Kelvin states the basis of its figures wherever it prints them. This is where its refrigerant properties come from, as Kelvin's own screens and reports name them.
Cycles and the calculations that follow
- R-744 is solved on property tables from the NIST Chemistry WebBook (the Span and Wagner reference equation of state), in every cycle type.
- The other pure refrigerants the NIST Chemistry WebBook covers are solved on its saturation tables.
- Blends and HFOs are solved on saturation tables computed with CoolProp. A zeotrope's evaporating side is read on its dew line and its condensing side on its bubble line.
- A refrigerant with no table, such as R-448A or R-450A, is solved on a simplified model built from its stored properties in Kelvin's refrigerant library. Its report says this is for comparative design sizing, not a substitute for full property tables.
For a refrigerant on a table, the report adds that compression runs at the isentropic efficiency you enter, not at a compressor's published performance, so it's design sizing to be verified against the equipment selected.
A saved cycle keeps the basis it was solved on, and its report words that basis, not today's. Save the design again to solve it on the current one.
The public pages and tools
The refrigerant tables and their pressure–enthalpy diagrams, the superheat and subcooling calculator, the P–T charts and the training questions use figures computed with CoolProp only.
Verification
Every calculation screen ends with a line saying its results are design aids based on published standards, aren't automatic compliance with AS/NZS, EN or other codes, and must be verified by a qualified engineer before implementation. Every report ends with a Verification line to the same effect, and names any check and approval with the date it was given: where none is named, none has been given.