OPTIMIZATION OF THERMOELECTRIC ENERGY CONVERTERS. Bimonthly Progress Report No. 2, June 15, 1960 through August 14, 1960

Technical Report · Wed Oct 31 00:00:00 EST 1962

OSTI ID:4802365

Klein, P.H. ed.

A preliminary analysis of the first thermal system to be investigated was nearly completed. This system consists of saturated steam at 533 deg K (500 deg F), a thermoelectric generator utilizing thermoelectric materials representative of the present state of the art, and a sea-water heat sink at 291 deg K (65 deg F). Leakage of heat through the thermal insulation was taken into account in the calculations, as were other factors, such as contact resistance, the dimensions of the container of the generator, and the dimensions of the conductors connecting the individual arms. The effects of vari-ation of these parameters on the power output per unit weight, volume, and area of the system are graphically portrayed. The results for cooling by free convection of the sea- water coolant, together with preliminary results for the forced-convection case are presented. A magnesia-titania ceramic body was tested and found to be a material suitable as a high-temperature encapsulating medium in conjunction with iron end-caps. Because its coefficient of thermal expansion more closely approximates that of iron than does forsterite, the new material may permit reduction of the wall-thickness of tubing used for encapsulation of thermoelectric materials, effecting a marked diminution in thermal losses through the encapsulant. Improvements in sealing technology include the construction of an improved sealing apparatus and its use for closing an easily-filled cell that will facilitate the study of thermoelectric properties of encapsulated materials. Encapsulation of p-type lead telluride was successfully accomplished, although further study is required in order to make the procedure completely reliable. Preliminary batches of Mg/sub 3/Sb/sub 2/ were prepared in an inert-atmosphere furnace desigmed for operation at temperature up to 1400 deg C. It appeared that problems arising from reaction of the constitutents with the container can be solved by use of a molybdenum vessel with a split-crucible design. A versatile zone-refining apparatus for purification of lithium was constructed and tested. lnfrared reflectance measurements on a specimen of CrSb indicated that its absorption edge lies in the l4-micron range, suggesting a lower band-gap energy than initially expected. If this conclusion is verified by thermal measurements, it will be necessary to alloy the compound with large-gap materials in order to produce an alloy with optimum properties at elevated temperatures. Leakage in a tantalum-lined iron bomb precluded the successful preparation of samples of Ca/ sub 2/Pb and Ca/sub 2/Sn. A welded vessel, made entirely of tanta lum, was designed in an effort to solve the problems arising from the volatility and corrosive nature of the calcium. (auth)

• Research Organization: General Electric Co. Aircraft Accessory Turbine Dept., Lynn, Mass.; General Electric Co. General Engineering Lab., Schenectady, N.Y., and General Electric Co. Electronics Lab., Syracuse, N.Y.
• DOE Contract Number: NOBS-78403
• NSA Number: NSA-16-013676
• OSTI ID: 4802365
• Report Number(s): AD-260368
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-62
• Country of Publication: United States
• Language: English

Related Subjects

PHYSICS
ABSORPTION
ALLOYS
ANTIMONY ALLOYS
CALCIUM
CALCIUM ALLOYS
CERAMICS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CONFIGURATION
CONVECTION
CONVERSION
COOLANTS
COOLING
CORROSION
DIAGRAMS
EFFICIENCY
ELECTRIC CONDUCTIVITY
ENERGY
ENERGY RANGE
EXPANSION
FORCED CONVECTION
FORSTERITE
FURNACES
HEAT TRANSFER
HIGH TEMPERATURE
INERT GASES
INFRARED RADIATION
INTERMETALLIC COMPOUNDS
IRON
JOINTS
LEAD ALLOYS
LEAD COMPOUNDS
LEAKAGE
LITHIUM
LOSSES
MAGNESIUM ALLOYS
MAGNESIUM OXIDES
MAGNESIUM SILICATES
MATERIALS TESTING
MEASURED VALUES
MOLYBDENUM
PLANNING
POWER
REFINING
REFLECTION
SEA
SEALS
SEMICONDUCTORS
SPECTRA
SPECTROSCOPY
NESDPS Office of Nuclear Energy Space and Defense Power Systems