Research Project Information

Research Project Summary Information

Oil Free air foil bearings: 200 kW Solar/Hybrid Fuel Turbine Power Generation System(ST9163-1)

Mohawk Innovative Technology, Inc.


New York State relies heavily on foreign petroleum products for energy production. The June 2002 State Energy Plan calls for increasing energy resource diversity in electricity generation by improving energy efficiency and demand management, and by increasing the use of indigenous renewable energy resources. Greater energy diversity will improve energy security by reducing the risk of supply disruption and the imported fuel price volatility. A balanced portfolio of energy resources will also provide greater economic development opportunities within the State. The RPS represents a commitment to integrate renewable energy production into the utility energy mix.

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Project Description

Arizona Public Service (APS) is developing and demonstrating a new and novel distributed generation (DG) system that combines renewable energy from biomass, solar, and/or wind with compressed air energy storage to provide economical load-following and peak-shifting capability. The APS system uses a Solar-Compressed Air Turbine (Solar-CAT) to convert renewable energy to electricity. Brayton Energy, LLC is the developer of the Solar-Cat turbo-alternator that operates at efficiencies up to 42% at 100,000 to 128,000 rpm. Given the size and operating speed of the rotor, and combined with the need for a 40,000 hour service life, Mohawk Innovative Technology, Inc.’s (MITI’s) compliant air foil bearings appear to be leading candidates for this service. A Solar-Cat based energy cycle can use the indigenous, renewable biomass, solar, and/or wind resources of NYS in accordance with the RPS to generate dispatchable electric power and reduce the need for imported energy sources.


The Solar-Cat DG system can use renewable energy sources available in NYS to generate dispatchable electric power, thereby reducing fossil fuel imports and the emissions from burning these fuels in generating plants. The power cycle can shift load from on-peak to off-peak periods. MITI will have the opportunity to become the compliant air foil bearing supplier to Brayton Energy, increase product sales revenue, and provide new employment opportunities.

Project Results

One area for further testing and development was identified during this program. Precise determination of design thrust loads that must be reacted by the thrust foil bearing is very difficult. As such, the designer must include considerable safety margin in the sizing and design of thrust bearings. Still, when operating at rotor surface speeds at and above the transonic region, as is the case with this Solar-Compressed Air Turbine, it has been shown that load capacity decreases somewhat and local thrust pad heating increases. In order to ensure an adequate safety margin as well as a highly reliable and durable system, more detailed testing of the thrust foil bearings with improved thermal management schemes is needed. Preliminary testing of an alternate thrust bearing design under this effort demonstrated that a reduction in foil localized temperatures is possible, even at tip speeds above 1500 ft/sec.


Mohawk Innovative Technology, Inc.
1037 Watervliet Shaker Rd
Albany, NY 12205

Principle Investigator

James Walton

Universities Involved


Project Type:

Product Development

Technologies Types:

Industrial Products
Waste Heat

NYSERDA Contact Information

James Foster


R&D -Transport & Power Systems

Contract Details

Start Date: 1/11/2010
Project Status: Active
Contract Number: ST9163-1

Last Updated: 12/16/2013