Performance Analysis of Cascade Refrigeration System with alternate Refrigerants (original) (raw)
Related papers
Performance Study of Cascade Refrigeration System Using Alternative Refrigerants
World Academy of Science, Engineering and Technology, International Journal of Mechanical, Aerospace, Industrial, Mechatronic and Manufacturing Engineering, 2014
Cascade refrigeration systems employ series of single stage vapor compression units which are thermally coupled with evaporator/condenser cascades. Different refrigerants are used in each of the circuit depending on the optimum characteristics shown by the refrigerant for a particular application. In the present research study, a steady state thermodynamic model is developed which simulates the working of an actual cascade system. The model provides COP and all other system parameters e.g. total compressor work, temperature, pressure, enthalpy and entropy at different state points. The working fluid in low temperature circuit (LTC) is CO2 (R744) while Ammonia (R717), Propane (R290), Propylene (R1270), R404A and R12 are the refrigerants in high temperature circuit (HTC). The performance curves of Ammonia, Propane, Propylene, and R404A are compared with R12 to find its nearest substitute. Results show that Ammonia is the best substitute of R12. Keywords—Cascade system, Refrigerants, T...
Analysis of Cascade Vapour Refrigeration System with Various Refrigerants
Materials Today: Proceedings, 2019
In this paper report the performance analysis of different refrigerants couples in cascade refrigeration system. Refrigerants such as R134a/R23, R410A/R23 and R404A/R170 have been successfully analyzed in the superheating and sub cooling range of 10 °C and 5 °C respectively. The variation in condenser temperature was from 30 to 50 °C in high temperature circuit while evaporator temperature in low temperature circuit varied in the range of-70°C to-50 °C. The compressor efficiency was assumed to be 0.7 throughout the experiment. It has been revealed that there is enhancement in coefficient of performance and flow rate with rise in compressor work and evaporator temperature. From the present study we conclude that the refrigerant pair R134a/R170 was found to have greater coefficient of performance and lower mass flow rate and the pair R404A/R508B was found to have smaller coefficient of performance and greater mass flow rate.
Performance parameters optimization of cascade refrigeration system using ecofriendly refrigerants
__________________________________________________________________________________ Abstract The present paper presents optimum thermodynamic performance of three cascade vapour compression refrigeration systems. The numerical thermal model have been developed for two stages cascade refrigeration systems and thermodynamic performances in terms of and first law efficiency, second law efficiency system exergy destruction ratio , first law efficiency of lower temperature and high temperature circuit have been computed. The effect of low temperature evaporator on the system first and second law performances and system exergy destruction ratio it was found that as low temperature evaporator temperature is decreasing , the first law and second law efficiencies are increasing and exergy destruction ratio is decreasing .The optimum performance parameters obtained from thermal model have been presented.
Research on alternative refrigerants has recently drawn increased attention due to the growing public awareness of global warming and the ozone depleting effect. Numerous research organizations have made significant progress in the replacement of refrigerants, looking for a refrigerant substitute in the low temperature cycle (LTC) and high temperature cycle (HTC) of cascade refrigeration systems with zero ozone depletion potential (ODP) and low global warming potential (GWP). An investigation of the thermodynamic performance of the system when operated by various refrigerant combinations is required in order to choose suitable and environmentally acceptable refrigerants in search of zero ODP and low GWP values for cascade vapour refrigeration systems. This paper discusses a number of research options, including different Cascade Vapour Refrigeration System designs, studies on refrigerants, system optimization efforts, and numerous experimental and analytical studies that have been conducted by utilizing exergy equations of the basic elements of the machine with various combinations of refrigerants to enhance overall Coefficient of Performance. The paper aids in the design and construction of a perfect thermodynamic system as well as the performance assessment of such a system in order to achieve high efficiency for addressing global needs for daily ultra-low temperature application and heat-sensitive temperature-controlled storage for maintaining vaccines, pharmaceuticals, blood products, and biological. Finally, conclusions are drawn, and recommendations for further research are made.
SIMULATION OF THERMODYNAMIC ANALYSIS OF CASCADE REFRIGERATION SYSTEM WITH ALTERNATIVE REFRIGERANTS
The main aim of this project is to analyses the cascade refrigeration system by employing various alternative refrigerant pairs and choosing the best pair for higher temperature circuit (HTC) and lower temperature circuit (LTC). The analysis was done in various refrigerants pairs which are R134a/R23, R290/R23, R404A/R23, R407C/R23, R410A/R23, R134a/R508B, R290/R508B, R404A/R508B, R407C/R508B, R410A/R508B, R134a/R170, R290/R170, R404A/R170, R407C/R170 and R410A/R170. Assuming the degrees of sub cooling and superheating as 5°C and 10°C, respectively. The condenser temperature in higher temperature circuit (HTC) was varied from 30°C to 50°C and evaporator temperature in lower temperature circuit (LTC) was varied from -70 to -50°C. The intermediate heat exchanger temperature is about -20°C. Furthermore, the efficiencies of the compressors are assumed to be equal as 0.7. It has been found that the coefficient of performance (COP) of the cascade refrigeration system increases and the mass flow rate of higher temperature circuit increases, along with the work of compressor with rise in evaporator temperature for all refrigerant pairs. On the other hand, the COP of the cascade refrigeration system decreases and the mass flow rate of higher temperature circuit increases, also there is increase in work of compressor with increase in condenser temperature. Finally, the refrigerant pair R134a–R170 has the highest COP and lowest mass flow rate, while R404A–R508B has the lowest COP and highest mass flow rate.
