Spray Angle on the Performance of Split-Type AC Condenser Installed on Concrete Rooftop in Tropical Climate

Kennedy Kennedy, I N Frenki Aryana, Basri Basri

Abstract


This study investigated the influence of different water spray angles (0°, 15°, and 30°) on the thermal and energy performance of a split-type air-conditioning (AC) condenser installed on a concrete rooftop in a tropical climate. An experimental setup was designed to replicate actual concrete rooftop conditions, focusing on the condenser inlet temperature, compressor power consumption, and system coefficient of performance (COP). A 6-minute ON and 6-minute OFF intermittent spray cycle was employed to optimise water usage and minimise excessive humidity. Experimental measurements were conducted on a 9,000 Btu/h split-type unit equipped with a nozzle system connected to a 200 L water tank. The results demonstrated that the 0° spray angle achieved the most significant improvement, reducing the condenser inlet air temperature by up to 22.5% and decreasing the compressor power consumption by 7.7% compared with the baseline. This configuration also enhanced the COP from 2.77 to 2.93, representing a 5.8% improvement in performance. Wider spray angles (15° and 30°) yielded moderate improvements but were less effective because of droplet dispersion and reduced surface wetting. Thermal imaging confirmed that the 0° angle produced the most uniform cooling distribution on the condenser surface. These findings underscore that spray cooling with an optimised nozzle orientation is a cost-effective and sustainable retrofit solution for rooftop AC condensers in tropical environments, offering improved energy efficiency and reduced environmental impact.

Keywords


spray cooling, nozzle angle, air-cooled condenser, rooftop AC unit, COP, energy efficiency, tropical climate

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References


H. Mao, Q. Meng, Z. Liu, and J. Wang, “Evaluation of water spray systems on transparent roofs,” Building and Environment, vol. 239, 110493, Sep. 2023, doi: 10.1016/j.buildenv.2023.110493.

S. Yuliani and W. Setyaningsih, “The impact of thermal performance on the roof surface to energy efficiency of high-rise buildings in the tropical region,” Arsitektura, vol. 16, no. 1, pp. 129–139, 2018, doi: 10.20961/arst. v16i1.20748.

H. Yang, N. Pei, M. Fan, and D. Wang, “Experimental study on an air-cooled air conditioning unit with spray evaporative cooling system,” International Journal of Refrigeration, vol. 131, pp. 645–656, Jul. 2021, doi: 10.1016/j.ijrefrig.2021.06.011.

R. Charoensin-O-larn, N. Kavee, and J. Klinbun, “Influence of water spray cooling on air-cooled condenser of a split-type air conditioner,” Case Studies in Thermal Engineering, vol. 61, 104941, Jan. 2024, doi: 10.1016/j.csite.2024.104941.

İ. Atmaca, A. Şenol, and A. Çağlar, "Performance testing and optimization of a split-type air conditioner with evaporatively-cooled condenser," Engineering Science and Technology, an International Journal, vol. 32,101064, August 2022, doi: 10.1016/j.jestch.2021.09.010

I.G. Wiratmaja, K.R. Dantes, and E.A.J. Artha, “Increasing the cooling rate of the room with a combination of air and air cooling media on the condenser side of a split type AC cooling machine,” Jurnal Pendidikan Teknik Mesin Undiksha, vol. 9, no. 1, pp. 50–58, Mar. 2021, doi: 10.23887/jptm.v9i1.33220 (in Indonesian).

B. Shen, J. New, and M. Ally, “Energy and economics analyses of condenser evaporative precooling for various climates, buildings and refrigerants,” Energies, vol. 12, no. 11, p. 2079, May 2019, doi: 10.3390/en12112079

S.G. Koç, “The effects of shading devices on office building energy performance,” Journal of Building Engineering, vol. 44, 103299, Feb. 2021, doi: 10.1016/j.jobe.2021.103299

D.E. Okonta, R.O. Olugboyega, O.A. Oni, and O.S. Adeniran, “Investigating the impact of building materials on energy efficiency,” Heliyon, vol. 9, no. 10, e105600, Oct. 2023, doi: 10.1016/j.heliyon.2023.e105600

M. Zhang, J. Xiong, Y. Liu et al., “Natural ventilation for cooling energy saving: Typical case of public building design optimization,” Applied Sciences, vol. 14, no. 2, p. 610, Jan. 2024, doi: 10.3390/app14020610.

L. Yu, Y. Huang, W. Li, and M. Chen, "Radiative-coupled evaporative cooling: Fundamentals, development, and applications," Nano Research Energy, vol. 3, 2024, doi: 10.26599/NRE.2024.9120003.

A. Tejero-González and A. Franco-Salas, “Direct evaporative cooling from wetted surfaces: Challenges for a clean air conditioning solution,” Wiley Interdisciplinary Reviews: Energy and Environment, vol. 11, no. 3, pp. 1–24, Nov. 2021, doi: 10.1002/wenw.432.

P. Larpruenrudee, D.K. Do, N.S. Bennett, S.C. Saha, M. Ghalambaz, M.S. Islam, “Computational fluid dynamics analysis of spray cooling in Australia”, Energies, vol. 16, no. 2317, 2023, doi: 10.3390/en16145317.

