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The Study on Thermal Environment and Airflow Pattern in an UFAD System Under a Cooling Mode

  • Research Article - Mechanical Engineering
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Abstract

In the present research, an investigation of the UFAD system for thermal comfort has been conducted in a high-rise building located in the tropics. The indoor air conditions including temperature, relative humidity, air velocity, and mean radiant temperature have been obtained by conducting the fieldwork while the clothing insulation value and the metabolic rate of the occupants have been obtained by observing the occupants, where these data were used to obtain the predicted mean vote (PMV) and the predicted percentage dissatisfied (PPD) of the examined areas. In addition, the effects of the airflow pattern in the indoor thermal comfort have been investigated, where two different types of diffusers have been compared in order to find out which diffuser can provide a better thermal comfort to the occupants. The FloEFD simulation software is used to simulate the airflow pattern of these diffusers and to analyze the indoor air conditions of the UFAD system and also to examine the local mean age value. Based on the results obtained, the average PMV is approximately − 1.5 for each examined area, where a proper design of heating, ventilation, and air-conditioning system in a hot and humid country, the PMV result should be approximately equal to − 1. As for the PPD, the range of the PPD obtained falls in between 27.4 and 67.5%, in which it indicates that about more than half of the occupants have dissatisfied with the indoor conditions in the examined building.

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Abbreviations

AHU:

Air handling unit

FVM:

Finite volume method

HVAC:

Heating, ventilating and air-conditioning

IAQ:

Indoor air quality

LMA:

Local mean age

MRT:

Mean radiant temperature

OHAD:

Overhead air distribution

PMV:

Predicted mean vote

PPD:

Predicted percentages dissatisfied

UFAD:

Underfloor air distribution

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Acknowledgements

The authors would like to acknowledge the partial financial assistance from the Daikin Fellowship Grant PV018-2016 for supporting the research work conducted at UM-Daikin Laboratory, University of Malaya. Thanks are extended to INTI International University for providing the internal research grant for the first and second co-authors to conduct the research work in HVAC&R Lab at the Department of Mechanical Engineering, University of Malaya. In addition, special thanks are extended to University of Malaya for providing partial RU Grants GPF004A-2018 and IIRG014A-2019 for the first author to conduct the research work at University of Malaya.

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Authors and Affiliations

  1. Department of Mechanical Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia

    Y. H. Yau

  2. UM-Daikin Laboratory, Faculty of Engineering, University of Malaya, 50603, Kuala Lumpur, Malaysia

    Y. H. Yau

  3. Faculty of Science, Technology, Engineering and Mathematics (Mechanical Engineering Division), INTI International University, 71800, Nilai, Malaysia

    K. H. Chuah & M. T. Siew

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  1. Y. H. Yau
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  2. K. H. Chuah
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  3. M. T. Siew
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Correspondence to Y. H. Yau.

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The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

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Yau, Y.H., Chuah, K.H. & Siew, M.T. The Study on Thermal Environment and Airflow Pattern in an UFAD System Under a Cooling Mode. Arab J Sci Eng 45, 891–908 (2020). https://doi.org/10.1007/s13369-019-04184-z

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  • DOI: https://doi.org/10.1007/s13369-019-04184-z

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