Jet-refrigeration cycles seem to provide an interesting solution to the increasing interest in environment protection and the need for energy saving due to their low plant costs, reliability and possibility to use water as operating fluid. A steam/steam ejector cycle refrigerator is investigated introducing a two-stage ejector with annular primary at the second stage. The steady_state refrigera...

A miniature steam ejector refrigeration system embedded with a capillary pump loop can result in a compact design which can be used for electronics cooling. In this paper, computational fluid dynamics (CFD) is employed to investigate the effects of the area ratio of the ejector constant-area mixing section to the nozzle throat, the length of the constant-area section, and the nozzle exit positi...

Ejector refrigeration is a promising technology for the integration into solar driven cooling systems because of its relative simplicity and low initial cost. The major drawback of such a system is associated with its relatively low coefficient of performance (COP) under variable operating conditions. In order to overcome this problem, an advanced ejector was developed that changes its geometri...

This paper presents the results of the analysis of an ejector refrigeration system operating with Freons as the working substance. Such a system is suitable for operating at subzero evaporator temperatures. The mass of motive refrigerant vaoour per hour per ton and the coefficient of performance are calculated for various assumed operating parameters such as boiler temperature, evaporator temoe...

This paper deals with a multi-objective optimization of a novel micro solar driven combined power and ejector refrigeration system (CPER). The system combines an organic Rankine cycle (ORC) with an ejector refrigeration cycle to generate electricity and cold capacity simultaneously. Major thermodynamic parameters, namely turbine inlet temperature, turbine inlet pressure, turbine back pressure, ...

The basic transcritical CO2 systems exhibit low energy efficiency due to their large throttling loss. Replacing the throttle valve with an ejector is an effective measure for recovering some of the energy lost in the expansion process. In this paper, a thermodynamic model of the ejector-expansion transcritical CO2 refrigeration cycle is developed. The effect of the suction nozzle pressure drop ...

The energy crisis in recent years has led to the use of thermodynamic cycles that work based on renewable energies. Low-temperature cycles—such as organic cycles—are suitable strategies for the application of renewable energies. The present study proposes a novel cycle through the integration of a two-stage compression refrigeration cycle with a combined Rankine power and ejector refrigerat...

We report the construction of an optically accessible flow test section made of quartz to simulate carbon dioxide flow through throttling devices in refrigeration systems. The existence of traces of lubricant oil (specifically Polyolester (POE)) in the working medium makes the flow amenable to Laser Induced Fluorescence (LIF) diagnostics. The molecular structure of these lubricants is rich in c...