CFD-driven design of an ejector for a novel combined power and cooling system: A thermodynamic and exergoeconomic analysis

This article studies a combined Organic Rankine Cycle (ORC) and Ejector Refrigeration Cycle (ERC) for generating power and cooling from low-grade heat sources. The ejector is simulated via Computational Fluid Dynamics (CFD) to calculate its entrainment ratio using three working fluids, which consist of R11, R123 and, R141b. As a valuable result, the highest error percentage of the ejector entrainment ratio is reduced to 13.53%, which is approximately 22.99% in Huang's one-dimensional modeling. Then, the ejector is applied in the combined energy conversion system to compute the performance of the ejector’s critical state operation through the two-dimensional method. Finally, the thermodynamic and exergoeconomic performance of the proposed system is analyzed using the selected working fluids. Interestingly, the highest cooling and power output belongs to R11 at 621.1 kW and 174.4 kW. Also, the maximum exergy destruction rate falls in the heat recovery vapor generator and then in the ejector at 118.1 kW and 44.75 kW. Another point worth mentioning is the investment cost rate of the set-up with the lowest quantity when R141b is selected as a working fluid at 6.42 $/h.