You are looking for 1d thermodynamic cycle evaluation software in linux. A software that can consider transients would be desireable to account for variable sun thermo-inputs and look at capacitances need in your system.
One linux example, I see is a python system called: MCycle: A Python package for 1D sizing and analysis of thermodynamic power cycles. Available from github. Looks like a text based system; not gui. I have no experience with this but superficially looks useful.
I use an old windows gui thermo-analysis software called "cyclepad". Ref: https://www.qrg.northwestern.edu/software/cyclepad/cyclesof.htm. Has gui build network capability. Runs fine in wine on openSUSE linux. This has many heat input modules but I dont know if solar input is available.