In recent years, the urgency of tackling global warming has been greater than ever, and the threat posed to humanity by climate change is growing. A report by the Intergovernmental Panel on Climate Change (IPCC) at the end of 2018 shows that in order to keep global temperature rises below 1.5C (compared to pre-industrial levels), we must ensure that carbon emissions are reduced by 45 per cent by 2030 and to zero by the middle of this century.
However, renewable seusit alone is difficult to do. It is also controversial whether 100% renewable energy can actually help humans fight climate change. At the heart of the debate is that the two biggest renewable sources, wind and solar, are “variable”. They change every day and are “non-regulated”.
Radiation cooling: “Anti-solar” device sitlifted
However, new breakthroughs in clean energy technologies may offer hope. Researchers at the University of California, Los Angeles and Stanford University have invented a new “anti-solar” device that can make up for the limits of solar energy and generate electricity in the dark for human use.
Appearance of “Anti-Solar” Devices AASWATH RAMAN
The device uses the concept of radiation cooling, in which objects on the Earth’s surface radiate heat into the atmosphere when the sky is cool at night, making it cooler than ambient air. Researchers at both universities have previously used the same concept to create a passive cooling system with very low energy consumption. In the study, the researchers used the same concept to generate electricity at night using temperature differences.
To create this new device for night-time renewable energy, the team began research ingening a commercial thermoelectric module that converts temperature differences into electrical energy. They fixed one side of the thermoelectric module to a 20 cm wide aluminum disc coated with a layer of commercial black paint. The researchers then placed it on a plastic attachment covered with polyester film and covered it with a transparent lid.
The covered side faces the sky and radiates heat to the sky, keeping it below the ambient air. The other side of the unit is made of an uncoated 20 cm aluminum plate, which is heated by ambient air to match the ambient air. At night, the temperature difference between the two plates will be several degrees Celsius.
Device schematics . . . AASWATH RAMAN
The painted disk acts as a radiation emitter, and when heat is radiated from the earth’s surface into the air, it enters the disk through a thermoelectric module, which then radiates heat upward. During the day, the device works in reverse to absorb sunlight, generating electricity using the heat that the sun transmits to the disk and the heat emitted into the external environment.
On a cloudless night in December 2018, researchers tested the model at Stanford University. The plant generates 25 milliwatts of electricity per square metre, which means it generates enough power to light an LED bulb at night. Other small electronic devices are also perfectly adequate, such as hearing aids with a power of about 1 milliwatt, or a laser pointer with a power consumption of about 5 milliwatts.
The advantages and disadvantages of new technology
The researchers say the device, which costs only $30 (about 214 yuan) to build, should be easy to produce on a large scale. But in the future, such equipment will require further engineering improvements, such as better insulation or increased radiator area. They say the device is more efficient in dry, warm conditions such as the Mediterranean or desert climate, producing 0.5 watts of electricity per square metre.
Light bulbs lit with this device . . . AASWATH RAMAN
To keep the Earth at a roughly constant temperature, the energy from the sun must be about the same as the heat that the Earth radiates, said Shanhui Fan, a professor of electrical engineering at Stanford University and the study’s author. This means that the energy available for “anti-solar cells” is huge.
Aaswath Raman, co-author of the study and an assistant professor of materials science and engineering at the University of California, Los Angeles, said the device is inefficient and cannot be compared to solar energy even at its limits, perhaps less than one percent of solar energy. But it’s low-cost, has a longer life than a battery, and has a wider range of applications than solar energy. Of course, it also provides a new way for humans to generate electricity when solar panels fail.
From proof of concept to practical use
The study, published in the journal Joule, found that 1.3 billion people on Earth lack reliable electricity. Although there are solar cells, these people also need night lighting, and the use of solar panels for battery storage can increase costs. So the researchers devised this technology for night-time power generation.
But for now, it’s just a proof of concept. The researchers believe that the device’s power generation will increase under more desirable conditions, such as increased insulation. With a larger disc, the device may be able to provide continuous lighting for a home.
An improved version of this night-time power plant is likely to light up a room one day, charge your phone, or power other electronic devices in remote and resource-poor areas. As a result, these areas are able to power normally when solar panels are not working at night.
Maybe one day this new technology will power your phone. Pixabay
Next, the researchers plan to improve it, for example by enhancing the insulation around the roof. The potential applications of this technology in the future are limitless. If the technology eventually improves and generates about the same amount of electricity as standard solar panels, it will transform the renewable energy industry as one of the strong contenders to replace fossil fuels.
Photo Source: Pixabay
This “Anti-Solar Panel” Could Generate Power From Darkness
Link: http://www.anthropocenemagazine.org/2019/09/65341/(This article contributed to storythings)