University of Washington researchers have created a power harvester that uses natural fluctuations in temperature and pressure as its power source. The device harvests energy in any location where these temperature changes naturally occur, powering sensors that can check for water leaks or structural deficiencies in hard-to-reach places and alerting users by sending out a wireless signal.

“Pressure changes and temperature fluctuations happen around us all the time in the environment, which could provide another source of energy for certain applications,” said Shwetak Patel, a UW associate professor of computer science and engineering and of electrical engineering.

A metal bellows about the size of a cantaloupe is filled with a temperature-sensitive gas. When the gas heats and cools in response to the outside air temperature, it expands and contracts, causing the bellows to do the same. Small, cantilever motion harvesters are placed on the bellows and convert the kinetic energy into electrical energy. The process powers sensors that also are placed on the bellows, and data collected by the sensors is sent wirelessly to a receiver.

The researchers say this technology would be useful in places where sun and radio waves can’t always penetrate, such as inside walls or bridges and below ground where there might be at least small temperature fluctuations.

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Also: Learn about Bi-Axial Vibration Energy Harvesting.