Paper 5
The Thermal Comfort of a Naturally
Ventilated House resulting from the Evaporative Cooling of a Ceiling Fan
in the Hot-Humid Climate of Chennai, India
J Vijayalaxmi
School of Architecture and Planning, Anna University,
Chennai, India
Abstract
In a hot-humid climate, comfort ventilation involving air movement over
the skin of the human body is a prime consideration for thermal comfort.
In developing countries with such a climate, the use of an air conditioner
is not economically feasible by a majority of the population. Therefore,
ceiling fan assisted cooling strategies hold significance. Fans increase
the air movement inside rooms, thereby causing the layer of sweat over the
occupant's body to evaporate. This paper aims to assess the evaporative
cooling effect of a ceiling fan in a naturally ventilated house. The study
was carried out in the hot-humid climate of Chennai City in India during
the hottest part of the year. The criterion for evaluating the indoor
thermal performance of this study is the difference in the standard
effective temperature SET under conditions of still air and under
conditions of using a ceiling fan at 2 m/s speed. Indoor air temperature
changes under still air (0.1 m/s) were collected in four rooms of varying
orientations (NW, NE, SW and SE) and with varying opening sizes for a 24
hour period. Using the software 'ASHRAE Thermal Comfort Standard Tool'
developed by Environmental Analytics (Berkeley, CA) for ASHRAE, the
difference in SET was calculated for these rooms and for eight conditions
of opening sizes. Also, indoor comfort conditions, based on the five-point
thermal discomfort scale, were recorded. It was found that the ceiling
fans are most effective in enhancing comfort during the early morning
hours. In addition, ceiling fans are consistent in providing thermal
comfort when opening sizes are very small (5% - 25% of the floor area).
They are most effective when opening sizes are of the order of 10% to 60%
of the floor area. It was found that the NW orientated room had the least
number of comfortable hours even in the presence of a ceiling fan.
Key words: thermal performance, natural ventilation, ceiling
fan, room orientation, opening size.
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Contents
Paper
1
Particulate Matter Mass Concentration (PM10) under Different Ventilation
Methods in Classrooms
Paper
2
Energy Efficiency Design for a House with Temporary Heating and Winter
Daytime Cross Ventilation
Paper
3
Strategies for Natural Ventilation of Urban Office Buildings
Paper
4
The Design and Development of an Adaptable Modular Sustainable Commercial
Building (Co2nserve) for Multiple Applications
Paper 5
The Thermal Comfort of a Naturally
Ventilated House resulting from the Evaporative Cooling of a Ceiling Fan
in the Hot-Humid Climate of Chennai, India
Paper 6
Investigating
Natural Ventilation Inside Walk-Up Housing Blocks in the Egyptian Desert
Climatic Design Region
Paper 7
Solar Chimney Geometry for Stack
Ventilation in a Warm Humid Climate
Paper 8
The Role of Wind
and Natural Ventilation in the Vernacular
Architecture of Zavareh
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