AdaptivEnergy has developed Joule-Thief™, an energy harvesting technology for use in environments containing both resonant, non-resonant, and impact-type ambient mechanical energy. In its present form and application space, the technology powers such devices as wireless switches, wireless sensor networks, and Active RFID tags in transportation and industrial environments. Joule-Thief provides a high energy density energy harvesting solution that provides a self‐powered intelligent sensor solution.
We are surrounded by significant amounts of energy which goes to waste; heat, sound, vibration, RF, solar, etc. AdaptivEnergy's Joule-Thief™ products convert otherwise wasted mechanical energy such as impulse shock, vibration, and footfall into usable amounts of electrical energy. This converted electrical energy can then be used to directly power electrical devices, be collected for intermittent higher power devices, or stored for later use.
These products are based on piezoelectric elements; ceramics and thin films. Piezoelectric materials generate an electric potential in response to applied mechanical strain or stress. Joule-Thief™ technology exploits this physical characteristic by extracting this electrical potential and converting it into electrical energy via their Energy Key™ electronics. The Energy Keys™ are a series of low or zero power, low leakage, high efficiency energy conversion and collection circuits with the right energy storage selected for capacity, current delivery, and environmental extremes. Piezoelectric materials allow for scalability to very small size while being sensitive enough to perform under barely perceptible levels of motion (vibration down to 10 milli-g's).
In all applications, the stress state of the piezoceramic materials is controlled in the compressive regime for high reliability. These products have been tested to billions of cycles with all components controlled below their endurance limits. They also function well over a wide temperature range of -40 C to >+85 C. The result is a "forever" power solution.
Depending on an application's environment and power needs, AdaptivEnergy's Joule‐Thief™ technology can either autonomously power the application as the sole power source, act as a recharging source for its batteries, or even augment non‐rechargeable batteries to extend device lifetime. Using freely available vibrational energy makes the end application independent from the finite lifetime of batteries and the physical challenges of running power lines. The result is a longer‐lasting, autonomous product with significantly lower installation and maintenance costs.
AdaptivEnergy presently offers four standard vibration‐based energy harvesters, in addition to the high power density (HPD) product line which will be available later in 2009.
Top image source: Mouser Electronics
For more attend: Energy Harvesting & Storage USA 2009