Numerical investigation of a PCM system for thermal management of large scale battery installation in remote area power systems

• New PCM configuration showed capability for thermal management of batteries. • Modelling results showed the capability of PCM to keep battery area around 47 °C. • 70% of PCM frozen in five and half hours using outdoor air as heat sink. • Optimal performance possible changing layout of electric-electronic devices. • Valuable insights into the viability of PCM using data from a real industrial case. Thermal energy storage can be used to fill the gaps caused by intermittency of renewable energy, as well as for thermal management of other systems including batteries and power electronic devices. This study investigates the potential of a thermal energy storage system to maintain temperatures below a certain limit as specified by a manufacturer of an existing battery energy storage in a remote site in Australia. The outdoor weather data from the Australian bureau of meteorology shows 39 °C as the mean maximum temperature during a hot summer day and an outdoor temperature of 27 °C to 35 °C for eight hours during the nights in a typical summer. Therefore, a phase change material (PCM) with melting point of 35 °C and heat of fusion equal to 198.8 kJ/kg was considered suitable to absorb heat, melt during the day, and solidify during the night with temperatures below 35 °C. Using ANSYS-Fluent, transient modelling of flow, mass and heat transfer was carried out under constraints defined by the layout of devices, heat rejected and outdoor conditions. For the inverter enclosure, the first arrangement of PCM panels covered the side walls and top of the enclosure while in two other arrangements, PCM panels with fins and fans were added. The average temperature reduced from 75 °C to 65 °C in the second arrangement with fins and to 60 °C with fans driving forced convection heat transfer. The results for the inverter enclosure showed that solidification of the PCM using outdoor air overnight is possible for the cases of minimal or no heat rejection. For the battery enclosure, PCM panels were included at the side walls and top of enclosure in addition to smaller PCM panels arranged in between the battery modules as a second model. The predicted battery temperature from the first model was 55 °C while for the second model with lower temperature gradients, it was 47 °C. The maximum temperature of batteries reaches 46 °C with the current air conditioning. Therefore, the PCM system is a viable alternative to maintain the interior temperature in the desired range if adequate space for PCM panels and air circulation are considered in future designs and layout of battery energy storage systems.