Corrosion of metal and metal alloy containers in contact with phase change materials (PCM) for potential heating and cooling applications

Thermal energy storage (TES) using phase change materials (PCM) can be used for load shaving or peak load shifting when coupled to a heating, ventilation, and air-conditioning (HVAC) system such as heat pump. In these systems the PCM is embedded in packages or used in bulk, so the compatibility of the encapsulation materials and the PCM is a key factor to ensure long operational life of the system. Although corrosion caused by salts is known from the chemical industry, when these salts are used as PCM no corrosion data is available, since the salts are used without being in water solution. Producing new corrosion data is essential for PCM utilisation in new applications. In this study the corrosion rate of two metals and two metal alloys when they are in contact with different salt hydrate PCM is evaluated; in total eleven PCM, being four of them commercial PCM, are tested. Since they are PCM to be used for heating and cooling applications they are classified in two different groups to present the corrosion study. Results present the recommendation of using each PCM with the different metals and metal alloys according to the obtained corrosion rate and visual observation of the samples.