Energy harvesting is a diverse field encompassing many technologies, which involve a process that captures small amounts of energy that would otherwise be lost as heat, light, sound, vibration, or movement. A thermoelectric generator (TEG) refers to a device that converts waste heat energy, such as solar energy, geothermal energy, and body heat into additional electrical power.
There has been a great increase in the study of wearable thermoelectric (TE) generators using the temperature difference between the body heat and surrounding environment. However, one of the main drawbacks of wearable TEG techniques driven by body heat was its temperature difference.
What is the measured temperature difference of wearable TEG techniques driven by body heat?
The temperature difference of wearable TEG techniques driven by body heat is only 1 -- 4 degrees Celsius.
A recent study, led by Professor Kyoung Jin Choi in the School of Materials Science and Engineering at UNIST has introduced a new advanced energy harvesting system, capable of generating electricity by simply being attached to clothes, windows, and outer walls of a building.
This new device is based on a temperature difference between the hot and cold sides. However, one of the main drawbacks of wearable TEG techniques driven by body heat was that such temperature difference is only 1 -- 4 degrees Celsius which hindered its further commercialization.
The research team solved this low temperature difference by introducing a local solar absorber on a PI substrate as shown above. The solar absorber is a five-period Ti/MgF2 superlattice, in which the structure and thickness of each layer was designed for optimal absorption of sunlight. This has increased the temperature difference as high as 20.9 °C, which is the highest value of all wearable TEGs reported to date.