Energy harvestingfrom floor using organic piezoelectric modules

Abstract

First, energy harvesting from floor is described as a sustainable method to generate electrical energy. Different solutions, available on the market, will be considered and evaluated. Second, the design, fabrication and test of organic piezoelectric harvesting modules will be discussed. These modules shall be used directly beneath the first layer of the floor to gain energy from people walking across this area. The harvesting modules consist of a polymeric thin film of PVDF. PVDF shows piezoelectric properties if it was be stretched during or after the foil fabrication. Besides this stretching, it is required to polarize the PVDF, too. This polarization process is fortunately realized at temperatures above room temperature. The better the polarization process the better the conversion efficiency of the material. Although the values of voltage conversion are not as high as with PZT-ceramics, PVDF offers some interesting properties making it very useful for such harvesting applications. Due to the use of organic polymers, the modules are characterized by a great flexibility and the possibility to create them in almost any geometrical size. The fabrication process of the harvesting modules is very simple and suited for mass production. Harvesting modules are built up as roller-type capacitors. The energy yield was determined depending on the dynamic loading force and the thickness of piezoelectric active material. An increase of the energy yield at higher loading forces and higher thicknesses of the modules is possible in general.