scholarly journals Advanced Thermodynamic Analysis of a Transcritical R744 Booster Refrigerating Unit with Dedicated Mechanical Subcooling

Energies ◽  
2018 ◽  
Vol 11 (11) ◽  
pp. 3058 ◽  
Author(s):  
Paride Gullo
Keyword(s):  
Low Temperature ◽  
Thermodynamic Analysis ◽  
Temperature Difference ◽  
Exergy Analysis ◽  
Refrigeration System ◽  
Outdoor Temperature ◽  
Medium Temperature ◽  
High Stage ◽  
Thermodynamic Performance ◽  
Priority Needs

In this work the thermodynamic performance of a transcritical R744 booster supermarket refrigeration system equipped with R290 dedicated mechanical subcooling (DMS) was exhaustively investigated with the aid of the advanced exergy analysis. The outcomes obtained suggested that improvement priority needs to be addressed to the manufacturing of more efficient high-stage (HS) compressors, followed by the enhancement of the gas cooler/condenser (GC), of the medium-temperature (MT) evaporators, of the R290 compressor, and of the low-temperature (LT) evaporators. These conclusions were different from those drawn by the application of the conventional exergy assessment. Additionally, it was found that GC can be enhanced mainly by reducing the irreversibilities owing to the simultaneous interaction among the components. The R290 compressor would also have significantly benefitted from the adoption of such measures, as half of its avoidable irreversibilities were exogenous. Unlike the aforementioned components, all the evaporators were improvable uniquely by decreasing their temperature difference. Finally, the approach temperature of GC and the outdoor temperature were found to have a noteworthy impact on the avoidable irreversibilities of the investigated solution.

Energy and Exergy Analysis of Cascade Refrigeration System Using MC22 and MC134 on HTC, R404A and R502 on LTC

2021 ◽  
Vol 80 (1) ◽  
pp. 73-83
Author(s):  
Hendri ◽  
Roswati Nurhasanah ◽  
Prayudi ◽  
Suhengki
Keyword(s):  
Low Temperature ◽  
Exergy Analysis ◽  
Refrigeration System ◽  
Low Temperature Storage ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Cascade Refrigeration System ◽  
Cascade Refrigeration ◽  
Better Than ◽  
Temperature Storage

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.

Thermodynamic Analysis of a R32/CO2 Cascade Refrigeration Cycle

2013 ◽  
Vol 732-733 ◽  
pp. 527-530 ◽  
Author(s):  
Jian Xiao ◽  
Ying Fu Liu
Keyword(s):  
Low Temperature ◽  
Thermodynamic Analysis ◽  
Working Conditions ◽  
Temperature Difference ◽  
Refrigeration Cycle ◽  
Cascade Refrigeration

A R32/CO2 cascade refrigeration cycle was analyzed thermodynamically, the results show that: Under given working conditions, there exists the best condensing temperature of the low-temperature circuit to make the maximum COP of the cycle. The lower evaporating temperature is, the lower the best condensing temperature of the low-temperature circuit is. Under the same evaporating temperature, COP increases and mH/mL decreases along with condensing temperature decreasing, under the same condensing temperature, COP decreases and mH/mL increases along with condensing temperature decreasing. To reduce the temperature difference in the cascade-condenser can increase COP and decrease mH/mL.

scholarly journals Analysis of Operation Parameters of Fish Refrigeration by Exergy Analysis. Case Study

2019 ◽  
Vol 23 (1) ◽  
pp. 229-241
Author(s):  
Edvins Terehovics ◽  
Ivars Veidenbergs ◽  
Dagnija Blumberga
Keyword(s):  
Energy Efficiency ◽  
Ambient Temperature ◽  
Working Conditions ◽  
Temperature Difference ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Single Stage ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
The Ideal

