Thermoelectrics Revisited

There is a tantalizing hope that someday someone will come up with a real breakthrough in direct heat-to-electricity conversion. No moving parts, “solid-state”, self-contained, scalable, and so on. Such miracles do exist, but they are costly and inefficient, and can find use only in specialized niche applications like satellite power, IC chip cooling, novelty items like picnic coolers, and most recently as comfort conditioning in automobiles.

The sought-after breakthrough would be in performance and cost, for example, to “make the internal combustion engine obsolete” and do many other marvelous things. As one example, cold climate utilities have attempted unsuccessfully to use thermoelectic generation to develop self-powered home heating systems which could continue to operate during power outages.

The fundamental underlying processes have been known for a long time, e.g., Thermoelectric (TE) (Seebeck, Peltier), Thermionic, ThermoPhotoVoltaic, etc. NASA, for one, has spent decades fine tuning these for use in space, and a hardy band of scientific, engineering and business people continue the quest. Some companies actually earn a decent living at making and selling such devices, but it is strictly a matter of small niches. Note that TE can be used reversibly to either provide cooling (heat pump) or generate electricity (heat engine).

There are some interesting stirrings of late. For a number of years, researchers at MIT and elsewhere have focused on nanostructures which create one and two dimensional worlds for electrons (known as “quantum wells”), which theoretically should yield higher efficiencies. Experimental results are slow in coming. Last October, the Research Triangle Institute published a major paper in Nature claiming dramatic improvements (in the lab) in TE performance, based on nanolayers of traditional TE materials. Most research in the field has focused on trying to find new bulk materials that have better properties, so this layering approach caught people by surprise. Prior claims to boost “ZT” (the figure of merit for TE) much above 0.7 – 1 haven’t held up, but RTI seems really to have a ZT of 2.4. Such a doubling or tripling of “ZT” could hugely expand the range of applications for both cooling and power — assuming of course that the cost is low enough.

RTI is putting on a conference Oct 28-30 in Dallas:
“Next Generation Thermal Management Materials and Systems – for Cooling and Power Conversion”
Full agenda at:

* The latest advances in thermal management materials and systems, and how recent developments can spur commercialization.
* Market trends and opportunities for new thermal management technologies in cooling and power conversion – in wide ranging applications – from micro electronics to refrigeration.
* The status of commercial applications – impact on enabling new markets and displacing current markets.

One of the speakers has recently given a paper at a recent TE conference*. (I have the papers if anyone is interested.) A clever way** of arranging an array of TE modules more than doubles the overall system efficiency for cooling. A commercial product using this technique already is in use, cooling seats of luxury cars. (

(The TE conference* was the ICT2002, held August 26-29, Long Beach, CA. This is an annual meeting of the worldwide thermoelectric R&D community. For a brief account of the conference, see the Sept 30 “ZTSpam” at Cronin Vining’s website:
Cronin is a renowned expert in TE, and a good friend and colleague of UFTO.)

Besides TE, thermionic and TPV continue to get attention. (In thermionic conversion, electrons boil off a heated surface and are collected on another electrode. In TPV, the heated surface sends out photons of a particular variety which go to a specialized PV cell. It’s PV with its own built-in custom light source, which is heat-driven.) Some of the most promising new developments use nanoscale approaches to overcome traditional obstacles to cost and performance. The “Nano-TPV” work is being done at Draper Laboratory, and involves reducing the spacing between the heated emitter and PV receiver to nanoscale dimensions. Experiments confirm a dramatic increase in the photo current. In another development, Eneco in Salt Lake City continues to make progress on its nanoscale method which they say combines thermionic and TE effects. (See UFTO Note 28 Nov 2001.)

** As explained in the papers, the configuration involves (as I describe it) a counterflow heat exchanger where a number of parallel heat pumps push heat from the cold side to the hot side. Each heat pump sees a temperature difference that is only half of the “delta-T” that the overall system provides, leading to higher overall efficiency. Whether this would be practical in a larger system using compressors is hard to say.

Ice Mitigation

— New NASA-developed Anti-Icing Fluids
— Ice-Storm Mitigation Workshop

As we cool down from one of the hottest summers in several years, utilities in the north must look forward to another winter. Back in January, a note appeared in a NASA publication about a new anti-icing fluid that was developed at the NASA Ames Research Center. Midwest Industrial Supply was named as the licensee, so I contacted the company.

Midwest markets a series of glycol-based products which adhere to vertical surfaces and are more resistant to wind, snow and rain dissipation. Less of it falls on the ground and fewer reapplications are needed, so smaller quantities suffice. They call their latest formulation “zero gravity”.

(Note: “anti-ice” isn’t the same as “de-ice”. Anti-ice sets up a barrier to prevent ice formation in the first place, whereas de-ice attempts to remove ice that’s already formed, and usually requires a lot more material be used.)

Midwest’s extensive product line is getting a good reception in mass-transit (especially 3rd rails). The company also markets anti-freezing and dust control products used widely in managing coal piles and conveyors (including at least 3 UFTO utilities)– “Ice Free Conveyor” & “Freeze Free”. (These sales are generally at the plant level- -it isn’t clear if utilities are taking a corporate approach to these purchases.)

Railroads use Midwest’s “Ice Free Switch” product, which could apply just as well to utility switches. Likewise, public transit railroads need help keeping ice off overhead lines, and Midwest is working to add a product for powerlines and towers.

Contact Mr. Shannon Noble, 800-321-0699

Midwest will be participating in the upcoming “Workshop on Ice Storm Mitigation”, sponsored by the Canadian Electrical Assocation Technologies (CEATI), Oct 6,7, Monteal
Contact Ms. Laurie Lang, 514 866-5377,

The workshop will cover the following topics:
– Preparation for Extraordinary Climatic Events
– Lessons to be drawn from recent major system outages
around the world due to catastrophic ice storms;
– De-icing techniques before, during and following ice storms;
– Curent Developments in de-icing techniques;
– Cost effectiveness of load control devices;
– Improvements in design approaches and comparison of
international standards;
– Ice modelling: comparison between the Canadian and
American approaches;
– Ice storm crisis management: Emergency restoration plan
and mutual assistance agreement.

The workshop is part of an ongoing program at CEATI called the Ice Storm Mitigation Interest Group.
Contact: Ray Del Bianco, 514-866-5355,


Argonne Visit notes

This is a quick highlights memo about the UFTO visit to Argonne, July 15, 16. A full report will be forthcoming early this Fall.

