Solar energy at night. Harvard physicists believe it’s possible
Federico Capasso and Steven Byrnes, Harvard physicists, believe a new type of renewable energy can be a solar cell-like device that could collect energy during the night. The idea that could change the solar industry is based on a principle: clean energy can be collected anytime a body transfers its hot energy to a cool body.
So, heated by the sun, our planet emits infrared radiations into the cool space. The solar cells we all know and appreciate can capture the energy from the sun during the day, but if connected to a emissive energy harvester, they could also do this at night.
“It’s not at all obvious, at first, how you would generate DC power by emitting infrared light in free space toward the cold. To generate power by emitting, not by absorbing light, that’s weird. It makes sense physically once you think about it, but it’s highly counter-intuitive,” as Capasso reports.
The two physicists discovered two types of models suitable. One could use modified cells to catch the infrared radiation. The process is named thermal EEH and it means the Earth would be a hot plate, and a cooler one would be above the ground. The accumulated energy would rapidly go into the air.
The idea is just in the concept phase tough. The scientist still don’t know if enough energy could be gathered from the process.
“It is possible to harvest energy from Earth’s thermal infrared emission into outer space. We calculate the thermodynamic limit for the amount of power available, and as a case study, we plot how this limit varies daily and seasonally in a location in Oklahoma,” said the team.
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