A portable design and demonstration of two-stage thermoelectric cooling system for 200 K cryogenic applications

High-sensitivity infrared detectors require stringent low-temperature operating conditions. For instance, the optimal operating temperature for short-wave infrared (SWIR) detectors based on colloidal quantum dots is around 200 K. Thermoelectric coolers (TECs), characterized by their compact size and high reliability, are extensively used in microdevice cooling. In cryogenic applications, multi-stage TECs outperform single-stage TECs by achieving greater temperature differentials. However, the cooling efficiency of TECs heavily depends on the heat dissipation method. While liquid cooling significantly enhances TEC performance compared to air cooling, it compromises portability. This paper presents a two-stage thermoelectric cooling system (TTECS) designed to meet the thermal management demands of SWIR detectors while maintaining excellent portability. The second stage (2-TEC) employs air cooling to reduce the temperature of the circulating fluid. This pre-cooled fluid is then used in the first stage (1-TEC), which employs liquid cooling to achieve lower temperatures at the cold end, enabling effective chip cooling. Both simulation and experimental investigations were conducted to assess the performance of the 1-TEC and 2-TEC modules. In this work, it has demonstrated that the 2-TEC effectively cools the circulating fluid, while the 1-TEC has achieved a cold-end temperature of −73.5 °C (199.6 K). Further optimization of air cooling, liquid cooling, and the use of nanofluids reduced the cold-end temperature to −78.2 °C (194.9 K). The proposed system achieves cryogenic conditions while maintaining portability, which has an excellent prospect for cryogenic applications.