 |
According to the "Popular Science" website on August 1 (Beijing time), thermal photovoltaic systems (TPV) can convert heat into electricity, but its conversion efficiency has been relatively low. American scientists have developed a new method. After a tungsten surface is operated, the light waves released by it can be used to the maximum by the photocell. Based on this idea, we have developed a button photoelectric cell whose energy conversion efficiency is 4 times that of a lithium-ion battery of the same size and weight. Related research was published in the magazine "Physical Review A".
Half a century ago, scientists developed a thermo-photovoltaic system that allows a photovoltaic cell to be “coupled†with any source of heat to heat a material called a heat emitter. Later, the heat emitters would face the photovoltaic cells. Diodes emit light and heat to generate electricity. This thermal emitter emits more infrared light than the solar spectrum. The low-energy bandgap photovoltaic materials that were introduced 10 years ago can absorb more infrared radiation than standard silicon-based photovoltaic cells. However, the waste of heat has always been severe, making these devices less energy efficient.
Ian Selanowitz, an engineer at the Massachusetts Institute of Technology’s Military Institute of Nanotechnology (ISN), who led the study, said that the solution is to design a new thermal emitter that only emits light-emitting diodes for photovoltaic cells. It absorbs, and converts it to the wavelength of electricity as much as possible, while suppressing other wavelengths.
The team of Seranovitic etched billions of nanometer-sized pits on the surface of tungsten. When tungsten absorbs heat—whether the heat comes from the sun, hydrocarbon fuels, decaying radioactive isotopes, or other heat sources—it emits bright light, and the emission spectrum constantly changes because each pit is like a resonator, energy Release light waves of a specific wavelength.
Based on this, they created a coin cell battery, which is fueled by butane. The running time is four times that of a lithium-ion battery of the same weight. When the power is exhausted, the battery can be charged immediately by adding a small amount of fresh fuel. They also created another battery, which is powered by the decay of a radioactive isotope. It can continue to generate electricity for 30 years without the need for fuel or maintenance. It is expected to be an ideal power source for long-time space missions.
The data provided by the US Department of Energy's Information Management Center shows that 92% of the energy used today needs to undergo the process of converting thermal energy into mechanical energy and then into electrical energy. However, existing mechanical energy systems are relatively inefficient and cannot be reduced in size for use in sensors, smart phones, or medical monitoring devices.
Selanowitz said: “It is very practical to be able to convert heat from different sources into electricity without moving parts. It is very important to do this cheaply and effectively and on a small scale.†Seranowitz is confident that further research The battery's energy density can be increased by a factor of three. "By then, the new battery will enable smartphones to continue to use for a week.
TV Stand Fixed Wall Mount Co.,Ltd , http://www.nstvstand.com