Demister
Metal mesh which eliminates liquid droplets in gases

Dewar
Vessel for storing gases such as nitrogen, hydrogen and helium at low temperatures

Ejector
Jet pump (suction of a flow through the expansion of another; used in cryogenics instead of a throttle valve to lower pressure)

Exergetic efficiency
Output exergy (e.g. contained in cold) divided by the input exergy (e.g. electrical energy of a system)

Exergy
The fraction of energy that can be converted into mechanical work (energy = exergy + anergy)

Forced draught cooling
Type of cooling in which the coolant is pumped or pressed through cooling ducts (in contrast to bath cooling, e.g. in magnets)

Fuel cell
Energy converter for reversing electrolysis. In a fuel cell, a reaction between hydrogen and oxygen takes place under controlled conditions ("cold" combustion)

Hydrogen
H2 – the first and lightest element in the periodic system

Inversion curve
Geometric locus of points where a differential throttling of pressure has no effect on the temperature of a gas