Cryogenics is the branches of physics and engineering that involve the study of very low temperatures, how to produce them, and how materials behave at those temperatures
Cryogenic refrigeration is a term that may be applied to the process of cooling to temperatures below 150 K. Cryogenic refrigeration systems are different from conventional refrigeration systems. The major components of a cryogenic system.
Cryogenic refrigerants are those refrigerants that produce a temperature in the range between-157 C to 273 C in the refrigerated space. The cryogenic refrigerants have exceptionally low boiling points at atmospheric pressure. The refrigerants used in cryogenic systems are often helium (He), hydrogen (H2), or nitrogen (N2).
A cryocooler is a standalone cooler, usually of table-top size. It is used to cool some particular applications to cryogenic temperatures.
Cryogenic refrigerators (cry coolers) may be classified:
- Functions performed
(e.g., the delivery of liquid cryogens, the separation of mixtures of gases, the maintenance of spaces at cryogenic temperatures)
2. Refrigerating capacities
3. Temperatures reached (like above and below 2K
These refrigerators are used for many different refrigerating applications:
- High-field superconducting electromagnets
- High-energy (nuclear) particle research
- Experimental superconducting electric generators
- Motors and superconducting magnets for levitation of railroad trains and etc…