PCM-Based Energy Storage System with High Power Output Using Open Porous Aluminum Foams

Thermal comfort (heating, ventilation and air conditioning, HVAC) and the energy consumption involved with it can put a strain on the driving range of fully electric vehicles (FEV), especially in certain times of the year as midsummer or winter. In order to reduce the energy consumption of HVAC, improved thermal management and adapted means of energy storage are needed. One part of the solution can be the use of phase change materials (PCM) for storing waste heat. For the specific application, however, a high loading/unloading power rate is required, which is challenging as the PCMs exhibit low heat conductivities. In the presented work, a storage demonstrator system was investigated which is part of an HVAC system of a specific fully electric vehicle. The profile of requirements of the system (power, stored capacity and allowed volume) make a new design of the storage necessary. Two demonstrator units, in which the PCM was combined with aluminum foam, were manufactured and their power output in dependency on the fluid flow of the coolant system was compared. An adapted squeeze casting process with polymer placeholders was used for the production of the aluminium foam. This process results in foams with a specific pore structure and allows the in-situ integration of the heat transfer fluid (HTF) pipes. Both newly developed PCM storage systems satisfy the HVAC system requirements.