Efficiency of an AMTEC recirculating test cell, experiments and projections
The alkali metal thermal to electric converter (AMTEC) is an electrochemical device for the direct conversion of heat to electrical energy with efficiencies potentially near Carnot. The future usefulness of AMTEC for space power conversion depends on the efficiency of the devices. Systems studies have projected from 15% to 35% thermal to electric conversion efficiencies, and one experiment has demonstrated 19% efficiency for a short period of time. Recent experiments in a recirculating test cell (RTC) have demonstrated sustained conversion efficiencies as high as 10.2% early in cell life and 9.7% after maturity. Extensive thermal and electrochemical analysis of the cell during several experiments demonstrated that the efficiency could be improved in two ways. First, the electrode performance could be improved. The electrode for these tests operated at about one third the power density of state of the art electrodes. The low power density was caused by a combination of high series resistance and high mass flow resistance. Reducing these resistances could improve the efficiency to greater than 10%. Second, the cell thermal performance could be improved. Efficiencies greater than 14% could be realized through reducing the radiative thermal loss. Further improvements to the efficiency range predicted by systems studies can be accomplished through the development and use of an advanced condenser with improved reflectivity, close to that of a smooth sodium film, and the series connecting of individual cells to further reduce thermal losses.
- Research Organization:
- California Institute of Technology (CalTech), Pasadena, CA (United States). Jet Propulsion Lab. (JPL)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AI01-86CE90237
- OSTI ID:
- 10159937
- Report Number(s):
- CONF-920801-9; ON: DE92016811
- Resource Relation:
- Conference: 27. intersociety energy conversion engineering conference,San Diego, CA (United States),3-7 Aug 1992; Other Information: PBD: May 1992
- Country of Publication:
- United States
- Language:
- English
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42 ENGINEERING
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SPACECRAFT POWER SUPPLIES
PERFORMANCE TESTING
MASS
THERMODYNAMIC CYCLES
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ROBOTS
LIQUID METALS
SODIUM
NESDPS Office of Nuclear Energy Space and Defense Power Systems
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420200
DESIGN AND DEVELOPMENT
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