For the first time, a sizable contingent of UFTO member companies was present for the whole visit. I hope this can become our standard practice, with even a bigger attendance. Argonne made excellent presentations for us. We all agreed that it was a good *beginning* of what must become an ongoing dialogue.

If you want a headstart on some of Argonne’s work, here are a few things we heard about that really piqued the group’s interest:

Comprehensive GIS with massive data on gas system. See separate NOTE, or go to this webpage:
**User Access is available on request, on a collegial basis.** The limitation is server capacity, so ANL is not in a position to throw it wide open. They are also very open to any companies that want to provide better data on their own gas T&D systems–which can be kept confidential.
Contact Ron Fisher, 630-252-3508,

— Ice Slurry District Cooling
UFTO reported on this back in 93/94. It is now privately funded, and has advanced considerably. Ice slush dramatically increases the capacity of new or retrofitted central cooling distribution systems.
Contact Ken Kasza, 630-252-5224,

— On-Line Plant Transient Diagnostic
Uses thermal-hydraulic first principles, along with generic equipment data, in a two-level knowledge system. Neural net models of the system can rapidly indicate what’s causing a transient, e.g. water loss, heat added, etc., and identify where in the system the problem lies. The system wouldn’t need to be custom built for each plant, except to incorporate the plant’s schematics. It’s been run in blind tests at a nuclear plant. Next step is to hook it up to a full scale simulator, and then go for NRC approval. A fossil application would be much easier.
Contact Tom Wei, 630-252-4688,
or Jaques Reifman 630-252-4685,

— Advanced NOx Control with Gas Co-firing
Closed-loop controller adjusts furnace control variables to get optimal distribution of gas injection to yield greatest NOx reduction. Typical systems use gas at 20% of heat input, but this system gets same or better NOx levels with only 7%. Joint effort with ComEd, GRI, and Energy Systems Assoc.
Contact Jaques Reifman 630-252-4685,
or Tom Wei, 630-252-4688,

Sensor monitor and fault detection system knows if the system is misbehaving or the sensor is wrong. Can see slow drift, signal dropout, and noise, giving early indicators of sensor failure, and providing assurance that the process itself is operating normally, thus reducing unneeded shutdowns. It also can monitor the process itself, for wide ranging quality control applications. MSET stands for Multivariate State Estimation Technique. A model learns expected relationships among dozens or hundreds of sensor inputs, and makes predictions for what each sensor should say, and this is compared with the actual sensor signal. Argonne has patented a unique statistical test for residual error (the difference) which replaces the usual setting of fixed limit levels. There are also important innovations in the neural net modeling, which is completely non-parametric.

Applications range from the NASA shuttle engine, to several power plants, to the stock market.
ANL contacts are Ralph Singer, 630-252-4500,
Kenny Gross 630-252-6689,

A spin off company is doing applications in everything else but electric generation. (Think of the possibilities in T&D!!) They call the product ProSSense. Website is at http//
Contact Alan Wilks, Smart Signal Corp, Mt. Prospect IL 847-758-8418,


Here is the text of ANL’s overview “Topic Capability Sheet”. Many of you got hardcopies of the complete set in the mail. They’re still available from Tom Wolsko ( I’ve also posted them on the UFTO website, until Argonne puts a final verion up on their own website.

Argonne National Laboratory:
A Science and Technology Partner for the Energy Industry

Argonne is a multidisciplinary science and technology organization that
offers innovative and cost-effective solutions to the energy industry.

— Introduction
Argonne National Laboratory understands that energy companies must meet growing customer demand by creating, storing, and distributing energy and using the most efficient, cost-effective, environmentally benign technologies available to provide those services. We also understand that they must use increasingly more complex information for decision-making, comply with a multitude of environmental regulations, and adjust to a rapidly evolving marketplace.

Argonne has more than 50 years of experience in solving energy problems and addressing related issues, for both its customers and its own needs. Combining specialities such as materials science, advanced computing, power engineering, and environmental science, Argonne researchers apply cutting-edge science and advanced technologies to create innovative solutions to complex problems.

— Argonne Solutions
Recent applications of that expertise include
– A Spot Market Network model that simulates and evaluates short-term energy transactions.
– A “fuel reformer” that allows fuel cells to use a wide variety of hydrocarbon fuels to make electricity.
– Advisory systems for plant diagnostics and management based on sensors, neural networks, and expert systems.
– MSET, a real-time sensor validation system that provides early warning of sensor malfunction.
– Decontamination and decommissioning techniques developed for Argonne’s own facilities.
– Advanced materials for system components, batteries, ultracapacitors, flywheels, and hazardous waste encapsulation.

— Contacts
Argonne’s Working Group on Utilities:
– Dick Weeks, 630-252-9710,
– Tom Wolsko, 630-252-3733,

For technical information, contact the person listed under the category of interest.

Nuclear Technology
David Weber, 630/252-8175,
– Operations and Maintenance
– Materials
– Reactor Analysis
– Safety
– Spent-Fuel Disposition

Fossil Technology
David Schmalzer, 630/252-7723,
– Basic and Applied Research
– Technology Research and Development
– Market, Resource, and Policy Assessments

Transmission and Distribution
John Hull, 630/252-8580,
– System Components
– Energy Storage
– Distributed Generation
– Data Gathering and Analysis
– Biological Effects

Energy Systems and Components Research
Richard Valentin, 630/252-4483,
– Component Reliability
– Sensors
– Systems Analysis

Materials Science and Technology
Roger Poeppel, 630/252-5118,
– Materials Characterization
– Modeling and Performance
– Advanced and Environmental Materials
– Materials Properties
– Superconductivity

Fuel Cell Research and Development
Walter Podolski, 630/252-7558,
– Fuel Processing
– System Design, Modeling, and Analysis
– Testing
– Energy-Use Pattern Analysis

Advanced Concepts in Energy Storage
K. Michael Myles, 630/252-4329,
– Secondary Batteries
– Ultracapacitors and High-Power Energy Storage
– Flywheels
– Superconducting Magnets

Information Technology
Craig Swietlik, 630/252-8912,
– Computer Security and Protection
– Independent Verification and Validation
– Information Management
– Advanced Computing Technologies

Environmental Science and Technology
Don Johnson, 630/252-3392,
– Environmental Characterization
– Process Modifications
– Emissions Controls
– Waste Management
– Site Management