G. Chen, C. Qiao, F. Liang, and Z. Xu, “CFD optimization study on heat transfer enhancement of air-cooled condenser spray cooling system,” in Proc. SPIE 13632, Photonics and Optoelectronics Meetings (POEM) 2024: Photonic Heat Transfer and Energy Conversion, 2025, p. 136323A, doi: 10.1117/12.3061142

L. Liu, W. Zhang, J. Li et al., “Crosswind effects on spray cooling for CNG systems,” International Journal of Refrigeration, vol. 167, pp. 59–69, Nov. 2024, doi: 10.1016/j.ijrefrig.2024.07.025.

P. Navarro, J. Ruiz, P. Martínez, and M. Lucas, “Numerical study of an ultrasonic spray atomiser as an evaporative cooler,” Applied Thermal Engineering, vol. 236, Part A, Art. no. 121455, Jan. 2024, doi: 10.1016/j.applthermaleng.2023.121455

G. Heidarinejad, M. Moghaddam, and M. Mehrabian, "Enhancing COP of an air-cooled chiller with integrating a spray cooler," Applied Thermal Engineering, vol. 154, pp. 348–357, 2019.

L. Wang and B. Li, “A water spraying box and its improving effect on the thermal environment around multi-story residential buildings to reduce released heat from air-conditioning units,” Energy Build., vol. 287, Art. no. 113484, 2023, doi: 10.1016/j.enbuild.2023.113484

Y. Wang, Y. Xu, R. Jin, and M. Zhang, “Experimental investigations of thermal performance of spray-cooling ventilated roof in hot climate region,” Energy Build., vol. 277, Art. no. 112605, Dec. 2022, doi: 10.1016/j.enbuild.2022.112605

A. Sanusi, A.Y. Shuaibu, and S. Abubakar, "Wind-induced evaporative cooling passive system for tropical hot and humid climate," Frontiers in Mechanical Engineering, vol. 9, 2023, doi:10.3389/fmech.2023.1069806

M. Alawadhi and P. Phelan, "Review of residential air conditioning systems operating under high ambient temperatures," Energies, vol 13, no. 8, art. no. 2880, 2022, doi: 10.3390/en15082880.

J. Wang, J. Meng, Q. Yang, C. Ren, and M. Santamouris, “Spray optimization to enhance the cooling performance of transparent roofs in hot-humid areas,” Energy Build., vol. 286, Art. no. 112929, May 2023, doi: 10.1016/j.enbuild.2022.112929

N. Kapilan, A.M. Isloor, and S. Karinka, “Comprehensive review on evaporative cooling systems,” Results in Engineering, vol. 18, p. 101059, Jun. 2023, doi: 10.1016/j.rineng.2023.101059.

Y. Du, F. Li, H. Zandi, K. Kurte, and J. Munk, “Demonstration of intelligent HVAC load management with deep reinforcement learning,” IEEE Power and Energy Magazine, vol. 20, no. 3, pp. 42–53, May 2022, doi: 10.1109/MPE.2022.3150825.

E.D. Giuseppe, G. Ulpiani, and M. Fioretti, “Numerical modelling and experimental validation of the microclimatic impacts of water mist cooling in urban areas,” Energy and Buildings, vol. 215, 109894, Jan. 2020, doi: 10.1016/j.enbuild.2020.109894.

L. Chen and A.P. Wemhoff, "The sustainability benefits of economization in data centers containing chilled water systems," Resources, Conservation and Recycling, vol. 192, 106925, 2023, doi: 10.1016/j.resconrec.2022.106925.

T. Roy and P.K. Dubey, “Thermodynamic performance assessment of air conditioner with spray cooler,” ASME Journal of Thermal Science and Engineering Applications, vol. 16, no. 5, 051003, 2023, doi: 10.1115/1.4058471

X. Hu, X. Chen, and R. Liu, "Study on the influence of spray characteristics and air flow direction on performance of evaporative condenser," Case Studies in Thermal Engineering, vol. 49, 104861, 2024, doi: 10.1016/j.csite.2024.104861.

X. Zhong, Z. Zhang, Z. Wang, M. Cai, and R. Zhang, “Influences of heat rejection from split A/C conditioners on mixed-mode buildings,” Energy and Buildings, vol. 14, no. 2, p. 318, Feb. 2024, doi: 10.3390/buildings14020318.

J. Ogundiran, M.G. Da Silva, and E. Asadi, “A systematic review on the use of AI for energy efficiency and indoor environmental quality in buildings,” Sustainability, vol. 16, no. 9, p. 3627, May 2024, doi: 10.3390/su16093627.

F. Ahmed, A.S. Ramana, and K. Jayakumar, “Experimental study on adiabatic pre‑cooling systems for air‑cooled condensers in hot and humid climates,” Scientific Reports, vol. 15, art. no. 4933, 2025, doi: 10.1038/s41598-024-82863-0.

T.F. Ishugah, J. Kiplagat, J. Madete, and J. Musango, “Current status, challenges, and opportunities of evaporative cooling for building indoor thermal comfort using water as a refrigerant: A review”, International Journal of Energy Research, Article ID 1026136, Nov. 2024, doi:10.1155/2024/1026136

X. Liu, L. Liu, R. Li, and Z. Wang, “Research on the performance and application of spray cooling in the gas phase space,” Thermal Science and Engineering Progress, vol 59, no. 103383, March 2025, doi: 10.1016/j.tsep.2025.103383




DOI: http://dx.doi.org/10.17977/um016v9i22025p451

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