Modeling and Control of Automobile Waste Heat Driven Ejector Refrigeration System

The aim of this paper is to investigate the feasibility of the ejector refrigeration system in automotive air-conditioning. The system uses water as the working fluid and a generator in which operates in the temperature range of 90-190 degrees C. This system has a condensing temperature of 54 degrees C and an evaporating temperature of 5 degrees C. The ejector thermodynamic model was established. The compression ratio, secondary fluid pressure of ejector as the input and the outlet pressure of ejector as the output, reflects the ability of ejector and performance of the ejector system. PID controller is applied to control the compression ratio by controlling the opening degree of the expansion valve of the injection fluid. Furthermore, simulation result shows that any output pressure value between the 0.3Mpa similar to 0.8Mpa can be stably tracked. It is suitable for automotive air-conditioning control.