Environmental and Economic Analysis
Jerry Gillette, 630/252-7475,
– Electric System Modeling and Analysis
– Risk Assessment and Management
– Environmental Assessment
– Cost and Economic Analysis
– Legal and Regulatory Analysis

Decontamination and Decommissioning
Tom Yule, 630/252-6740,
– Operations
– Technology
– Technical Analysis

End-Use Technologies
William Schertz, 630/252-6230,
– Plasma Processes
– Ultrasonic Processing
– Electrodialysis Separation Processes
– Recycling Technologies
– Aluminum and Magnesium Production

Thermal Energy Utilization Technologies
Kenneth Kasza, 630/252-5224,
– Compact Heat Exchangers
– Ice Slurry District Cooling
– Advanced Thermal Fluids

For information on working with Argonne, contact Paul Eichamer, Industrial Technology Development Center, Argonne National Laboratory, Bldg. 201, 9700 South Cass Avenue, Argonne, Illinois 60439; phone: 800/627-2596; fax: 630/252-5230,

National Combustor Code (NCC)–new software from NASA

Based on contacts made during the UFTO visit last year to NASA Lewis, we received an early notice about this soon-to-be announced Technology Opportunity. NASA has developed a major new combustion modeling code, and is looking for new areas that it can be applied. Private companies can submit problems. Terms and scope of an agreement would then be negotiated, giving the company a one year head start in evaluating the merits of seeking a commercial license.

(I have a full color acrobat pdf file of the notice that I can send you on request.)

April 15, 1998


It was a pleasure speaking with you today and thank you for agreeing to send your utility clients a copy of the attached NASA Technology Opportunity sheet which describes the National Combustion Code (NCC).

Please have interested clients contact me prior to contacting Nan-Suey Liu (NASA Lewis Combustion Branch ph: 216-433-8722). Nan-Suey is the NASA Lewis contact who will discuss technical features of the NCC with interested parties.

Please give me a call if you have any questions and thank you for your cooperation!

Dan DeMiglio
Great Lakes Industrial Technology Center
(Div of Battelle Memorial Institute)
NASA Midwest Regional Technology Transfer Center

—- text of the notice ———————————
Technology Opportunity National Aeronautics and Space Administration

Lewis Research Center Turbomachinery TOP3-00093

A new software program – the National Combustor Code (NCC) – has been developed for aerospace and non-aerospace engineers and designers to enhance their understanding of physical and chemical processes which occur during continuous combustion. The NCC provides insight – for the first time – to the entire combustion process using a versatile and comprehensive set of tools. The National Aeronautics and Space Administration (NASA) seeks to transfer this multidisciplinary combustor design system to U.S. companies for advanced liquid and gaseous continuous combustion applications. The NCC utilizes computer-aided design (CAD) tools for geometry creation, advanced mesh generators for creating solid model representations, a common framework for fluid flow and structural analyses, and powerful tools for post and parallel processing. The National Combustion Code: A Multidisciplinary Combustor Design System

Potential Commercial Uses

• Evaluate the performance of current liquid and gas combustion systems leading to product improvement.

• Optimize the design of future liquid and gas combustion systems leading to increased performance and reliability.

• Examples of relevant liquid and gas combustion systems are:
– Aviation gas turbine engines
– Industrial/ground power gas turbines
– Industrial combustion devices involving continuous burning of liquids and gaseous fuels
– Hazardous waste incinerators
– Steel treating furnaces
– Domestic gas fired appliances


• Product improvement for current combustion devices with respect to efficiency and durability
• Reduced time and costs for the design cycle of future combustion devices
• Optimized performance and reliability for future combustion devices

The Technology

The development of the National Combustion Code was pursued under a NASA/Department of Defense/ Department of Energy/U.S. industry partner-ship. Recent efforts have been focused on developing a computational combustion dynamics capability that meets combustor designer requirements for model accuracy and analysis turnaround time, incorporating both short–term and long–term technology goals. As a first step, a baseline solver for turbulent combustion flows was developed under a joint modeling and code development effort between the Aero-Industry and the NASA Lewis Research Center. This baseline solver is a Navier–Stokes flow solver based on an explicit four-stage Runge– Kutta scheme that uses unstructured meshes and runs on networked workstations. The solver can be linked to any computer-aided design system via the Patran file system. Turbulence closure is obtained via the standard k–e model with a high Reynolds number wall function. The following combustion models have been implemented into the code: finite– rate reduced kinetics for Jet–A and methane fuels, turbulence–chemistry interactions via an assumed probability density function for temperature fluctuations, and thermal emissions of nitrogen ox-ides. The solver can switch between a parallel virtual machine (PVM) interface and a message-passing interface (MPI) by using compiler flags. Its parallel performance on several platforms has been analyzed, and on the basis of the results, several improvements have been made. To date, the baseline solver has been used in the following applications: simulation of swirling flow experiments, computation of a generic swirling flow can combustor, computation of a multi-shear low NOx fuel nozzle and calculation of a multi-walled production fuel nozzle, and calculation of a flame holder/Cyclone 1-cup sector.

Options for Commercialization

The executables of the National Combustor Code, Beta Version 2.0, and the corresponding nonproprietary source code will be available for release to the non-aerospace industry by summer 1999. Beginning in the summer of 1998, NASA would be willing to demonstrate the accuracy and reliability of the NCC by applying it to a wide range of areas where it would be helpful to have accurate predictions of the combustor process.


Gynelle Steele, Technology Utilization Engineer
NASA Lewis Commercial Technology Office
NASA Lewis Research Center
Cleveland, OH 44135
Phone: (216) 433-8258 FAX: (216) 433-5012

Dan DeMiglio, Client Services
Great Lakes Industrial Technology Center
Phone: (440) 734-1209 (440) 734-0686

Technology Transfer Opportunities – Wright Laboratories



Final Report

Technology Transfer Opportunities in the Federal Laboratories

Wright Laboratories

U.S. Air Force

Dayton OH

February 1998

Prepared for:

Utility Federal Technology Opportunities (UFTO)


Edward Beardsworth


This report is part of a series examining technology opportunities at National Laboratories of possible interest to electric utilities


1. Summary
1 Overview & Organization
3. Technologies & Programs

This report is proprietary and confidential. It is for internal use by personnel of companies that are subscribers in the UFTO multi-client program. It is not to be otherwise copied or distributed except as authorized in writing.


