Air Force Research Laboratory Technical Report
This paper provides a description of research seeking to experimentally verify the effectiveness of a thermal switch used in series with TE devices for waste heat recovery for constant and variable source heat input and for variable source thermal capacitance (mass). Using an experimental set-up comprised serially of a fixed heat source, a variable thermal resistance air gap serving as a thermal switch, a thermoelectric device and a heat sink, the time-averaged power output to power input ratios improved up to 15% and 30% respectively for constant and variable heat input in certain design space conditions. The experimental results, as supported by model predictions, suggest that the thermal capacitance of the heat source must be greater than the thermal capacitance of the TE device in order for thermal switching to improve the time-averaged power output to power input ratios of waste heat recovery systems. The results have direct application to aircraft energy harvesting.
Approved by the Air Force Research Laboratory for public release; distribution unlimited.
Air Force Materiel Command
Place of Publication
Wright-Patterson Air Force Base, OH
McCarty, Robin; Monaghan, D.; Hallinan, Kevin P.; and Sanders, Brian, "Experimental Verification of Source Temperature Modulation Via a Thermal Switch in Thermal Energy Harvesting" (2007). Mechanical and Aerospace Engineering Faculty Publications. 41.