Other Turbo-Green Machinery
Nuclear power plants. Considering that nuclear fuel releases a million times (projected up to 50 million times) more energy per unit than fossil fuels, with zero harmful emissions, this alternative energy technology is gaining renewed interest for refinement — but not for application in the U.S. If nuclear generating capabilities are to be expanded in the U.S., what you can expect for future plants (and their turbomachinery systems) is one standardized design to dramatically confine costs. Variations to accommodate some variables will be developed and supplied by capable vendors.
Fuel cells. Although extraordinary electrical efficiencies have resulted from fuel cell and turbine-compressor combinedcycle, closed-loop systems, turbomachinery development is currently focused on future hydrogen supply-line compressors for fuel cells. Reciprocating compressors currently in use rely on lubricants that can seep into cylinders and contaminate the hydrogen. A centrifugal compressor avoids such contamination and allows higher compression efficiency for an equivalent duty.
A large-scale centrifugal compressor now being designed for hydrogen pipeline transmission is expected to service a future demand to be created by the adoption of practical fuel cell power plants and cars. The 8,000-hp, six-stage compressor will move 240,000 kg of hydrogen a day at pressures up to 1,200 psi, and be considerably smaller (1/4 the size) and more efficient than compressors currently in use on hydrogen pipelines.
Energy storage. The rapidly advancing development and acceptance of green energy technologies for both distributed generation and to supply the smart grid, demand that renewable energy be paired with energy storage. With the exception of battery systems, all other storage methods depend on the efficiency of various turbomachines for pumping fluids and compressing gases.
Of recent interest is a new generation of flywheels using multi-ton carbonfiber rotors spinning on magnetic bearings in a vacuum. Each flywheel is expected to store up to several megawatts of backup power for buffering power fluctuations from intermittent energy sources (wind and solar) or to stabilize power for changing loads. In one system, a motor powered by green energy accelerates a flywheel to terminal speed, then the rotor maintains its inertial energy “indefinitely” until released by reversing the process and using the motor as a generator.
The success of a highly effective and sustainable turbo-green machine operating over a wide range of conditions can often depend on advances and breakthroughs in turbomachinery design and manufacturing facilitated by highly specialized CAE and CAM software systems. To meet optimum performance goals, many turbo-green impeller designs will utilize thin, highly sculpted, and closely spaced blade shapes. But to be cost-competitive with fossil-fueled power generation, these elegant solutions must be complemented with sophisticated toolpath programs for accurate and economical 5-axis milling.
This article was contributed by Concepts NREC, White River Junction, VT. For more information, visit http://info.hotims.com/45603-121.