James S. Nash

Micro, Industrial, and Advanced Gas Turbines Employing Recuperators

Recuperators increase system efficiencies in gas turbine engines by recovering exhaust heat to the compressor discharge stream. In this study, the performance and economics of recuperation are evaluated and presented for a practical range of effectiveness with typical pressure-loss-fractions. The strong correlation between recuperator cost and engine specific-power is shown, using a recuperator designed and manufactured at a highly automated facility by Ingersoll-Rand. This commercially available recuperator is also described, with specific emphasis on features contributing to its exceptional durability.Copyright

Preliminary Design and Projected Performance for Intercooled-Recuperated Microturbine

The Inter-Cooled-Recuperated (ICR) cycle is recognized for its high efficiency potential in gas-turbine applications. This paper reports on a proposed implementation of the ICR cycle in a microturbine setting, using a three-spool configuration incorporating a variable-geometry nozzle on the low-pressure ‘free’ power turbine. Hardware specified for the high-pressure turbine is an existing ceramic rotor fabricated and spin-tested in connection with a prior DOE-sponsored program. Rated engine design-point power and efficiency are projected at 378kWe and 39.5% (net LHV), under realistic prescriptions for component efficiencies and parasitic losses, and with TIT = 1366K (2000°F) specified for the ceramic rotor. Detailed off-design performance projections are carried out, demonstrating exceptional range and part-load efficiency. A key attraction of the ICR compared to a non-intercooled recuperated cycle is its compatibility with high cycle pressure ratio, making for dramatic size and cost reductions for high-pressure components, most importantly the recuperator. A related advantage is reduced ceramic-turbine rotor diameter for a given power level, extending the applicability of ceramic components under conservative manufacturability limits. Engine layout and preliminary mechanical designs for the major subassemblies are developed for application to a forty-foot transport bus with hybrid-electric drive. Further applications under evaluation for the proposed microturbine are stationary power generation, and in a hybrid powerplant setting using a solid-oxide fuel cell.© 2008 ASME

High-Efficiency Low-Cost Solar Receiver for Use Ina a Supercritical CO2 Recompression Cycle

• Numerical Modeling is used to capture the highly nonlinear physical properties of S-CO2 within the highly-effective enhanced heat transfer. region, where fluid temperature is changing rapidly • Manufacturing Trials are used to demonstrate reliable methods for fabricating the enhanced heat transfer surfaces that will reside within the high-flux environment of the receiver • Historical Data from a baseline installation location will be used to provide a year-long solar profile which feeds into the overall performance model to produce an annualized performance metric • Subcomponents will undergo simulated operating conditions in test rigs to demonstrate their suitability and performance • Ultimately a prototype receiver will be tested on sun in a power-tower application to demonstrate the full receiver system performance