Multiple properties per single state calculation

[matthew-kapp]

This is a question.

Is it possible to define the state once (using PH), and then obtain multiple properties from this one calculation?

According to the docs, you need to call temperature, mass_density, etc. and I assume it computes the state each time.

Compared to CoolProp low-level, you can compute the state once, and then obtain multiple properties without recalculating the state. Is there something similar in Clapeyron?

[longemen3000]

Hello,

The way Coolprop and Clapeyron works is by transforming all input pairs to the VT state. (our flashes do this, their state input does that).

Once the VT state was calculated, you can get all properties easily, as the VT state does not require any iterative calculations.

Also, as you may know, in a volume-temperature basis, all properties (except volume and temperature) can be obtained by combinations of the derivatives of the helmholtz energy. I think that Coolprop stores up to second derivative information, and then calls the rest on demand.

We have an internal function that calculates all the values up to the second derivative too, so providing something multiple properties at once could be done

There is a slight problem with second derivative properties. Those are not defined in two phase states (the speed of sound in a two-phase mixture is not the mixture of speed of sound for each phase). But for one phase states, there is no problem.

On the implementation, you can calculate all derivatives (up to second order) of a single state point with Clapeyron.∂2f, and almost all properties of interest can be derived from that result. What is missing st the moment is a convenient api for that.