A comprehensive study of two-stage vapor compression cycles with vapor-injection for heating applications, taking into account heat sink of finite capacity. (September 2018)

• Record Type: Journal Article
• Authors: Tello-Oquendo, Fernando M.; Navarro-Peris, Emilio; Gonzálvez-Maciá, José
• Is Part Of: International journal of refrigeration. Volume 93(2018)
• Page Start: 52
• Page End: 64
• Publication Date: 2018-09
• Subjects: Two-stage compression -- Vapor-injection -- Flash tank -- Economizer -- Optimization -- Intermediate pressure; Compression bi-étagée -- Injection de vapeur -- Réservoir de détente -- Économiseur -- Optimisation -- Pression intermédiaire; Refrigeration and refrigerating machinery -- Periodicals; 621.56
• DOI: 10.1016/j.ijrefrig.2018.05.039
• Languages: English
• ISSNs: 0140-7007

Abstract

Highlights: Determination of influential variables on the optimum COP in two-stage cycles. Thermodynamic optimization of two-stage cycles with vapor-injection with economizer and flash tank. Analysis of the influence of the subcooling on the optimum COP in two-stage cycles. Correlation to estimate the optimum intermediate pressure in two-stage cycles. Study of the influence of the size of the system components on the COP. ABSTRACT: This paper presents a comprehensive study of two-stage vapor compression cycles with vapor-injection for several refrigerants considering that the heat sink has a limited capacity. The key parameters of the cycle performance are identified and the influence of these parameters on the heating COP is analyzed. The optimum intermediate conditions of the cycle are evaluated using a general model of the cycle, considering two configurations (flash tank and economizer). Based on the optimization results, a correlation is proposed in order to estimate the optimum intermediate pressure, taking into account the temperature lift in the secondary fluid imposed by the application. The correlation uses cycle subcooling as an input, which is a novelty from the current correlations proposed in the literature. In addition, an optimum subcooling control strategy is proposed and finally, the influence of the size of the system components on the COP is studied.