The Freepiston Stirling Engine

Free Piston Stirling Generator

As in the case of kinematic Stirling engines, there are numerous implementations of the free-piston version. Much of the development of this type of engine is owed to Sunpower Inc. of Athens, Ohio. Figure 3.16 shows a simple form of the engine dating from 1986. There is no rigid mechanical connection between piston and displacer. Both fit snugly in the cylinder with no intentional leakage. The motion of the displacer must lead that of the piston by more than 0 and less than 360 . The power...

Characteristics of Fuel Cells

Polarization Curve Fuel Cell

Reversible fuel cells will deliver to a load a voltage, VL Vrev, which is independent of the current generated. Their V-I characteristic is a horizontal line. Such ideal cells require reaction kinetics fast enough to supply electrons at the rate demanded by the current drawn. Clearly, reversible cells cannot be realized. In practical fuel cells, two major deviations from the ideal are observed 1. The open-circuit voltage, Voc, is smaller than Vrev. 2. The load voltage, VL, decreases as the load...