Model error

[balaji3112]

I was trying to add a new self.rhs equation inside the lumped.py for calculating the phase change material temperature, I'm receiving the following error:

File "C:\Users\Welcome.virtualenvs\Python_model\lib\site-packages\pybamm\discretisations\discretisation.py", line 157, in process_model
model.check_well_posedness()
File "C:\Users\Welcome.virtualenvs\Python_model\lib\site-packages\pybamm\models\base_model.py", line 697, in check_well_posedness
self.check_well_determined(post_discretisation)
File "C:\Users\Welcome.virtualenvs\Python_model\lib\site-packages\pybamm\models\base_model.py", line 798, in check_well_determined
raise pybamm.ModelError("model is underdetermined (too many variables)")
pybamm.expression_tree.exceptions.ModelError: model is underdetermined (too many variables)

[rtimms]

In the code above you are overwriting the rhs dict. You should do e.g.

self.rhs = {
    T_vol_av: ...,
    T_pcm: ...,
}

and similar for the initial conditions.

It would probably make more sense to eventually have a separate submodel for the phase change material.