Hi-Z Technology, Inc.

Technical Papers from 2004

Milliwatt Modules and Generators: Design, Fabrication, and Life Testing

N. Elsner, J. Bass, N. Hiller and S. Ghamaty

Abstract
Milliwatt modules for space applications are being fabricated and life tested for long life NASA applications that use Pu 238 as the heat source. Module testing using series circuit and redundant circuitry is in progress while generator testing using vacuum baked out multifoil insulation is just being initiated. Also, a milliwatt generator design, using multilayer quantum well materials, that offer a large gain in efficiency, will be presented.

Full-text article available for download. (PDF)

New Technology for Thermoelectric Cooling

John C. Bass, Daniel T. Allen, Saeid Ghamaty, and Norbert B. Elsner

Abstract
Thermoelectric coolers in use today have a coefficient of performance (COP) of only about 0.5. This compares to COPs of larger scale machines, such as air conditioners and refrigerators at levels of 3.0 to 5.0. For electronic component cooling there is a new thermoelectric technology emerging for improved efficiency. This paper discusses this new technology which is multi-layer quantum well (MLQW) thermoelectrics, that should increase by four or five times the COP of present thermoelectric coolers used in electronic cooling applications. It also details and updates the experimental work in MLQW thermoelectric materials and will detail the supporting analysis of the predicted higher performance cooling. A specific example of an electronic cooling module configuration is presented.

Full-text article available for download. (PDF)

Fabrication and Testing of Thermoelectric Modules and Milliwatt Power Supplies

Daniel T. Allen, Nathan D. Hiller, John C. Bass and Norbert B. Elsner

Abstract
This paper reports the recent progress at Hi-Z technology, Inc., following from earlier work in development of milliwatt radioisotope power supplies for space applications. Several generator units have been built and tested. From the results of these tests, from ongoing design and analysis and from continued communication with DOE and with potential users of these generators at NASA, there have been suggested revisions and improvements. In this paper we discuss the most recent testing of power conversion modules and of units representing a Flight System MRPS design, and we describe two improved generator designs and their features.

Full-text article available for download. (PDF)