Solar panels are a valuable source of renewable energy but their performance is highly dependent on the conditions. First of all, until today, panels work during the day given that there are no clouds in the atmosphere to block the sunlight. When those panels produce more power than a household consumes, the excess energy is stored in batteries or is transferred to a power grid. Even so, due to their aforementioned limitations, the panels are considered as less efficient power sources.
According to Jeremy Munday, co-author of the study and a professor at the department of electrical and computer engineering at the University of California - Davis, to develop a panel capable of producing energy during the night, a technique that is opposite to the process that a conventional solar panel works was employed.
The method is based on the fact that a cooler object receives heat from a hotter surrounding one. Therefore, a typical solar panel absorbs heat from the sun. However, the developed device is designed to emit heat during the night to the environment.
In particular, the developed panel has a higher temperature than its surrounding environment during the night and heat is transferred in the opposite direction. This procedure does not affect the power storage. "A regular solar cell generates power by absorbing sunlight, which causes a voltage to appear across the device and for current to flow. In these new devices, light is instead emitted and the current and voltage go in the opposite direction, but you still generate power. You have to use different materials, but the physics is the same," Prof. Munday, stated.
The researchers created a photovoltaic cell capable of generating about 1/4 of the total power that a normal solar panel can produce (200W per square meter) during the day. Scientists are optimistic about increasing the efficiency of the new devices.
The panels could be heated by residues produced during industrial procedures, highly reducing the global environmental footprint.
Click the video below to watch details about how the new panels work.