In present study the comparison of thermodynamic analysis of cascade refrigeration system has been done with refrigerant pairs such as CO2-HFE7000, CO2-R134a, CO2-R152a, CO2-R32, CO2-R1234yf, CO2-NH3, CO2-Propane and CO2-Propylene. In these systems, performance of two stage cascade compression system using above different refrigerant couples, have been studied and the effect of condenser temperature & evaporator temperature, has been done. Thermodynamic analysis is carried out by developing computational model in Engineering Equation solver (EES).
There has been plenty of research work carried out related to Comparison of Thermodynamic Analysis of Cascade Refrigeration System. However, very few studies are done on different refrigerant pairs to improve the performance of Cascade Refrigeration System. The following research is based on systematic literature review of A. D. Parekh, P. R. Tailor, Thermodynamic Analysis of Cascade Refrigeration System Using R12-R13, R290-R23 and R404A-R23, International Journal of Mechanical Engineering. The published authors have researched Thermodynamic analysis shows that out of three refrigerant pairsR12-R13, R290-R23 and R404A-R23
PERFORMANCE EVALUATION OF TWO STAGE CASCADE REFRIGERATION SYSTEM USING NATURAL REFRIGERANTS
IAEME PUBLICATION, 2020
This paper deals with the performance evaluation of two stage cascade refrigeration system with three different natural refrigerants R290(propane), R600a(isobutane) and R1270(propene) in high temperature cycle cascaded independently with R1150(ethene) in low temperature cycle. Analysis of two stage cascade system is carried out with different parameters like mass ratio of refrigerants, total work, coefficient of performance of system and volumetric flow rate of refrigerant(HTC) at i) fixed evaporator temperature, fixed cascade condenser temperature and varying condenser temperature ii) fixed condenser temperature, fixed cascade condenser temperature and varying evaporator temperature and iii) fixed evaporator, fixed condenser temperature and varying cascade condenser temperature.
Experimental comparison of a cascade refrigeration system operating with R744/R134a and R744/R404a
2016
This study evaluates the performance of a cascade system in subcritical operation using the pair R744 / R134, as an option to conventional systems in supermarkets, which usually uses R404A, or R22. The experimental apparatus consists of a variable speed reciprocating compressor for R744 and an electronic expansion valve that promotes direct evaporation of the CO2 inside a cold room (2.3m x 2.6m x 2.5m) to maintain the internal air temperature stable. The high-temperature cycle consists of a reciprocating compressor for R134a, a thermostatic expansion valve, and an air-cooled condenser. A plate heat exchanger, which is at the same time, the condenser for the R744 and evaporator to R134a completes the setup. Two parameters were manipulated: The superheating degree of the R744, 5-20 K, and the R744 compressor operation frequency, 40-65 Hz. In order to contribute to the improvement of the cooling processes, mainly about the sustainability and energy efficiency, a drop-in has been made at the hightemperature cycle, whose R134a load has been replaced by R404A. The alternative cooling system (R744 / R404A) was subjected to two stages of tests which allowed the energy comparison between the two refrigerant sets. Through the obtained results, it was estimated maximum COP equivalent to 1.36 and a minimum value of 1.06 for the R744 / R134a pair, demonstrating the applicability of this cascade system of variable thermal load conditions, the values of capacity cooling, settled between 4.09 and 5.13 kW. The minimum value of the air temperature within the cold room was-28 °C and-5 °C the maximum. Finally, it was found that the results obtained for R744 / R404A pair attended the air temperature condition inside the cold room with similar COP values. However, R744 / R404A pair operated at lower refrigeration capacities, these settled between 2.16 and 3.00 kW. This reduction is due to the large difference between the volumetric cooling capacity values of these HFCs in question, resulting in adaptation problems of the R404A to the compressor and the expansion mechanism.
International Journal of Refrigeration-revue Internationale Du Froid, 2019
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Highlights Thermodynamic performance of a cascade refrigeration system was investigated. Three mixed refrigerants (R744/R1270, R744/RE170, R744/R717) were tested in both subcycles. Mixed refrigerants allow a better thermodynamic performance than pure fluids. R744/RE170 presented the greatest global COP, 2.34, for a fixed cooling rate of 100 kW. Exergetic efficiency increased up to 30% and refrigerant mass flow rate was reduced up to 34%.