Path to higher SWaP-C for cooled IR through thermoelectrics with distributed transport properties

Abstract

Thermoelectric (TE) coolers are solid-state heat pump systems with no moving parts that directly use electric power to cool. Benefits are very small size, extremely light weight, low cost, vibration free operation, refrigerant-free, and excellent durability and reliability. Conventional TE (CTE) systems have limited capability to cool quantum infrared detectors because of insufficient cooling capacity and the inability to achieve the low operating temperatures required by high performance systems. Our studies show the capabilities of TE systems can be significantly improved by using Distributed Transport Properties (DTP) technology, which has the potential to make practical, inexpensive, light weight and highly reliable deep cooling systems and thus enable a new class of deep cooled infrared sensors. Our studies demonstrate the feasibility of creating a single-stage TE device operating in cooling mode with a maximum temperature differential that exceeds state-of-the-art TE systems by more than 35%. The enabling technology is the optimization of transport property distribution within the TE legs. We project that coefficient of performance (COP) and cooling power increase greater than 150% and 200% respectively at high temperature differentials. We also show that such TE devices will have superior performance under all operating conditions (both nominal and off-nominal) and can be smaller than conventional TE devices. Using DTP technology in multi-stage devices (and appropriately optimizing DTP within each stage), the large temperature differentials required to provide temperature control to quantum infrared sensors becomes achievable.