Thermodynamic and thermoeconomic analysis and optimization of a novel combined cooling and power (CCP) cycle by integrating of ejector refrigeration and Kalina cycles

Abstract

In the present work, a novel combined power and ejector refrigeration cycle is proposed by an appropriate combination of a Kalina cycle (KC) and an ejector refrigeration cycle (ERC) to produce power output and cooling output, simultaneously. The exhaust of the turbine is fed to the ejector as a primary flow to draw the secondary flow into the ejector. Energy, exergy, and exergoeconomic analysis of the proposed cycle are carried out using Engineering Equation Solver (EES) software. In addition, considering the thermal efficiency, exergy efficiency, and sum unit cost of the product (SUCP) of the system as objective functions, single- and multi-objective optimizations are carried out by genetic algorithm (GA) leading to determination the optimum design variables including the vapor generator pressure, evaporator temperature, condenser pinch point temperature, heat source temperature, ammonia concentration, and expander ratio. The results of the optimization demonstrated that the proposed cycle performs in an optimum state based on the selected objective functions when vapor generator pressure, evaporator temperature, condenser pinch point temperature, heat source temperature, ammonia concentration, and expander ratio work at 17.5 bar, 285 K, 8 K, 473 K, 15%, and 2.5, respectively. In this case, the optimum thermal efficiency, exergy efficiency, SUCP of the system are calculated 20.4%, 16.69%, and 2466.36 $/MWh, respectively. Moreover, it is demonstrated that the thermal efficiency can be maximized for the proposed cycle with respect to the vapor generator pressure, vapor generator temperature, and heat source temperature. Furthermore, it is shown that ejector has the main contribution in the exergy losses which is followed by the condenser. At the end, the effect of some key parameters on the main thermodynamic performance criteria are examined. It is shown that one can obtain a higher thermal and exergy efficiencies at lower ammonia concentration and condenser pinch point temperature as well as at higher evaporator temperature.