Ultra-efficient Thermoelectric Cooling Module for Satellite Thermal Management

ABSTRACT: Military space assets can have special constraints in form factor and function. For example, fluid cooling systems normally used for electronics and sensor cooling suffer numerous drawbacks in space applications. Conversely, compact, solid-state thermoelectric devices provide many advantages in refrigeration and power generation. These highly reliable devices have no moving parts, operate over a large range of temperatures, do not emit toxic or environmentally-unfriendly gases and are easily integrated into thermal systems, and offer a number of advantages in spot cooling of microsensors and microelectronics. While successful in a number of commercial applications (e.g. beverage cooling, mattresses, industrial and biomedical tools), engineering applications of thermoelectric devices overall have been relatively limited. The adoption of solid-state thermoelectric devices into these and other markets has been hampered by two primary challenges- 1) materials composition with relatively low ZT compared to other cooling methods, and the ability to cost-effectively manufacture low-profile, earth-abundant thermoelectric devices in high-throughput. Thin film devices fabricated using vapor epitaxy are showing promise at companies such as Nextreme, but adoption has been limited by the production cost and overall limited volume that can be generated from thin films. What is needed is a process that can result in conformable, large-area, thin film thermoelectric devices produced using methods that are not hampered by vapor epitaxy deposition. To solve this challenge, Nanohmics Inc., working in collaboration, proposes to develop thermoelectric devices based on high-ZT thermoelectric nanopowders. BENEFIT: In addition to niche applications such as payload cooling (~$100 500M/year), needs in a number of large commercial applications would be met by the proposed technology. Unrecovered waste heat from energy-consuming industrial processes is estimated by the DOE at 5-13 quads/yr (1 quad = 1015 BTU). If we conservatively assume 9 quads, 6% efficiency for TE devices constructed with our approach, 50% losses due to parasitic heat transfer losses and integration, and penetrating 10% of the waste heat market, the team estimates an economically viable TE device could enable recovery of ~20 trillion BTU of waste heat/year. Additionally, the incorporation of TE devices in automobiles can improve the efficiency of their power system by up to 5%. This level of waste heat energy recovery would lower the average consumer gas consumption ~15-20 gallons per year on a 750 gallon consumption/year basis with a cost savings on the order of $70-$100/year. A low cost manufacturing solution at the ~$100 price point would payback in the first year, passing the savings onto the lifetime of the device, which based on non moving parts, should be relatively long.