Comparison of conventional and regenerative electrostatic energy harvesters

Abstract

This study presents a performance comparison of two green electrostatic energy harvesters based on force‐sensitive mechanically variable capacitors. A startup battery is required in the conventional electrostatic energy harvester to precharge the mechanically variable capacitor. This adds an extra element to the device and increases the harvester's size and weight. The proposed harvester does not need a startup battery, operates in a regenerative mode, and provides a similar output power. It has a compact size and can start from low voltages. The conventional and regenerative harvesters were developed using mechanically variable capacitors fabricated with renewable materials (i.e. nanocellulose and carbon‐coated nanocellulose). The flexible nanocellulose films and the cost‐effective fabrication process make the energy harvesters suitable for powering low‐power and wearable devices. The bio‐based materials further reduce the environmental impact of the devices. Prototypes of the two energy harvesters were built, and their performances were compared on the basis of simulation and measurement results. Both simulation and experimental results are shown to demonstrate the startup and scalable energy availability of the proposed regenerative electrostatic energy harvester for driving low‐power devices, such as wireless sensor networks.

Keywords

• regenerative electrostatic energy harvesters
• green electrostatic energy harvesters
• force-sensitive mechanically variable capacitors
• startup battery
• regenerative mode
• renewable materials