Cycle calculation
Read. Plot. Calculate.
Build confidence on the chart.
Download the selected pressure-enthalpy chart, plot the cycle, enter your readings and reveal the worked answer.
01
Chart discipline
Use dew point for evaporating and superheat readings, and bubble point for condensing and subcooling when working with zeotropic blends.
02
UK units
All exercises use °C, K, bar(a), MPa, kJ/kg, kg/s and kW. Chart pressure is absolute, never gauge pressure.
03
Safety context
This is training support, not proof of competence or system compliance. BS EN 378 governs wider safety and environmental requirements.
Reference archive
Know what belongs in practice.
Active exercises are separated from legacy and specialist material so obsolete refrigerants are never presented as choices for new installations.
Legacy awareness
R11, R12 and R22
Retained for recognition, environmental history and installed-base context only. They are not offered as new-system selections.
Specialist source material
Cryogens & absorption
The supplied collection also includes specialist gases and ammonia/water or lithium-bromide solution diagrams. These remain outside random RACHP cycle practice.
Standards: BS EN 378 series — BSI
Great Britain F-gas guidance: GOV.UK guidance
Last reviewed: 5 October 2026. Great Britain and Northern Ireland can have different regulatory arrangements; check the rules for the job location.