SIMULATION AND DESIGN OF CO2 TRANSCRITICAL REFRIGERATION SYSTEM WITH EJECTOR EXPANSION DEVICE

• Main Author: PRATAMA SADIKA (NIM : 23110029); Tim Pembimbing : Prof. Dr. Ir. Aryadi Suwono; Dr. Ir. Ari Dar, EDGAR
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/15473
• Institution: Institut Teknologi Bandung

Carbon dioxide (CO2) now has come back as one of natural refrigerant for refrigeration. Carbon dioxide had been used since 20th century. But because of low efficiency compare to other refrigerant, CO2 not used again as a refrigerant on the middle of 21th century. Nowadays, along with environmental that getting worse because of refrigerant containing CFC, CO2 is become one of alternative refrigerant which is environtmental friendly. CO2 as a refrigerant needs a high operating pressure that occurs on supercritical and also subcritical range which it calls transcritical refrigeration. This research wants to see the performance (COP) that occurred on CO2 transcritical refrigeration cycle. Beside that purpose, the characteristics of CO2 transcritical cycle using ejector expansion device will be reviewed on this research. This research also review the design and simulation of CO2 transcritical system using ejector expansion device. <br /> <br /> <br /> The first step of this research is literature study about CO2 transcritical refrigeration. And then this research reviews CO2 transcritical refrigeration cycles using thermodynamics to find the most efficient cycle. CO2 transcritical cycle that using ejector expansion device will be reviewed more deeply to know the cycle characteristics. This review will use Microsoft Excel software and fluid properties from REFPROP 8. Next step is designing an ejector expansion device using Autodesk Inventor and simulated using FLUENT. This simulation will get fluid condition inside ejector expansion device. CO2 transcritical refrigeration system using ejector expansion device will be simulated to get equilibrium point of operation and COP of the system. This simulation are using performance data from all components that support the system. The result shows that CO2 transcritical cycle using ejector expansion device is the most efficient cycle with COP with 4.998 compare to other cycle. Thermodynamics review for this cycle shows that the performance of the cycle is affected by gas cooler pressure, evaporation temperature, and gas cooler outlet temperature. Designing ejector expansion device has some important dimensions that must be noted. That dimensions are motive nozzle diameter and mixing section diameter. This two diameter will form other dimension of the ejector. There is two parameters that must be noted on designing an ejector, that is reversed flow and supersonic velocity. CFD (computational fluid dynamic) simulation show that motive nozzle diameter affect the two parameter. tersebut. CO2 transcritical refrigeration system using ejector expansion device simulation results shows that the system has lower COP than ideal thermodynamics review. Highest COP is 2.7.