Researchers have designed an off-grid, low-cost modular energy source that uses radiative cooling to efficiently produce power for lighting at night.
Lingling Fan and Wei Li, Stanford University
Rooftop radiative cooling system could provide lighting power when solar energy is unavailable
Researchers have designed an off-grid, low-cost modular energy source that can efficiently produce power at night. The system uses commercially available technology and could eventually help meet the need for nighttime lighting in urban areas or provide lighting in developing countries.
Although solar power brings many benefits, its use depends heavily on the distribution of sunlight, which can be limited in many locations and is completely unavailable at night. Systems that store energy produced during the day are typically expensive, thus driving up the cost of using solar power.
To find a less-expensive alternative, researchers led by Shanhui Fan from Stanford University looked to radiative cooling. This approach uses the temperature difference resulting from heat absorbed from the surrounding air and the radiant cooling effect of cold space to generate electricity.
In The Optical Society (OSA) journal Optics Express, the researchers theoretically demonstrate an optimized radiative cooling approach that can generate 2.2 Watts per square meter with a rooftop device that doesn’t require a battery or any external energy. This is about 120 times the amount of energy that has been experimentally demonstrated and enough to power modular sensors such as ones used in security or environmental applications.
“We are working to develop high-performance, sustainable lighting generation that can provide everyone – including those in developing and rural areas – access to reliable and sustainable low cost lighting energy sources,” said Lingling Fan, first author of the paper. “A modular energy source could also power off-grid sensors used in a variety of applications and be used to convert waste heat from automobiles into usable power.”
Maximizing power generation
One of the most efficient ways to generate electricity using radiative cooling is to use a thermoelectric power generator. These devices use thermoelectric materials to generate power by converting the temperature differences between a heat source and the device’s cool side, or radiative cooler, into an electric voltage.
In the new work, the researchers optimized each step of thermoelectric power generation to maximize nighttime power generation from a device that would be used on a rooftop. They improved the energy harvesting so that more heat flows into the system from the surrounding air and incorporate new commercially available thermoelectric materials that enhance how well that energy is used by the device. They also calculated that a thermoelectric power generator covering one square meter of a rooftop could achieve the best trade-off between heat loss and thermoelectric conversion.
“One of the most important innovations was designing a selective emitter that is attached to the cool side of the device,” said Wei Li, a member of the research team. “This optimizes the radiative cooling process so that the power generator can more efficiently get rid of excessive heat.”
The researchers demonstrated the new approach by using computer modeling to simulate a system with realistic physical parameters. The models reproduced previous experimental results faithfully and revealed that the optimized system designed by the researchers could come close to what has been calculated as the maximum efficiency using thermoelectric conversion.
In addition to carrying out experiments, the researchers are also examining optimal designs for operating the system during the day, in addition to nighttime, which could expand the practical applications of the system.
The Latest Updates from Bing News & Google News
Go deeper with Bing News on:
Rooftop radiative cooling
- Coors Light Unveils Energy-Efficient Rooftop Ads, Inspiring Americans to Reduce Home-Cooling Costs This Summer
Globally, 2021 was ranked the fifth warmest year on record since 1880.* Heat waves are more frequent, and in Miami, there have been more 90-degree days than ever before. Air conditioners are humming ...
- Israeli Startup Using Sunlight To Cool Cars Strikes Deal With Volkswagen
The cooling effect is created when natural sunlight generates a reaction in SolCold’s cooling material converting the heat accumulated in the object into radiation and releasing ... be presented with ...
- This rooftop coating uses sunlight to actively cool your house
A second layer in the material reacts to specific radiation, emitting particles of light at a higher frequency. That makes the material lose energy and get cooler. When it’s attached to a roof ...
- Solar cell keeps going after sunset
At night, the cells lose heat to their surroundings, leaving them several degrees cooler than the ambient air due to radiative cooling ... Fan and colleagues tested their device on a rooftop at ...
- Radiation watchdog chief condemns Russia's 'very very dangerous' occupation of Chernobyl
Chernobyl's radiation levels are have returned to normal ... generators to support the critical work of circulating water for cooling the spent fuel rods. Russia's invasion marks the first ...
Go deeper with Google Headlines on:
Rooftop radiative cooling
Go deeper with Bing News on:
Thermoelectric power generator
- A Ridiculous Way To Light An LED: Candle-power
If you’ve used a thermocouple thermometer or a semiconductor thermoelectric generator then you’ll ... and has just enough power to light an LED. While it might seem pointless to barely light ...
- 3D-Printed Thermoelectric Device Sets New Efficiency Record
“Turning waste heat into electrical power can boost energy efficiency significantly ... and then a 3D-printing technique that uses that ink to produce a small thermoelectric generator. In experiments, ...
- A wearable air conditioner? Chinese team creates wristband that could help beat the summer heat
We can use thermoelectric strings and textiles to make a comfortable thermoelectric generator that can create ... uses the heat of a wearer to power a watch that the company claims does not ...
- Thermoelectric Generator Shines Where The Sun Doesn’t
The drearier places on the planet might benefit from this high-power thermoelectric generator (TEG) developed and tested by [TegwynTwmffat] for use on a wood burning stove. The TEG modules ...
- Thermoelectric Generator Market Insights, Growth Analysis, Forecast to 2030
Market Research Future (MRFR) projects the thermoelectric generator market to advance ay an approximate rate of 14% from 2022 to 2030 (review period). We will provide covid-19 impact analysis with the ...