OPTIMUM THERMODYNAMIC EXERGY ANALYSIS AND DESIGN OF AN EJECTOR REFRIGERATION CYCLE

In this paper the ejector refrigeration cycle is analyzed utilizing the first and second law of thermodynamics. We compute the relative COP, exergy efficiency and other parameters for a range of important refrigerants (R134a, R142b, R152a, R290, R600 and R600a). The computations are conducted for a heat exchanger temperature difference (ΔT) in the range of 1-10 Celsius. The simulation conditions for generator temperature (TG,in), condenser temperature (TC,in) and evaporator temperature (TE,in) and also evaporator heat (QE), are constant and heat is transferred from the generator, condenser and evaporator by three heat exchangers. Engineering Equation Solver (EES) software is implemented to perform thermodynamic computations. The results have shown that the highest and lowest exergy destruction values are obtained with the ejector and pump, respectively. Furthermore with an increase in the generator pressure at constant ΔT, the coefficient of performance and efficiency exergy is enhanced, while the primary mass flow rate is reduced. Applications of the study include industrial foodstuffs freezing systems, micro-spacecraft propulsion cooling systems and cryogenic biotechnology.

Ejector cycle, mass flow rate, exergy, EES, COP, heat exchangers, refrigeration systems, biotechnology