Open Access

ARTICLE

Analysis of Airflow Distribution in Class 100 and Class 1000 Semiconductor Cleanrooms with a Shared Return Air Chamber

Indra Permana^1,*, Zulvi Alfiqri Hidayatulloh¹, Alya Penta Agharid², Pramod Vishwakarma³

1 Department of Refrigeration, Air Conditioning and Energy Engineering, National Chin-Yi University of Technology, Taichung, Taiwan
2 Graduate Institute of Precision Manufacturing, National Chin-Yi University of Technology, Taichung, Taiwan
3 Stokes Laboratories, Bernal Institute, School of Engineering, University of Limerick, Limerick, Ireland

* Corresponding Author: Indra Permana. Email:

(This article belongs to the Special Issue: Innovative Strategies for Energy-Efficient Buildings in a Sustainable Future)

Energy Engineering 2026, 123(11), 20 https://doi.org/10.32604/ee.2026.085663

Received 15 May 2026; Accepted 02 July 2026; Issue published 24 September 2026

Abstract

Semiconductor cleanrooms require stable airflow distribution to control airborne contamination, maintain pressure balance, and protect process-critical zones. However, cleanroom performance is not determined only by cleanliness classification or supply airflow rate; the interaction between raised floor design, FFU velocity, and return airflow distribution can strongly influence recirculation and airflow uniformity. This study evaluates the airflow performance of a semiconductor cleanroom consisting of Class 100 and Class 1000 zones using field measurements and computational fluid dynamics (CFD) simulation. Field measurements of particle concentration, airflow velocity, temperature, and relative humidity were conducted under as-built conditions. The measured air velocities were used for CFD model validation, while the temperature, relative humidity, and particle-count results were used to verify stable environmental operation and the intended cleanliness conditions. A three-dimensional CFD model was then developed to analyze airflow behavior, pressure distribution, and recirculation patterns. Two design parameters were investigated: raised floor height and FFU supply velocity. The results show that raised floor height has a significant influence on underfloor return airflow and vertical airflow stability. Insufficient floor height restricts return airflow and increases the risk of local recirculation, while an optimized raised floor configuration improves airflow uniformity in the clean zone. Increasing FFU velocity strengthens downward airflow, but excessive velocity may increase local turbulence and energy consumption. Overall, the optimized configuration improved airflow distribution and reduced recirculation risk in process-critical areas. The findings indicate that semiconductor cleanroom performance should be improved not only by increasing airflow rate, but also by optimizing airflow paths and raised floor design to balance contamination control and energy-efficient operation.

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