Evaluation of thermal comfort in library buildings in the tropical climate of Kumasi, Ghana

Abstract

Adaptive comfort considerations and passive design are crucial in tropical, hot and humid climates where the straightforward response to discomfort in this climate, such as in Ghana, has been the adoption of air conditioners and mechanical cooling. This approach, along with following the provisions of current international comfort standards, has resulted in higher electricity demand and excessive emissions of greenhouse gases into the atmosphere. This paper presents an adaptive thermal comfort field study in library buildings in the tropical Aw climate of Kumasi, Ghana considering naturally-ventilated (NV) and air-conditioned (AC) buildings. The proposed models in this study are compared with existing studies and current international standards. Using the Griffiths coefficient of 0.5, the mean neutral temperature of 27.4 °C and 30.3 °C were predicted for AC and NV mode, respectively. Although Fanger's predicted mean vote (PMV) method overestimates the extent of changes in thermal sensation votes (TSV) by indoor operative temperature in AC mode, the neutral temperature predicted from PMV (27.8 °C) is analogous to the one estimated using TSV. The adaptive equations for Kumasi's hot and humid climate predict higher slopes of 0.17 K−1 and 0.41 K−1 in AC and NV modes, respectively, than the standards; this indicates that the Ghanaian respondents were more sensitive to the outdoor temperature changes. The average difference of 2.1 °C in AC mode and 1.8–3.3 °C in NV mode were estimated when comparing the proposed model with those in the international standards