Melhoramento de um sistema de absorção por absorção agua-amonia para a fabricação de gelo

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

It is focused the technological developments that must be done on absortion freezing systems using the couple water-ammonia as absorber refrigerant for ice inclustries. This study was made over this kind of plant which actually is found in the service area of Hospital das ClinicaslHC in UNICAMP. That plant was freely given to this University by MADEF S.A., producer of this kind of industry in Brazil. Energetic and exergetic evaluations were used jointly to verificative account of heat exchangers. To achieve this goal it was installed a data adquisition system by means of computer through which we got the pressure and temperature values of the solution in different points, genera1ly defined by input and output of each equipment. Using this data, it was determined the thermod:ynamics properties in each point, with AQUAM software help as well as enthalpy exergy diagram ofMerkel and Bonsjakovic. Since the exergetic and energetic evaluations, it was found the weak points of the system verifying irreversibility values of each equipment by applying the entropy theory concept (Gouy-Stodola s Theorem), which is considered an appropriate methodology to analyze any kind of system. The evaluated system presented a coefficient of performance, COP of 0,42, major irreversibilities representing 32% on the generator complex rectifYing column, a major exergetic efficiency, 81%, in rich solution pre-heating and the minor, 14,29%, in the liquid sub-cooling. The calcu1atedvalues indicate the absorber subdimension of the weak solution pre-cooling and of the evaporative condensation, little time of cooling, low ammonia concentration in the evaporator, excessive size of the constant pressure valve and great heat losses

ASSUNTO(S)

absorção ice gelo freezing refrigeração absorption

ACESSO AO ARTIGO

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