Volume 10 Issue 3 ( September 2023 )

In order to assess the ejector cooling cycle performance and the ejector dimensions, a one-dimensional ejector model is proposed in this paper. The velocity and pressure inside the ejector are examined using thermodynamic governing equations for the eco-friendly working fluids, presuming them as ideal gases. Using conservation of mass, momentum, and energy, the system performance is evaluated. The coefficient of performance (COP) describes the cycle performance, while ejector performance is evaluated in terms of entrainment ratio (ER), mixing area ratio ARMix and primary nozzle area ratio AR_Nozzle. The performance of the cycle is found to improve with the increase in generator and evaporator temperatures, and the decrease in condenser temperature. The area ratios also followed the same trend with the variation of these parameters. At the designed cooling load of 1 kW, the coefficient of performance is found to be 0.182 for R1234ze and 0.061 for R1234yf; and the entrainment ratio of the ejector is 0.237 for R1234ze and 0.08 for R1234yf. As the temperature of the evaporator is increased from 0 to 10℃, the COP is found to rise by 41.41% and 35.56% for R1234ze and R1234yf, respectively. The COP is increased by 6.63% and 40.98% for R1234ze and R1234yf, respectively when the degree of superheat in the generator is enhanced from 2℃ to 6℃ at constant 3000kPa generator pressure.

Keywords: Coefficient of performance, area ratios, entrainment ratio, throat diameters, working fluids-R1234yf, R1234ze.