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PCM and latent thermal storage successfully simulated with Polysun

A latent thermal storage system with PCM capsules is simulated in Polysun in an advanced thesis at HSLU.

In his thesis at the Lucerne University of Applied Sciences and Art (Switzerland), Mr. Markus Lacher tackled the problem of simulating latent thermal storage systems with PCM capsules using the Polysun software from Vela Solaris.

First, the system of latent thermal storage was analyzed in detail to determine the different influencing parameters. Then, a parameter analysis was performed on the fluid properties specified in Polysun to understand the calculations of the storage temperatures as well as capacities in Polysun. The next step was to program three different PCMs and test the PCMs through an experimental simulation. Then, the programming of an experimental memory in Polysun was done, giving the opportunity to validate the memory design. Finally, the simulation of an energy system of a single-family house took place.
The experiment was successful: “The simulations showed that both PCM and the latent thermal storage in Polysun can be simulated with the given components. The simulated capacity of the experimental storage tank of about 7.97 kWh corresponds quite closely to the measured capacity of 7.9 kWh or the temperature calculated 8.1 kWh.”

Find here the complete thesis (in german): link

Vela Solaris congratulates on the exciting work!

Are you interested in learning more about the possibilities of simulating PCM and latent thermal storage with Polysun? Feel free to contact us at

campus of Lucerne University of Applied Sciences and Art (Switzerland)

With the Polysun software from Vela Solaris you can rely on a multi-practice simulation of your energy system with reliable results in terms of functionality, energy efficiency and profitability – from single-family homes to districts, worldwide and for all market-standard technologies.