Due to its excellent performance, resistive random access memory (RRAM) has become one of the most appealing and promising types of memory. However, RRAM has significant problems concerning understanding and modelling the resistive-switching mechanism, despite being very promising from the perspectives of scalability and techniques. This paper presents an analysis of thermodynamic resistive switching and fundamentals of thermal energy flow in a ZnO-based RRAM stack. The field and thermal energy flow within the device are analysed using the thermodynamic process. The influence of parameter variations during the SET and RESET operations is shown and their effect on the switching characteristic is characterized. The real I-V characteristics show fixed current vibrations and field-driven ion transport is evidenced and more prominent at higher currents. It shows that the nucleation of the filament as well as the growth of the gap complements the increase in the free energy (FE) of the system. These studies contribute to better comprehension and account for SET-RESET characteristics, rightly unfolding the thermal energy flow during dynamic switching operations that causes device degradation and allowing stability for future data storage projections. © 2023 IOP Publishing Ltd.