Defense

October 18, 2012

New ARL thermoelectric technology, approaches to reclaim wasted energy

In one of its latest research projects, the U.S. Army Research Laboratory is investigating thermoelectric properties of materials on the Shadow Tactical Unmanned Aerial System, and techniques that could convert heat into energy. A small-scale demonstration of more than 80 watts of power from the exhaust heat of an M1 Abrams tank set the stage for developing a full-scale system to recover waste heat from the vehicle.

In one of its latest research projects, the U.S. Army Research Laboratory is investigating thermoelectric properties of materials on the Shadow Tactical Unmanned Aerial System, and techniques that could convert heat into energy.

The Shadow Unmanned Aerial System, or UAS, is used by the Army and Marine Corps for reconnaissance, surveillance, target acquisition and battle damage assessment.

The special effect they are leveraging is called “thermoelectric power generation,” and researchers are relying on a unique effect that produces electric energy between hot and cold temperatures, like on one side of a device – a tailpipe which easily can climb past 2,000 degrees Fahrenheit – that meets with frigid flowing air at high altitudes above ground.

It’s wasted energy that U.S. Army Research Laboratory, or ARL, researchers are looking to harness, package and shrink in hopes it could one day lead to soldier-worn power sources converted from body heat and cool ambient air, or reduce the size of a vehicle alternator.

This work, like similar research throughout ARL, is expected to gain defense department attention because of its promising early signs to increase efficiency and improve fuel utilization, especially given constraints in energy budgets imposed on micro scale systems, said John Gerdes, mechanical engineer with the Technology Development and Transition Team of ARL’s Vehicle Technology Directorate.

“Perhaps if the technology is advanced in later years, it will be possible to extend flight times, increase available mission scope and add additional sensors or payloads,” he said.

Earlier this year, ARL teamed with Research Triangle Institute International, General Dynamics Land Systems and Creare, Inc., to demonstrate a prototype robust energy harvesting solution that converts residual thermal energy from an M1 Abrams tank exhaust into useable electric power. The waste heat recovery system captures heat from the exhaust of the turbine engine, converts this heat into electrical power with a thermoelectric generator, and dissipates the heat through a heat-rejection system.

A small-scale demonstration of more than 80 watts of power from the exhaust heat of an M1 Abrams tank set the stage for developing a full-scale system to recover waste heat from the vehicle.

A report of that effort revealed that the prototype waste heat recovery system, once scaled up, could be retrofitted to existing tanks without requiring any modification to the engine or powertrain. A small-scale demonstration of more than 80 watts of power from the exhaust heat of an M1 Abrams tank set the stage for developing a full-scale system to recover waste heat from the vehicle.

Patrick Taylor and Jay Maddux, of the Sensors and Electron Devices Directorate’s, or SEDD’s, Electro Optic Materials and Devices Branch at ARL, recently co-authored a report stating that although the efficiency of thermoelectric power generation is generally considered low, there are many military needs for electrical power that thermoelectric technologies can uniquely and successfully address.

“Thermoelectric power generation has rich potential to contribute to electrical power generation scavenged from waste heat and, hence, improve fuel utilization on vehicles,” Taylor said. “As more electrical components are delivered to Army assets, the electrical power needs grow dramatically, so all methods of producing electrical power are of acute interest. Thermoelectric power generation is preferred because it directly and simply converts heat to electrical power in a form factor that can be highly miniaturized and made extremely covert.”

“As a matter of fact, applying thermoelectric power generators along the exhaust train of the Shadow will also reduce its infrared signature, and therefore reduce its detect-ability from adversaries,” he continued.

Lauren Boteler, also with SEDD, teamed on this effort to develop advanced packaging technologies required for successful integration with the Shadow.

Automakers General Motors, Volkswagen and BMW are developing thermoelectric generators that recover waste heat from commercial car and SUV combustion engines, and ultimately reduced mechanical load (alternator) and fuel consumption.

Thermoelectric power promising for microsystems, major weapon systems

ARL’s unmanned aerial vehicle, or UAV, study began as a first principles analysis that looked at the total energy available in the fuel, and made certain assumptions about how much was used in generating power and how much was lost as waste heat.

