Gas heating and thermodynamics

Adiabatic Compression Heating Calculator

Compressing a gas can raise its temperature even without adding heat from an external source. This calculator estimates the outlet temperature for an ideal-gas, reversible adiabatic compression.

Estimate outlet temperature

Why compression raises gas temperature

During compression, mechanical work is done on the gas. In an adiabatic model, none of that energy leaves as heat during the process, so the gas internal energy rises and its temperature increases.

Why real compressors differ

Real compression is not perfectly reversible. Friction, turbulence and other irreversibilities increase entropy, while the compressor casing and cooling system may remove heat. The actual discharge temperature therefore depends on compressor efficiency, cooling, gas composition and operating conditions.

Why pressure must be absolute

The thermodynamic pressure ratio must use absolute pressure. Gauge pressure omits atmospheric pressure and can produce a materially wrong ratio, especially at modest pressures.

Heat-capacity ratio matters

The exponent depends on γ, the ratio of constant-pressure to constant-volume heat capacity. A value near 1.4 is often used as an approximate room-temperature value for dry air, but γ varies with gas composition and temperature.

Where this effect appears

Compression heating matters in air compressors, turbochargers, gas turbines, refrigeration compressors and rapid gas compression. The reverse process, expansion, can reduce gas temperature under suitable conditions.