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R1234yf is a synthetic refrigerant with global warming potential (GWP) of 4 and similar thermodynamic properties to R134a. This paper experimentally compares the performance of R1234yf with R134a in an oil-free vapour compression refrigeration (VCR) system. The oil-free VCR system consisting of oil-free linear compressors, an off-the-shelf condenser and an evaporator with an electric heater avoids the impact of oil lubricant on the heat transfer so that the two refrigerants can be appropriately compared with each other. Experiments for two refrigerants were carried out for compressor strokes of 9-13 mm, operating frequency of 32-38 Hz, pressure ratios of 2-4, and condenser temperatures of 40-50 degrees C with refrigerant charge of 250 g. The experimental results show that the coefficient of performance (CoP) of R1234yf is 20% lower than R134a with condenser temperature of 40 degrees C and evaporator temperature of 0 degrees C. The volumetric efficiency of R1234yf is 5% lower than R134a with condenser temperature of 40 degrees C and evaporator temperature of -1.5 degrees C. Results of evaporator pressure drop, superheat, power input, and cooling capacity are also reported.