Combined Gas Law Calculator
Apply the combined gas law to find how pressure, volume or temperature changes when a fixed amount of gas is compressed, heated or cooled.
- P2 = P1 V1 T2 ÷ (T1 V2) = 9.0916 bar(a)
Combined Gas Law
Pressures must be absolute and temperatures in kelvin. The law assumes ideal gas behaviour and a fixed mass of gas.
Worked example
A closed 1 m³ receiver at 8 bar(a) and 20 °C heated to 60 °C rises to 8 × 333.15 ÷ 293.15 = 9.09 bar(a).
Frequently Asked Questions
Why must I use absolute pressure?
Gas laws describe the physical pressure from zero. Gauge pressure is relative to atmosphere and gives wrong answers.
What is Boyle’s law?
At constant temperature, pressure times volume is constant: halving the volume doubles the absolute pressure.
How much free air does a receiver hold?
Use Find V2 with P2 = atmospheric pressure: the result is the volume the stored air would occupy at atmospheric pressure.
Learn more on the blog
Pressure transmitter installation tips
A practical, field focused guide on instrumentationblog.in that explains the theory behind this calculator and how engineers apply it on real plants.
Read Full Article