Aprimoramento da bancada didática portátil de refrigeração

Abstract

This project presents the detailed implementation of a temperature control system in a refrigeration bench and its impact on the refrigeration cycle. Such a bench was intended for the basic teaching of calorimetry in middle and high school, so this project aimed to make possible its use and study for thermodynamics in higher education. For this purpose, an equipment was used to control the temperature in the condenser or evaporator reservoir. Experiments were carried out with three different temperatures in each reservoir, and then the graphs of the cycles were assembled. It was observed that the cycles have the same behavior, independent of the temperature chosen as constant. In the experiments carried out on the evaporator, the performance coefficient drops as the condenser warms up, while in the experiments carried out at constant temperature in the condenser, the performance coefficient drops as the evaporator temperature decreases. To perform the analysis of the obtained cycles comparing them with the theoretical cycle, an experiment was chosen maintaining the constant temperature in the evaporator and one in the condenser, it was possible to verify that the real cycle follows the theoretical, but with losses. The coefficient of performance of the theoretical and real cycle followed the same curve, but the numerical results of the real cycle should be disregarded because the manometer of the evaporator output is malfunctioning. For future work, it is recommended to calibrate the pressure gauges.