Rubber Tyred Gantry (RTG) cranes are mobile material handling devices that operate in shipyards and rail yards for the movement of containers. These mobile systems can load/unload containers, which may weigh up to 50 tons, at a rate of once every minute.
Each crane is powered by an on-board diesel generator set. Variable-speed AC hoist motors receive power from an inverter that provides the required voltage and frequency for the lift and lowering functions. These AC motors demand short-duration peak power from the generator for each lift cycle. Then, when lowering the containers, the AC motors are used as brakes, actually becoming generators that create free regenerated energy, which could be put to use, if that energy could be stored.
Up until now, this regenerated energy from the lowering cycle has been directed to onboard resistor banks and wasted as heat. The high-cycling characteristics of RTG cranes have limited any technology from being able to put this free energy to productive use.
The VYCON REGEN system is an energy storage device designed to not only store energy, but also to discharge it on demand. Its patented technology consists of a highly reliable permanent magnet motor/generator, active magnetic bearings and integrated control schemes. Using VYCON's flywheel technology, the REGEN system is able to charge each time the AC motors regenerate power, and then store that energy to be used when the power demand burns the most fuel, and therefore produces the most emissions. With the instantaneous response of the REGEN system during every hoist cycle, the RTG efficiency is increased, making the REGEN system a smart energy storage device.
There are many benefits that can be quickly achieved through the installation of the VYCON REGEN into an RTG crane for crane manufacturers, port operators, service groups and port authorities. Maintenance is minimal over the 20-year life of the system.
Source and images: VYCON
For more read : Energy Harvesting and Storage for Electronic Devices 2010-2020