Alternate thermoelectric power generation thermodynamic cycles with improved efficiencies
L. E. Bell
BSST, LLC, Irwindale, CA 91706, USA
Solid-state thermoelectric power generation has not seen broad application because either the efficiency has been too low to justify the expense of such systems, or competing technologies have been available that offer better efficiencies. Alternate thermodynamic cycles compatible with thermoelectric systems offer the promise of substantially higher efficiency. Further, the configurations of such systems exhibit high power densities as an attendant benefit. The cycles offer significant efficiency improvement for power extraction from hot fluid streams, such as are associated with automotive exhaust, catalytic combustors, and co-cycle power generators.
It is shown that in addition to intrinsic efficiency gain, performance of certain cycles can be further enhanced to optimize power conversion over temperature ranges for which the material figure of merit of available thermoelectric materials are highest. These techniques are shown to be especially useful to maximize conversion efficiency by using optimally the recently announced high performance super lattice materials that are restricted by their material properties to operate at relatively low temperatures. Several important operational cycles, co-generation cycles and cycles using segmented legs are analyzed. Efficiencies, power densities and other pertinent results are compared.