This report details findings about technology and technology transfer opportunities at the Wright Laboratories that might be of strategic interest to electric utilities. It is based on a visit to the lab in June 1997 and subsequent contacts, as part of the UFTO multiclient project.


Noting the tremendous scope of research underway in the research facilities of the U.S. government, and a very strong impetus on the government’s part to foster commercial partnering with industry and applications of the technology it has developed, the UFTO program has been established as a multi-client study of the opportunities thus afforded energy utilities and their many subsidiaries.

Air Force Research Laboratory

In a major reorganization just put into effect in mid 1997, all the Air Force R&D activities were brought together into one single entity called the Air Force Research Laboratory.

From the AFRL website:


The mission of the Air Force Research Lab is to lead the discovery, development, and transition of affordable, integrated technologies for our air and space forces — to keep our Air Force "the best in the world." Our mission is executed by our nine technology directorates, located throughout the United States; the Air Force Office of Scientific Research; and our central staff. Our partners include universities and industry, with whom we invest almost 80% of our budget, and our customers include the Air Force major commands, who operate and maintain the full spectrum of Air Force weapon systems. We are a full-spectrum laboratory, responsible for planning and executing the Air Force’s entire science and technology budget: basic research , applied research, and advanced technology development. The work is done at facilities all across the country (Wright-Patt, Kirtland, Brooks, Edwards, Eglin, Tyndall, Bolling, Hanscom, Rome).

The AFRL is made up of more than 6400 government people, which includes over 1500 military and over 4800 civilian personnel. We have about 3500 scientists and engineers, of which over 800 have PhDs.


Budgets and staffing of research groups and facilities are relatively stable over time, as the Air Force regards its research capability as vital to the conduct of its overall mission, and takes a long view of its future technological needs.

• Technology Transfer

The Air Force, like all of DOD, has a strong commitment to Tech Transfer, and like DOE and other agencies,has a wide latititude of contracting mechansims and ways of working together with private industry and academia. One of the primary motivations for working with the commercial sector is to enhance the capabilities of private industry so as to lower costs to the Air Force of the high-value manufactured items they need.

The AFRL operates Tech Connect, the main point of contact for tech transfer for the entire Air Force. It provides search and contact services and facilitation.

In addition, each operating location (not just labs) have their local point of contact or ORTA (Office for Research and Technology Application).


Call – (937) 656-2530 Toll Free (800) 203-6451 FAX (937) 656-2138

Web site —

Wright Labs Overview

Wright Laboratories, located at Wright Patterson Air Force Base, Dayton OH, is oldest and largest of the Air Force research laboratories, with a history stretching back to 1917.

Wright Labs is headquarters for a number of Directorates (e.g. armament, avionics, flight dynamics, etc.).

Propulsion Directorate

One of these, the Propulsion Directorate, has the highest relevance for utilities.

The Propulsion Directorate’s work has many potential non-aerospace and commercial uses in:

– Materials and Materials Application
– Measurement and Sensing
– Modeling and Visualization
– Energy and Power

With an annual budget of about $150 Million, and about 300 mostly technical and scientific personnel, its technical divisions are:

Division – Office Symbol (Primary Site/Secondary Site)

– Power Division – AFRL/PRP (WP)
– Propulsion Sciences and Advanced Concepts Division – AFRL/PRS (Edwards/WP)
– Turbine Engine Division – AFRL/PRT (WP)
– Rocket Propulsion Division – AFRL/PRR (Edwards)
– Integration and Operations – AFRL/PRO (WPAFB/Edwards)

Principal Point of Contact: Kristen Schario, 937-255-2131,

Power Division

The Power Division plans, formulates, manages and executes research, exploratory and advanced development programs in energy conversion and storage, and power generation, transmission, conversion, and thermal management. This includes electrical, mechanical, thermal, and fluid power for aircraft, missile, terrestrial, and special Air Force applications.

Technologies & Programs

Covered in this report:

• More Electric Aircraft (MEA) 4
Power generation
Power systems and distribution components
Passive components – Capacitors
Power electronics/motor drives
• Ground Power 4
Remote Small Scale (10-120 watts)
Cryogenic Lightweight Deployable (1-4 MW)
• Turbine Compressor Research Facility 8
• Electronics Cooling
• Mechanical Testing of Electrical Machinery
• Silicon Carbide High Power Electronics
• Superconductors, Cryogenic Power Electronics
• Batteries 4
• Lubrication Technology 4

• More Electric Aircraft (MEA)

Contact: Maj. Michael Marciniak, 937-255-6226,

The Air Force has a major effort on the "More Electric Aircraft" (MEA), from which many "dual-use" applications arise. As with the more electric ship and tank, the PNGV hybrid/electric vehicle efforts share many common requirements and opportunities.

The goal of MEA is to replace hydraulic and pneumatic systems, which account for more than 1/2 of all downtime and failres of fighter aircraft, with electrical ones. A wide range of technologies are involved, including actuators, electronics cooling, motor/alternators, supercapacitors, batteries, power system controllers, and high power semiconductor devices.

The MEA will require a highly reliable, fault tolerant, autonomously controlled electrical power system to deliver high quality power to the aircraft’s loads. Also, reliable high power density motors and motor drives ranging from a few horsepower to hundreds of horsepower will be required

Military aircraft have numerous subsystems powered by one or more sources of secondary power: hydraulic, pneumatic, electrical and mechanical. Secondary power is typically extracted from the main engines mechanically by a driven shaft and pneumatically by bleeding the compressor. Mechanical power is distributed to a gearbox to drive lubrication pumps, fuel pumps, hydraulic pumps and electrical generators. Pneumatic power typically drives air turbine motors for engine start systems and environmental control systems. Electrical power and hydraulic power are distributed throughout the aircraft for driving subsystems such as flight control actuators, landing gear brakes, utility actuators, avionics, and weapon systems.

Recent and projected advancements in aircraft electrical power system and component technologies have resulted in renewed interest in the MEA. For example, hydraulically driven actuators would be replaced by electric motor driven actuators, gearbox driven fuel and lubrication pumps would be replaced by electric motor driven pumps, and a pneumatically driven compressor for environmental control would be replaced by an electric motor driven compressor. Studies on two different military fighter aircraft have shown that the MEA concept provides significant reliability, maintainability and supportability payoff.

