Current Science Research Bulletin

Mini water chillers are small-capacity cooling systems widely used in laboratory applications and light industries due to their ability to maintain stable temperatures with relatively low power consumption. Nevertheless, the thermal efficiency of these systems can be further improved through optimization of fluid flow configurations in the secondary loop. This study investigates the effect of a counter-flow heat exchanger configuration on the energy and exergy performance of an economical mini water chiller secondary system. The research employs both theoretical and experimental approaches by measuring inlet and outlet fluid temperatures, mass flow rates, and electrical power consumption. Energy analysis is applied to determine the coefficient of performance (COP), while exergy analysis is used to evaluate exergy efficiency (ηₑₓ) and the rate of exergy destruction (Ėd). The results indicate that the counter-flow configuration enhances the system COP by approximately 8–12% compared to a parallel-flow model. In addition, overall exergy efficiency increases by up to 9%, with the most significant reduction in exergy destruction occurring in the secondary heat exchanger. These findings demonstrate that the implementation of a counter-flow model is effective in improving both energy performance and exergy quality in energy-efficient mini cooling systems.

counter-flow configuration; water chiller; energy efficiency; exergy efficiency; secondary system

1. Yıldız, G. (2024). Energy-exergy-environment and economic (4E) analysis of a PV/T-assisted vapour compression refrigeration system. Energy Reports. 
2. Al-Qazzaz, A. H. S. (2024). Energy and exergy analysis with environment benefit of the underground heat exchanger vs wet cooling tower. Sustainable Energy Research.
3. Prajapati, P. (2024). Energy-exergy-economic-environmental (4E) analysis and optimization of a cascade refrigeration cycle. International Journal of Refrigeration / Institutional Repository. 
4. Kaminski, K. (2024). A comparative analysis on the theoretical and experimental thermal performance of selected counter-flow heat exchangers. Energies. 
5. Palacios-Lorenzo, M. E., et al. (2024). Analysis of internal heat recovery capability in air-cooled chillers. Scientific Reports / PMC. 
6. Rashid, F. L. (2025). Enhancing efficiency in double-pipe heat exchangers: a review. Heat Transfer Journal. 
7. Mróz, T. (2025). Energy-Environmental Analysis of Retrofitting of a Chilled Water Production System. Applied Sciences (MDPI). 
8. Aized, T. (2022). Energy and Exergy Analysis of Vapour Compression Refrigeration Systems (various refrigerants). Conference/Proceedings (LAPSE 2023 / PSEcommunity). 
9. Ashour, A. M., et al. (2025). Energy, exergy and environmental analysis of five low-GWP refrigerants considered as alternatives to R410A. SN Applied Sciences / Springer. 
10. Jiménez-García, J. C., et al. (2023). Exergy analysis of an experimental ammonia/water absorption cooling system. Journal of Cleaner Production / Energy Reports. 
11. Ghodrati, A., et al. (2024). Energy, exergy, exergy-economic, and environmental assessment of hybrid heat pump systems. Energy Science & Engineering. 
12. Sow, M., et al. (2025). Energy and exergy assessment of a solar driven single-effect H2O-LiBr absorption chiller. Energies (MDPI). 
13. Deharkar, R., et al. (2025). Advanced exergy analysis of vapor compression systems with different expansion devices. Journal of Energy Conversion. 
14. Letlhare-Wastikc, & Yang, X. (2025). Triply Periodic Minimal Surface (TPMS) heat exchangers: performance and exergy implications. Preprints / Engineering. 
15. Moffat, R. J. (1988). Describing the uncertainties in experimental results. Experimental Thermal and Fluid Science, 1(1), 3–17. (metode propagasi ketidakpastian)
16. Bejan, A. (2020). Advanced Engineering Thermodynamics. John Wiley & Sons.
17. Zhang, Y., Liu, T., & Chen, J. (2022). Comparative performance study of parallel and counter-flow heat exchangers in secondary cooling systems. Energy Conversion and Management. (gunakan sebagai rujukan perbandingan flow arrangement — bila perlu saya dapat ambil link lengkapnya).
18. Khalid, A., Singh, R., & Patel, R. (2023). Effectiveness and exergy-based evaluation of counter-flow heat exchangers in refrigeration systems. International Journal of Refrigeration. (sumber terkait efektivitas/eksers heat exchanger; saya bisa ambil DOI jika kamu mau).
19. Rahman, M. A., et al. (2021). Exergy analysis and optimization of small-scale vapor compression chillers. Energy Reports.
20. Hassan, M., Rahman, M., & Karim, M. (2022). Performance analysis of compact water chiller systems for laboratory applications. Applied Thermal Engineering.