APPLICATION OF FUZZY LOGIC IN THE CONTROL OF CRYSTALLIZATION IN A COOLING SYSTEM BY ABSORPTION WITH WATER- LITHIUM BROMIDE PAR
João Erivando Soares Marques1; Carlos Antonio Cabral dos Santos2; Francisco Antônio Belo2
1 Federal Institute of Education, Science and of Bahia, Campus Vitória of Conquista; 2 Federal University of Paraíba, Graduate Program in Mechanical Engineering -UFPB/PPGEM. Technology
doi:10.20906/CPS/COB-2015-1199
Resumo
This paper presents the theoretical and experimental study of a control system for a steam generator. This system was developed to control the crystallization of an absorption refrigeration system. The control system maintains the pressure generating zone above the crystallization temperature-pressure diagram, the concentration of saturated solution of LiBr-water. The control is performed through the simultaneous use of the relay and the frequency converter. The frequency converter operates at the speed of the pump drive of the condenser cooling tower motor, while the relay operates the burner generator, consecutively thermal input of combustion. The control system may operate under any pressure reference values above the crystallization zone of the absorption refrigeration system. In checking the flow were used techniques of control and Fuzzy modeling and control the heat input of the combustion, the on-off control, where the generator pressure values around 68-86 mbar in the control system were fixed. The generator pressure control variables reached the reference values and remained within the allowed range. With increased pressure generator, there was also increased the flow of the cooling tower condenser. The condenser temperature was kept constant (34°C). The concentration of the water solution of lithium bromide in the generator (56.14 to 52.75%), but the concentration in the absorber solution ranged from 54.31 to 55.32%. Therefore, the control system performance proved satisfactory, and can operate with any pressure reference values above the crystallization zone.
Palavras-chave: Absorption Refrigeration; Fuzzy Control; Crystallization; Frequency Converter