Development and Validation of a Dynamic Vapor Compression Cycle Model

Abstract

Heating, ventilation and air conditioning systems have widespread household and industrial applications and play a leading role in the energy consumption of countries around the world. By analyzing the dynamic behavior of these systems, it is possible to make them operate more efficiently. In this study, the dynamic behavior of a vapor compression cycle is analyzed. The evaporator and condenser are modeled with the finite-difference method and the expansion valve and compressor are modeled with static relationships. Gungor-Winterton and Travis et al. correlations are, respectively used as the evaporation and condensation correlations. The expansion valve openness and compressor motor speed are selected as the input variables to the system. Another model with the same design specifications is developed in the SimulationX environment to verify the proposed model. Both models are perturbed with the two input variables with varying values over constant intervals and the transient behavior of the system is investigated. The results showed that the outcomes of the two models agree well with each other. The largest prediction difference is observed as 2x10-4 kg/sec. for the mass flow rates and 1.4 K for the heat exchangers inlet temperatures.