A JSON-based file format for the exchange of thermo-physical model parameters

We present a **proof-of-concept, JSON-based, **vendor-independent file format for the exchange of thermo-physical model parameters. You can try it out in this browser-based demo tool.

We started from what is already avaiable: the IK-CAPE PPDX format, a vendor-independent file format for the exchange of thermo-physical property data and model parameters.

But although IK-CAPE PPDX was developed in 1997, it looks a lot like it’s still the 1970‘s:

sample IK-CAPE PPDX file

Its shortcomings are:

  1. It is a soup of data, thermo set-up and parameters; BTW for experimental data we now have ThermoML, an XML-based, IUPAC-backed standard;
  3. And it looks like it’s punched on a card: it is a text file, 80-columns wide, totally unstructured, write-your-own parser type of affair.

But then XML is so 2000-ish, so we propose to update IKC-PPDX adding a JSON format variant.

Also to make things tidier, we restrict it to the exchange of thermo-physical parameters, and we exclude data and thermo set-up.

Our proof-of-concept JSON-based file format divides the thermo-physical model parameters in four groups:

  1. Pure scalars, for pure component constant parameters
  2. Pure vectors, for pure component T and/or P dependent parameters
  3. Binary scalars, for binary constant parameters
  4. Binary vectors, for binary T and/or P dependent parameters

Here is the JSON schema.

And here is the simplest possible sample JSON file, with only one pure component scalar parameter:

  "components": [
      "cid": "H2O",
      "name": "water",
      "cas": "1-11-111",
      "formula": "H2O"
  "pure_scalar": [
      "name": "PC",
      "parameters": [
          "cid": "H2O",
          "value": 3800000

Get the JSON schema, the sample JSON files and the source code of the demo from the gitlab repo here.