scholarly journals Application and Exploration of Carbon Dioxide R744 as Refrigerant and Secondary Refrigerant in Refrigerating Unit of Commercial Super

2021 ◽  
Vol 267 ◽  
pp. 02008
Author(s):  
Li Guangpeng ◽  
Wang Qi ◽  
Shao Changbo

In this paper, the cascade refrigeration system and the load cooling system of the natural working medium are integrated as one unit system, which can meet the needs of different temperature zones of refrigerating in supermarkets. The concrete implementation scheme of the unit system with R717 as high temperature refrigerant, CO2 as low temperature refrigerant and carrier refrigerant was designed. According to the actual load of commercial super, the design and calculation of NH3 refrigerant system, CO2 refrigerant carrier system and CO2 cryogenic system were carried out. Through calculation and testing, the ideal refrigeration effect of the unit is obtained. Compared with the traditional unit, the energy saving is 20%, emission reduction (translated into CO2 emission) is 40%, and the operation cost is reduced by 20%.

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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