Energy Harvesting Wireless Sensor Networks: Design and Modeling

Abstract

Wireless sensor nodes are usually deployed in not easily accessible places to provide solution to a wide range of application such as environmental, medical and structural monitoring. They are spatially distributed and as a result are usually powered from batteries. Due to the limitation in providing power with batteries, which must be manually replaced when they are depleted, and location constraints in wireless sensor network causes a major setback on performance and lifetime of WSNs. This difficulty in battery replacement and cost led to a growing interest in energy harvesting. The current practice in energy harvesting for sensor networks is based on practical and simulation approach. The evaluation and validation of the WSN systems is mostly done using simulation and practical implementation. Simulation studies, despite their wide use and merits for network systems validation, have some drawbacks such as long simulation times, and practical implementation without knowing the details of the parameters and mathematics involved is cost ineffective and waste lots of resources. In most times, the energy scavenged is directly wired to the sensor nodes. We, therefore, argue that simulation – based and practical implementation of WSN energy harvesting system should be further strengthened through mathematical analysis and design procedures. In this work, we designed and modeled the energy harvesting system for wireless sensor nodes based on the input and output parameters of the energy sources and sensor nodes. We also introduced the use of supercapacitor as buffer and intermittent source for the sensor node. The model was further tested in a Matlab environment, and found to yield a very good approach for system design.