For decades we have been taught not to waste energy. We know that we should turn off lights and water when we aren't using them. We know we should insulate our homes to prevent heat loss and cut down on air conditioning. We know everything should be done as efficiently as possible. But still we are wasting an endless amount of energy and most of this is heat energy. It follows, of course, that scientists are working to find a way to turn that waste heat back into a usable energy source.
Physicists at the University of Arizona have created a simulation of a device with no moving parts that can convert heat directly into electricity. In theory, this device would eliminate ozone-depleting materials that are often carried along with the waste heat from factories and automobiles. This proposed device is expected to be 100 times more effective than previous attempts to use waste heat. It contains no machines or harmful chemicals. Alternatively, it is an electrode made of a polymer sandwiched between two metals. This device could feasibly help the solar power industry by eliminating the need for photovoltaic cells, instead converting the Sun's heat directly to electricity. It could also be used to increase the efficiency of electric cars by up to 25%.
Other waste heat utilization methods are also showing tremendous potential. Scientists at Northwestern University have discovered that by infusing nanocrystals of rock salt into lead telluride they can create a material that is capable of converting up to 14% of waste heat into usable electricity, an unprecedented amount. This could make energy production from vehicle exhaust, industrial facilities, machinery, and even sunlight more efficient than ever.
At the U.S. Department of Energy, scientists have discovered that lead chalcogenides undergo a change in their physical arrangement at the nanoscale level, allowing them to trap heat energy. When the material is exposed to heat on only one side, the trapped heat energy is then diffused over the surface. Researchers are currently trying to find a way to capture the energy created during this process.
Since we are always looking for new ways to produce renewable energy, wouldn't it be wise to look further into converting waste heat into electricity? Waste heat is created by almost every human activity: driving cars, operating equipment, manufacturing processes, and the deterioration of landfills. Simply capturing and utilizing as much of this waste heat as possible could fill a large portion of our energy need and, aside from the technology needed to capture and convert it, it would be cost-free. Considering this, waste heat could be the solution to many of our renewable energy problems.
