scholarly journals Comparative analysis of a cooling systems working on an environmentally friendly refrigerants

Author(s):  
Adam RUCIŃSKI ◽  
Mateusz DALBA ◽  
Rafał LASKOWSKI

The paper treats with refrigerants which affect on excessive heating of atmosphere. They are in group offluorinated greenhouse gases which are regulated by European and polish law. The main aim is to lower their amount in industry leading to overall removal from use. We present possible way to design refrigeration system lowering their adverse effect on natural environment. So three options of cooling systems are analyzed: one-stage refrigeration system working with R449A, cascade refrigeration system with R744 (carbon dioxide)/ R134a and R717 (ammonia) refrigeration plant. Due to the nowadays raising use of the cascade systems, an analysis of the operating parameters of such installation was carried out with considering the cascade heat exchanger as a condenser/evaporator. The installations concerned are three alternative offers for meat processing manufactory. A thermal balance was prepared for chambers located in building and the operating parameters of the installation were assumed. The equipment corresponding to the required cooling capacities were selected.

2012 ◽  
Vol 20 (03) ◽  
pp. 1250010 ◽  
Author(s):  
ANTONIO MESSINEO ◽  
DOMENICO PANNO

Due to the negative effects of synthetic refrigerants on the environment, natural refrigerants have obtained again interest as alternative refrigerants for different applications because of their zero ODP and negligible GWP. This paper presents a thermodynamic analysis of different two-stage cascade refrigeration systems using as refrigerant carbon dioxide (R744) in low-temperature circuit, and, respectively, ammonia (R717), propane (R290), butane (R600), R404A, R410A and R134a in high-temperature circuit. The operating parameters considered in this study include condensing and evaporating temperatures in high-temperature circuit, temperature difference in the cascade heat exchanger, and evaporating and condensing temperatures in the low-temperature circuit. The results obtained show that a cascade refrigeration system using natural refrigerants is an interesting alternative to systems using synthetic refrigerants for energetic, security and environmental reasons.


2013 ◽  
Vol 388 ◽  
pp. 96-100
Author(s):  
Nasruddin ◽  
M. Idrus Alhamid ◽  
Darwin R.B. Syaka ◽  
Arnas

Medicine and biomedical research activities require cold storage to store biomedical specimens such as, for example, stem cell, sperm, blood and other organs. During storage, to prevent the specimen from damage required a special cold storage reaches -80°C [1]. Using single cycle refrigeration machine can only reach -40°C, and performance deteriorates below -35°C drop in pressure associated with evaporation. Thus, to reach lower temperatures, use cascade refrigeration machine [2]. During this low-temperature circuit cascade refrigeration systems still use refrigerants that contain ozone-depleting or global warming (CFCs and HCFCs). To overcome this, a mixture of carbon dioxide and ethane azeotropic a promising alternative refrigerants. Simulation studies and experiments indicate a mixture of carbon dioxide and ethane were able to achieve the minimum temperature to -80°C [4-7]. With the mass ratio 70% R170 and 30% R744 circuit at low temperature refrigeration systems and uses a capillary tube expansion device 0.054 inch diameter with a length of 6 meters and 3 meters then use an electric heater as the cooling load. Cooling load is given by the variation of 90 W, 120 W and 150 W at a cabin in the low temperature circuit. From the experiment will be known characteristics of cascade refrigeration system with refrigerant mixture and will get the parameter data to make cascade refrigeration machine.


2013 ◽  
Vol 291-294 ◽  
pp. 1740-1745
Author(s):  
Wei Zhao ◽  
Rui Xi Liu ◽  
Hai Dong Zhang ◽  
Hua Zhang ◽  
Shu Chun Zhang

The mixed refrigerants R22/R23/R14/R740/R728 and R134a/R23/R14/R740/R728 are used in a five-stage auto-cascade refrigeration system for study in this paper. Through theoretic comparison of high temperature stage refrigerant R22 and R134a and repeated experiments we can get the results that the discharge temperature of the refrigerant R134a can be effectively controlled and a lower refrigeration temperature can be got than the refrigerant R22.


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