Análise comparativa entre dados experimentais de operação de um evaporador com resultados obtidos via software comercial

Abstract

In industrial refrigeration, liquid supercharging systems are the most efficient. This is because there is always liquid evaporating along the equipment circuit. In companies, designers should look for a higher heat transfer rate from each manufactured equipment. To facilitate these calculations of thermal efficiency, commercial software is used to determine which configuration of the equipment has the best efficiency. This work aimed to understand which data the software considerations and if their values correspond to those found in the literature, comparing with the experimental data taken from the equipment in operation. To achieve this goal, the global coefficient of external heat transfer (U_e) was corrected, where the fin efficiency, global fin efficiency, an internal and external fouling rate, due to a gradual deposit that occurs on the surface, is considered. be it rust, oil, a series of things that happen during the operation of the equipment, the fouling factors were extracted from the TEMA (Tubular Exchanger Manufacturers Association) standard. For the internal convective heat transfer coefficient, in the equations developed by Kattaan was used, where the updated average value was 9,409.90 W / m²K. The external convective coefficient was used to Wang's equations, which considers all data from the finned block, the temperature and humidity of the air at the evaporator inlet, with these data it was possible to calculate the value of 65.57 W / m²K, using all of these value it was possible to calculate the U_e with the value of 22.10 W / m²K, calculate the logarithmic average temperature difference in the value of 6.39 ° C, the thermal capacity of the evaporator was analytically 15.11 kW, the value entered by software is 15.90 kW, and the upgrade experimentally got 9.95 kW, similar calculated values given by the software, showing that these developed equations can be used for evaporator thermal performance calculations. [resumo fornecido pelo autor]