Hi-Z Technology, Inc.

Technical Papers prior to 1999

Preliminary Development of a Milliwatt Generator for Space

John C. Bass, Hi-Z Technology, Inc.

Presented at the XVII International Conference on Thermoelectrics, May 1998, Nagoya, Japan

Abstract:
This paper presents the results of a Phase I STTR program to develop a small thermoelectric generator for use in space. The generator is designed to use the existing 1 watt radioisotope heater unit (RHU) which is currently used to keep instruments warm in space. The design and manufacture of the monolithic thermal conversion unit (TCU) is discussed as is a conceptual design of a generator which uses both the RHU and the small TCU to produce 40 mW of power at 5 volts D.C.

Full-text article available for download. (PDF)

Examples of Power From Waste Heat for Gas Fields

John C. Bass, Hi-Z Technology, Inc., San Diego, CA
Robert L. Farley, Power Sources, Inc., Farmington, NM

Abstract:
This paper describes the design of three unique thermoelectric generators developed to supply electric power in natural gas fields. The unique feature of these generators is that they do not contain their own heat source but all convert the waste heat produced by equipment already used in the gas field as the thermal power source for the generators.

The first generator described uses the difference in temperature between the hot and cold legs of the glycol natural gas dehydrator cycle to produce power for cathodic protection of the well. The second system uses waste heat from the pilot light of the gas dehydrator boiler to produce power for electronic instruments. The third system used waste heat from the gas dehydrator boiler stack to provide power for instruments, communications, and other uses around the well site.

The description of these generators includes both photographs of the prototype units and performance curves from each of the generators. Each generator has unique features and advantages which are discussed in the paper.

Full-text article available for download. (PDF)

A Stove-Top Generator for Cold Areas

Anders Killander, Royal Institute of Technology, Stockholm, Sweden
John C. Bass, Hi-Z Technology, Inc., San Diego, California

Abstract:
This paper discusses the development and test of a prototype thermoelectric generator which is designed to use the heat of existing wood fired stoves that are typically used in the area for home heating. This generator is being developed by the Royal Institute of Technology, in Sweden, to provide small amounts of power to homes in the remote northern areas of the country which are beyond the electric grid. The paper will discuss some of the aspects of the generator design, as well as the early results obtained and some of the lessons learned from the first home test site in Skerfa, Sweden, which is located near the Arctic Circle. The bismuth-telluride thermoelectric modules used in the generator are also discussed.

Full-text article available for download. (PDF)

Performance of the 1 kW Thermoelectric Generator for Diesel Engines

J. C. Bass, N. B. Elsner and F. A. Leavitt

Abstract:
Hi-Z Technology, Inc. (Hi-Z) has been developing a 1 kW thermoelectric generator for class eight Diesel truck engines under U.S. Department of Energy and California Energy Commission funding since 1992. The purpose of this generator is to replace the currently used shaft-driven alternator by converting part of the waste heat in the engine’s exhaust directly to electricity. The preliminary design of this generator was reported at the 1992 meeting of the XI- ICT in Arlington, Texas. This paper will report on the final mechanical, thermal and thermoelectric design of this generator.

The generator uses seventy-two of Hi-Z’s 13 Watt bismuth- telluride thermoelectric modules for energy conversion. The number of modules and their arrangement has remained constant through the program.

The 1 kW generator was tested on several engines during the development process. Many of the design features were changed during this development as more information was obtained. We have only recently reached our design goal of 1 kW output. The output parameters of the generator are reported.

Full-text article available for download. (PDF)