Document Type : Research Paper


1 Energy Engineering Department, College of Engineering, Duhok Polytecnic University, Duhok, Iraq

2 Mechanical Engineering Department, College of Engineering, University of Zakho, Duhok, Iraq


The present study is an experimental investigation to improve the performance of the air conditioning unit (ACU) by precooling the condenser with a cooling water loop using a water heat exchanger with the employment of energy and exergy analyses under various ambient temperatures between 30 – 45°C at different inlet water temperatures; 15, 19, 24 and 30°C and water flowrates; 9, 11, 14 and 15.8 L/min. The results indicated that the cooling water loop have a large effect on the exergy destructions as compared with those of the no water case. When a cooling water loop is used, the compressor, evaporator, and expansion valve irreversibilities reduced. The exergy efficiency of the unit decreases as Tamb increases to about 23%; while, the exergy efficiency increases when cooling water loop is used depending on the inlet water temperature and water flowrates. The maximum enhancement in the exergy efficiency is obtained at high water flowrate for Twi = 15°C with a percentage value about 13% as compared with those of the conventional ACU.


Main Subjects

[1]     E. Firouzfar, M. Soltanieh and M. Saidi, “Application of heat pipe heat exchangers in heating, ventilation and air conditioning (HVAC) systems,” Acad. Journals, vol. 6(9), no. 1992-2248 ©2011, pp. 1900–1908, 2011.
[2]     I. Ardita, “The application of condensate water as an additional cooling media intermittently in condenser of a split air conditioning,” Int. Jt. Conf. Sci. Technol., 2018, doi: 10.1088/1742-6596/953/1/012059.
[3]     A. Siricharoenpanich, S. Wiriyasart, R. Prurapark and P. Naphon b, “Effect of cooling water loop on the thermal performance of air conditioning system,” Case Stud. Therm. Eng., vol. 15, pp. 1–8, 2019, doi: 10.1016/j.csite.2019.100518.
[4]     I. Dlncer, M. M. Hussain and I. A1-Zaharnah, “Energy and exergy use in the utility sector of Saudi Arabia,” Desalination, vol. 169, no. 3, pp. 245–255, 2004, doi: 10.1016/j.desal.2003.12.007.
[5]     M. Pons, “Exergy Analysis and process optimization with variable environment temperature,” Energies, vol. 12, no. 24, p. 4655, 2019, doi:10.3390/en12244655.
[6]     X. Song et al., “Energy and exergy analyses of a transcritical CO2 air conditioning system for an electric bus,” Appl. Therm. Eng., vol. 190, 2021, doi: 10.1016/j.applthermaleng.2021.116819.
[7]     L. Zhang, X. Song, and X. Zhang, “Theoretical analysis of exergy destruction and exergy flow in direct contact process between humid air and water/liquid desiccant solution,” Energy, vol. 187, 2019, doi: 10.1016/
[8]     I. Dincer and M. A. Rosen, Exergy: energy, environment and sustainable development. Newnes, 2012.
[9]     A. KARAKURT, U. GUNES and Y. UST, “Exergetic and Economic Analysis of Subco” Power Conference. Charlotte, North Carolina, pp. 1–6, 2016.
[10]  B. Kílíc, “Exergy analysis of vapor compression refrigeration cycle with two-stage and intercooler,” Heat and Mass Transfer/Waerme- und Stoffuebertragung, vol. 48, no. 7. pp. 1207–1217, 2012, doi: 10.1007/s00231-012-0971-4.
[11]  J. Ahamed, R. Saidur, 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.
[12]  M. H. Yang and R. H. Yeh, “Performance and exergy destruction analyses of optimal subcooling for vapor-compression refrigeration systems,” Int. J. Heat Mass Transf., vol. 87, pp. 1–10, 2015, doi: 10.1016/j.ijheatmasstransfer.2015.03.085.
[13]  R. Saravanakumar and V. Selladurai, “Exergy analysis of a domestic refrigerator using eco-friendly R290/R600a refrigerant mixture as an alternative to R134a,” Journal of Thermal Analysis and Calorimetry, vol. 115, no. 1. pp. 933–940, 2014, doi: 10.1007/s10973-013-3264-3.
[14]  Y. Ust and A. S. Karakurt, “Analysis of a Cascade Refrigeration System (CRS) by Using Different Refrigerant Couples Based on the Exergetic Performance Coefficient (EPC) Criterion,” Arab. J. Sci. Eng., vol. 39, no. 11, pp. 8147–8156, 2014, doi: 10.1007/s13369-014-1335-9.
[15]  S. Anand and S. K. Tyagi, “Exergy analysis and experimental study of a vapor compression refrigeration cycle: A technical note,” in Journal of Thermal Analysis and Calorimetry, 2012, vol. 110, no. 2, pp. 961–971, doi: 10.1007/s10973-011-1904-z.
[16]  M. Chandrasekharan, “Exergy Analysis of Vapor Compression Refrigeration System Using R12 and R134a as Refrigerants,” International Journal of Students’ Research in Technology & Management, vol. 2, no. 04. pp. 134–139, 2014, [Online]. Available:
[17]  A. K. Shaker, “Energy-Exergy Performance Comparison of an Ideal Vapor Compression Refrigeration Cycle using Alternatives Refrigerants of R134a for Low Potential of Global Warming,” Basrah journal of engineering science, vol. 17, no. 1. pp. 35–39, 2017, doi: 10.33971/bjes.17.1.5.
[18]  W. V. Payne and P. A. Domanski, “A Comparison of an R22 and an R410A Air Conditioner Operating at High Ambient Temperatures,” Gaithersburg, Maryl. USA, no. January, pp. 2–9, 1999.