Abstract Unlike energy efficiency, in terms of exergy efficiency it is possible to compare the existing operation of an energy conversion system with the ideal operation. Exergy loses and exergy destruction make it possible to identify the shortcomings of an existing system, which should be improved immediately. With exergy analysis, it is possible to identify the priority actions that need to be taken in order to improve the functioning of the system: greater exergy loss prevention is the highest priority. Energy efficiency refers to the useful work and investments needed to obtain useful work and investments needed to obtain energy efficiency; this is important to some extent, but the effectiveness of exergy makes it possible to compare system performance with the ideal. Results shows that the highest exergy destruction of a single-stage compressor refrigeration system from all working condition is found when ambient temperature and freezer temperature difference is 10 ºC, pressure in compressor is 0.62 MPa, ammonia temperature after compressor is 90 ºC, total exergy destruction of single-stage compressor refrigeration system 97.84 kW. The highest exergy efficiency of a single-stage compressor refrigeration system from all the working conditions is found when ambient temperature and freezer temperature difference is 39 ºC, pressure in compressor is 0.45 MPa, ammonia temperature after compressor is 128 ºC, exergy efficiency of a single-stage compressor refrigeration system is 59.76 %. The highest total exergy destruction of a two-stage compressor refrigeration system from among all the working conditions is found to be when the ambient temperature and freezer temperature difference is at 13 ºC, pressure in compressor 0.44 MPa, ammonia temperature after compressor 76 ºC, total exergy destruction 83.86 kW. The highest exergy efficiency of a two-stage compressor refrigeration system from among all the working conditions is found to be at an ambient temperature and freezer temperature difference of 39 ºC, pressure in compressor 0.56 MPa, ammonia temperature after compressor 92 ºC, exergy efficiency 53.55 %.

Thermodynamic Analysis of R134a-R23 Cascade Refrigeration System

2015 ◽  
Vol 787 ◽  
pp. 117-123
Author(s):  
P.L. Rupesh ◽  
J.M. Babu ◽  
R. Mariappan
Keyword(s):  
Regression Analysis ◽  
Thermodynamic Analysis ◽  
Minimum Temperature ◽  
Exergy Analysis ◽  
Operating Parameters ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
Cascade Refrigeration System ◽  
R 134A ◽  
Cascade Refrigeration

The present work deals with thermodynamic analysis of a R-134a/R-23 cascade refrigeration system to evaluate the maximum COP and the minimum temperature difference (DT) corresponding to , by considering different operating parameters. The operating parameters includes: the condensing () and evaporating temperature () of R-134a and the condensing () and evaporating temperature () of R-23. A computational model has been developed for the considered system to evaluate the and DT corresponding to based on the thermodynamic principles. A mutilinear regression analysis has been carried out to evaluate two correlations for calculating and minimum DT considering the above operating parameters. The exergy analysis of the system is also performed to determine the irreversibility losses of the system as well as for the components. It has been found that the total exergy destruction rate of the system is lower at minimum .

scholarly journals Thermodynamic Performance Investigation of Commercial R744 Booster Refrigeration Plants Based on Advanced Exergy Analysis

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 354 ◽  
Author(s):  
Paride Gullo ◽  
Armin Hafner ◽  
Krzysztof Banasiak
Keyword(s):  
Exergy Analysis ◽  
Performance Enhancement ◽  
Exergy Destruction ◽  
Outdoor Temperature ◽  
Food Retail ◽  
Destruction Rate ◽  
Performance Improvements ◽  
Refrigeration Unit ◽  
Thermodynamic Performance ◽  
The One

After the recent renewed interest in CO2 as the refrigerant (R744) for the food retail industry, many researchers have focused on the performance enhancement of the basic transcritical R744 supermarket refrigeration unit in warm climates. This task is generally fulfilled with the aid of energy-based methods. However, the implementation of an advanced exergy analysis is mandatory to properly evaluate the best strategies needing to be implemented to achieve the greatest thermodynamic performance improvements. Such an assessment, in fact, is widely recognized as the most powerful thermodynamic tool for this purpose. In this work, the advanced exergy analysis was applied to a conventional R744 booster supermarket refrigerating system at the outdoor temperature of 40 °C. The results obtained suggested the adoption of a more sophisticated layout, i.e., the one outfitted with the multi-ejector block. It was found that the multi-ejector supported CO2 system can reduce the total exergy destruction rate by about 39% in comparison with the conventional booster unit. Additionally, the total avoidable exergy destruction rate was decreased from 67.60 to 45.57 kW as well as the total unavoidable exergy destruction rate was brought from 42.67 down to 21.91 kW.

Sign in / Sign up

Export Citation Format

Share Document