scholarly journals THEORETIC-EXPERIMENTAL EVALUATION OF A CASCADE REFRIGERATION SYSTEM FOR LOW TEMPERATURE APPLICATIONS USING THE PAIR R22/R404A

2012 ◽  
Vol 11 (1-2) ◽  
pp. 07
Author(s):  
J. J. Fiori ◽  
C. U. S. Lima ◽  
V. Silveira Jr

This paper presents a thermodynamic analysis of a cascade refrigeration system using the refrigerant R22 as the working fluid in the high temperature circuit (HT) and the refrigerant R404a as the working fluid in the low temperature circuit (LT). The present analysis aimed to obtain the condensing temperature of the LT that provides an optimal value for the coefficient of performance (COP) of the cycle. Parameters involved in the analysis included the evaporation temperature, the condensing temperature and the difference between the condensing temperature of the LT (TC_LT) and evaporation temperature of the HT (TE_HT) – ΔTCAS. Simulations were performed using the software EES (Engineering Equation Solver). In addition to the analysis, experimental data obtained from a prototype was compared with the simulated results which showed good agreement. The COP varies with the increase in the intermediate temperature; however this variation does not exceed 1%.

Energies ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 6003
Author(s):  
Min-Ju Jeon

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.


2014 ◽  
Vol 889-890 ◽  
pp. 321-324
Author(s):  
Da Yu Zheng ◽  
Dan Li ◽  
Jia Zheng ◽  
Li Ping Gao ◽  
Yi Ming Zhang

Non-azeotropic auto-cascade refrigeration system utilizes various components of different boiling refrigerant to get low-temperature. With R22, R23 and R14 as a non-azeotropic refrigerant auto-cascade refrigeration cycle system. Through the experimental study of non-azeotropic refrigerant charging and the ratio between the amount of charge, to analyze the effect of these three refrigerants charging and relationship of the fraction on the whole refrigeration cycle refrigeration temperature. To improve overall non-azeotropic auto-cascade refrigeration systems working efficiency. So as to achieve the purpose of energy saving.


2015 ◽  
Vol 75 ◽  
pp. 504-512 ◽  
Author(s):  
Yingjie Xu ◽  
FuSheng Chen ◽  
Qin Wang ◽  
Xiaohong Han ◽  
Dahong Li ◽  
...  

Author(s):  
Hendri ◽  
Roswati Nurhasanah ◽  
Prayudi ◽  
Suhengki

Low temperature storage with a single refrigeration system only stable up to 228 K temperature. The purpose of this study is to develop a low temperature cool storage with cascade refrigeration system, with hydrocarbon refrigerants in terms of energy and exergy analysis. Experimental research in laboratories using refrigerant hydrocarbon MC22 and MC134 on the hight temperature circuit, and R404A and R502 using on low temperature circuit. Condenser heat exchanger using a type of exchanger plate. Resulting from this research, obtained that result the MC22/R404A, MC22/R502 and MC134/R404A refrigerant pair can reach a temperature of 220 K. The MC22/R404A refrigerant pair has god performance, COP, total loss exergy, and exergy efficiency is better than MC22/R502, and MC134/R04A refrigerant pairs.


Processes ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 210 ◽  
Author(s):  
Xiaojing Sun ◽  
Linlin Liu ◽  
Yu Zhuang ◽  
Lei Zhang ◽  
Jian Du

Compression–absorption cascade refrigeration system (CACRS) is the extension of absorption refrigeration system, which can be utilized to recover excess heat of heat exchanger networks (HENs) and compensate refrigeration demand. In this work, a stage-wise superstructure is presented to integrate the generation and evaporation processes of CACRS within HEN, where the generator is driven by hot process streams, and the evaporation processes provide cooling energy to HEN. Considering that the operating condition of CACRS has significant effect on the coefficient of performance (COP) of CACRS and so do the structure of HEN, CACRS and HEN are considered as a whole system in this study, where the operating condition and performance of CACRS and the structure of HEN are optimized simultaneously. The quantitative relationship between COP and operating variables of CACRS is determined by process simulation and data fitting. To accomplish the optimal design purpose, a mixed integer non-linear programming (MINLP) model is formulated according to the proposed superstructure, with the objective of minimizing total annual cost (TAC). At last, two case studies are presented to demonstrate that desired HEN can be achieved by applying the proposed method, and the results show that the integrated HEN-CACRS system is capable to utilize energy reasonably and reduce the total annualized cost by 38.6% and 37.9% respectively since it could recover waste heat from hot process stream to produce the cooling energy required by the system.


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