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Experimental studies of comfort levels of east-west and north-south solar-oriented buildings in a warm-humid climate.

Article Excerpt
Abstract: Thermal comfort problems need to be addressed at the architectural design stage, particularly in Nigeria's warm, humid climate. Through experimental studies, this paper compares the indoor comfort levels of buildings with different solar orientations. Experimental model buildings with east-west and north-south solar orientations respectively were constructed for this study. Data on indoor comfort factors were obtained together with meteorological data and indoor thermal comfort parametric ranges. The experimental data were analyzed with descriptive statistical tools involving central tendency and dispersion. The hypotheses were tested using z-tests. The case study results showed that the differences of the indoor comfort levels of the model buildings were significantly different for the air temperature and not for relative humidity. The study also showed that the comfort levels of the buildings do not conform to comfort standards despite their orientations. This paper therefore concludes that solar orientation can contribute significantly to a more acceptable indoor comfort condition in buildings in warm-humid climates.

Keywords: Building, Comfort levels, Orientation, Solar houses, Warm humid climates

Introduction

Thermal comfort is a state in which a person will judge the environment to be neither too cold nor too warm, a neutral point defined by the absence of any feeling of discomfort (Marcus & Morris, 1980). It is a subjective sensation that expresses satisfaction (or dissatisfaction) with the thermal environment.

Six major factors determine thermal comfort:

* Air temperature in the occupied space

* Net radiant exchange rate between the body and the environment

* Relative humidity of the air in the space

* Rate of air movement around a person

* Rate of activity (or metabolic rate)

* Insulation level of a person's clothing (Heerwagen, 2004; Koenigsberger, Ingersoll, Mayhem & Szokolay, 1973)

The first four points are factors of the thermal environment, while the other two are personal or subjective factors. Marcus and Morris (1980) and Evans (1980) gave other subjective factors that may have an effect on comfort. These factors include state of health, subcutaneous fat, gender, age, acclimatization, race, and colour of clothing among others.

These environmental and personal parameters for the achievement of thermal comfort have been identified and numerical values for these parameters produced. The comfort range for air temperature in the occupied space is between 20 and 27[degrees]C. The relative humidity of the air in the space somewhere between 25 and 55%, the mean radiant temperature ([t.sub.mrt]) of the occupant...