Performance evaluation of NH3/CO2 cascade refrigeration system with ejector subcooling for low-temperature cycle

Author(s):  
Weikai Chi ◽  
Qichao Yang ◽  
Xiaonan Chen ◽  
Guangbin Liu ◽  
Yuanyang Zhao ◽  
...  
2011 ◽  
Vol 19 (03) ◽  
pp. 203-212 ◽  
Author(s):  
DUSHYANTHA GUNAWARDANE ◽  
PRADEEP BANSAL

This paper presents a mathematical model for the evaporator of a cascade refrigeration system, operating down to -40°C. The system uses Carbon dioxide (R744) and Propylene (R1270), respectively, as the low temperature and high temperature cycle refrigerant. The model is developed in Engineering Equation Solver software package following the elemental Number of Transfer Units-effectiveness method, where frost has not been considered. The evaporator is a cross-flow finned tube serpentine heat exchanger, which was divided into numerous elements along the flow path of the refrigerant. The inputs to the model include inlet temperatures and mass flow rates of both the streams along with the heat flux, while the main outputs are the outlet temperatures, refrigeration capacity and HX effectiveness. The model is found to underpredict the refrigeration capacity by about 10% when compared with experimental data.


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.


Author(s):  
Cleison Henrique de Paula ◽  
Willian Moreira Duarte ◽  
Thiago Torres Martins Rocha ◽  
Raphael Nunes de Oliveira ◽  
Antônio Augusto Torres Maia

In this work, a cascade refrigeration system operating with four different ecological refrigerant pairs was modeled. This system uses R744 (Carbon dioxide) in the low-temperature cycle and operates with R290 (propane), R1234yf (2,3,3,3-tetrafluoropropene), R152a (1,1-difluorethane), and R717 (ammonia) in the high-temperature cycle. Energetic, exergetic, environmental, and economic performance of the cascade system was investigated to determine the most appropriate ecological refrigerant couple. The parameters used in each mentioned performance were COP (Coefficient of Performance), [Formula: see text] (Exergy Efficiency), TEWI (Total Equivalent Warming Impact), ECOP (Ecological coefficient of performance), and [Formula: see text] (Total plant cost rate), respectively. The results showed that the cascade refrigeration system operating with R744/R717 provided the best performance for the thermodynamic conditions analyzed, presenting a COP of 2.10, [Formula: see text] of 56.9%, [Formula: see text] of 24 334 USD/year, ECOP of 4.86, and TEWI of 25.67 tons of CO2. Finally, evaluating the total plant cost rate of this cascade system, it was noted that the capital and maintenance cost rate [Formula: see text] corresponds to 89.1% of the [Formula: see text] value, the operational cost rate [Formula: see text] corresponds to 10.27% of the [Formula: see text] value and the environmental cost rate [Formula: see text] corresponds to 0.63% of [Formula: see text].


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