Currently, the usage of double-sided solar panels is consistently increasing. In order to manipulate both sides of those panels, the cells are placed either vertically or horizontally. Even when one side is not directly lightened, it can produce energy due to sunlight's reflections.
Nevertheless, until today, the amount of solar energy produced by the side that is unlit could not be predicted. The new study introduces a mathematical formula that utilizes the laws of thermodynamics to calculate the power produced assessing the performance of double-side cells.
The formula predicts the maximum power that the double-sided panel can produce in a range of physical environments and ground conditions (soil, concrete, grass etc.). Implementations of the equations derived show that, on average, the two-sided panels produce about 15-20% more energy.
The results show the terrain in which the sunlight is reflected is crucial to the amount of generated power. For example, the formula reveals significantly higher production when light is reflected on a concrete surface rather than on a surface with vegetation.
Muhammad Ashraful Alam, lead author of the study and Jai N. Gupta Professor of Electrical and Computer Engineering at the University of Purdue, mentions that the formula is quite simple but it was formed after years of solving complicated physics problems. He also added that calculating the exact amount of energy produced by double-sided panels is important for investments and development. “The formula involves just a simple triangle, but distilling the extremely complicated physics problem to this elegantly simple formulation required years of modeling and research. This triangle will help companies make better decisions on investments in next-generation solar cells and figure out how to design them to be more efficient,” Prof. Alam, stated.
The authors suggest that this formula will aid in manipulating more solar power and develop new technologies in the future. According to Mohammad Ryyan Khan, co-author of the study and Assistant Professor at East West University in Bangladesh, one-sided solar panels are currently an efficient mean to produce energy. However, their future development is highly limited because their efficiency cannot increase further while their cost cannot be significantly reduced. Therefore, manipulating the "dark" side is probably the only way for solar panels to develop. “It took almost 50 years for monofacial cells to show up in the field in a cost-effective way. The technology has been remarkably successful, but we know now that we can’t significantly increase their efficiency anymore or reduce the cost. Our formula will guide and accelerate the development of bifacial technology on a faster time scale,” Prof. Ryyan Khan, said.
Authors suggest the utilization of double-sided panels in farmlands and in buildings. In the first case, panels would be transparent in order to avoid creating large shadows over the crops while, in the second case, panels would be installed in buildings' windows and would produce significant amounts of renewable energy in cities.
Source: Purdue University