EXPERIMENTAL INVESTIGATION OF EFFECTS OF NANOREFRIGERANTS ON VAPOR COMPRESSION REFRIGERATION SYSTEM USING R1234yf INSTEAD OF R134a

In this study, the usage of refrigerant R1234yf was experimentally investigated with the addition of various nanoparticles instead of R134a as a working fluid in a VCRS. Firstly, the usage of pure R1234yf instead of R134a was experimentally investigated with energy and exergy approaches without any modification in the VCRS. As a result of pure refrigerant experiments, it was determined that the compressor power input increased by around 9%, cooling capacity decreased by around 8% and EER decreased by around 17% in the system using R1234yf compared to the system using R134a. Additionally, it was determined that the second law efficiency of the VCRS reduced by around 8% in the system using R1234yf compared to the system using R134a. Then, Al2O3, graphene or CNT nanoparticles were added for compensate for performance drops to the VCRS using R1234yf via compressor oil at various mass fractions. Thus, the best enhancement in the system performance parameters was obtained with the usage of R1234yf including 0.250% graphene by mass. Accordingly, it was observed that the cooling capacity of the system with R1234yf including 0.250% graphene by mass was improved up to 24% and 14% compared to the VCRS with pure R1234yf and R134a, respectively. Consequently, the EER value of the VCRS with R1234yf including 0.250% graphene by mass was enhanced up to 32% and 13% compared to the system using pure R1234yf and R134a, respectively. Additionally, the second law efficiency of the system slightly increased with the usage of R1234yf including 0.250% graphene by mass.