Evaluation of thermal comfort conditions in a classroom with three ventilation methods

Authors

  • M. L. Fong,

    1. Building Energy & Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, Kowloon, Hong Kong
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  • Z. Lin,

    1. Building Energy & Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, Kowloon, Hong Kong
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  • K. F. Fong,

    1. Building Energy & Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, Kowloon, Hong Kong
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  • T. T. Chow,

    1. Building Energy & Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, Kowloon, Hong Kong
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  • T. Yao

    1. Building Energy & Environmental Technology Research Unit, Division of Building Science and Technology, City University of Hong Kong, Kowloon, Hong Kong
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Zhang Lin
Building Energy & Environmental Technology Research Unit
Division of Building Science and Technology
City University of Hong Kong
Kowloon
Hong Kong
Tel.: 852 2788 9805
Fax: 852 2788 9716
e-mail: bsjzl@cityu.edu.hk

Abstract

Abstract  Thermal sensation is studied experimentally under mixing ventilation, displacement ventilation, and stratum ventilation in an environmental chamber. Forty-eight subjects participated in all tests under the same boundary conditions but different ventilation methods in the classroom. Thermal comfort analysis was carried out according to the designated supply airflow rate, room temperature, and relative humidity for the three ventilation methods. The thermal neutral temperature under stratum ventilation is approximately 2.5°C higher than that under mixing ventilation and 2.0°C higher than that under displacement ventilation. This result indicates that stratum ventilation could provide satisfactory thermal comfort level to rooms of temperature up to 27°C. The energy saving attributable to less ventilation load alone is around 12% compared with mixing ventilation and 9% compared with displacement ventilation.

Practical Implications

The confirmation of the significantly elevated thermal neutral temperature can have a number of implications for both thermal comfort in an air-conditioned room and energy consumption of the associate air-conditioning system. With respect to the former, it provides scientific basis for the feasibility of elevated room temperatures, and with respect to the latter, it reveals considerable potentials for energy saving.

Ancillary