Perpustakaan Digital ITB

The thermodynamic simulator plays important role on thermodynamic cycle analysis. It should be supported with accurate thermodynamic properties database. User-friendly thermodynamic simulator for refrigeration system has was developed in this study as possible as most available working fluids are included. It was developed on basis of available thermodynamic property models which can be selected and the thermodynamic properties of fluid are directly calculated for selected model. Several refrigeration cycles were included inside the simulator. The thermodynamic simulator was used for simulating alternative refrigerant in accordance with mean of retrofitting the existing R-22 refrigeration and air-conditioning systems. Effect of using of different alternative refrigerants and effect of modified vapor-compression cycles were investigated. Their application on a real air-conditioning system, analysis of redesign of air-conditioning system was concerned to make clear the problems. The results confirm that a right selection of refrigerants to air-conditioning system can improve its performance. Energy saving and costs reduction can be improved significantly. Several refrigerants from groups of hydrocarbons (HC) and hydrofluorocarbons (HFC) have good thermodynamic performance even better than R-22 that is assigned to be phased out. R-152a, R-600, R-600a is possible to replace R-22 in new machine and R-290 has more significant possibility to replace R-22 in existing machines. Compared to the simple cycle, the vapor compression cycle with a heat exchanger could improve the COP about 0.85% higher than that of the simple cycle, while the cycle with intercooler yields COP of 9.51% higher than the simple cycle. Simulating of alternative refrigerants from the developed simulator found five refrigerants of R-152a, R-600, R-600a, R-134a and R-290 would replace R-22. Generally, refrigerants have a strong point at one side and a weak point at the other side. The alternative refrigerants were considered based on substitution process. Refrigerant R-152a, R-600 and R-600a have a good theoretical cooling capacity, good performance and less effect to the environment. For retrofitting process when initial cost for replacing machine becomes one of important constraints, replacement R-22 with R-290a or R-134a would give moderate solution due to fairly performance and less environment effect. Simulation results for transient of refrigeration cycle with integrated hot-water system will be discussed with respect to plausibility. Refrigeration cycle with integrated hot-water system result confirms that heat rejected from condenser of commercials refrigerator and air-conditioner can be recovered. Refrigerants R-32 and R-22 are suitable working fluids.