A novel thermoelectric generator (TEG) design by PNNL allows the conversion of ambient thermal energy into electric power for a variety of low-power uses. These miniature TEGs are able to power wireless sensors and their associated radio frequency transmitters used in a wide range of remote monitoring applications including building energy management, automotive component controls, agricultural monitoring, security surveillance, and wildlife management.  

The Thermoelectric Ambient Energy Harvester uses an assembly of ultra-thin thermocouples in a unique configuration that can exploit small (>2°C) temperature differences occurring naturally in the environment of the application (i.e. ground to air, water to air, or skin to air interfaces). The TEG is constructed from reliable and stable components that offer maintenance-free, continuous power for the lifetime of the application.   

The individual thermocouples, which are typically no more than 1 cm high by 1.5 cm wide and only a few micrometers thick, are deposited in a linked “chain” onto a thin, flexible plastic substrate (similar to camera film), using sputtered thin-film deposition techniques developed by PNNL. This plastic substrate is coiled around a spool enabling up to several thousand thermocouples to be assembled into a cylindrical TEG  1 to 2 cm in diameter.  Depending on the magnitude of the temperature range they experience, their electrical output can be designed over a range from a few microwatts to 100’s of milliwatts and more.

PNNL evaluated these miniature TEGs as power sources for wireless sensors used to optimize energy management in buildings, as part of the Building Technology Project conducted by PNNL for the U.S. Department of Energy. Other applications are currently anticipated in many areas including automotive performance monitoring, homeland and military security and surveillance, biomedicine, and wilderness area and agricultural management. The Thermoelectric Ambient Energy Harvester may be suitable for many other stand-alone, low-power applications not mentioned above.