❄️ Helium Refrigerator: Reverse-Brayton Cold Box, Heat Exchanger Loss, COP and Cooldown (2D)

Flow diagram of a single-stage helium reverse-Brayton refrigerator. Set pressure ratio, turbine efficiency, heat-exchanger effectiveness, flow, cold load and load mass, and see the gas temperatures around the loop, the cold-end temperature, the work input, COP against Carnot and the cooldown curve. It is the cold-box idea of the 3D helium plant, with four in-page numerical checks.