Improving thermal simulation: PCM characterization with heat flux measurements

greenTEG AG: Together with our partner GlassX AG we conducted a study to improve thermal simulations in building physics with a better understanding of the behavior of phase change materials (PCM).  An existing PCM window installation was thermally characterized with heat flux measurements.

Abstract

Phase Change Materials (PCM) are finding their way into buildings as high performance storage materials for improving energy efficiency. For construction planning, in terms of investment cost vs. cost savings by energy reduction, models are required. The theoretical models are often not accurate enough matching the real use case.

This study shows, how such models can be improved by characterizing existing PCM window installations made by GlassX in a new building using heat flux sensors from greenTEG’s gSKIN® U-Value Kit. Moreover, it is evident that heat flux measurements give a better general understanding of how to use the PCM installation.

For example, the results recommend that it is crucial to shadow the PCM window in summer to get the full effect of cooling. Furthermore, it was shown, that the model could be improved drastically through calibration. For an outlook it can be concluded, that the model even could further be optimized by adapting the heat transfer coefficient. Also there is high potential in using heat flux sensors for measuring the state of the PCM material, which will become important for controlling the material actively (by ventilation or air-condition) to optimize the insights gained from weather forecasts.

• Full study available for download here