Pump manufacturer Grundfos has developed a motor, the MGFlex motor, which is able to run off solar power or mains, when necessary, for solar-powered surface pump booster applications.
Published in : Engineering News, 2011-09-30
The company recently launched its solar-driven booster pump for industry, as well as its solar-driven pool pump, each with an MGFlex motor.
The motor has a built-in protection feature to protect the pump itself, with a wide voltage range in ac or dc operations. “This is the first nonsubmersible motor that can be run from a solar panel, power mains or a generator,” says Grundfos South Africa technical director Les Ingle.
The motor has maximum power point tracking, which optimises speed accord- ing to the input power available and oper- ates only when the pump is connected to the dc supply.
Further, the motor has variable-speed power transmission and has monitoring systems, which keep track of overloading, overheating, the load condition and voltage, and are able to monitor the system from a distance.
Meanwhile, the solar-driven booster pump, the CRFlex, is a nonself-priming, vertical multistage centrifugal pump that consists of a base and a pump head, with a chamber stack and the outer sleeve secured between the pump head and the base by means of stay bolts.
The base has suction and discharge ports on the same level and all pumps are equipped with a maintenance-free mechanical shaft seal of the cartridge type.
CRFlex pumps can be used in thin, clean, nonaggressive, nonexplosive liquids that do not contain solid or long-fibred particles larger than sand grains.
Meanwhile, the PoolFlex solar-powered pump is a normal swimming pool pump to which an MGFlex motor has been added and it requires solar panels to operate. This pump is able to handle domestic pools up to 75 000 ℓ in capacity.
The solar-powered pumps allow access to water where conventional water supply systems fail or simply cannot reach.
Although the initial investment for this pump and solar panel is higher than for the average pump, the operating cost of a normal pump – taking into account the increase in electricity prices – is a lot higher than the solar-powered pump and the return on investment period is short.
“The price of solar-powered pumps is currently the most significant challenge in the market. “Solar panels can be the most expensive component of the unit but, as technology advances, the cost is expected to decrease significantly,” says Ingle.
He adds that a new thin-film solar panel technology has been developed which has already cut the cost almost by half.
South African scientist Dr Vivian Alberts, of the University of Johannesburg, invented the thin-film solar panels, which comprise a thin layer, about 5 μm thick, of a unique metal alloy that converts light into energy at a fraction of the cost. The photoresponsive alloy can operate on virtually all flexible surfaces.
The film is thinner than a human hair, which is 20 μm thick.
“As solar panel technology continues to improve and becomes more affordable, the applications of solar-powered pumps will become limitless,” Ingle concludes.