High Density Cooling and Efficient Thermoelectric Heat Pumps

Robotic science rovers operating on the Lunar surface over diurnal cycles face extreme temperature environments beyond operating limits, even with shielded and articulated radiator assemblies. In general, a heat pump provides the common extensibility for thermal control over the lunar diurnal. Active cooling systems or heat pumps such as mechanical cryocoolers and thermoelectric coolers are commonly used on spacecraft for small heat loads while vapor compression systems have been flown and, more recently, reverse turbo Brayton-cycle coolers are being developed for high load, high temperature heat lift. However, technology gaps exist for mid-range heat pumps that are suitable for small science rovers where internal heat dissipation may range from 20 Watts to 100 Watts. To address this limitation, Nanohomics Inc., in consultation with Dr. Bed Poudel at Penn State University, proposes to design a high cooling density and efficient V-shunt thermoelectric cooling (TEC) system (heat pumps) suitable for small science rovers. The V-shunt TEC will employ recently invented BiTe-based thermoelectric materials at Penn State University which have the best figure-of-merit (ZT) at the temperature of interest (lt; 100 deg;C) to meet the required 20 ndash; 100 Watts of heat load and coefficient of performance (COP). Furthermore, the increase in effective TE fill factor would enhance the overall cooling power and efficiency as required for the lunar science rovers. The proposed TEC cooling system will be fabricated based on the Nanohmicsrsquo; recently developed modular and conformal TE technology and addresses the cooling need of small science rovers at lunar surface below 50 deg;C by lifting 20 ndash; 100 Watts (at the rate of 230 W/m2) of heat to environmental sink temperature of around 75 deg;C, i.e., ∆T gt; 25 deg;C.