How do solar panels work ?
It is common knowledge how solar panels work during the day. The vast majority of people will be able to tell you that they collect rays of light, which are then converted to energy in the form of heat. However, only true enthusiasts will be able to describe the exact process of their operation.
However, regardless of the level of knowledge generally available about the use of solar panels, the use of night-time panels remains a novelty for many.
Surprisingly, very rapid progress is being made in this field. There is real optimism about how solar panels could generate a significant amount of energy at night in the future. This offers the possibility of developing a hybrid system that could use current ‘conventional’ solar panels and a new form of ‘night-time solar panel’.
Operation of night-time panels
While the term ‘night-time solar panel’ will surprise many people, the project has a strong scientific rationale and is steadily gaining in popularity.
The science behind the development of night-time panels is based on research presented by Tristan Deppe and Jeremy N. Munday, researchers at the University of California Davis.
In their paper, Deppe and Munday point out that a panel that would operate at night is only able to generate 25% of the energy compared to traditional solar panels. Their aim is to improve the efficiency of these panels, which already have considerable potential for creating hybrids.
By using a concept where the night sky is used as a heat sink and the ground as a heat source – a photovoltaic cell that generates energy at night can be effective. Put simply, while conventional solar panels are cold, the sun is hot. The concept of nighttime panels would essentially reverse this way of working, by emitting infrared radiation, which would then form electron-hole pairs in space, thanks to the low temperature.
Tristan Deppe / Jeremy Munday
(A conventional photovoltaic or solar cell (left) absorbs photons of sunlight and generates electricity. A thermoelectric cell (right) generates electricity by emitting infrared light (heat) towards the extreme cold of space. UC Davis engineers suggest that such cells could generate a significant amount of energy and help balance the power grid on a day-night cycle).
”An ordinary solar cell generates energy by absorbing sunlight, which causes voltage to appear on the device and current to flow. In these new devices, light is emitted instead, and the current and voltage go in the opposite direction, but still generating energy. This requires the use of, different materials, but the physics remains the same”
How do the night panels compare with conventional panels ?
Although using only night panels would not be as effective as using conventional solar panels, it is worth mentioning that the run time of night panels is much longer.
The fact that they use conventional fuel sources for part of their process can be seen as a disadvantage. However, there is a theory that says they can work by using energy left over from other existing industrial processes. So hypothetically, if they were available for use today, they could serve as a tool to achieve carbon neutrality.
Currently, Munday and his colleagues are in the prototype building stage, aiming to turn his theory into practice. They plan to build new panels suitable for widespread use, functional and able to rival traditional ones. A prototype has already been developed, by Munday. It worked, but was only able to generate 25% of the power that a conventional panel could provide. This is no small achievement, highlighting that further research and development could lead to an increase in its efficiency.
It is reasonable, in this case, to say that we can expect a long wait before these panels move, from the design stage to the finished product. However, with rapid progress, we see not only the technological possibilities of solar energy, but also more government funding and public support for the sector.