Segment-Type Energy Harvester Powering Wireless Sensor for Building Automation

This paper presents an innovative design platform of piezoelectric energy harvester (EH), named segment-type EH, and its application to a wireless sensor. Energy harvesting technology is motivated to minimize battery replacement cost for wireless sensors, which aims at developing self-powered sensors by utilizing ambient energy sources. Vibration energy is one of widely available ambient energy sources which can be converted into electrical energy using a piezoelectric material. The current state-of-the-art in piezoelectric EH technology mainly utilizes a single natural frequency which is less effective when utilizing a random ambient vibration with multimodal frequencies. This research thus proposes the segment-type harvester to generate electric power efficiently which utilizes multiple modes by separating the piezoelectric material. In order to reflect the random nature of ambient vibration energy, a stochastic design optimization is solved to determine the optimal configuration in terms of energy efficiency and durability. A prototype is manufactured and mounted on a heating, ventilation, air conditioning (HVAC) system to operate a temperature wireless sensor. It shows its excellent performance to generate sufficient power for a real time temperature monitoring for building automation.