Published November 8, 2022 | Version V3.0
Software Restricted

TRNSYS Type 840: Simulation model for PCM/water storage tanks (Version 3.0)

  • 1. ROR icon Graz University of Technology


The simulation model Type 840 was developed at the Institute of Thermal Engineering, Graz University of Technology, within the framework of the European Project PAMELA (2004), the IEA SHC TASK 32 and a national research project (2006). The model enables a detailed simulation of water tanks with integrated PCM modules of different geometries (cylinders, spheres and plates) or tanks filled with a PCM slurry. An update was made by Christoph Moser in the European project Hybrid-BioVGE (2022). 

The heat transfer in the PCM modules is calculated assuming conduction only, convection effects in the liquid phase are neglected. The transient heat conduction in the PCM modules is modelled with a two-dimensional (cylinders, plates) or one-dimensional (spheres) finite differences approach. The phase change process is modelled with the enthalpy method, assuming the specific enthalpy as a continuous function of temperature. The model also takes into account the supercooling and hysteresis that occur with many PCMs. The model is available in a TRNSYS 17 and a TRNSYS 18 version.

Version 3.0 contains bugfixes concerning temperature sensor positioning and stratified charging via double ports.

Other (English)

We want to keep track of who is using the model. Therefore, if you would like to download the files, please write an email to We will then send you a link for the download.

Other (English)

The European Commission is thanked for funding the work undertaken as part of the project PAMELA (ENK6-CT2001-00507). 

The Austrian ministry BMVIT is thanked for the financing of the following projects:

  • "Fortschrittliche Wärmespeicher zur Erhöhung von solarem Deckungsgrad und Kesselnutzungsgrad sowie Emissionsverringerung durch verringertes Takten, Projekt zum IEA-SHC Task 32" Proj. Nr. 807807
  • "N-GL. IEA SHC; Task Solarthermische Anlagen mit fortschrittlicher Speicher¬technologie für Niedrigenergiegebäude" Proj. Nr. 805790

The financial support of the European Union's Horizon 2020 Research and Innovation Programme under grant agreement number 818012 (Hybrid-BioVGE) is gratefully acknowledged.


The record is publicly accessible, but files are restricted to users with access.

Additional details

November 8, 2022
April 26, 2023