An Empirical Energy Model for Supercapacitor Powered Wireless Sensor Nodes

The modeling of energy components in wireless sensor network (WSN) simulation is important for obtaining realistic lifetime predictions and ensuring the faithful operation of energy-aware algorithms. The use of supercapacitors as energy stores on WSN nodes is increasing, but their behavior differs from that of batteries. This paper proposes a model for a supercapacitor energy store based upon experimental results, and compares obtained simulation results to those using an ´ideal´ energy store model. The proposed model also considers the variety and behavior of energy consumers, and finds that contrary to many existing models, the energy consumed depends on the store voltage (which varies considerably during supercapacitor discharge). Furthermore, energy models in a node´s embedded firmware are shown to be paramount for providing energy-aware operation.