There are four major technical thrusts in the roadmap: (1) power generation, (2) power systems and distribution components, (3) passive components, and (4) power electronics/motor drives

Power Generators — Independent Power Units (IPU)

A High Reliability Generator was developed from a conventional 400 Hz Variable Speed Constant Frequency (VSCF) system to a dual output (270 VDC and 400 Hz) system capable of supporting the near-term MEA.

The Switched Reluctance Starter/Generator program developed the preliminary design for a 375 KW, 270 VDC switched reluctance starter/generator in which the electrical machine is integrated internally with an advanced gas turbine engine.

A smaller 250 KW unit was built and tested to demonstrate the critical technologies. The switched reluctance starter/generator system offers a robust, high temperature, fault tolerant solution for the environmental demands of the turbine engine and the performance demands for the MEA.

Feasibility is based upon recent advancements in power electronic component technologies, high temperature wire insulation, and high temperature, high strength magnetic materials. The power electronic inverter is essential to the system since it provides the means to excite and process power to and from the unit. An Electro-Magnetic Interference (EMI) filter will reduce unwanted frequency components.

These systems are directly applicable to ground applications. In fact, Allied Signal is the contractor, which no doubt contributes to their civilian microturbine program.

In another development, an internally integrated 375 KW Starter/Generator for large aircraft enginees will include the critical step of eliminating the engine gearbox and aircraft mounted accessory drive. Integration into the gas turbine engine is enabled by high strength, high

temperature permanent magnet materials (cobalt-iron) and reliable high temperature wire insulation.

Power Systems and Distribution Components

The MEA will need a highly reliable, fault tolerant, autonomously controlled electrical power system to deliver high quality power from the sources to the load.

There are several challenges in designing an electrical power system for a MEA. Total onboard power requirements will be much greater, ranging as high as 1-10 MW per aircraft. It adds substantial amount of high power dynamic motor loads which could impact power quality. Most of these loads will have a low input impedance "capacitive" EMI filter which could present an in-rush current problem. Some MEA loads such as flight control actuators could provide regenerative energy back to the power distribution system.

Most important, these loads are flight critical, and loss of power to these loads could result in the loss of the aircraft. Thus, the performance and integrity of the power distribution system becomes a critical network which links sources to loads.

Presently, the Air Force has two programs for power systems and distribution components for the MEA.

– Power Management and Distribution for More Electric Aircraft (MADMEL) program
– Remote Terminal utilizing 270 VDC Solid State Power Controller program.

Future programs include development of: (a) high current (>50 ampere) intelligent power controllers and contactors that provide control, protection, and status feedback. (b) smart, overcurrent, differential current, and ground fault protection systems, (c) arc detection circuits to trigger protection devices in the event of an arc. (d) highly reliable and rugged connectors and interconnect components.

Passive Components – Capacitors

— Contact: Sandra Fries-Carr, 937-255-6016,

State-of-the-art aircraft capacitors are considered to be the weakest link in power electronic systems. They are also large, heavy and lossy. This is a real concern for the MEA since 100s to 1000s of capacitors will be required for filtering and energy storage. The Air Force is pursuing several organic and inorganic capacitor technologies under contract that promise improvements in reliability, size, weight, and electrical and thermal performance.

Foster-Miller Corp. was awarded an SBIR contract to examine the application of PBZT polymer film for capacitors. This film demonstrated dielectric strengths as high as 100,000 Volts/Mil and low dissipation factor at high temperatures (up to 300*C). A follow-on SBIR contract to Foster-Miller further developed the PBZT film to make highly reliable, high energy density capacitors with operating temperatures to 300*C.

Westinghouse Science and Technology Center was under contract to develop and demonstrate high temperature (>200*C) AC and DC filter capacitors using a FPE polymer film from 3M Corporation. The capacitors were tested with a Variable Speed Constant Frequency (VSCF) generator system and demonstrated over 2000 hours of trouble free operation at 225*C.

Olean Advanced Products, Division of AVX Corporation is under contract to develop multilayer ceramic capacitors with increased operating temperature (up to 300*C) and reduced dissipation factor over a wide frequency and temperature range. Ceramic capacitors offer tremendous volumetric density compared to other capacitor technologies.

Wright Labs, in-house, is using low temperature RF sputtering to make very thin film ceramics (600 angstroms) which can be put directly on a circuit board.

Ultra high energy density pseudo capacitors have been developed, demonstrating energy densities over 11 Joules/gram and possibly as high as 30 J/g. An inexpensive device about the size of a quarter, weighing 6 grams, is rated at 5 farads at 5 volts. These are use in burst power and other aircraft and civilian applications, and can be stacked to the 1 KV level.

Diamond Thin Film Capacitors

The Air Force is conducting an in-house research program to investigate the possibility of using diamond-like carbon and polycrystalline diamond films as dielectric materials for capacitors. Diamond has the highest thermal conductivity of any material known and a very high dielectric strength, electrical resistivity and operating temperature capability. Wright Labs has made thin films using microwave plasma-enhanced chemical vapor deposition that have very stable performance over a wide temperature range. Capacitors continue to work well at 600 deg C, with a power density of 7 Joule/gram.

The Air Force has recently awarded several contracts to investigate other promising dielectric materials and construction techniques for capacitors. This includes silicon carbide, barium titanate, and multi-layer diamond capacitors.

Power Electronics and Motor Drives

— Contact: Clarence Severt, 937-255-6235

Advancements in power semiconductor devices, capacitors, and integrated circuits for control has enabled high density, reliable power electronic and motor drive systems that are essential for the MEA. These include generators, battery chargers, DC to AC inverters, and DC to DC converters, and motor drives, which provide the interface between the electrical power system and the motor.

To date, the Air Force has focused on MOS Controlled Thyristor (MCT) switching device and the MCT driver. Future work will center on Application Specific Integrated Circuit (ASIC) technology for motor drive controls and the development of advanced drives for induction, permanent magnet, and switched reluctance motors.

In September 1986, the Air Force awarded a contract to the General Electric Corporate Research and Development Center to develop a high power MCT device. At that time, GE had only demonstrated a small MCT device capable of a few Amps and a 200 Volts. The objective of this contract was to develop and demonstrate a high power device (with several orders of magnitude increase in power handling capability) that would be applicable to aircraft power conditioning. The goal was to develop a 150 Ampere 900 Volt device capable of high speed operation (200 nanosecond turn-on and 1 microsecond turn-off capability), low forward voltage drop (1 Volt) and high temperature capability (>200*C junction temperature).

