A numerical study on the design of sorption cells for multistage compressors

A research on sorption compressors, for driving Joule-Thomson cryocoolers in space application, is conducted in our lab. Sorption compressors are thermally driven, and unlike mechanical compressors, they do not have moving parts, and therefore do not emit vibrations and are highly reliable. There exist different sorption compressor configurations for different operating conditions and various gases. The current research focuses on nitrogen-activated carbon systems, since nitrogen is usually used as the working fluid for cooling to temperatures between 80 and 100 K and activated carbons are the best adsorbent for this purpose. The objective of the research is to allow the design of sorption compressors for different purposes, such as maximum effectiveness, maximum specific power, maximum volumetric power, and maximum flow rate per adsorbent mass. A numerical one-dimensional heat and mass transfer model is developed to enable the investigation of different sorption cell configurations. The model provides the performance dependency on the heater dimensions, the maximum temperature of the cycle, the sorption cell volume, and the different compressor stages, at steady states. In addition, all the physical dimensions and material properties are parametric, hence, the investigation can include numerous options of design options. The numerical model allows the investigation of many working pairs (adsorbent-adsorbate), and for a variety of applications.