Tomoaki Inoue

Development of an Advanced Microturbine System Using Humid Air Turbine Cycle

A prototype machine for a next generation microturbine system applying a simple humid air turbine system (design target of electrical output: 150 kW, electrical efficiency: 35% LHV) was developed for its laboratory evaluation. A low NOx combustor which applied a lean-lean zone combustion concept and water lubricated bearings were developed for the prototype machine. Operation using two water lines for the humid air turbine (HAT) was proposed as an effective way to obtain rated electric output to ambient temperature of 40 deg C. Tests for the main components were done successfully. Motoring tests, full speed test with no load, 50% load and 70% load tests as preliminary tests for rated load tests were also carried out successfully. Low NOx emission of 7.6 ppm and high efficiency of 95.6% for the power conversion system were achieved in the partial load tests. At the first rated load test without HAT and Water atomizing inlet air cooling (WAC) that followed those partial load tests, 150.3 kW electric output with electrical efficiency of 32% was obtained.© 2004 ASME

An Advanced Microturbine System with Water-Lubricated Bearings

A prototype of the next-generation, high-performance microturbine system was developed for laboratory evaluation. Its unique feature is its utilization of water. Water is the lubricant for the bearings in this first reported application of water-lubricated bearings in gas turbines. Bearing losses and limitations under usage conditions were found from component tests done on the bearings and load tests done on the prototype microturbine. The rotor system using the water-lubricated bearings achieved stable rotating conditions at a rated rotational speed of 51,000 rpm. An electrical output of 135 kW with an efficiency of more than 33% was obtained. Water was also utilized to improve electrical output and efficiency through water atomizing inlet air cooling (WAC) and a humid air turbine (HAT). The operation test results for the WAC and HAT revealed the WAC and HAT operations had significant effects on both electrical output and electrical efficiency.

Development of a 150kw Microturbine System Which Applies the Humid Air Turbine Cycle

A prototype machine for a next generation microturbine system incorporating a simplified humid air turbine cycle has been developed for laboratory evaluation. Design targets of electrical output were 150 kW and of electrical efficiency, 35% LHV. The main feature of this microturbine system was utilization of water for improved electrical output, as lubricant for bearings and as coolant for the cooling system of the generator and the power conversion system Design specifications without WAC (Water Atomizing inlet air Cooling) and HAT (Humid Air Turbine) were rated output of 129 kW and efficiency of 32.5% LHV. Performance tests without WAC and HAT were done successfully. Electrical output of 135 kW with an efficiency of more than 33% was obtained in the rated load test. Operation tests for WAC and HAT were carried out under the partial load condition as preliminary tests. Water flow rates of WAC were about 0.43 weight % of inlet air flow rate of the compressor and of HAT, about 2.0 weight %. Effects of WAC and HAT were promptly reflected on electrical output power. Electrical outputs were increased 6 kW by WAC and 11kW by HAT, and efficiencies were increased 1.0 pt % by WAC and 2.0 pt % by HAT. Results of WAC and HAT performance tests showed significant effects on the electrical efficiency with an increase of 3.0 point % and electrical output with an increase of 20% by supplying just 2.4 weight % water as the inlet air flow rate of the compressor.Copyright