scholarly journals Comparative Analysis of Electric Energy Consumption of Cascade System R134a/CO2 with Single Stage R404a and Two-Stage CO2 Installation

2020 ◽  
Author(s):  
Dimitrije Ninković ◽  
◽  
Uroš Milovančević ◽  
Milena Otović ◽  
Vladimir Černicin
Keyword(s):  
Energy Consumption ◽  
Comparative Analysis ◽  
Electric Energy ◽  
Cooling Capacity ◽  
Single Stage ◽  
Refrigeration System ◽  
Two Stage ◽  
Electric Energy Consumption ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration

The paper analyzes electric energy consumption of three different refrigeration installations: cascade refrigeration system with R134a in the high temperature circuit and CO2 in the low temperature circuit, single stage refrigeration system operating with R404A and two-stage transcritical CO2 system. The indirect impact of the refrigeration system on global warming through electric energy consumption was examined. Thermodynamic cycles of these installations have been described and models have been developed to analyze the electric energy consumption required to drive the compressor as the largest consumer, for the cooling capacity of the evaporator 5,7 kW at evaporation temperature -30 °C for meteorological 2017, in the city of Belgrade. As a basis for comparative analysis, the existing cascade refrigeration system, which is located in the Laboratory for Thermal Science at the Faculty of Mechanical Engineering in Belgrade, was selected.

Comparison of Various Alternative Refrigerants for Vapour Compression Refrigeration Systems

2011 ◽  
Author(s):  
Ahmet Selim Dalkilic¸ ◽  
Somchai Wongwises
Keyword(s):  
Heat Exchanger ◽  
Single Stage ◽  
Refrigeration System ◽  
Performance Study ◽  
Alternative Refrigerants ◽  
Two Stage ◽  
Stage Process ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration ◽  
Vapour Compression

Single-stage vapour compression refrigeration system was compared with an actual vapour compression cycle, single-stage process with internal heat exchanger, and a two-stage process with economiser using the refrigerants of HCFC-22, CFC-502 and their alternatives such as HFC-134a, HFC-32, HFC-152a, HFC-404A, HFC-407C, HFC-507, HFC-410A. A theoretical performance study on a cascade refrigeration system was performed using two refrigeration cycles connected through the heat exchanger in the middle working as the evaporator for the high pressurized cycle and condenser for the low pressurized cycle. Other performance study was performed using a two-stage cascade refrigeration system having low and high pressure compressors connected through the mixing chamber in the middle. The condensation temperatures were between 30 and 50 °C, evaporation temperatures were between −50 °C and 5 °C and heat exchanger and economiser temperatures were kept as constant for the comparisons. Some of the alternative refrigerants’ coefficients of performance values are found to be higher than their base traditional pure refrigerants. The effects of the main parameters of performance analysis such as refrigerant type, degree of subcooling, and superheating on the performance coefficient, refrigerant charge rate and volumetric refrigeration capacity are investigated for various operating conditions as case studies.

scholarly journals COP enhancement of vapour compression refrigeration system using dedicated mechanical subcooling cycle

2020 ◽  
Vol 39 (3) ◽  
pp. 776-784
Author(s):  
T.S. Mogaji ◽  
A. Awolala ◽  
O.Z. Ayodeji ◽  
P.B. Mogaji ◽  
D.E. Philip
Keyword(s):  
System Performance ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Condensation Temperature ◽  
Refrigeration System ◽  
Wide Range ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration ◽  
Vapour Compression ◽  
Better Than

This study focused on development of an improved vapour compression refrigeration system (IVCR system). Dedicated mechanical subcooling cycle is employed in attaining the developed IVCR system. The system is composed of two cycles cascade refrigeration system working with R134a. It consists of a rectangular shape with total storage space of 0.582 m3, made of galvanized mild steel and internally insulated with 0.05 m polystyrene foam. Tests under a wide range operating temperature conditions were carried out on the developed IVCR system. Performance evaluation of the system was characterized in terms of cooling capacity and coefficient of performance (COP). Experimental results showed that the COP of the subcooled system improved better than that of the main system from 18.0% to about 33.5% over an evaporating temperature range of -10 to 30oC. It can be concluded that the use of dedicated sub cooling cycle in VCR system is more efficient and suitable for the betterment of thermal system performance. Keywords: Vapour compression Refrigeration system, Coefficient of performance, dedicated subcooled system, Condensation temperature, Evaporation temperature.

The Comparative Analysis of R22 and R134a Applied in a Five-Stage Auto-Cascade Refrigeration System

2013 ◽  
Vol 291-294 ◽  
pp. 1740-1745
Author(s):  
Wei Zhao ◽  
Rui Xi Liu ◽  
Hai Dong Zhang ◽  
Hua Zhang ◽  
Shu Chun Zhang
Keyword(s):  
Comparative Analysis ◽  
High Temperature ◽  
Refrigeration System ◽  
Discharge Temperature ◽  
Cascade Refrigeration System ◽  
High Temperature Stage ◽  
Cascade Refrigeration

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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