Energy Harvesting Concepts

Interesting applications for energy harvesting have caught my eye recently. To get Wikipedia with it;

Energy harvesting (also known as Power harvesting or energy scavenging) is the process by which energy is captured and stored. Frequently this term is applied when speaking about small autonomous devices, like those used in sensor networks. A variety of different methods exist for harvesting energy, such as solar power, ocean tides, piezoelectricity, thermoelectricity, and physical motion.

The first example I came across was in Electronic Design, and the piece refers to piezoelectricity, an electric charge generated by certain materials (notably crystals and certain ceramics) in response to stress, pressure, shaping, etc.

The piece describes the application of such technology to potentially harvest the energy of the beating heart - which would be applicable for powering a pacemaker. Other applications discussed include piezoelectric pushbutton switches, which according to the piece, represent a large portion of potential applications - including powering your overhead lamp during air travel on a commercial airliner.

Then, in Green Options, I read about two grad students from MIT's School of Architecture and Planning that are devising a way to create a sub-flooring system made of movable blocks that harvest human energy created by the footsteps of crowds. The friction created by the blocks sliding against one another in response to the pressure above would create electrical current.

For further exploration, this piece in Electronics Design describes energy harvesting in greater depth, and reviews advances in the fabrication of materials made purposely for piezoelectric applications.