A sorption compressor cell basically consists of a container that is filled with an adsorbent. When such a cell is thermally cycled, a pressure difference is created by the subsequent adsorption and desorption of the gas. As a consequence, a single sorption compressor cell inherently provides an intermittent flow. A Joule–Thomson expansion stage requires a more or less continuous flow. The standard way to obtain a continuous flow out of a sorption compressor is to use three or more compressor cells that are operated out of phase. This paper presents an alternative compressor concept that uses only one compressor cell, two buffer volumes and two check valves. Such a compressor is easier to construct and to operate and has a higher reliability at the expense of a slight variation in the cooler’s cold-end temperature. The principle was demonstrated using a sorption compressor cell that is filled with Maxsorb [The Kansai Coke & Chemicals Co. Ltd., 1-1 Oh-Hama, Amagasaki, Japan 660] activated carbon, is equipped with a gas-gap heat switch, and uses xenon as the working fluid. A flow of 0.52 mg/s was achieved with a low pressure of 1.39 bar and a high pressure of 17.0 bar, giving a theoretical cooling power of 42 mW at 172 K. A sensitivity analysis on several control parameters has been performed experimentally.
- Sorption coolers
- Joule–Thomson coolers