Electricity is a major driving force behind industrial and civilization growth. But sources of electricity are becoming crucial because of pollution concerns. Scientists are digging hard to find alternative non polluting energy sources. A Malaysian entry into James Dyson Award proposed a solution to harvest electricity from waste heat. Dubbed PosHEAT, the solution applies ‘thermoelectric effect’ for generating electricity from wasted heat.
According to the ‘thermoelectric effect’ heat gradient creates a voltage difference. By physical principle, heat always trickles down from higher temperature to lower temperature zone. This flow of charge moves toward a particular direction creating voltage difference between both the sides – hot and cold ends of the conductor.
How it works?
The magnitude of voltage difference depends on the degree of heat gradient between both the ends of the conducting material and thermoelectricity or Seebeck coefficient of the material. PosHEAT project uses Bismuth Telluride as a conducting material for its high thermoelectricity. For higher voltage difference, PosHEAT uses several thermoelectric couples (bismuth telluride). A converter boosts the electrical energy, generated from heat, and stores in battery for future uses like cell phone charging and LED lighting. Energy generated by PosHEAT may not drive motors but their uses in charging smaller devices can free up traditional electricity partially.
Via: James Dyson Award