COMPARATIVE ANALYSIS OF CASCADE REFRIGERATION SYSTEMS’ PERFORMANCE and ENVIROMENTAL IMPACTS

Abstract

The aim of our study is to propose a theoretical model to analyze the energy efficient and environment friendly cascade system for various refrigerant pairs. In order to realize, the optimum cascade evaporation temperature (T_OPT,CAS,E) which maximize the performance, COP values are determined for different refrigerant pairs of the system. After the optimization, two different cases have been investigated through a thermodynamic analysis to discover the best refrigerant pair for the system. Natural refrigerant CO₂ is selected instead of R404A which has high Global Warming Potential (GWP) value for the low temperature cycle (LTC). On the other hand, synthetic refrigerants (R134a, R152a) and a natural refrigerant (NH₃) are chosen for the high temperature cycle (HTC). In order to determine, an energy efficient and environmentally friendly cascade system, R134a/CO₂, R152a/CO₂ and NH₃/CO₂ refrigerant pairs are investigated in Case 1. On the other hand, R134a/R404A, R152a/R404A and NH₃/R404A refrigerant pairs are investigated in Case 2. In calculations, the evaporation temperature (T_E) is varied from -20^oC to -40^oC in LTC. The condensation temperature (T_C) is considered to be between 30^oC and 45^oC in HTC. Mass flow rate requirements of systems for various refrigeration capacities (Q_Evap) are calculated for different refrigerant pairs. Moreover, the COP_max and total equivalent warming impact (TEWI) values of the system’s refrigerant pairs are evaluated and compared for various operating conditions.

Keywords

• Cascade system,Optimization,TEWI,COP

References

1. [1] Llopis , R., Torrella, E., Cabello, R., and Sanchez, D., Performance evaluation of R404A and R507A refrigerant mixtures in an experimental double-stage vapour compression plant,” Appl. Energy, 87(5), 2010, 1546-1553.
2. [2] Kilicarslan A., Hosoz M., Energy and irreversibility analysis of a cascade refrigeration system for various refrigerant couples. Energ. Convers. Manage., 51, 2010, 2947-2954.
3. [3] Cabello R., Sanchez D., Llopis R., Catalan J., Nebot-Andres L., Torella E., Energy evaluation of R152a as drop in replacement for R134a in cascade refrigeration plants, Appl. Therm. Eng, 110, 2017, 972-974.
4. [4] Oruc V., Devecioglu A.G., Ender S., Improvement of energy parameters using R442A and R453A in a refirigeration system operating with R404A, Appl. Therm. Eng, 129, 2018, 243-249.
5. [5] Baakeem S.S., Orfi J., Alabdulkarem A., Optimization of a multistage vapor-compression refrigeration system for various refrigerants, Appl. Therm. Eng, 136, 2018, 84-96.
6. [6] Vaghela J.K., Comparative evaluation of an automobile air-conditioning system using R134a and its alternative refrigerants, Energy Procedia, 109, 2017, 153-160.
7. [7] Karampour, M., Sawalla, S., State-of-the-art integrated CO2 refrigeration system for supermarkets: A comparative analysis, Int. J. Refrig., 86, 2018, 239-257.1148.
8. [8] Cengel, Y.A., Boles, M.A., Thermodynamics: An engineering Approach, McGraw-Hill, Singapore, 2007.

9. [9] Pearson, A., Carbon dioxide e new uses for an old refrigerant. Int. J. Refrig., 28, 2005, 1140-1148.
10. [10] IPCC. Climate Change 2013: The Physical Science Basis, Cambridge University Press, Cambridge, United Kingdom and New York, USA, 2013.
11. [11] AIRAH, Methods of Calculating Total Equivalent Warming Impact (TEWI) 2012, Best Practice Guidelines. The Australian Institute of Refrigeration, Air Conditioning and Heating.
12. [12] EES., 2017, Engineering Equation Solver, Academic Commercial, V10.326, fChart Software Inc.
13. [13] Sınar, U., Numerical analysis of a cascade refrigeration system operating at ultra-low temperatures, Marmara University, Master Thesis, 2018.
14. [14] Horton, W.T., Modelling of secondary loop refrigeration systems in supermarket applications, Purdue University, PhD thesis, 2002.