Abstract
In this study, saturation efficiency and pressure drop, two critical parameters for the direct evaporative cooling phenomenon, were numerically investigated and optimized. For this purpose, the direct evaporative cooling process was simulated at inlet air velocities in the range of 1–3 m/s on different thicknesses of CELdek 7090 evaporative cooling pad from 100 to 300 mm. The mathematical model of pressure drop and saturation efficiency was developed by analyzing variance at R-squared values of 99.53% and 99.99%, respectively. Finally, the non-dominated sorting genetic algorithm II (NSGA-II) was applied to minimize the pressure drop while maximizing the saturation efficiency simultaneously. The results indicate that applying mathematical models makes it possible to predict the saturation efficiency and pressure drop of direct evaporative cooling systems with a 4% and 7.9% deviation, respectively. It can also be concluded that the pad thickness effect is more significant on the saturation efficiency than on the pressure drop. On the other hand, the inlet velocity has a greater impact on the pressure drop. NSGA-II optimization demonstrated that, regardless of the pad thickness, optimal saturation efficiency and pressure drop were obtained at the inlet air velocity of 1 m/s. Accordingly, when using direct evaporative cooling systems, efficiency and pressure drop can be optimized whenever the fan is set at a low speed. Depending on the researchers’ and designers’ goals, the findings of this research can be used in the design of direct evaporative cooling systems for different applications to achieve maximal saturation efficiency at the minimum possible energy consumption.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
Abbreviations
- ANOVA:
-
Analysis of variance
- CD:
-
Crowding distance
- DEC:
-
Direct evaporative cooling
- NSGA-II:
-
Non-dominated sorting genetic algorithm II
- RSM:
-
Response surface method
- C p :
-
Specific heat capacity (kJ/(kg K))
- D :
-
Mass diffusion coefficient (m2/s)
- H :
-
Height (mm)
- h :
-
Specific enthalpy of moist air (kJ/kg)
- h s :
-
Specific enthalpy of saturated air at wet-bulb temperature (kJ/kg)
- k :
-
Thermal conductivity (W/(m K))
- k a :
-
Volumetric mass transfer coefficient (kg/(m3 s))
- L :
-
Width (mm)
- m v :
-
Mass source term (Kg/m3)
- P :
-
Pressure (pa)
- q v :
-
Energy source term (W/m3)
- T :
-
Temperature (°C)
- d :
-
Pad thickness (mm)
- V :
-
Velocity (m/s)
- w :
-
Absolute humidity (Kgw/Kga)
- w s :
-
Saturated air humidity (Kgw/Kga)
- a:
-
Air
- db:
-
Dry-bulb
- in:
-
Inlet
- out:
-
Outlet
- w:
-
Water
- wb:
-
Wet-bulb
- η sat :
-
Saturation efficiency
- ν :
-
Kinematic viscosity (m2/s)
- ρ :
-
Density (Kg/m3)
References
Abaranji S, Panchabikesan K, Ramalingam V (2021) Experimental study on the direct evaporative air-cooling system with vermicompost material as the water storage medium. Sustain Cities Soc 71:102991. https://doi.org/10.1016/j.scs.2021.102991
Alamdari P, Saedodin S, Rejvani M (2020) Do non-metallic material and radiation shields affect the operation of direct evaporative cooling systems? Int J Refrig 114:98–105. https://doi.org/10.1016/j.ijrefrig.2020.02.038
Al-Badri AR, Al-Waaly AAY (2017) The influence of chilled water on the performance of direct evaporative cooling. Energy Build 155:143–150. https://doi.org/10.1016/j.enbuild.2017.09.021
Al-Suliman F (2002) Evaluation of the performance of local fibers in evaporative cooling. Energy Convers Manag 43:2267–2273. https://doi.org/10.1016/S0196-8904(01)00121-2
Beshkani A, Hosseini R (2006) Numerical modeling of rigid media evaporative cooler. Appl Therm Eng 26:636–643. https://doi.org/10.1016/j.applthermaleng.2005.06.006
Chiesa G, Huberman N, Pearlmutter D, Grosso M (2017) Summer discomfort reduction by direct evaporative cooling in southern mediterranean areas. Energy Proc 111:588–598. https://doi.org/10.1016/j.egypro.2017.03.221
Chiesa G, Huberman N, Pearlmutter D (2019) Geo-climatic potential of direct evaporative cooling in the mediterranean region: a comparison of key performance indicators. Build Environ 151:318–337. https://doi.org/10.1016/j.buildenv.2019.01.059
Cui X, Yan W, Chen X, Wan Y, Jon K (2020) Energy and buildings parametric study of a membrane-based semi-direct evaporative cooling system. Energy Build 228:110439. https://doi.org/10.1016/j.enbuild.2020.110439
Dai YJ, Sumathy K (2002) Theoretical study on a cross-flow direct evaporative cooler using honeycomb paper as packing material. Appl Therm Eng 22:1417–1430
