Puristuslämmin

Puristuslämmin is a Finnish term describing the heating effect that occurs when a gas or, less commonly, a liquid is compressed. The word combines puristus (compression) and lämmin (warmth) and is used in thermodynamic and engineering contexts to refer to the conversion of mechanical work into internal energy, which raises temperature.

In theoretical terms, puristuslämmin is associated with compression heating. If a gas is compressed rapidly with little heat exchange to the surroundings (an adiabatic process), its temperature increases according to the gas’s properties; for an ideal gas, the relation T2 = T1 (P2/P1)^((gamma-1)/gamma) describes the temperature rise. When heat transfer is possible (non-adiabatic compression), the temperature rise is smaller because part of the work goes into raising internal energy while some energy is lost to the surroundings.

Applications of the concept appear in various engineering and industrial contexts. It is relevant to internal combustion engines, where compression of air-fuel mixtures increases temperature before ignition; to turbocharging and supercharging, where compressed intake air becomes warmer; and to pneumatic and hydraulic systems, where compression affects system temperatures. Understanding puristuslämmin aids in thermal management, material selection, and efficiency optimization in devices that rely on or must withstand compressed-state heating.

See also: thermodynamics, adiabatic process, isentropic compression, compression ratio, heat transfer.