A New Class of Miniaturized Lightweight Highly Efficient Solid State Cryogenic Cooler

A new class of solid-state, high-performance cryogenic coolers is proposed for space-based applications. Traditionally, cryocoolers for such applications have been Stirling or pulse tube refrigerators. These cryocoolers, although effective, are heavy, bulky, inefficient, and may cause vibrations. A high-performance solid-state cryocooler based on thermomagnetic cooling via the Ettingshausen effect can be lighter, smaller, vibration free, and use less power than the alternatives. Historically, the practical development of the Ettingshausen coolers was discouraged as they required a magnetic field difficult to reach by traditional ferrite magnets. However, recent rare-earth permanent magnets can produce the required field reliably. We propose an Ettingshausen cooler consisting of advanced permanent magnets combined with a novel semiconductor heterostructure predicted to significantly enhance the efficiency of the solid-state cryogenic cooling in a compact size. The Phase I work will demonstrate the preliminary materials properties and the design required to achieve cooling power larger than 0.2?0.3W in 30-35 K temperatures ranges for the rejection temperature of 150 K, while consuming less than 5 W power. The grown heterostructure in phase I will be utilized for the manufacturing of a high-efficiency Ettingshausen thermomagnetic cryocooler in Phase II for specific applications in SmallSat or other micro platforms.