Energy comes in many forms, such as mechanical (or kinetic), nuclear, thermal, and electric. When we build machines and devices to do work for us, we usually power them with one form of energy but end up converting some of that into another form of energy that is lost as waste. Your car’s internal combustion engine, for example, converts chemical energy from gasoline into rotary motion, but also generates a lot of heat as a byproduct. Your car has a cooling system that requires even more energy just to deal with that heat. To put all of that wasted energy to use, engineers have developed a device that converts waste heat into clean electricity.
Cars aren’t the only source of wasted energy; no type of machine can achieve 100% efficiency. Friction and other factors will always cause some loss of efficiency, and the wasted energy often comes in the form of heat. Incandescent light bulbs, as another example, are considered bad for the environment because so much of the power that is put into them just gets emitted as heat instead of light. There is a list of example like that which is virtually endless. Thermoelectric generators can convert heat into electricity and Penn State ngineers have developed new devices that can harness waste heat energy more efficiently.
Thermoelectric generators aren’t new and are already used to collect waste heat energy in many applications, such as in power plants. This new device design is simply more efficient and tailored to use on a smaller scale. Each device is about the size of a matchbox and can be attached to a heat source. They are ideal for hot water pipes, for instance. As heat pass through the device, from the hot side to the cool side, it carries electrons and produces electricity. That electricity can then be used to power anything nearby, like sensors. They were able to improve the conversion efficiency in part by tailoring the design of the device to the particular heat source. An open flame would require a different design than a car’s muffler, because of heat transfer coefficient differences and other factors. This research will be invaluable for a more sustainable future as energy becomes more and more precious.