Vibration harvesting» Vibration harvesting
Vibration harvesting is not yet a big business because it is difficult to get appreciable amounts of electricity from an affordable, reliable vibration harvester. Nevertheless, in development programs, it is the most popular alternative to the leading form of energy harvesting - photovoltaics - where adequate sunshine is not available and human power for electrodynamics in the form of crank driven dynamos etc is unavailable. That means industrial rather than consumer applications in the main. Harvesting of vibration is almost always carried out using electrodynamics, piezoelectrics or, less often, capacitive harvesting but there is a modest amount of work on alternatives, such as magnetostriction. It can rely on resonance: indeed that is the most popular option at present. In principle, all can be used for movement harvesting that is not vibration but vibration is the most ubiquitous and therefore the priority. The traditional inorganic lead zirconate titanate PZT is still the most commonly used material for piezoelectric harvesting but many alternatives are receiving some attention, usually where efficiency and temperature performance of the material itself is not the primary consideration but factors such as flexibility and light weight come to the fore. For instance, there are organic piezoelectrics such as polyvinylidene difluoride and below we look at nanotechnology applied to inorganic piezoelectrics such as zinc oxide nanowires.