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.

Energy Efficient TV with 0 Watt Standby Mode

Toshiba Corp is reportedly releasing a 32 inch (visual size) LCD TV model "Regza 32BE3" equipped with its so-called "Eco Chip." The Eco Chip consumption current is said to be as low as about 95μA. This chip is used to detect ON signals from the remote control after the TV is turned off. It cuts off the AC power entirely through a relay as if you an unplugged TV. As the result, the power consumption in standby mode is 0 watt. The relay and the sensor that receive signals from the remote are powered by a large storage capacitor. Unfortunately, the report does not state the size of this capacitor and what happens when you leave the TV off for a long time. I guess either the chip needs to turn on the relay and re-activate standby bias supply before the cap is discharged too low, or you would need to turn on the TV by hand if the cap is discharged. Also they did not state power consumtpion or internal power supply efficiency in active mode (I wonder if they use bridgeless PFC front end?) In any case, such a "zero power standby" circuit is cute, but it is nothing more than a marketing gimmick. Obviously, you need to charge the storage cap during on-mode of the TV set. Whatever energy you save in 0W standby mode you need to spend to put this energy into this cap.

More Troubles with Energy Efficient Bulbs

U.S. Consumer Product Safety Commission just announced a voluntary recall of LED night lights imported from China by Corvest Acquisition Inc. It was reported these LED lights can overheat, smolder, and melt which may cause burns to consumers. The affected part has model number SBD01 stamped on the back of the plastic base.