169 kelvin cryogenic microcooler employing a condenser, evaporator, flow restriction and counterflow heat exchangers

This paper presents the first cryogenic micromachined cooler that is suitable to cool from ambient temperature to 169 kelvin and below. The cooler operates with the vapor compression cycle. It consists of a silicon micromachined condenser, a flow restriction/evaporator and two miniature glass-tube counterflow heat exchangers, which are integrated with the silicon components using a novel gluing technique. The system was tested with ethylene gas from 20 to 1 bar, and produces a cooling power of 200 mW at 169 K with a mass flow of 0.5 mg/s.