Experimental assessment of a phase change material storage tank

• A storage tank with PCM capsules was tested experimentally.
• The complete data set from all tests (3 repetitions/test) is made available.
• State of charge cannot be determined from outlet temperature.
• Interrupting cooling or heating alters phase change temperature.
• PCM behaviour varies but tank behaviour can be predicted from operating conditions.

This paper describes the experimental study carried out to assess the performance of a Phase Change Material (PCM) storage tank in various operating conditions in a dynamic test bench. The studied horizontal PCM tank contains stacks of slab-like PCM capsules between which heat transfer fluid can circulate. The commercially available capsules were instrumented so the PCM behaviour could be measured in addition to that of the PCM tank as a whole. Numerous melting and solidification cycles were completed with different inlet fluid temperatures, flowrates and load profiles for which at least three repetitions were made. Analysis of test results shows significant variations in the PCM behaviour under the same tests conditions including varying degree of supercooling and differing phase change temperature. The outlet fluid temperature from the tank can however be predicted accurately from operating conditions and the initial state of the PCM. Interrupting phase change processes before the PCM is completely melted or solidified affects the temperature at which the PCM changes phase as well as the degree of supercooling measured. Results from this investigation will be especially useful for researchers developing and validating numerical models for use in various building energy systems as the complete experimental data set is made available as an online companion to this paper.