Paint these days is becoming much more than it used to be. Already researchers have developed photovoltaic paint, which can be used to make “paint-on solar cells” that capture the sun’s energy and turn it into electricity. Now, in a new study, researchers have created thermoelectric paint, which captures the waste heat from hot painted surfaces and converts it into electrical energy. “I expect that the thermoelectric painting technique can be applied to waste heat recovery from large-scale heat source surfaces, such as buildings, cars, and ship vessels,” Jae Sung Son, a co-author of the study and researcher at the Ulsan National Institute of Science and Technology (UNIST), told Phys.org.
“For example, the temperature of a building’s roof and walls increases to more than 50°C in summer,” he said. “If we apply thermoelectric paint on the walls, we can convert huge amounts of waste heat into electrical energy.” In the new study published in Nature Communications, Sung Hoon Park et al., from UNIST, the Korea Institute of Science and Technology (KIST), and the Korea Electrotechnology Research Institute, have addressed this issue of incomplete contact by demonstrating that the thermoelectric paint easily adheres to the surface of virtually any shape. The thermoelectric paint contains the thermoelectric particles bismuth telluride (Bi2Te3), which are commonly used in conventional thermoelectric devices. The researchers also added molecular sintering aids which, upon heating, cause the thermoelectric particles to coalesce, increasing the density of these particles in the paint along with their energy conversion efficiency.
The researchers demonstrated that the thermoelectric paint can be painted onto a variety of curved heat-emitting surfaces. After sintering for 10 minutes at 450-degrees Celsius, the painted layers form a uniform film about 50 micrometers thick. Tests showed that the devices painted with the thermoelectric paint exhibit a high output power density. “We are planning on developing room-temperature-processable, air-insensitive, and scalable thermoelectric paint and painting processes for practical applications,” Son said.
— Source: www.phys.org
