Researchers suggest better use of photovoltaic energy through an integrated device
The energy crisis in Brazil signals the urgent need for new solutions for energy generation. According to the Generation Information System (SIGA) of the National Electric Energy Agency (ANEEL), the electrical generation capacity in Brazil is currently made up mainly of renewable sources (82,69%), with only 2,14% originating of solar energy. In a scenario with room for new technologies, researchers from the “Gleb Wataghin” Institute of Physics (IFGW) at Unicamp developed a hybrid system that responds to this demand for more sustainable alternatives.
Working in the field of Photonics, professor Newton Frateschi and researcher Arthur Vieira de Oliveira suggest the best use of photovoltaic energy through an integrated device, with special application in industries. It enables fluid heating and photovoltaic generation with increased efficiency of each element of the system, in a complementary and innovative way.
"The main starting point for this patent is the excessive consumption of electricity used in Brazil to heat water”, assesses the professor. “As it happens today, the same energy source capable of sustaining the activity of a computer, or complex and sophisticated processes, is used for the most trivial task possible in the use of electricity, which is heating water. The idea is to have a system that generates electricity through photovoltaic conversion coupled to a direct water heating system,” he describes.
Much of the solar energy that falls on photovoltaic cells is not used in this conversion, being reflected and wasted. In the proposal, the arrangement of photovoltaic panels is such that this reflected energy is directed to impact directly on water heating systems, simultaneously promoting the generation of electrical energy and heating. Furthermore, as water passes under the photovoltaic cells before heating, they become more efficient by being cooled, particularly when the required water flow is high, as occurs in several industrial sectors and even in hotels and other large installations. .
Complement in energy generation
"While in Europe and the United States the use of photovoltaic energy is already much more structured and electrical water heating systems are less used, in Brazil we still find many electrical systems for water heating, despite many places already having systems direct solar water heating. But the presence of photovoltaic panels is still low”, compares Professor Frateschi.
Since direct solar water heating systems and photovoltaic systems compete for the same spaces for sun exposure, it is important to have a solution that does not favor photovoltaic generation so that it is then lost to water heating. The hybrid system provides a solution combining the two systems in an efficient and sustainable way of generating electrical energy and, in a complementary way, water heating.
The technology innovates by developing a system that simultaneously couples water heaters and photovoltaic cells within the same structure. This structure can then be installed in the same way as photovoltaic converters or water heaters, with the advantage of offering, in addition, water heating.
Furthermore, in cases of industrial use, hotels or large installations, where the demand for heated water is greater, the system proves to be more efficient thanks to the inflow of water that cools the photovoltaic part of the system, increasing its efficiency.
"In this patent, it is possible to combine the components directly, so that the electrical energy used in the photovoltaic converter is not subsequently used to generate heat. Everything is produced and used within the same hybrid system”, explains the professor.
According to Frateschi, the technology can be used in domestic applications, but has more advantages in large installations, with high demand for hot water, such as factories and hotels. “The more fresh water enters the system, the greater the efficiency of the photovoltaic cells. With a single system it is possible to heat water and generate electricity at the same time”, he points out.
The innovation is especially advantageous because, in addition to generating electrical energy from sunlight more efficiently, it can, at the same time, heat large volumes of water. Solar energy becomes better utilized. “This way we are able to reserve electricity for more noble activities and still obtain hot water, without the need for electricity for heating”, describes Frateschi.
Solar energy and energy crisis
The researcher considers electricity as a jewel that ends up being wasted in processes for which simpler solutions already exist. “This patent proposes a completely sustainable system, from an environmental, commercial and economic point of view.” In relation to the solar panel, which is built separately from the water heating system, the coupled structure presents an efficiency percentage of 15 to 20% higher.
Unicamp's Inova Agency filed a patent application in 2010, which has already been granted by the National Institute of Industrial Property (INPI) and is ready to be licensed by companies that wish to develop and commercially exploit it.
The energy crisis is a global problem, especially in Brazil. The current one is considered the worst in 90 years. The lack of rain, climate change and high consumption have led plant reservoirs to very low levels. “Using renewable energy is fundamental. There is no way to generate electrical energy without causing problems, especially in the current consumption scenario. Even hydroelectric plants cause severe disturbances to the environment”, explains the professor.
"There are alternatives, and among them, photovoltaic energy is the most applicable. It makes no sense to transform electrical energy into heat when it can be obtained from solar energy. This is a tremendous waste.” From a sustainability point of view, investments in solar sources can have an impact on the environmental future of the planet.
Original article published on the Inova Unicamp Innovation Agency website.
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