Doğramacı PA, Riffat S, Gan G, Aydın D (2018) Energy consumption by human enhanced activities has led to distinctive environmental. Renew Energy. https://doi.org/10.1016/j.renene.2018.07.005
Duan Z, Wang M, Dong X, Liu J, Zhao X (2022) Experimental and numerical investigation of wicking and evaporation performance of fibrous materials for evaporative cooling. Energy Build 255:111675. https://doi.org/10.1016/j.enbuild.2021.111675
Dung NV, Hung NT, Chien NB, Vinh ND (2022) Experimental investigation of performance of cellulose cooling Pad BT—the AUN/SEED-Net joint regional conference in transportation, energy, and mechanical manufacturing engineering. In: Le AT, Pham VS, Le MQ, Pham HL (eds) Springer Nature Singapore, Singapore, pp 1033–1041
Elmetenani S, Yousfi ML, Merabeti L, Belgroun Z, Chikouche A (2011) Investigation of an evaporative air cooler using solar energy under Algerian climate. Energy Proc 6:573–582. https://doi.org/10.1016/j.egypro.2011.05.066
Ergün A, Acar B, Aydin M (2016) Psychometric and thermodynamic analysis of new ground source evaporative cooling system. Energy Build 119:20–27. https://doi.org/10.1016/j.enbuild.2016.03.017
Farmahini-farahani M, Delfani S, Esmaeelian J (2012) Exergy analysis of evaporative cooling to select the optimum system in diverse climates. Energy 40:250–257. https://doi.org/10.1016/j.energy.2012.01.075
Fouda A, Melikyan Z (2011) A simplified model for analysis of heat and mass transfer in a direct evaporative cooler. Appl Therm Eng 31:932–936. https://doi.org/10.1016/j.applthermaleng.2010.11.016
Guan L, Bennett M, Bell J (2015) Evaluating the potential use of direct evaporative cooling in Australia. Energy Build 108:185–194. https://doi.org/10.1016/j.enbuild.2015.09.020
Halasz B (1998) A general mathematical of evaporative cooling model devices. Revue Générale De Thermique 37:245–255
Hao X, Zhu C, Lin Y, Wang H, Zhang G, Chen Y (2013) Optimizing the pad thickness of evaporative air-cooled chiller for maximum energy saving. Energy Build 61:146–152. https://doi.org/10.1016/j.enbuild.2013.02.028
Heidarinejad G, Heidarinejad M, Delfani S, Esmaeelian J (2008) Feasibility of using various kinds of cooling systems in a multi-climates country. Energy Build 40:1946–1953. https://doi.org/10.1016/j.enbuild.2008.04.016
Heidarinejad G, Khalajzadeh V, Delfani S (2010a) Performance analysis of a ground-assisted direct evaporative cooling air conditioner. Build Environ 45:2421–2429. https://doi.org/10.1016/j.buildenv.2010.05.009
Heidarinejad G, Farmahini M, Delfani S (2010b) Investigation of a hybrid system of nocturnal radiative cooling and direct evaporative cooling. Build Environ 45:1521–1528. https://doi.org/10.1016/j.buildenv.2010.01.003
Ibrahim E, Shao L, Riffat SB (2003) Performance of porous ceramic evaporators for building cooling application. Energy Build 35:941–949. https://doi.org/10.1016/S0378-7788(03)00019-7
Jain JK, Hindoliya DA (2011) Experimental performance of new evaporative cooling pad materials. Sustain Cities Soc 1:252–256. https://doi.org/10.1016/j.scs.2011.07.005
Johnson DW, Yavuzturk C, Pruis J (2003) Analysis of heat and mass transfer phenomena in hollow fiber membranes used for evaporative cooling. J Membr Sci 227:159–171. https://doi.org/10.1016/j.memsci.2003.08.023
Kabeel AE, Bassuoni MM (2017) A simplified experimentally tested theoretical model to reduce water abstract. The aim of this study is to introduce a simple modified experimentally tested. Int J Refrig. https://doi.org/10.1016/j.ijrefrig.2017.06.010
Kachhwaha S, Prabhakar S (2010) Heat and mass transfer study in a direct evaporative cooler. J Sci Ind Res 69:25
Kavaklioglu K, Koseoglu MF, Caliskan O (2018) Experimental investigation and radial basis function network modeling of direct evaporative cooling systems. Int J Heat Mass Transf 126:139–150. https://doi.org/10.1016/j.ijheatmasstransfer.2018.05.022
Ketwong W, Deethayat T, Kiatsiriroat T (2021) Performance enhancement of air conditioner in hot climate by condenser cooling with cool air generated by direct evaporative cooling. Case Stud Therm Eng 26:101127. https://doi.org/10.1016/j.csite.2021.101127
Kim MH, Kim JH, Choi AS, Jeong JW (2011) Experimental study on the heat exchange effectiveness of a dry coil indirect evaporation cooler under various operating conditions. Energy 36:6479–6489. https://doi.org/10.1016/j.energy.2011.09.018
Koseoglu MF (2013) Investigation of water droplet carryover phenomena in industrial evaporative air-conditioning systems ☆. Int Commun Heat Mass Transfer 47:92–97. https://doi.org/10.1016/j.icheatmasstransfer.2013.07.002
Kovačević I, Sourbron M (2017) The numerical model for direct evaporative cooler. Appl Therm Eng 113:8–19. https://doi.org/10.1016/j.applthermaleng.2016.11.025
Laknizi A, Mahdaoui M, Ben A (2019) Case studies in thermal engineering performance analysis and optimal parameters of a direct evaporative pad cooling system under the climate conditions of Morocco. Case Stud Therm Eng 13:100362. https://doi.org/10.1016/j.csite.2018.11.013
Laknizi A, Ben Abdellah A, Mahdaoui M, Anoune K (2021) Application of Taguchi and ANOVA methods in the optimisation of a direct evaporative cooling pad. Int J Sustain Eng 00:1–11. https://doi.org/10.1080/19397038.2020.1866707
Lekwuwa CJ, Ogbu AC, Hubert AC (2012) A mathematical model of an evaporative cooling pad using sintered nigerian clay. J Miner Mater Charact Eng 2012:1113–1120
Obando FA, Montoya AP, Osorio JA, Damasceno A, Norton T, Agrarias FDC (2020) ScienceDirect evaporative pad cooling model validation in a closed dairy cattle building. Biosyst Eng. https://doi.org/10.1016/j.biosystemseng.2020.08.005
Rehman D, Mcgarrigle E, Glicksman L, Verploegen E (2020) A heat and mass transport model of clay pot evaporative coolers for vegetable storage. Int J Heat Mass Transf 162:120270. https://doi.org/10.1016/j.ijheatmasstransfer.2020.120270
Saberian A, Sajadiye SM (2020) Assessing the variable performance of fan-and-pad cooling in a subtropical desert greenhouse. Appl Therm Eng 179:115672. https://doi.org/10.1016/j.applthermaleng.2020.115672
Sellami K, Feddaoui M, Labsi N, Najim M, Oubella M, Benkahla YK (2019) Direct evaporative cooling performance of ambient air using a ceramic wet porous layer. Chem Eng Res Des 142:225–236. https://doi.org/10.1016/j.cherd.2018.12.009
Sohani A, Zabihigivi M, Moradi MH, Sayyaadi H, HasaniBalyani H (2017) A comprehensive performance investigation of cellulose evaporative cooling pad systems using predictive approaches. Appl Therm Eng 110:1589–1608. https://doi.org/10.1016/j.applthermaleng.2016.08.216
Tewari P, Mathur S, Mathur J (2019) Thermal performance prediction of office buildings using direct evaporative cooling systems in the composite climate of India. Build Environ 157:64–78. https://doi.org/10.1016/j.buildenv.2019.04.044
Watt J (1986) Evaporative air conditioning handbook. Chapman and Hall, New York
Wu JM, Huang X, Zhang H (2009a) Numerical investigation on the heat and mass transfer in a direct evaporative cooler. Appl Therm Eng 29:195–201. https://doi.org/10.1016/j.applthermaleng.2008.02.018
Wu JM, Huang X, Zhang H (2009b) Theoretical analysis on heat and mass transfer in a direct evaporative cooler. Appl Therm Eng 29:980–984. https://doi.org/10.1016/j.applthermaleng.2008.05.016
Xuan YM (2001) Theory and Experimental study of inorganic pad direct evaporative cooling air conditioner. Xi’an Polytechnic University
Yan M, He S, Gao M, Xu M, Miao J, Huang X, Hooman K (2021) Comparative study on the cooling performance of evaporative cooling systems using seawater and freshwater. Int J Refrig 121:23–32. https://doi.org/10.1016/j.ijrefrig.2020.10.003
Zhang XJ, Dai YJ, Wang RZ (2003) A simulation study of heat and mass transfer in a honeycombed rotary desiccant dehumidifier. Appl Therm Eng 23:989–1003. https://doi.org/10.1016/S1359-4311(03)00047-4
Zhang Q, He S, Cheng J, Zhao B, Wu X, Yan M, Gao M, Geng Z, Zhang S (2022) Numerical simulation of evaporative cooling process in a medium-gap-medium arrangement. Int J Therm Sci 179:107700. https://doi.org/10.1016/j.ijthermalsci.2022.107700
Author information
Authors and Affiliations
Corresponding author
Appendices
Appendix A
This appendix presents the results of the unsteady DEC simulation. In Fig. 15, the temperature contours are shown in seconds 5, 10, and 15 for the 2 (m/s) inlet velocity, 37.06 (°C) inlet temperature, and 23.42 (°C) inlet wet-bulb temperature boundary condition. There is no discrepancy in the temperature contours from second 5, which indicates that the flow became steady in a few seconds.
The temperature contours in different seconds. a: second 5, b: second 10, and c: second 15
Appendix B
This appendix presents detailed saturation efficiency and pressure drop optimization output and their optimum inlet velocity and evaporative cooling pad thickness in Table 5.
Rights and permissions
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
About this article
Cite this article
Alamdari, P., Rejvani, M., Alinejadi, S. et al. The Best Design for a Direct Evaporative Cooling System Based on Pressure Drop at Desired Saturation Efficiency: A Cost–Benefit Optimization. Iran J Sci Technol Trans Mech Eng (2024). https://doi.org/10.1007/s40997-023-00729-8
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s40997-023-00729-8