Wednesday, April 1, 2009
Rotorcraft Report: Test Cells That Can Generate Electricity
Traditionally, engine test cells are a cost center. The money spent running the engine during testing is money lost. But what if you could use this excess energy to make money by connecting the engine shaft to an electrical generator whose power can then be used in-house or sold to utilities? At the very least, you could recover some of the money spent on fuel. At best, you might even turn a profit.
That’s exactly the concept being promoted by Atec, Inc. maker of the Phoenix Series modular test facility. The Phoenix is a factory-built engine testing facility installed inside a 40’ x 12’ x 12’ modular box that can be hauled to a testing site, used, and then moved as needed.
The idea of using excess engine power to generate electricity came up during a brainstorming session, said Atec senior development engineer Arnie Gunderson. Rather than just letting the engine shaft spin during testing, "We asked, ‘what if there were a way to capture the energy and use it?’" he told Rotor & Wing. It was then that Atec’s engineers realized that, by connecting the shaft to an electrical generator, the engine under test could be used to create power. Since power companies gladly pay for extra electricity during peak periods, "They will give you very favorable rates on how fast your meter spins backwards," Gunderson said.
Because helicopter engine shafts spin at very high speeds, the process of generating electricity requires a few steps to make it happen. Specifically, the AC generated by a helicopter engine is converted into DC, and then brought to the 120V AC standard using an inverter, "The kind you see on a camper trailer with solar panels," Gunderson said. As for power output, most of the energy generated by an engine like a Rolls-Royce A250 will make its way into electricity, he noted. Some will be lost to the inefficiencies inherent in any generator system, "but the vast majority will end up being fed back to the grid."