Geometrically and thermally non-optimum ejector heat pump analysis

Abstract

A determinate mathematical compressible flow model, which removes two improper assumptions in Elrod's optimum ejector theory and was based on the control volume approach for a constant area ejector, was formulated. Through suitable manipulation, the set of governing equations was reduced to a single implicit equation for the primary variable P 0. The flow parameters of the primary, secondary, mixed and diffused flow can be calculated directly by using the solved P 0 Some empirical data of a heat pump with various ejectors were compared with the predicted values of the present and Elrod's theories. The comparisons show that the present theory gives better agreement than Elrod's predictions. The geometrical offset effects in the heat pump analysis were analyzed by varying the primary, secondary inlets and diffuser exit areas. The optimum ejector and the optimum refrigeration system are found numerically in this parametric study. The factors which influence the ejector suction capability to the secondary flow can be observed. The thermal offset effects of the boiler, evaporator and condenser are also presented in this study.