A recirculating thermoelectric generator based on sodium β″ alumina

Abstract

A convectively cooled, recirculating thermoelectric generator based on β″ alumina has been designed and operated over the temperature range of 400–600 °C. The design employs a stainless-steel wick and flame sprayed molybdenum electrodes and the unit can be assembled and operated with ease. A full treatment of all thermal and electrical flows is given and theoretical efficiencies of 10%–15% are predicted. Critical parameters are the internal resistance and radiation coefficients for thermal losses, while it is also shown that the flow of sodium within the electrode and the geometry of the evaporating and condensing surfaces is of importance in limiting the measured efficiency to 1%–3%. Units have been operated for up to 3000 h.

Poling of soft piezoceramic PZT

“…Although the poling of piezoceramics after manufacturing is a crucial process and the effect of poling conditions on the piezoelectric properties has been studied by many authors, [5][6][7][8][9] there is not yet a solid model or theory that governs the poling mechanism for a wide spectrum of piezoelectric materials. In the present paper, we give preliminary results for studying the effect…”

Summer Research Program - 1998 Summer Faculty Research Program. Volume 3, Phillips Laboratory

“…The efficiency of this final conversion is governed by variety of irreversible kinetic and transport processes occurring at the electrode interfaces, within the BASE material, internal impedance, and thermal conduction and radiation losses [12][13][14]. A number of efforts are underway to develop practical and high efficiency cells [18,[40][41][42][43][44][45]. AMPS, in collaboration with AFRL, has been manufacturing and testing for improving efficiency of PX series of AMTEC cells [26][27][28][29][30].…”