Produced at the Polytechnic School of the University of São Paulo, the equipment generates thermal radiation similar to Sol
The Indoor Solar Simulator is a equipment designed to artificially simulate solar radiation in controlled environments and used to test devices and technologies that use solar radiation, such as thermochemical reactors, steam production and hot oils.
High intensity xenon lamps emit light, reflected and concentrated by satellite mirrors, generating a thermoluminous beam similar to the sun. Thus, it is possible to perform the tests without the need for ideal external weather conditions, of clean sky without clouds.
Researchers at the University of São Paulo Polytechnic School have developed and tested a new high -flow indoor simulator designed to optimize high temperature thermal processes and improve concentrated solar energy technologies.
The work was done at the Laboratory of Alternative and Renewable Energy Systems. And the simulator is already operational and can be used in various applications, such as thermochemical reactions for hydrogen production and synthesis gas (hydrogen mixture and carbon monoxide, with high energy value); catalyst search to optimize chemical reactions; foundry of metals and other materials that require high temperatures; Tests in solar ovens for industrial processes.
“Our simulator uses 8 high temperature xenon arc lamps. The emitted light is reflected by a set of parabolic mirrors, which generate collimated radiation beams, ie with parallel rays. These beams focus on a second set of parabolic mirrors to be concentrated in a common focal point, allowing the simulation of intense sun conditions within the laboratory. The main objective of creating this ‘artificial sun’ is to enable controlled experiments in closed environments, surpassing the dependence on natural solar radiation, which is always subject to the day cycle and climate variations ”says researcher José Roberto Simões Moreira, Full Professor at POLI-USP, Sisa coordinator and main responsible for the work on the agenda.
The reactions take place in a thermochemical reactor based on the concept of “black cavity”, installed in the common focus of reflective mirrors, in which concentrated radiation is absorbed and may reach temperatures capable of overcoming 2,000 ° C.
These conditions are ideal for performing specific chemical reactions, such as the production of hydrogen gas by metal oxirreduction process. In this case, this is in two steps: in the 1st, a metal is oxidized in the presence of water vapor, releasing hydrogen gas; In the 2nd, the oxidized metal is reduced to reuse, closing the cycle.
Alternatively, the equipment also makes it possible to produce synthesis gas through water vapor (H2O) methane reaction (CH₄), generating carbon monoxide (CO) and hydrogen (H₂), a process widely used in industry. Other reactions may also occur, involving biomass as a raw material, for example.
Simões informs that the main differential of the new poly-USP simulator in relation to other equipment of the genre is the use of secondary satellite mirrors.
“They reflect the rays collimated to the focus of the master parabolic mirror, enabling more realistic conditions for laboratory tests and eventual applications in outdoor environments, contrary to traditional ellipsoidal reflectors.”it says.
Security measures
Special security measures were adopted to ensure operators’ integrity. To avoid risk of lamp explosion, a plate associated with a cooling system maintains the system temperature in a secure range. In addition, each lamp is protected by a front glass window that blocks accidental exposure to ultraviolet emissions and, in case of explosion, prevents debris from flying.
A locking system enables the activation and deactivation of light sources externally to the test room. And each lamp is individually controlled, allowing you to adjust the amount of irradiation on the target as needed. Additionally, the whole set is installed in a room endowed with an interlocking system so that if someone enters during operation, the entire lamp set is turned off. Because exposure to concentrated thermal radiation of lamps can be fatal, especially in the adjacencies of the main focus.
The study used computational techniques (Monte Carlo method) to track the rays, simulate the optical path of light and quantify system efficiency. Experimental measurements were performed with a spectrophotometer and a heat flow sensor to determine concentrated thermal power and map the distribution.
“The simulator is already active and the next step is to enable thermochemical reactions within the black cavity. To this end, our group is focused on catalyst research. In addition, we are studying technology adaptation to external applications, directly using solar radiation instead of lamps. There is a great potential for applications in industry and in the production of clean fuels, water vapor and power cycles ”says Simões.
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