Energy and exergy analysis study of heat exchanger in a refrigeration system with different lengths of capillary tube

Abstract

An experimental study was conducted to demonstrate the effect of the capillary tube length on the refrigeration system performance by adding heat exchanger. The heat exchanger was designed by welding 70cm of the capillary tube with the suction line laterally, which included different lengths of the capillary tubes are 160, 175, 190cm. Besides, the experimental part has been tested at different refrigerant flow rates and air fan velocities of the condenser for each case of the adiabatic and nonadiabatic capillary tube. The experimental results showed an increase in the system performance by 17.96% with a decrease in capillary tube length from 190 to 160 cm for the nonadiabatic capillary tubes at the mass flow rate was 17.3kg/hr and air velocity 3m/s. In addition, the increase in the air-speed of condenser has led to elevate COP by 17.47% at the mass flow rate of 18.9 kg/hr and the capillary tube length of 190 cm. Finally, at the capillary tube length 190cm and refrigerant mass flow rate 2.4g/s is achieved the maximum enhancement of the refrigeration system performance and exergy efficiency by 6.7% and 35% at airspeed 1m/s and 3 m/s respectively compared to the reference one of the adiabatic capillary tubes.

Keywords

• Capillary tube length,Suction line,Exergy,Heat exchanger,R134a

Supporting Institution

There are no Supporting Institution

Thanks

The authors would like to thank the Tikrit University for supporting us to use the laboratory facilities in the mechanical engineering department.

References

1. [1] Threlkeld J.L., etal.,"Thermal environmental engineering", 3rd Ed., Prentic Hall, 1998.
2. [2] W. F. Stoeker, refrigeration and air condition, 2nd Ed., Mc Graw-Hill, 1982.
3. [3] A. D. Etal., Modern refrigeration and air conditioning. 2004.
4. [4] D. K. Aljudi, principles of enginerring air conitioning and refrigeration. 1986.
5. [5] Khuehl S.J. and Goldsshmidt V.W., “steady flow of R-22 through capillary tube: test data,” ASHRAE Trans., vol. 96, 1990.
6. [6] O. García-Valladares, “Numerical simulation of non-adiabatic capillary tubes considering metastable region. Part II: Experimental validation,” Int. J. Refrig., vol. 30, no. 4, pp. 654–663, 2007. doi:10.1016/j.ijrefrig.2006.10.003
7. [7] S. Park, K. Son, J. Jeong, and L. Kim, “Simulation of the effects of a non-adiabatic capillary tube on refrigeration cycle,” 2008.
8. [8] T. K. S. Etal., “an experimental study to show the effect of difference in capillary tube length on compression refrigeration system performance by using the refrigerant R134a,” Tikrit J. Eng. Sci., vol. 15, pp. 14–28, 2008.

