Sunday, September 15, 2013

Record-Setting Power, Reliability, and Efficiency in a Low Mass, Free-Piston Stirling Convertor

Technology developed through a series of Small Business Innovation Research (SBIR) contracts with Ohio-based Sunpower, Inc., in partnership with NASA’s Glenn Research Center has resulted in the Advanced Stirling Convertor (ASC), an 80-watt free-piston Stirling power convertor that produces electric power from any source of heat. The ASC can be used in any application that requires conversion of heat into electric power with high efficiency and low mass.
The ASC provides a state-of-the-art power conversion system for potential future NASA deep space and planetary missions enabled or significantly enhanced by the application of radioisotope power systems. Other terrestrial applications being considered are a liquid-fueled, soldier-carried, portable power system and an efficient portable solar-to-electric convertor.
The ASC consists of a free-piston Stirling engine and an integral linear alternator that converts the piston reciprocating motion to electrical output. Weighing just 1.3 kg, the lightbulb-sized ASC has evolved to demonstrate 38-percent conversion efficiency, extended operation, and a twofold improvement in specific power over competing power sources. The higher efficiency reduces the amount of radioisotope material or fuel required by a factor of 4 or more, thereby decreasing costs.
Key technologies that enable high efficiency and low mass are hydrostatic gas bearings, moving-magnet linear alternators, high-frequency operation, high-temperature hot end materials and fabrication processes, and high-temperature, high-porosity regenerators.  The ASC is similar in design configuration and size to thousands of commercial terrestrial Sunpower cryocoolers. The company has produced five generations of ASC-related hardware, evolving the technology progressively with each build. ASCs have been running continuously in Glenn’s test facilities to demonstrate their ability to be used in generators. Glenn has contributed its expertise in reliability testing, materials assessment and risk reduction, and has provided access to unique facilities that have allowed for more than 165,000 hours of testing and operation on ASC research and experimental models, as well as the prototypes for flight.
ASC development, funded by the SBIR program, began in 2001 as one of 10 competitively awarded contracts intended to address the power conversion needs of future radioisotope power systems. The convertor efficiency and low mass objectives were met early in Phase 1, with continued technology refinement and improvement in Phases 2 and 3. These successes led to NASA’s decisions to accelerate development by increasing technical support from Glenn and subsequently integrating the ASC in 2007 as a critical component of the Advanced Stirling Radioisotope Generator (ASRG) being developed by Lockheed Martin Space Systems Company for the Department of Energy. Dual opposed convertors are used in the ASRG to achieve balanced operation, and their use has led to more than a twofold increase in specific power when compared with radioisotope thermoelectric generators used in prior missions. The ASC’s small physical size, high conversion efficiency, capability for long-life operation, and high specific power make it a candidate for future deep space missions and military portable power systems. Potential space missions include providing electric power for deep space missions, surface rovers, and stationary power generators.
For more information, contact Office of Technology Partnerships and Planning, NASA Glenn Research Center, 216-433-3484 or

DLR team develops demonstrator of free-piston linear generator as range extender for EVs; technology transfer to Universal Motor Corp.

Researchers at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Institute of Vehicle Concepts in Stuttgart have developed a demonstrator multi-fuel free-piston linear generator (FPLG, or Freikolbenlineargenerator, FKLG in German) as a range extender for electric vehicles. The FPLG comprises an internal combustion component, a linear generator and a gas spring; the researchers have demonstrated the feasibility of the technology on a test bench specifically developed for this purpose.

The free-piston linear generator works in a similar manner to a conventional combustion engine, but instead of converting the linear movement of the piston into the rotational movement of the crankshaft, it generates electricity directly. A fuel-air mix is ignited in the combustion chamber. This expands and pushes the piston towards the gas springs. These springs decelerate the piston movement and push it back. The linear generator converts the kinetic energy of the piston into electricity and this in turn powers the electric motor. 

Research on this type of drive unit has been fairly widespread. As one example, GM Global Technology Operations LLC and the Regents of the University of Michigan recently were recently awarded a US patent (Nº 8,261,860) for a plug-in series hybrid or range-extended electric vehicle powertrain using multiple free piston linear alternator (FPLA) engines. (Earlier post.) As another, researcher at the Nanjing University of Science & Technology has proposed a novel opposed-piston free-piston linear generator for use in series hybrid electric vehicles. (Earlier post.)
The DLR researchers says that through the installation of a gas spring in their system, they have now succeeded, for the first time, in operating such a system in a stable manner. The control system devised by the DLR engineers is able, for example, to control piston movement accurately to within one tenth of a millimeter. At the same time, it recognizes fluctuations in the combustion process and compensates for them.
The challenge here was to develop a particularly powerful mechanism with a highly dynamic control unit that regulates the complex interactions between the individual component.
—Ulrich Wagner, DLR Director of Energy and Transport
The core module operates at high efficiency even at partial load, with an indicated power of up to 35 kW per module; operating frequency is 40-50 Hz.

WMAP Cold Spot


3 cups chopped tomatoes
1/2 cup chopped green bell pepper
1 cup onion, diced
1/4 cup minced fresh cilantro
2 tablespoons fresh lime juice
4 teaspoons chopped fresh jalapeno pepper (including seeds)
1/2 teaspoon ground cumin
1/2 teaspoon kosher salt
1/2 teaspoon ground black pepper

Stir all ingredients together. Refrigerate. Best to let marinate overnight. But several hours will suffice, if you can't wait to dig in! Serve chilled.

Saturday, September 07, 2013

Avocado and Tomato Salad

4 cups avocados, diced medium
2 cups grape tomatoes or 2 cups cherry tomatoes
2 cups cucumbers, peeled and diced medium
1 cup red onion, diced small
4 tablespoons fresh cilantro, chopped
2 teaspoons fresh garlic, minced
2 tablespoons lime juice
1/4 cup olive oil
fresh black pepper
Lettuce (if you want)

Toss all ingredients in a bowl and top on a bed of lettuce (if desired)
Makes 8 servings
Calories 201.9 Total Fat 17.9 g Sodium 10.2 mg Total Carbohydrate 11.6 g Dietary Fiber 5.8 g Sugars 1.8 g

Jennie McDaniel Barker

Kool Freaking Chicken

Disclosure: Add Catchup...This makes it my recipe' KFC = Kool Freaken Chicken

1 whole chicken, cut into pieces
3 beaten eggs
4 tablespoons oil

For the coating

2 cups flour
4 teaspoons paprika
2 1/2 teaspoons salt
1 teaspoon pepper
1 teaspoon poultry seasoning
1 teaspoon thyme
1 teaspoon oregano
1 teaspoon tarragon
1/2 teaspoon garlic salt
1/2 teaspoon onion salt
1/2 teaspoon celery salt


1. Sift together all the coating ingredients and place in a clean plastic bag. Coat each chicken piece first with the beaten egg, then with the flour mixture in the bag. Make sure you coat each piece completely with the flour.
2. Heat the oil in a skillet. Brown the chicken in oil slowly, uncovered. Once browned, cover the skillet and keeping frying on a very gentle heat until the chicken is fully cooked. Place on paper towels to drain out the excess oil.

Edward A. Villarreal. Powered by Blogger.


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