Converting Electricity Into Heat And Vice Versa
A new University of Wollongong (UOW) study in Australia overcomes a major challenge of thermoelectric materials, which can convert heat into electricity and vice versa,improving conversion efficiency by more than 60%. Current and potential future applications range from low-maintenance, solid-state refrigeration to compact, zero-carbon power generation, which could include small, personal devices powered by the body’s own heat.
“The decoupling of electronic (electron-based) and thermal (phonon-based) transport will be a game-changer in this industry,” says the UOW‘s Prof Xiaolin Wang.
Bismuth telluride-based materials (Bi2Te3, Sb2Te3 and their alloys) are the most successful commercially-available thermoelectric materials, with current and future applications falling into two categories: converting electricity into heat, and vice versa:
- Converting electricity into heat: reliable, low-maintenance solid-state refrigeration (heat pump) with no moving parts, no noise, and no vibration.
- Converting heat into electricity including fossil-free power generation from a wide range of heat sources or powering micro-devices ‘for free‘, using ambient or body temperature.
Heat ‘harvesting‘ takes advantage of the free, plentiful heat sources provided by body heat, automobiles, everyday living, and industrial process. Without the need for batteries or a power supply, thermoelectric materials could be used to power intelligent sensors in remote, inaccessible locations.
An ongoing challenge of thermoelectric materials is the balance of electrical and thermal properties: In most cases, an improvement in a material’s electrical properties (higher electrical conductivity) means a worsening of thermal properties (higher thermal conductivity), and vice versa.
“The key is to decouple thermal transport and electrical transport“, says lead author, PhD student Guangsai Yang.