Gerdes said researchers then applied that waste heat to a model thermoelectric device and showed that this work, at a minimum, is promising and there is perhaps some region of overlap between the operating conditions of the UAV and the operating range of the thermoelectric device that wiill be useful to the military

ARL developed novel techniques to miniaturize and manufacture custom thermoelectric devices to increase the scope of applicable missions. For example, miniature autonomous microsystems that have curved exhaust ducting that generate heated surfaces from air swirling inside the duct, could offer could offer new potential areas for applying new thermoelectric devices.

ARL’s Vehicle Applied Research Division is investigating more practical measures of efficiency from a systems engineering perspective, Gerdes said.

“This means that we will consider factors like the match between a given device and the expected operational environment, the cost of the device, potential energy savings, the mass and volume of the device, and other more practical considerations that don’t matter as much in a lab but matter a lot in the real world,” he explained.

Researchers say developing thermoelectric technology is a worthy pursuit, because it has no moving parts, low weight, modularity, covert and silent, high power density, low amortized cost and long service life with no required maintenance.

“Many of the potential uses for mounted/dismounted power, such as recharging batteries, are therefore ideal for thermoelectric technologies. However, these applications will require interconnected, smaller-scale modular devices than are currently available. Most commercial-off-the shelf thermoelectric devices are optimized for cooling, not for generating power, so new device structures with materials and geometries better optimized for power generation are needed for broader use of thermoelectric technologies,” said Gerdes.

He said taking a systems engineering approach to solving a problem is nothing new, but ARL’s focus is on developing an application specific approach that may be useful in showing where thermoelectric devices could be placed, especially in areas that might not be obvious.

“Hopefully our work will illuminate some kind of a procedure for determining how best to match a given thermoelectric device to an application with some kind of general framework that may be applied to future unknown combinations of missions and such devices,” said Gerdes.

 




All of this week's top headlines to your email every Friday.


 
 

 

Headlines September 15, 2014

News: Navy identifies pilot presumed dead in crash - A Navy fighter pilot presumed dead after two fighter jets crashed in the far western Pacific Ocean has been identified.   Business: Boeing eyes 737-700 solution for new JSTARS - Boeing is officially planning a variant of its 737-700 commercial jetliner as a competitor for the Air Force’s...
 
 

News Briefs September 15, 2014

Australia contributing planes for anti-IS campaign Australia is preparing to contribute 600 troops and up to 10 military aircraft to the increasingly aggressive campaign against the Islamic State extremists in Syria and Iraq, Prime Minister Tony Abbott said Sept. 14. Abbott said Australia was responding to a formal request from the United States for specific...
 
 
Courtesy graphic

Lockheed Martin conducts flight tests of aircraft laser turret for DARPA

AFRL photograph The Aero-adaptive Aero-optic Beam Control turret that Lockheed Martin is developing for the Defense Advanced Research Projects Agency and the Air Force Research Laboratory has completed initial flight testing. T...
 

 

Lockheed Martin advances live, virtual, constructive training in flight test

https://www.youtube.com/watch?feature=player_embedded&v=jvXmOW8L3mU Lockheed Martin successfully tested a new solution for integrated live, virtual and constructive training during a flight demonstration at the company’s Aeronautics facility in Fort Worth, Texas. During the flight test, a pilot flying in a live F-16 engaged in a synthetic training exercise with a pilot flying as wing...
 
 
Image courtesy of NASA/JPL-Caltech/Univ. of Arizona

NASA’s Mars Curiosity rover arrives at Martian mountain

NASA’s Mars Curiosity rover has reached the Red Planet’s Mount Sharp, a Mount-Rainier-size mountain at the center of the vast Gale Crater and the rover mission’s long-term prime destination. “Curiosity n...
 
 

Raytheon begins full rate production on TALON Laser Guided Rockets

Under a $117 million contract awarded to Raytheon, Raytheon Missile Systems has begun production of the TALON Laser Guided Rocket. In 2013, the Armed Forces General Headquarters of the United Arab Emirates awarded Tawazun a contract to procure the TALON Laser Guided Rocket. “Full rate production of the TALON LGR is a significant milestone for...
 




0 Comments


Be the first to comment!


Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>