A study of working fluids for heat driven ejector refrigeration using lumped parameter models

• Five models have been selected and validated with literature benchmarks.
• The working fluids and operating conditions have a great impact on the COP.
• Each refrigerant has its own range of operating conditions.
• Ejector component efficiencies have a significant effect on ejector performance.
• The working fluids and operating conditions affect the optimum area ratio.

This paper studies the influence of working fluids over the performance of heat driven ejector refrigeration systems performance by using a lumped parameter model. The model used has been selected after a comparison of different models with a set of experimental data available in the literature. The effect of generator, evaporator and condenser temperature over the entrainment ratio and the COP has been investigated for different working fluids in the typical operating conditions of low grade energy sources. The results show a growth in performance (the entrainment ratio and the COP) with a rise in the generator and evaporator temperature and a decrease in the condenser temperature. The working fluids have a great impact on the ejector performance and each refrigerant has its own range of operating conditions. R134a is found to be suitable for low generator temperature (70–100 °C), whereas the hydrocarbons R600 is suitable for medium generator temperatures (100–130 °C) and R601 for high generator temperatures (130–180 °C).