A few days ago researchers at Duke University in the US invented a solar energy hydrogen production system that can be laid on the roof. The hydrogen produced by this system has no obvious impurities, and its efficiency is much higher than that of traditional technologies, allowing solar energy to play a greater role.
The new system differs from conventional solar collectors in appearance, but in reality it consists of a series of vacuum tubes plated with aluminum and alumina. Some of the vacuum tubes are also filled with nanoparticles that act as catalysts. The reaction materials are mainly water and methanol. Like other solar-based systems, the new system begins by collecting sunlight, but the process is quite different. When the liquid in the copper tube is heated at a high temperature, hydrogen gas can be generated under the action of the catalyst. These hydrogens can be converted into electrical energy via hydrogen fuel cells and can also be stored in compressed form for future use.
Nick Hortz, an assistant professor of mechanical engineering and materials at Duke University’s School of Engineering, said that the device can absorb up to 95% of solar heat, and very little is emitted from the environment. This device allows the temperature in the vacuum tube to reach 200 degrees Celsius, while a standard solar collector can only heat the water to 60 degrees Celsius to 70 degrees Celsius. Under the effect of high temperature, the purity and efficiency of hydrogen production in this system is much higher than traditional technologies.
Hortz said that he compared the efficiency of the new system with that of the solar electrolysis water hydrogen production system and the photocatalytic hydrogen production system (part of the given energy given that it is likely to make useful work). The theoretical exergy efficiency of the system is 28.5% (summer) and 18.5% (winter), respectively, while the exergy efficiency of conventional systems in summer and winter is only 5% to 15% and 2.5% to 5%. Relevant research results were announced at the American Society of Mechanical Engineers' 2011 Energy and Fuel Cell Conference.
The solar methanol mixing system is the cheapest solution, but the cost and efficiency of the system can differ depending on the installation location. The installation of such solar installations on the roofs of sunny areas can generally meet the electricity demand of the entire building during the winter months, and the electricity generated in the summer can even have surpluses. The owner can then consider closing part of the hydrogen production system or selling excess electricity to the grid.
Hortz said that this new type of solar hydrogen production system will be a very good choice for regions that are more remote or less accessible to other sources of energy. He is currently building a test system at Duke University to conduct a more comprehensive test. (Wang Xiaolong)
High Temperature And High Pressure Special Valves
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