Solar panels are a popular form of harvesting clean energy, but they have their limitations. They work best in bright, direct sunlight, so overcast and rainy days can limit energy efficiency. As for nightfall, solar panels can’t work without direct or indirect sunlight. However, in the latest and remarkable invention a new type of solar panel has been developed that can generate electricity at night.
Traditionally solar panels, or photovoltaic cells, have suffered from the effects of changeable seasons and the fact that they don’t work at night. From cloudy weather to dwindling day length, it’s not just the dusk that stops them from providing a viable renewable energy source. But now specially designed panels could help solve the current problems with solar energy, by generating power once the sun has gone down.
Methodology of Night Solar Panels
Researchers at Stanford University created a photovoltaic (PV) cell that uses a process called radiative cooling to allow for 24 hour renewable energy generation. It works by tapping into the heat being radiated from the surface of the solar cells as infrared light into outer-space on clear nights. By incorporating a thermoelectric generator into a conventional PV solar panel, the scientists achieved 50 mW/m2 nighttime power generation. Functioning like a conventional solar panel during the day to harvest the Sun’s energy, the panel then “runs in reverse” to keep generating electricity at night, however any clouds at night can hinder the system by reflecting the infrared radiation back to Earth.
In these new devices light is instead emitted and the current and voltage go in the opposite direction but it still generate power. They also work in the daytime if the light is blocked or if they are pointed away from the sun.
Efficiency & Performance of Night Solar Panels
The nighttime solar cells essentially work the same way as their daylight counterparts but in reverse. Every night, heat escapes the earth in the form of infrared radiation in order to keep the planet at a constant temperature. The nocturnal devices are able to generate up to 50 watts of power per square metre, a quarter of what conventional panels can generate in the daytime.
Research conducted this year now confirms these nighttime solar panels produce enough energy to charge a mobile phone. For now, the amount of energy produced in the tests is incredibly small compared to solar panel output, about 0.001%. But it does show hope in developing solar panels that can produce energy, even at night. For now, the team is looking to do more research and form industry partnerships.
By
Editorial, Infocus
