Transient Simulation of a Transcritical Carbon Dioxide Refrigeration System

Transient simulations of refrigeration cycles are crucial for evaluating new refrigerants. Previously developed transient simulation tool was capable of simulating refrigeration systems using refrigerants R22 and R134a and was validated with experimental data; however, incorporating non-traditional refrigerants such as R744 (carbon dioxide) change the cycle operation beyond the capabilities of the original code. This paper introduces a new enthalpy based solver that accounts for the transcritical behavior of R744. In the proposed transient solver, enthalpy and pressure are the independent properties being passed between system component models. The simulation software was developed in an object-oriented framework, allowing for easy component inter-changeability and the use of custom control algorithms. This paper presents the system level solution procedure of refrigeration cycles. Results of the current solver along with new heat exchanger model provided coherent results that need to be further validated for future purposes.