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Building Simulation 2011, 4(2): 169-180 https://doi.org/10.1007/s12273-011-0036-5
Research Article | Issue | Published: 04 December 2011

Predictions of thermal comfort in stratified room environment

Show Author's Information Issa F. Almesri1,2,  Hazim B. Awbi1( )
School of Construction Management and Engineering, University of Reading, Whiteknights, Reading RG6 6AH, UK
Department of Mechanical Engineering, College of Technological Studies, Shuwaikh, Kuwait
Keywords:
thermal comfort, displacement ventilation, non-uniform thermal environment, air terminal device
Cite this article:
Almesri IF, Awbi HB. Predictions of thermal comfort in stratified room environment. Building Simulation, 2011, 4(2): 169-180. https://doi.org/10.1007/s12273-011-0036-5
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Abstract Full text About this article

Studies of thermal comfort of occupants started in the early part of the 20th century to describe the comfort level in terms of environmental variables. Field studies have indicated that many of the complaints about unsatisfactory indoor environment can be attributed to the thermal environment. Hence, heating, ventilation, and air conditioning (HVAC) systems are used in buildings to create thermal environments that are capable of providing comfort to the occupants. Among different ventilation systems, displacement ventilation (DV) systems have become popular as more energy efficient room air distribution systems compared with the other more common forms of air distribution systems, such as mixing ventilation. However, local cold discomfort at the lower extremities due to vertical temperature gradient is often reported with DV systems. Although many studies are reported in the literature that compare the performance of the DV systems with the other more conventional types of ventilation systems, the performance of different displacement ventilation types in providing thermal comfort need further investigation. The aim of the current work is to compare the ventilation performance, as predicted by an advanced thermal comfort model, of three commonly used DV air terminal devices (ATDs) for room ventilation: a flat wall diffuser (ATD1), semi-cylindrical wall diffuser (ATD2) and floor swirl diffusers (ATD3). The CBE (Center for the Built Environment at Berkeley) comfort model has been implemented in this study to compare the thermal comfort provided by the three ATDs due to its good performance in non-uniform thermal environments. Based on the test conditions and the results obtained from the comfort model, the predicted occupant’s local sensations for the case of ATD2 were better than those for ATD1 and ATD3 and it showed better overall thermal sensation. Since the local comfort of the CBE model is a function of both local and overall thermal sensations, the predicted occupant’s local comfort values for ATD2 were better than those for ATD1 and ATD3 and consequently it provided better overall thermal comfort.


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About this article

Predictions of thermal comfort in stratified room environment

Show Author's information Issa F. Almesri1,2, Hazim B. Awbi1( )
School of Construction Management and Engineering, University of Reading, Whiteknights, Reading RG6 6AH, UK
Department of Mechanical Engineering, College of Technological Studies, Shuwaikh, Kuwait

Abstract

Studies of thermal comfort of occupants started in the early part of the 20th century to describe the comfort level in terms of environmental variables. Field studies have indicated that many of the complaints about unsatisfactory indoor environment can be attributed to the thermal environment. Hence, heating, ventilation, and air conditioning (HVAC) systems are used in buildings to create thermal environments that are capable of providing comfort to the occupants. Among different ventilation systems, displacement ventilation (DV) systems have become popular as more energy efficient room air distribution systems compared with the other more common forms of air distribution systems, such as mixing ventilation. However, local cold discomfort at the lower extremities due to vertical temperature gradient is often reported with DV systems. Although many studies are reported in the literature that compare the performance of the DV systems with the other more conventional types of ventilation systems, the performance of different displacement ventilation types in providing thermal comfort need further investigation. The aim of the current work is to compare the ventilation performance, as predicted by an advanced thermal comfort model, of three commonly used DV air terminal devices (ATDs) for room ventilation: a flat wall diffuser (ATD1), semi-cylindrical wall diffuser (ATD2) and floor swirl diffusers (ATD3). The CBE (Center for the Built Environment at Berkeley) comfort model has been implemented in this study to compare the thermal comfort provided by the three ATDs due to its good performance in non-uniform thermal environments. Based on the test conditions and the results obtained from the comfort model, the predicted occupant’s local sensations for the case of ATD2 were better than those for ATD1 and ATD3 and it showed better overall thermal sensation. Since the local comfort of the CBE model is a function of both local and overall thermal sensations, the predicted occupant’s local comfort values for ATD2 were better than those for ATD1 and ATD3 and consequently it provided better overall thermal comfort.

Keywords: thermal comfort, displacement ventilation, non-uniform thermal environment, air terminal device

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Publication history
Copyright
Acknowledgements

Publication history

Received: 07 December 2010
Revised: 08 April 2011
Accepted: 20 April 2011
Published: 04 December 2011
Issue date: June 2011

Copyright

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2011

Acknowledgements

The authors would like to express their gratitude to Dr. Hui Zhang for providing the software for the CBE comfort model and also to Dr. Dusan Fiala for providing the software for the modified Fiala model and for their valuable advice on how to use their models correctly and efficiently.

Special thanks are due to Dr. T. Sakoi for providing detailed information on his study which is used to validate the CBE and the modified Fiala models in non-uniform thermal environments.

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