Converting Waste Heat to Electricity

A company called Nextreme Thermal Solutions, based in Durham, N.C developed a thermoelectric generator (eTEG) that converts heat directly to low-level electrical power. Their technology uses the Seebeck Effect in which the temperature difference between two metals creates an electrical potential difference. Their generator uses Linear Technology LTC 3108 ultralow voltage step-up converter and power manager chip and can produce voltages up to 5V at power level up to 1 mW on a temperature difference of 15 to 20°K (the temperature difference in Kelvin is the same as in Celsius). Higher temperature gradients will result in higher power. Such devices can be used to feed micropower wireless and battery-free sensors. Unfortunately, the eTEG power levels are not sufficient to increase efficiency of power supplies by recycling heat energy from heatsinks. Also unfortunately, the prices starting at about $500 make this technology cost-prohibitive for regular consumers and hobbyists. By the way, the thermoelectric effect has been known for almost two centuries since Thomas Johann Seebeck discovered that electrical current flows between two dissimilar metals which have different temperatures.