Later in the contract, an integrated circuit driver chip was developed that provides an interface between logic control signals and the gate of the MCT. This program was successful in meeting its goals, and several hundred first generation MCT devices and driver circuits were produced, with significant performance improvements as well as size and weight reductions when compared to bipolar junction transistor technology available at that time.

A second contract was awarded to GE to make the MCT an acceptable and preferred device for military weapon systems such as the MEA. This contract is focused on advanced hermetic packaging, radiation hardening, and symmetrical voltage blocking for AC applications. Also improvements to the MCT are being investigated which offer improvements in peak current turn-off capability and current density.


Ground Power

Remote Small Scale (10-120 watts)
— Contact: Tom Lamp, 937-255-6235,

The Air Force has over 80 remote sites in Alaska that need ultra high reliability power sources in the 10-30 watt range, for sensor systems, to 120 watts. Most are equipped with thermoelectric generators (TEG) that operate on propane, with some photovoltaic. The transportation costs run to $30-40 per pound of fuel, so the low efficiency of TEG, typically about 5%, is obviously a concern. Requirements are unattended operation, low health and safety risk to local population and Air Force personnel, and low environmental risk. Installation must be quick, by heliocopter drop-in. Weather conditions are very extreme.

But for the social outcry that would result, RTG’s are the obvious best choice (radionuclear thermal generators–as used on space missions). Other mature technologies include batteries, fuel cells, wind and engines, none of which meet the objectives.

Other choices are Stirling, Thermionic, Thermophotovoltaic, and AMTEC, all of which are small scale heat-to-electricity conversion devices with higher efficiency than TEG.

Stirling is under development by NASA for slightly larger systems (350 watts), and DARPA is funding some work on TPV and AMTEC ( a 500 watt compact system for the Army).

For the Alaska sites, the conclusions are that AMTEC and Stirling are the best candidates. Work is underway to develop prototype systems, building on the work done for space power systems. Commercial applications could include gas metering, navigation stations, weather monitors, and cathodic protection.

Cryogenic Lightweight Deployable (1-4 MW)
— Contact Jerry Beam, 937-255-6226

The Air Force needs lightweight deployable power plants to support, as one example, ground based radar (GBR) systems. Conventional technology and it’s supporting infrastructure is larger and heavier than wanted, and one of the Air Force’s key goal is to reduce the "logistics tail" whenever possible. A study showed that the conventional GBR plant with 5 semi-trailers and 140 cubic meters in volume, could be reduced to 2 trailers by the use of a superconducting cryogenic power generator. Since the radars already need cryogenic support, this is not an additional requirement, and the size and efficiency gains are significant. A prototype system will be tested in 2000, and could be in the field by 2005.

Turbine Compressor Research Facility (CRF)
— Contact: Mark Reitz, 937-255-6802

The CRF is a major facility for conducting tests and evaluations of full scale multi stage and single shaft fans and compressors for gas turbine engines. Extending over four buildings, it is capable of 30,000 hp at speeds to 16,000 rpm, and 15,000 hp from 16 to 30,000 rpm. It can create steady-state and transient phenomena on full size test articles under conditions that are similar to those of actual operation. It has been used for many advanced turbine development programs to evaluate fans and core compressors.

Solar Turbines, Inc. is developing gas fired turbine engines for cogeneration and industrial drive applications in industry, under a CRADA with DOE’s advanced turbine program. The compressor for this engine is now under test at the CRF to identify any possible design deficiencies. This is the first major commercial use of the CRF.

Electronics Cooling
— Contact John Leland, 937-255-2922

Cooling of power electronics is particularly important as systems become more compact and powerful. Anticipating cooling requirements up to 600 W/sq cm, a number of initiatives at the Lab include:

— testing performance of heat pipes in aircraft-type environments, e.g. under acceleration and vibration. Contact Kirk Yerkes, 937-255-6241
— integration of direct spray cooling into a 270 V 400 A single phase inverter, leading to a reduction in size of 10X. Direct immersion, jet impingement and flow boiling are also receiving attention. Contact Brian Donovan, 937-255-6241
— Venturi flow cooling is another technique under consideration

Mechanical Testing of Electrical Machinery
— Contact Tim Young
— Characterization of soft magnetic materials at higher speeds and temperatures encountered in IPU’s
— Windage in generators can become a significant power loss (as much as 30-40%) at high RPM due to viscous air losses.

Silicon Carbide High Power Electronics
— Contact: Clarence Severt, 937-255-6235

Compared with silicon, Silicon Carbide semiconductors have 3 times the band gap, and a operating temperature range reaching 4-600 deg. C, compared with 125 deg. C for silicon. It also has higher breakdown strength, which can mean thinner devices. Also, increased circuit efficiencies can reduce heat loads as much as 5X.

The main obstacle to using SiC in power electronics is the difficulty in making it without defects. "Micropipes" form too easily as the material is built up by vapor deposition.

The Air Force program has focused on development of high quality semiconductor grade material, improving on both wafer size and defect rates, for an aggressive development effort for power electronic devices. They have set a goal to demonstrate a 100-amp 600-V 572 deg F SiC switch by the year 2002.

For the power industry, discussions were well along with EPRI last year on possible cofunding of several device programs, but EPRI backed out. No new initiatives have come forward since.

——press release by CREE Research, one of the key developers in this program——–

Cree Unveils New Product Offerings for Silicon Carbide Wafers 40% Reduction in Micropipe Densities on Silicon Carbide Material

(Durham, NC May 27, 1997) Cree Research Inc. [NASDAQ: CREE] today announced that it has made tremendous progress in its efforts to reduce micropipes within its silicon carbide (SiC) material. Cree will now offer its 4HN type SiC wafers with reduced micropipe densities (MPD) and graded to three categories. The low grade will have a maximum of 30 micropipes/cm2, which represents a reduction in MPD of 40%. A new select grade will be added, which will have a range of 31 to 100 micropipes/cm2. In addition to Cree’s low and select grades, the standard grade will have a range of 101 to 200 micropipes/cm2. This represents a reduction in MPD of 50%.

Christer Ovren, Director of Silicon Carbide Device Development at Asea Brown Bovari (ABB), commented that "Cree continues to lead the world in making lower micropipe substrates available for the research and development of next generation devices. This latest advance is another step forward in maturing the manufacturing process for silicon carbide technology." ABB has purchased SiC wafers from Cree for a number of years.

