SEP 18, 2019 9:00 AM PDT

Prototype Generator Sucks Energy Out of "Complete Darkness"

WRITTEN BY: Daniel Duan

(Daniel Reche/Pixabay)

The way we humankind harvest energy has come a long way. Our ancestors burned organic matters (wood, wax, and dry grass), and took advantage of the kinetic energy of flowing water and air. Thanks to advances in science and technology, nowadays our society have access to a greater diversity of energy source, such as fossil fuels (coal, oil, and natural gas), renewables (solar and wind power), and nuclear.

Recently, a team of researchers at the University of California Los Angeles and Stanford University announced that they have developed a new device that can harness the process of heat release during nighttime for generating electricity, literally sucking the energy out of its surrounding.

This prototype device, capable of lighting a tiny LED bulb, actually shares certain similarities with solar panels, even though the ways they function seem like "day and night" apart.

Inside a solar panel, its semi-conductive parts are capable of creating electric potential upon exposure to sunlight. The absorption of photonic energy causes excitation of electrons and make them "jump up" to a higher-energy state. 

Depending on the type of semi-conductor, an excited electron can either escape or remain within the material. The former is known as the photoelectric effect, and the latter is called the photovoltaic effect, which is the energy harvesting mechanism of solar panels

Besides via the direct excitation of electrons, a photovoltaic effect can also be observed when a semiconductor gets heat up, which creates temperature gradients. 

Thermoelectric generators, such as the one developed by the Californian scientists, can generate electric currents by taking advantage of thermal gradients, a phenomenon known as the Seebeck effect (named after discoverer and physicist Thomas Johann Seebeck). 

Novel power generator harvesting energy and generating light (Aaswath Raman/UCLA)

As for the source of heat, one need not to look further than what's beneath our feet. After a full day of sunlight, the ground gets heat up and become warmer than the atmosphere. In the night time, the heat escapes through the radiative cooling effect, the loss of heat by thermal radiation. 

Humans have a long history to utilize this phenomenon. For example, in ancient India people invented a refrigeration method without the use of electricity: they made ice by placing a shallow ceramic tray covered by a thin layer of water outside under the night sky. The migration of heat from the water to its environment by convection was fast enough to allow the water to freeze overnight.

In their study, the proof-of-concept power generating system was constructed with a 20-centimeter (8-inch) aluminum disk painted black, which is connected to commercial thermoelectricity generators. As the disks radiate heat into ambient air, its thermoelectricity generator starts to work.

The researchers hopes that their design can address the problem of solar panels, which only generate power under the sun and don't work at night. Batteries can be used to store energy and mitigate the issue but they aren't cheap. And the use of rare metal for semiconducting materials in solar panel makes them less affordable and environmentally friendly.

With the future improvement of their prototype devices, scientists believe that they will be able to raise the efficiency of its power production and bring this up to 0.5 watts per square meter of the disk, which allows the system to light up a house overnight.

This latest invention is reported in the journal Joule.

Want to know more about the radiative cool effect? Check out this video from Stanford University.

Shanhui Fan | Nighttime radiative cooling: Harvesting the darkness of the universe (Stanford ENERGY)

Source: Gizmodo

About the Author
  • Graduated with a bachelor degree in Pharmaceutical Science and a master degree in neuropharmacology, Daniel is a radiopharmaceutical and radiobiology expert based in Ottawa, Canada. With years of experience in biomedical R&D, Daniel is very into writing. He is constantly fascinated by what's happening in the world of science. He hopes to capture the public's interest and promote scientific literacy with his trending news articles. The recurring topics in his Chemistry & Physics trending news section include alternative energy, material science, theoretical physics, medical imaging, and green chemistry.
You May Also Like
APR 22, 2020
Chemistry & Physics
Want to Peek at Atoms? There's a Microscope for That
APR 22, 2020
Want to Peek at Atoms? There's a Microscope for That
Optical microscopes can help us see the microscopic world, but to use them to examine individual atoms is like measuring ...
APR 24, 2020
Chemistry & Physics
Do you like your produce bacteria-free?
APR 24, 2020
Do you like your produce bacteria-free?
Researchers from Texas A&M University have developed a hydrophobic dual functionality coating that can be applied to ...
MAY 07, 2020
Chemistry & Physics
What can we learn from catnip?
MAY 07, 2020
What can we learn from catnip?
Findings from a recent study published in Science Advances report new insights on the evolution of a commonly enjoyed pl ...
MAY 28, 2020
Chemistry & Physics
Smart sponge selectively absorbs oil
MAY 28, 2020
Smart sponge selectively absorbs oil
New research published in the journal Industrial Engineering and Chemical Research describes the development of a smart ...
JUN 16, 2020
Technology
How True Is Teleportation?
JUN 16, 2020
How True Is Teleportation?
Teleporting worlds is something only seen through the lens of science fiction. For example, many Star Trek fans can reca ...
JUL 03, 2020
Chemistry & Physics
Uber white paint improves passive daytime radiative cooling
JUL 03, 2020
Uber white paint improves passive daytime radiative cooling
A report published in the journal Joule describes an innovative paint that is capable of reflecting up to 98% of solar h ...
Loading Comments...