THERMODYNAMIC MODEL ANALYSIS OF VCR SYSTEM WITH AL2O3-ETHYLENE GLYCOL-WATER MIXTURE BASED NANOFLUID AS SECONDARY FLUID AND R1234YF AS PRIMARY REFRIGERANT

Abstract

In this study, theoretical analysis of thermodynamic model incorporating nanofluid in the secondary loop refrigeration as secondary fluid is studied. In secondary loop refrigeration system, there are two loops which are interconnected by an intermediate heat exchanger. The thermodynamic model of vapour compression refrigeration system with Al2O3 nano particle (13nm) mixed in ethylene glycol-water mixture (50:50) in secondary loop and R1234yf refrigerant in the primary loop is used for theoretical analysis. The evaporator of the model is a double tube counter flow heat exchanger in which refrigerant circulate inside the inner tube and secondary fluid in the outer tube. The effect of nano particle aggregation, nano fluid mass flow rate and variation of temperature of evaporator and condenser on the of the system is studied. The results have shown that the Al2O3 nano particle (13nm) mixed in ethylene glycol water mixture (50:50) as the secondary refrigerant in the system operating at 274.5 K evaporator temperature can improve the COP of the system by 11.94 %, 15.45 %, and 25.16 % for 321 K, 323 K, and 328 K condenser temperature respectively. From obtained results it can be concluded that as the evaporator temperature or pressure increases the COP of the system with and without nano fluid increases but the improvement of COP of system with the secondary fluid is greatly enhance at lower evaporator temperature.