Deep freezing refers to the cryogenic technology up to -150 C.Essentially the technology of gas liquefaction.Usually mechanical methods are used.For example, low temperatures as low as -210 C can be obtained by throttling expansion or adiabatic expansion; low temperatures below 1K (absolute temperature) can be obtained by adiabatic demagnetization.Depending on deep freezing technology, the properties of substances near absolute zero can be studied and used for liquefaction of gases and separation of gas mixtures.
