Transient, Modeling, Flash Tank, Vapor Injection, Simulink
Dynamic simulations of vapor compression system are an important field of research since they allow investigation into the behavior of a system under time-varying conditions, which is essential for development of an effective control strategy for the system. It is particularly important for advanced cycles such as a flash tank vapor injection (FTVI) cycle since additional control parameters, such as injection vapor temperature or flash tank liquid level, are involved in such systems. In this study, a mathematical model for an R410A-based FTVI cycle is developed in Simulink. The model is based on an actual system that consists of two sets of heat exchangers, a high-side EEV, a low-side TXV, a flash tank and a scroll compressor with a vapor injection port The injection port can be turned off or on. The model has been used to simulate the operation of the system at ASHRAE High Temperature Cyclic test conditions with both the injection port on and off. The simulation results with the injection port open are compared to with measured data, The test methodology involved a startup cycle lasting for 1000 seconds, followed by several step changes in the EEV opening area lasting for 1500 seconds, and concluding with a shutdown of the system. The suction, injection and discharge pressures and temperatures have been compared, along with the indoor unit capacity and compressor power consumption. The TXV opening and flash tank liquid level have also been recorded. The results compare well with the experimental results, as well as with the simulation results from models developed on the Modelica platform. The model shows good potential for application to simulation of advanced cycles.