These reduced micropipe densities are a result of Cree’s continuous commercialization of its SiC material technology. Cree expects this technology breakthrough to enable SiC material for more applications and improve device performance of existing applications. North Carolina based Cree Research, Inc. is the world leader in the development of silicon carbide-based semiconductors which have potential advantages in certain optoelectronic, RF and microwave, power, and high temperature applications. Cree owns outright or licenses exclusively 40 patents related to its process and device technology.


Superconductors, Cryogenic Power Electronics
— Contact: Charles Oberly, 937-255-4814

As noted above, cryogenic systems can have dramatically improved efficiency, size reduction, and performance as compared with standard counterparts. Power conversion efficiency of an alternator/motor, for example, can reach 99%, including the refrigeration needed, compared with 92% for conventional copper based components. Wright Lab is developing both the high temperature SC materials and designs for generators, motors, actuators and power transmission lines.

Perhaps less well recognized, cryogenic cooling (i.e. to liquid Nitrogen temperatures) dramatically improve the performance of standard commercial solid state electronic components. Devices such as MOSFETS exhibit significantly reduced heating and faster switching. Ceramic capacitors have lower losses and higher capacitance when cooled.

— Contact Steve Vukson 937-255-7770, Dick Marsh

Aircraft battery systems are a major concern, particularly in regard to weight, reliability and maintenance. For example, vented NiCd battery maintenance costs are $3000/yr for each battery, amounting to $1/2 billion over a 20 year period. Wright Labs has developed a maintenance-free sealed NiCd cell technology, which uses low cost separator materials and which they’ve married with a microprocessor-based smart charger. These new systems will eliminate all scheduled maintenance costs, and also to save another $1/2 billion by reducing flight mission interruptions.

The bulk of the Lab’s battery program budget is devoted to advanced lithium polymer technology, doing work in molecular engineering in cooperations with Cornell, Berkeley and other academic institutions. The program has demonstrated prototype rechargeable lithium batteries with energy densities above 80 W-Hr/kg.

Thermal batteries are a special class of one-shot primary batteries used in weapons systems to deliver a large burst of power, very reliably, after waiting as long as one or two decades. Sandia National Lab is also well versed in this technology. ( –Would this have a useful role to play in nuclear power plant emergency systems?)

Lubrication Technologies
— Contact Bob Wright, 937-255-4230,

This separate branch provides field support, development and advanced technology research. Their services to the Air Force include comprehensive testing facilities, bearing systems development, lubricant testing, magnetic bearings, etc.

For lubricants, increasing operating temperatures and longevity of lubricants are ever present goals. Some state-of-the-art compounds (polyphenyl ethers) have higher temperature capability but cannot be used below 40 deg. F, an obvious limitation for tactical systems. Others (perfluoro ethers) perform extremely well over a wide temperature range, but degrade quickly leading to corrosion. The overall paradigm is shifting from use of bulk oils to vapor phase lubricants, soft magnetic materials, and expendable coatings, although conventional ester lubricants are still foreseen to be the mainstay of aviation lubrication for some time to come. Meanwhile, integration of on-engine (on-line) oil condition diagnostics is an important theme. Off-line diagnostics are effective, but not optimal. This is a vital issue, as lubricant systems are implicated in 1.5 aircraft losses per year.

Magnetic Bearings — The Lab has a major development program, foreseeing big opportunities in engines to do active rotor dynamics control, increase temperature, do active control of compressor stability and blade tip clearance, and to have less logistics and better real time diagnostics.

On-line spectrometer — The Lab is sponsoring development of a very small infrared spectrometer for on-line oil analysis. The device measures the condition of the basestock and additives, and can detect the presence of unwanted contaminants, such as water, fuel, glycol, or wrong oil type.


"RULER" — Remaining Useful Life Evaluation Routine — off-line test system measures antioxidant levels in lubricants quickly and accurately by "voltammetric analysis". Results enable operators to determine remaining useful life of lubricants in less that a minute. RULER System consists of an "RULER" — Remaining Useful Life Evaluation Routine — off-line test system measures antioxidant levels in lubricants quickly and accurately by "voltammetric analysis". Results enable operators to determine remaining useful life of lubricants in less that a minute. RULER System consists of an instrument with probe, R-DAS (RULER Data Acquistion Software) pre-installed on a desktop or laptop computer. RULER System cost about $15,000. Proprietary solvents are used in the tests.

The RULER was originally developed at the University of Dayton Research Institute for Wright-Patterson Labs, for quick tests on aircraft oils between missions. It is manufactured by Fluitec Ltd., based in Dayton, OH with operations in Brussels. RULER customers cover a large range of industries world wide in oil, additive, manufacturing plants, power generation, aerospace and fleets. It’s applied to turbine, hydraulic, synthetic, working fluid, IC engine, and even biodegradable oils.

Contact: Lawrence Contreras, Fluitec, 937-223-8602,

Space Solar Power, A Fresh Look

Subject: UFTO Note – Space Solar Power, A Fresh Look
Date: Sun, 15 Jun 1997 21:58:39 -0700
From: Ed Beardsworth <>

| ** UFTO ** Edward Beardsworth ** Consultant
| 951 Lincoln Ave. tel 415-328-5670
| Palo Alto CA 94301-3041 fax 415-328-5675

Space Solar Power, A Fresh Look

In 1968, Peter Glaser of AD Little put forth a concept to put solar power stations in earth orbit and beam power to ground stations using microwaves. After extensive study in the 1970’s by NASA and DOE, the idea was found infeasible for many reasons, especially the costs to put payloads into orbit and the a design approach that involved massive amounts of equipment and people in space, i.e. many large geostationary space stations. Even if the approach could could have claimed overall cost effectiveness, the huge upfront capital investment (with no incremental revenues along the way) would have prevented it from going forward.

NASA has just completed a new review entitled “Space Solar Power, A Fresh Look at the Feasibility of Generating Solar Power in Space for Use on Earth”. April 4, 1997. SAIC-97/1005. The NASA/HQ Advanced Concepts Office directed the 18 month study, which assessed newer concepts that might have the potential to enable affordable production of energy in space for use on Earth.

The NASA team characterizes the work as *very preliminary*, but is optimistic that technologies and systems approaches have emerged in the last 20 years that make the potential for space solar power far more feasible than traditionally believed, perhaps as soon as 10-15 years from now.

