Automatización de la adquisición de datos de un banco de pruebas de aire acondicionado automotriz con la finalidad de medir el flujo másico de refrigerante, y controlar las temperaturas de evaporación y condensación

Abstract

The Automotive Engineering career of the School of Mechanics has automotive air conditioning simulator benches that do not allow performing performance studies of the system under stationary conditions, because they lack mechanisms to set the temperatures in the evaporator and condenser and instrumentation for data acquisition in real time. The objective of this work is to instrument and automate a new automotive air conditioning system test bench to evaluate its performance under various operating conditions, with the possibility of controlling the temperatures in the heat exchangers and determining the refrigerant mass flow. For this purpose, industrial measurement components were used to acquire pressure and temperature data of the R-134a refrigerant at characteristic points of the cycle. The system was instrumented with Logo 8 controllers, pressure transducers and resistance thermometers that have a maximum deviation of ±1.46% and ±1.44 K, respectively. The air temperature in the evaporator was controlled by a climatic chamber and a 1 kW resistor to simulate cabin temperatures between (22 to 50) °C, while, temperature control and drive of the second fan in the condenser was performed with STC1000 controllers. The evaporator climate chamber allows calculating the refrigerant mass flow by the calorimetric method with a maximum uncertainty of ±4.85%. The test bench allows evaluating the influence of cabin temperature and condenser airflow on the performance of the automotive air conditioning system. In addition, calculating compressor efficiencies and consumption, cooling capacity and COP. The system coefficient of performance improved by 21% by activating the second condenser fan at a cabin temperature of 40°C, with a reduction in compressor consumption of 110 W.