Perpustakaan Digital ITB

Conventional vapor compression-refrigeration systems used in automobiles as air-conditioning systems directly consume high grade mechanical energy of engine; therefore their operations increase fuel consumption or CO2 generation. A theoretical analysis of ejector refrigeration system performance is conducted for various environmental friendly refrigerants, HCs and HFCs, under the operating condition ranges suitable for automotive cooling application. Engine mechanical energy could be saved in a range from 0.99 to 2.77 kW, depending on the working fluids. Fuel consumption and fuel cost saving are approximately determined in terms of the energy saving of total tourist buses operated in Indonesia due to the implementation of the ejector refrigeration system. It causes negative impact on environment and operation cost. Ejector refrigeration system would be a good alternative for cooling system in automobile due to ability to utilize waste heat of engine. Even though the ejector system requires mechanical pump, its energy consumption is smaller than that required by compressor of vapor compression system. Moreover, design of main components such as generator, evaporator, and condenser for utilizing waste heat as heat source are proposed to work in an ejector refrigeration system. The pressure drops (Δp) of all main equipments of an ejector refrigeration system are calculated in order to obtain an accurate non-isentropic performance estimation for various environmental friendly refrigerants, HFCs and HCs. Thermodynamic state at each station is determined in accordance with the design configuration of the system and reasonable operating conditions implemented in an automobile. Thermodynamic evaluations for coefficient of performance (COP) at non-isentropic and isentropic conditions are simulated by using a program code C++. The comparison between non-isentropic and isentropic performance points out that the COP of a non-isentropic process is lower than the COP of an isentropic one at the same operating conditions. Other adjustments required to justify the design systems based on components weight, evaporator drag force, and generator flow rate supply and demand are included in this study. Finally, among of the refrigerants studied, propane (R-290) as an excellent working fluid is dedicated for its higher COP either non-isentropic or isentropic processes or smaller component sizes than that other refrigerants. Not only the acceptable of COP, energy saving, and space design, but also adequate energy and mass flow supplies are required. Therefore, R-290 is justified to enable to be operated in automobile application, especially for high generator temperature, respectively.