate buildings in South Africa to install a solar-powered borehole system. The system is designed in such a way that water is pumped from the borehole to the building at no cost. In addition, the system also supplies irrigation water — also at no cost. This cost-effective way of using borehole water fits perfectly with the bank’s purpose to use their financial expertise for the good of society.

BENEFITS OF THE SYSTEM

Water supply to the building is now completely off the grid, meaning that it is not reliant on municipal infrastructure or supply. This not only reduces dependence on electricity generated by fossil fuels, but also reduces the strain that the building’s water consumption puts on the local domestic supply network. The system has come at a time where water saving has become critical in South Africa.

An added benefit with the system is the reduced dependence on electricity, especially since the cost of electricity has increased by over 400% in the past 10 years. The transition to the use of sustainable power sources, such as solar, is a positive way in which Nedbank can reduce costs on electricity consumption.

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.


The system has come at a time where water saving has become critical in South Africa.


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 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.

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.

The filtration plant. The Rivers Projects and Plumbing Services, Grundfos, and Nedbank teams who were involved with the solar panel installation, on the building’s roof. Cover.JPGSolar panels generating over 2kW direct power to the pump. The CU 200 solar controller — simple, smart, and innovative. Pumps, UV, and RO filtration system.

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 10 000 litres of water. The treated water is supplied to a UV filtration plant on the property through a CM 5-3 pump from Grundfos. The entire filtration plant is not solar powered; however, it also currently uses 220V electricity from the building — which is planned to be converted in a future phase to utilise the excess energy created from the solar PV system. The pump supplies water to a twin pump set that pumps treated water to the building, which is then used for all applications required.

An additional pump is connected to the tanks that hold the untreated water. This particular pump directs water to the sprinklers only. The entire system is powered by eight 260W solar panels from Grundfos. Overall, the panels can generate up to 2 080W of power (2kW at peak). The panels come with a 25-year warranty. Even on a cloudy day, the pump will continue to work because it derives power from the UV rays and not necessarily directly from the sun. Because of the pump’s versatile motor, it can get power from different sources, including a generator, the sun, and single-phased power. The pump motor has an inverter built into it and can also operate on 12V or 220V AC or DC power.

The entire system includes a display that shows when the pump is in operation. This is able to pick up and create an alert on any problems with the pump. The display can be incorporated into a building management system so that it can be monitored regularly.

EMERGENCY AND BACKUP

The system is connected to a 220V IO crossover switch. This switch can be used as backup in a situation where the system does not receive power from the solar system. Should there be a problem with the solar system, one would manually need to turn on the IO crossover switch, which would then revert to the municipal electricity 220V grid. The crossover does not happen automatically for this system; however, an automatic crossover switch is available.

A monitor that tracks the water level is installed in the system for situations where the borehole has insufficient water. If the water level falls below the level sensor, the pump will automatically cut out. At five-minute intervals, the pump will try to restart; however, should the water remain below the level sensor, the pump will not engage until the water level is at a satisfactory level. It is only then that the pump will automatically start operating again.

GRUNDFOS PRODUCT CENTRE AND PROJECT MATERIALS

After drafting a design of the system, Rivers approached Grundfos for recommendations on the required materials for the project. All the information was loaded onto the Grundfos Product Centre (GPC) system, which could determine what materials and specifications would be required for the whole project. The GPC provided a full quotation on pump, motor, control box, and all the required wiring. Additional information such as accessories, recommended sizes, and tilt angles were also provided through the GPC. All the products from Grundfos used in the project are stainless steel.

The SQFlex 14-3 borehole pump formed part of the recommended products from Grundfos for the project. The pump is robust and can fit into almost any hole. The pumps have undergone tests in Namibia in the most extreme conditions. The pump also requires very little maintenance and although standard with a two-year warranty, it is able to last for up to 20 years in some instances. It has a built-in over voltage and under voltage protection, as well as dry run protection in case the borehole runs dry.

Other products from Grundfos that were used during the project included the CU 200 controller and a CM 5-3 pump. A 4 core 6mm cable and a 50mm HDPE class 16 pipe were also used in the installation.

Grundfos SQF 14-3 centrifugal pump. From left: David Jiyane (maintenance assistant at Nedbank), Ashley Sams (facilities manager at Nedbank), Errol Dobson (team leader building services at Grundfos), Sibahle Mthembu (student), Vumani Zondi (solar and renewables technician at Rivers), Edwin Molele (solar and renewables technician at Rivers), and Frank Crisafulli (managing director of Rivers). Water reticulation plant, storing 40 000 litres of water. Filtration system purifying 25 000 litres per day. The UV filtration system. IO 101 manual crossover switch for emergency 220V power supply.

WHAT’S NEXT FOR THE FUTURE

This project’s payback period is expected to be two years. It can be regarded as an investment because Nedbank will not be paying for water and electricity to operate the borehole. Once installed, the borehole pump requires little maintenance and can last for a long time, which also makes it a sustainable solution.

Nedbank hopes to expand the project to a point where the entire building’s water reticulation system does not rely on the municipal water and electricity grid. Rivers also hopes to add another controller that will take the surplus energy not used by the borehole pump and direct it to the building.

Both Nedbank and Rivers believe that this project is a step closer to going completely ‘green’ and positively contributing to environmental awareness and sustainability in the process. Green solutions should always be a forethought with all projects and will always be on the table for the Rivers team as the preferred solution.

LIST OF PROFESSIONALS

 Project manager  Rivers Projects and Plumbing Services
 Equipment/products  Grundfos
 HDPE pipe  House of Plumbing

Click below to read the November 2017 issue of Plumbing Africa

PA NOV2017

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