Experimental analysis and validation of a numerical PCM model for building energy programs

Abstract

The increase in peak electricity demand in recent years has stressed the importance of peak electricity demand shifting technologies. Phase Change Materials (PCMs) have a potential to improve the building envelope by increasing the thermal mass as well as contribute to a significant peak shift in whole building power demand. Therefore, special attention is given to properly capture the thermal behavior of PCMs in advanced building energy modeling software. Design of effective PCM thermal storage systems requires accurate energy modeling. There are analytical and numerical models developed during last few decades for this purpose, many have not been fully validated. Based on the current status of literature, the study identifies the limitations and drawbacks of existing methods. A parametric study is conducted to identify the optimum PCM thermo-physical properties, PCM locations in building envelope, under forced convection and a 5 hour pre-cooling strategy. Furthermore, an improved advanced numerical building envelope model is created in MATLAB to simulate the PCM performance in building envelope and an experimental apparatus is constructed to obtain useful experimental data for PCM included wall assemblies for validation purposes. This thesis also uses two datasets from laboratory studies of shape-stabilized and field studies nano-encapsulated PCMs to validate and compare PCM modelling algorithms of 6 modules in 5 building energy modelling software. Finally, two macroencapsulated PCMs (Bio based PCM and hydrate salts) are tested using the experimental apparatus to obtain data for validation purposes. To approximate the heat transfer through a wall assembly with PCM pouches several techniques are investigated that can capture 3D heat transfer characteristics. Method with the highest agreement is used to validate and compare the developed MATLAB algorithm and different building energy modelling software.