9. [9] M. K. Khan, R. Kumar, and P. K. Sahoo, “Experimental investigation on diabatic flow of R-134a through spiral capillary tube,” Int. J. Refrig., vol. 32, no. 2, pp. 261–271, 2009.
10. [10] C. J. L. Hermes, C. Melo, and F. T. Knabben, “Algebraic solution of capillary tube flows. Part II: Capillary tube suction line heat exchangers,” Appl. Therm. Eng., vol. 30, no. 6–7, pp. 770–775, 2010. doi:10.1016/j.applthermaleng.2010.01.001
11. [11] L.-S. Kim, K. Son, D. Sarker, J. H. Jeong, and S. H. Lee, “An assessment of models for predicting refrigerant characteristics in adiabatic and non-adiabatic capillary tubes,” Heat mass Transf., vol. 47, no. 2, pp. 163–180, 2011. doi 10.1007/s00231-010-0697-0
12. [12] S. Y., “experimental investigation of condensation of refrigerant R134a and R12 in air cooled horizontal condenser,” J. Eng. Dev., vol. 15, pp. 155–172, 2011.
13. [13] M. M. Shah, “A general correlation for heat transfer during film condensation inside pipes,” Int. J. Heat Mass Transf., vol. 22, no. 4, pp. 547–556, 1979.
14. [14] J. U. Ahamed, R. Saidur, and H. H. Masjuki, “A review on exergy analysis of vapor compression refrigeration system,” Renew. Sustain. Energy Rev., vol. 15, no. 3, pp. 1593–1600, 2011. doi:10.1016/j.rser.2010.11.039
15. [15] D. Sarker and J. H. Jeong, “Development of empirical correlations for non-adiabatic capillary tube based on mechanistic model,” Int. J. Refrig., vol. 35, no. 4, pp. 974–983, 2012. doi:10.1016/j.ijrefrig.2012.01.021
16. [16] K. C. Mendonca, C. Melo, R. T. S. Ferreira, and R. H. Pereira, “Experimental study on lateral capillary tube-suction line heat exchangers,” 1998.
17. [17] D. A. Wolf and M. B. Pate, “Capillary tube-suction line heat exchanger performance with alternative refrigerants,” ASHRAE Res. Proj. RP-762, Final Rep., 2002.
18. [18] J. H. Jeong, S.-G. Park, D. Sarker, and K. S. Chang, “Numerical simulation of the effects of a suction line heat exchanger on vapor compression refrigeration cycle performance,” J. Mech. Sci. Technol., vol. 26, no. 4, pp. 1213–1226, 2012.
19. [19] N. A. Ansari, B. Yadav, and J. Kumar, “Theoretical exergy analysis of HFO-1234yf and HFO-1234ze as an alternative replacement of HFC-134a in simple vapour compression refrigeration system,” Int. J. Sci. Eng. Res., vol. 4, no. 8, p. 137, 2013.
20. [20] M. Chandrasekharan, “Exergy analysis of vapor compression refrigeration system using R12 and R134a as refrigerants,” Int. J. Students’ Res. Technol. Manag., vol. 2, no. 04, pp. 134–139, 2014.
21. [21] J. D. and D. K. Mudaiya, “Mathematical modelling for refrigeration flow in diabatic capillary tube,” Int. J. Latest Trends Eng. Technol., vol. 6, no. 3, 2016.
22. [22] N. N. Raja and A. D. Khanderao, “Experimental Investigation on the Effect of Capillary Tube Geometry on the Performance of Vapor Compression Refrigeration System,” Asian J. Eng. Appl. Technol., vol. 5, no. 2, pp. 29–35, 2016.
23. [23] M. dos Santos Guzella, L. Cabezas-Gómez, L. G. M. Guimarães, and C. B. Tibiriçá, “A modified approach for numerical simulation of capillary tube-suction line heat exchangers,” Appl. Therm. Eng., vol. 102, pp. 283–292, 2016. http://dx.doi.org/10.1016/j.applthermaleng.2016.03.139
24. [24] C. L. Z. and G. L. Ding, “Modified general equation for the design of capillary tube,” Trans. ASME, pp. 914–919, 2001.
25. [25] C. Melo, J. M. Zangari, R. T. S. Ferreira, and R. H. Pereira, “Experimental studies on non-adiabatic flow of HFC-134a through capillary tubes,” 2000.
26. [26] C. Melo, L. A. T. Vieira, and R. H. Pereira, “Non-adiabatic capillary tube flow with isobutane,” Appl. Therm. Eng., vol. 22, no. 14, pp. 1661–1672, 2002.
27. [27] A. A. Mohammed and A. A. Nasser, “Experimental And Mathematical Evaluation Of The Refrigeration System Performance With Different Ambient Temperature,” J. Eng. Sustain. Dev., vol. 21, no. 6, pp. 1–19, 2017.
28. [28] L. A. A.-A. Mahdi, W. S. Mohammad, and S. A. Mahmood, “Exergy Analysis of a Domestic Refrigerator,” J. Eng., vol. 24, no. 9, pp. 1–20, 2018.
29. [29] S. K. Dubba and R. Kumar, “Experimental investigation on flow of R-600a inside a diabatic helically coiled capillary tube: Concentric configuration,” Int. J. Refrig., vol. 86, pp. 186–195, 2018.
30. [30] C. Melo, R. T. S. Ferreira, C. B. Neto, J. M. Goncalves, and M. M. Mezavila, “An experimental analysis of adiabatic capillary tubes,” Appl. Therm. Eng., vol. 19, no. 6, pp. 669–684, 1999.
31. [31] I. M. A. Aljubury and M. A. Mohammed, “Heat Transfer Analysis of Conventional Round Tube and Microchannel Condensers in Automotive Air Conditioning System,” J. Eng., vol. 25, no. 2, pp. 38–56, 2019.
32. [32] C. Stanciu, A. Gheorghian, D. Stanciu, and A. Dobrovicescu, “Exergy analysis and refrigerant effect on The operation and performance limits of a One stage vapor compression Refrigeration system,” Termotehnica, vol. 1, pp. 36–42, 2011.
33. [33] S. A. Klein, D. T. Reindl, and K. Brownell, “Refrigeration system performance using liquid-suction heat exchangers,” Int. J. Refrig., vol. 23, no. 8, pp. 588–596, 2000.
34. [34] M. Yilmaz, O. N. Sara, and S. Karsli, “Performance evaluation criteria for heat exchangers based on second law analysis,” Exergy, an Int. J., vol. 1, no. 4, pp. 278–294, 2001.
35. [35] Ammar A. F. (2016), “Experimental and Numerical Study for Refrigerant Flow through Capillary Tube within Metastable Region”, (Master dissertation), University of Babylon.
36. [36] M. Fatouh and H. Abou-Ziyan, “Energy and exergy analysis of a household refrigerator using a ternary hydrocarbon mixture in tropical environment–Effects of refrigerant charge and capillary length,” Appl. Therm. Eng., vol. 145, pp. 14–26, 2018.