Transverse Thermoelectric Effects for Cooling and Heat Flux Sensing

While thermoelectric technology has developed steadily over the last 50 years, transverse thermoelectrics have generally been ignored in the industrial and commercial uses of thermoelectric devices to date. This project focuses on investigating transverse thermoelectric effects for localized cooling and heat flux sensing. Thermoelectric cooling devices are useful when their advantages (small size, solid state, active temperature control) outweigh their relatively poor efficiency. Transverse heat flux sensors, which generate an electric field in a direction orthogonal to the heat flow, have the advantage that the signal depends on the length of the device rather than the thickness. Thus, they can be made very thin for fast response times while maintaining a large signal. A prototype transverse device was built out of bulk samples of bismuth and bismuth telluride, which are common thermoelectric materials. The device was constructed of alternating layers of the constituent materials to simulate the effects of an intrinsically anisotropic material. The device was tested for its cooling and heat flux sensing capabilities, and the results of this testing were compared to predicted values. Although the device failed to demonstrate cooling, its heat flux sensing capabilities were promising. The device was tilted to several angles of inclination between 44° and 84° from horizontal, and the output voltage was recorded for several values of heat flux. The signal strength varied between 190.2 and 2321.6 ìV/(W/cm2), at inclination angles of 84° and 44°, respectively. The results followed the trend of the predicted values well, but the magnitude of the output voltage was significantly lower than expected. An uncertainty analysis was performed, and it was determined that the most likely source of error was the uncertainty in the amount of heat flux that went through the device during testing. This thesis outlines the process of building and testing the device, and the analysis of the results. Recommendations for future work are also given.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Department dc:contributor.department

Mechanical Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2006

Author dc:creator

• Mann, Brooks Samuel

Chair dc:contributor.committeechair

• Huxtable, Scott T.

Committee members dc:contributor.committeemember

• Diller, Thomas E.
• Scott, Elaine P.

• semiconductor
• bismuth telluride
• Seebeck
• anisotropy
• transverse thermoelectrics
• cooling
• heat flux sensing
• Peltier

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Dc Identifier Other

etd-06232006-132342

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/33709