Researchers have designed a low-cost, off-grid modular energy source that can efficiently produce power at night. The system uses commercially available technology and can ultimately help meet nighttime lighting needs in urban areas or provide lighting in developing countries.
While solar energy offers many benefits, its use is highly dependent on the distribution of sunlight, can be limited in many locations and completely unusable at night. Energy storage systems created during the day are often expensive, thus increasing the cost of using solar energy.
To find a less expensive alternative, researchers led by Shanhui Fan from Stanford University turned to radiation cooling. This method uses the temperature difference due to the absorbed heat from the surrounding air and the radiant cooling effect of the cold space to generate electricity.
In the magazine The Optical Society (OSA) Optics ExpressResearchers have theoretically demonstrated an optimal radiant cooling method that can generate 2.2 Watts per square meter with a rooftop device without batteries or any lateral power. out. This is approximately 120 times the amount of power that has been experimentally proven and is sufficient to power modular sensors, such as those used in security or environmental applications.
Lingling Fan, the first author of the article, said: “We are working hard to develop a generation of sustainable, high-performance lighting that can be provided by everyone – including those in existing areas. development and rural areas – access to sustainable and low-cost lighting energy sources ”, said Lingling Fan, the first author of the article. “Modular power sources can also power off-grid sensors used in a variety of applications and used to convert waste heat from cars into usable energy.”
Maximize power generation
One of the most effective ways to generate electricity using radiant cooling is by using a thermoelectric generator. These devices use thermoelectric materials to generate energy by converting the temperature difference between the heat source and the cooler side of the device, or radiant cooler, into voltage.
In the new project, the researchers step-by-step optimized thermal power generation to maximize nighttime energy generation from a device that will be used on the rooftop. They improved the energy capture so that more heat was transferred into the system from the surrounding air and incorporated new commercially available thermoelectric materials to increase the equipment’s energy use. They also calculated that a thermoelectric generator covering one square meter of roof could achieve the best balance between heat loss and thermal conversion.
“One of the most important innovations is the design of a selective transmitter that attaches to the cooler side of the device,” said Wei Li, a member of the research team. “This optimizes radiant cooling so that the generator can drain excess heat more efficiently.”
Researchers have demonstrated a new approach by using a computer model to simulate a system with realistic physical parameters. The models faithfully reproduced previous experimental results and revealed that the optimized system designed by the researchers was able to roughly achieve what was calculated as maximum efficiency when used. heat converter.
In addition to performing experiments, the researchers are also examining the optimal designs for operating the system during the day, outside of the night, which could extend the actual applications of the system.
The cooling mechanism increases the solar capture capacity for self-powered outdoor sensors
Lingling Fan et al., Generating maximum power at night through optimized radiant cooling, Optics Express (Year 2020). DOI: 10.1364 / OE.397714
Provided by The Optical Society
Quote: Researchers design efficient low-cost systems for generating electricity at night (2020, August 13), retrieved August 13, 2020 from https://phys.org/news / 2020-08-e toan-low-cost-power-night.html
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