The U.S. Army's Portable Power Program includes developing small turbine engines to operate in the 300 to 500 Watt range on approved military fuels. The program also envisages developing planar solid oxide fuel cells (SOFC), thermophotovoltaics (TPV) and alkali metal thermal to electric converters (AMTEC). These small units are intended to be carried by soldiers to replace larger, trailer-mounted diesel generator sets. These power sources are intended to also be used as distributed power generation and for co-generation to produce heating, hot water, or cooling, in addition to electricity. Distributed power offers the reliability of redundancy and partial load capability, which reduces signature and increases efficiency. Direct methanol oxidation fuel cells (DMFCs) are intended to provide an instantly rechargeable power source.

CEC is promoting a system based upon a sub-atmospheric Brayton cycle that operates between ambient pressure and a partial vacuum.  This is similar to a jet engine operating at high altitude.  By using this cycle, larger aerodynamic components are required for optimum performance that results in higher efficiency. In addition a simple gravity fuel system can be used.

Following the schematic, ambient air is first heated by a recuperator using turbine exhaust gas to approximately 972°F. The air is then heated to 1500°F in the combustor using fuel supplied by a gravity feed system.  The hot air is then expanded through the turbine to a pressure of approximately 5.14 psia providing the energy to the compressor and the generator.  The turbine discharge temperature is approximately 1133°F.  The turbine discharge gas is next sent through the recuperator where it is cooled to approximately 260 °F and then further cooled by the sink heat exchanger to near ambient temperature, 65 °F.  The cooled gas is then compressed back to slightly above ambient pressure and provides the energy necessary to suck the cooling air through the sink heat exchanger by means of an ejector.

The rotating assembly shown FULL SIZE includes the magnet shaft for the permanent magnet generator, the compressor impeller, turbine wheel, and bearings. The unit runs at approximately 300,000 RPM, weighs less than 10 lb and uses less than half a pound of fuel per hour for a power output of 500 watts.

This design is intended for front-line use to recharge the soldiers' batteries and can easily be carried by a single soldier with a day's worth of fuel .

These characteristics fall within the range of current U.S. Army requirements for future mobile force portable power systems and is consistent with the Department of Defense Portable Power Program which focuses on projects to produce electric power for soldiers or small groups of soldiers.

Given the impact of the war on terror which created stronger emphasis on smaller, well trained, highly mobile fighting units, each fully equipped with intelligence, communications and command devices there is a realistic expectation for increasing demand of easily carried battery chargers as described. CEC is pursuing the evaluation, development and adoption of its system with the Defense Advanced Research Projects Agency (DARPA) and the U.S. Army.