Comprehensive investigation of human thermal comfort conditions in a room equipped with radiant ceiling cooling system

Document Type : Research Article

Authors

1 Faculty of Mechanical Engineering University of Guilan

2 University of Guilan, Rasht, Iran

Abstract

In this study, the cooling process and thermal comfort conditions in a room containing an occupant and equipped with a radiant ceiling cooling system were numerically investigated. The room was subjected to direct solar radiation on its external wall and coated glass window. Simulations were conducted for the four main geographic orientations on the hottest average day over the past decade in Tehran. The Low Reynonlds k-ε turbulence model, discrete ordinates method, and ray-tracing model were employed to simulate airflow, radiation, and solar heat transfer, respectively, while thermal comfort conditions were assessed using Fanger’s model. The results indicated that the room with a west-facing external wall required the highest cooling load at 2:00 PM, with the ceiling surface temperature needing to be maintained at approximately 12°C. For transparent glass windows, this temperature must be further reduced to7°C, resulting in a 27% increase in cooling load. Additionally, the use of coated glass significantly reduced the PMV index and dissatisfaction percentage; for the west-facing wall at 2:00 PM, the PMV decreased from 0.5 to 0.32, and dissatisfaction decreased from 10.2% to 7.1%. Dissatisfaction caused by vertical temperature differences was below 3% in all cases. However, dissatisfaction due to warm floors exceeded acceptable limits for east- and west-facing walls with transparent glass, reaching 25.1% and 25.5%, respectively. Furthermore, dissatisfaction from draft rates remained below 10% in all scenarios.

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Amirkabir Journal of Mechanical Engineering
Volume 56, Issue 10
January 2025
Pages 4-4

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