A cm scale electret-based electrostatic wind turbine for low-speed energy harvesting applications. (14th March 2016)

• Record Type: Journal Article
• Authors: Perez, M; Boisseau, S; Gasnier, P; Willemin, J; Geisler, M; Reboud, J L
• Is Part Of: Smart materials and structures. Volume 25:Number 4(2016:Apr.)
• Publication Date: 2016-03-14
• Subjects: energy harvesting -- airflows -- windmill -- electrostatic converter -- electret -- wireless sensor network; Smart materials -- Periodicals; Strucural design -- Periodicals; 620.11
• DOI: 10.1088/0964-1726/25/4/045015
• Languages: English
• ISSNs: 0964-1726

Abstract

Abstract: This paper presents a small-scale airflow energy harvester built on an axial turbine architecture and exploiting an electret-based electrostatic converter. When the airflow velocity is high enough, the windmill starts rotating and creates a periodic relative motion between a stator and a rotor which induces variations of capacitance. These ones are directly converted into electricity thanks to the use of Teflon electrets charged at −1400 V which polarize the variable capacitors. We focus our study on a 4-blade axial turbine with a diameter of D = 40 mm, a depth of W = 10 mm, for a total volume of 12.6 cm 3 . This windmill has been tested with various blade angles and different types of electrostatic converters and output powers up to 90 μ W at 1.5 m s −1 (7.5 μ W cm −3 ) and 1.8 mW at 10 m s −1 (111 μ W cm −3 ) have been obtained so far. The coefficient of power reaches C p = 5.8% and among the small-scale airflow energy harvesters previously reported, this one has the lowest cut-in speed (1.5 m s −1 ).