**They want involvement and participation by the utility industry in the next phases.**

For more information, or to request a copy of the report, contact:

John Mankins, Advanced Projects Office, NASA Headquarters.

A good summary also appears in the May 1997 issue of Aerospace America, published by the American Institute of Aeronautics and Astronautics (AIAA). (I have a copy.)

(The following summary was prepared by UFTO, based on material contained in the report)

“Space Solar Power, A Fresh Look at the Feasibility of Generating Solar Power in Space for Use on Earth”. April 4, 1997. SAIC-97/1005.

With the original SSP from the 70’s, as a “reference concept”, the new study looks at new concepts, architectures, and techologies that have been identified or developed since that time. These include modular designs, advanced materials, automated assembly and deployment (in orbit), and new orbital configurations. Most interesting are ideas that produce incremental returns for incremental investment (e.g., small self-deploying launch packages).

Six concept architectures were defined and studied in detail,, based on many ideas identified through exhaustive brainstorming and elicitation of ideas at “Interchange Meetings”

The study’s findings include:
1. Markets — the global need for power will increase dramatically, with advances in the developing countries, and more and more concerns about global climate. SPP could play a significant role.

2. System Architecture — New concepts involving modularity, non-geo stationary configurations, small launch vehicles make a major difference in the cost outlook, and in possible approaches to financing.

3. System Cost — High efficiency PV arrays achieving 500 watts or more per kg could be sufficient for economic viability, but low cost space transportation (less than $200 per pound to low earth orbit) is the most important factor.

4. Public Acceptance — The study is refreshingly forthright in discussing the challenges that safety claims will face, though they are convinced that health and safety risks are negligble.

5. Other Applications — The technology will have a better chance if it can also be applied in other applications. In particular, a lot of work was done under SDI to develop concepts for beaming power to satellites and aircraft. NASA could use the same techniques to power space craft.

***One especially intriguing idea is to use satellites to relay power from place to place on the earth, much as telecommunications are handled. The implications would be truly staggering, with power deliverable from anywhere to anywhere.***

6. Critical Technologies
— Space Transportation: Needto have modular launch packages of 20,000 kg or less, to be able to use general purpose launch systems currently under development for a wide array of projected space industries (NASA Reusable Launch Vehicle and Advanced Space Transportation Program). Payload costs must approach $100-200 per pound.
— Wireless Power Transmission: a new generation of solid state devices might enable the use of a higher microwave frequency. Existing klystron technology may be initially cheaper but would not offer improved packaging and beam steering capabilities. Trade offs need to be carefully examined.
— Energy Storage: Storage (on board or on Earth) was not considered in this study, but might be needed to have the ability to deliver uninterrupted quality power.
— Solar Conversion: Terrestial PV has made dramatic gains in the last 20 years, and their space counterparts must be developed (radiation hardening in particular).
— Guidance, Navigation, and Control: Advanced concepts proposed in the study are potentially less cumbersome than conventional (gyro-thruster) techniques.
— On Board Power Transmission and Thermal control: The ability to use high voltage high temperature superconductors is critical (to move power from the PV array to the RF beam system).
— Telecommunications/Data Processing/Autonomy/Command and Control: Systems must have a high degree of operational autonomy. Staffing levels must be low. New data system architectures may be required, involving a high degree of distributed computing power.
— Structure: Very light weight tension-stabilized structures will be used, instead of the trusses and braces of the original space station approach.

——-Upcoming Events——————

Space Power Systems for Humanity Conference,
August 24-28, 1997, Montreal

Space Technology & Applications International Forum, (Staif-98)
January 25-29, 1998, Albuquerque, New Mexico.

Announcements & Other Business

Subject: UFTO Announcements & Other Business
Date: Sun, 22 Sep 1996 13:03:48 -0700
From: Ed Beardsworth

| *** UFTO *** Edward Beardsworth * Consultant |
| 951 Lincoln Ave. tel 415-328-5670 |
| Palo Alto CA 94301-3041 fax 415-328-5675 |
(Since we don’t do the “Bulletin” anymore, here’s a new way to feed you bits and pieces of information.)

1. T&D Workshop Plans are firming up for the UFTO T&D Workshop at PNL. Date will be either Nov 4-5 or Nov 11-12, from noon to noon. We’ll have a decision about the dates by the end of this week. There will also be a number of other things for you to see or do after we adjourn, by arrangement with PNL. Details forthcoming.

A few of you haven’t responded yet about whether you or someone from your company plans to attend, so please let me know. Also, ideas and issues for the program/agenda would be very helpful. What would YOU consider to be a successful outcome?

2. Travelin’ I’ll be out of the office Mon – Wed, and back on Thurs. Sept 26. I will be checking tel. messages, but will NOT have access to email.

I will be visiting Ontario Hydro Technologies (OHT) in Toronto, to look at the technologies and services they have to offer UFTO (and maybe convince them to join UFTO — as a user as well as a supplier of technology). As you probably know, OHT is Ontario Hydro’s former in-house R&D division, now a separate subsidiary.

October 8,9, I’ll attend the (invitation only) DOE/Dawnbreaker “Commercialization Opportunity Forum” in DC, to see presentations by 42 SBIR awardees–startup companies that are looking for investors and partners.

Technology 2006, the big annual NASA conference, is in Anaheim Oct 29-31. I plan to attend, particularly the exhibits. It’d be great to see you there, too. For registration info, call 1-800-844-NASA.

CETI & Patterson Cell

SUBJECT: Latest on CETI & Patterson Cell

The publicity I’d told you might be happening last month will be postponed until the end of June, according to more recent rumors. Apparently, CETI held a meeting at Miley’s lab in Champaign Urbana at the end of March. Two utilities (who are following all this very closely), GE, NASA, and a couple of foreign automakers were there, along with EPRI and SRI. Motorola was notable for its absence. The story goes that a deal was struck that everyone who got cells to test agreed to hold off making any announcements at least until the end of June. We’ll see what happens then.

Meanwhile, ENECO is putting together a proposal to utilities and other energy companies to offer a detailed State of the Art report. (This would be a first step towards setting up a private investment consortium to fund research at several sites around the world to get definitive answers that the individual participants can then go and develop further on an individual proprietary basis.)

Sincerely yours,
Edward Beardsworth, Consultant
951 Lincoln Ave___________Tel 415-328-5670___Fax 415-328-5675
Palo Alto CA 94301________EMAIL: