Energy-efficient indirect evaporative cooler design framework: An experimental and numerical study

Muhammad Ahmad Jamil*, Muhammad Wakil Shahzad, Ben Bin Xu, Muhammad Imran, Kim Choon Ng, Syed M. Zubair, Christos N. Markides, William M. Worek

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


A remarkable surge in cooling demand is observed in the last decades. Currently, the cooling market is dominated by mechanical vapor compression chillers which are energy intensive and use harmful chemical refrigerants. Therefore, the current focus of the current research in cooling is the development of unconventional, sustainable cooling systems. In this regard, indirect evaporative coolers have shown significant potential (particularly under hot-dry climates) with high energy efficiency, low cost, water-based sustainable operation, and benign emissions. However, these systems are in the development stage and have not yet been fully commercialized because of certain design challenges. An innovative indirect evaporative cooler is proposed, fabricated, and experimentally tested in this study. Particularly, the study is focused on the development of heat transfer coefficient correlation for the system for commercial-scale design and expansion. This is because the earlier available correlation is based on simple airflow between parallel plates assumption and does not incorporate the effect of the evaporative potential of the system resulting in under/over-estimation of the heat transfer characteristics. The results showed that the proposed system achieved a temperature drop of 20 °C, a cooling capacity of around 180 W, and an overall heat transfer coefficient of up to 30 W/m2K. Moreover, the study presents an experiment-regression-based heat transfer coefficient correlation that satisfactorily captures the effect of outdoor air temperature and airflow rate ratio which are critical in the design of evaporative coolers. The proposed correlation showed a high (±5%) with experimental data thus making it suitable for the future design of IEC systems over assorted operating scenarios.

Original languageEnglish
Article number117377
Number of pages17
JournalEnergy Conversion and Management
Early online date12 Jul 2023
Publication statusPublished - 15 Sept 2023

Bibliographical note

Copyright © 2023 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY license (

Funding Information: The authors would like to thank Northumbria University UK for funding under reference #RDF20/EE/MCE/SHAHZAD, and Northern Accelerator Proof-of-Concept award for AD4DCs (NACCF-232) Awarded to Dr. Muhammad Wakil Shahzad. Also acknowledged is the support provided by the KAUST cooling initiative (REP/1/3988-01-01). This work was supported by the UK Engineering and Physical Sciences Research Council (EPSRC) [grant number EP/R045518/1]. For Open Access, the authors have applied a CC BY public copyright license to any Author Accepted Manuscript version arising from this submission.


  • Experiments
  • Heat transfer coefficient correlation
  • Novel indirect evaporative cooler
  • Sustainable cooling


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