Experimental Analysis of the R744/R404A Cascade Refrigeration System with Internal Heat Exchanger. Part 1: Coefficient of Performance Characteristics

Abstract

This study evaluates the performance of an R744/R404A cascade refrigeration system (CRS) with internal heat exchangers (IHE) in supermarkets. R744 is used as the refrigerant in a low-temperature cycle, and R404A is used as the refrigerant in a high-temperature cycle. In previous studies, there are many studies including theoretical performance analysis of the CRS. However, experimental studies on the CRS are lacking, and experimental research on the R744/R404A system with an IHE is scarce. Therefore, this study provides basic data for optimal refrigeration system design by experimentally evaluating the results of modifying various parameters. The operating parameters considered in this study include subcooling and superheating, condensing and evaporating temperature, cascade evaporation temperature, and IHE efficiency in the R744 low- and R404A high-temperature cycle. The main results are summarized as follows: (1) By applying the results of this study, energy efficiency is achieved by optimizing the overall coefficient of performance (COP) of the CRS, and the refrigerant charge of the R404A cycle is minimized and economic efficiency is also obtained, enabling operation and maintenance as an environment-friendly system. (2) When designing the CRS, finding the cascade evaporation temperature that has the optimum and maximum COP according to the refrigerant combination should be considered with the highest priority.

Experimental Analysis of the R744/R404A Cascade Refrigeration System with Internal Heat Exchanger. Part 2: Exergy Characteristics

“…Figure 2 was designed to analyze the characteristics of the R744/R404A CRS [13]. Additionally, the experimental procedure including the description of the experimental apparatus, the experimental conditions (Table 2), the main components and detailed characteristics of the experiments are the same as in a previous paper [13]. The main components of the experiments are listed in Table 3.…”

Multi-objective optimization and 4E (energy, exergy, economy, environmental impact) analysis of a triple cascade refrigeration system

“…It has been practically employed and analyzed in vaccine storage task as well by Liu et al [ 34 ]. Some notable contributions to the experimental analysis include the works of S. Cabello et al [ 35 ], Bingming et al [ 36 ], Dopazo and Ferna'ndez-Seara [ 37 ], Sanz-Kock et al [ 38 ], Wang et al [ 39 ] and Jeon [ 40 ]However, for sectors that require ultra-low temperatures, maintaining the corresponding high-pressure ratio is not feasible with a double cascade system. Cascade refrigeration systems with three stages, a relatively recent innovation in this field, could be a cost-effective solution to this problem [ 41 ].…”

Experimental study on the pull‐down performance of a −80°C cascade refrigeration freezer

“…It was found that the volumetric efficiency of HTC compressor greatly deteriorated during pull‐down process. Jeon 26 experimentally researched a CRS with refrigerant couple R744‐R404A. They suggested that refrigerant R404A could be replaced by R448A and R449A in CRS.…”