Climatic Pattern and Design for Indoor Comfort in Ogbomoso, Nigeria

Abstract

Climate is one of the basic factors for consideration in building design in Nigeria. It determine the occupants physiological conditions especially in the indoor spaces. Most climate studies in Nigeria have concentrated mainly on Agriculture and Aviation Sectors. This paper examines and analyses the climate pattern of Ogbomoso, a climatic transitional town in South West Nigeria with a view to suggesting appropriate guidelines for comfort design.Average climatic data of Ogbomoso for a period of five (5) years were examined and analysed for building design purpose using control potential zone techniques on bio-climatic chart. The climatic pattern of Ogbomoso showed that the annual mean temperature values are high for most of the years with 26.24⁰C 24.69⁰C, 26.21⁰C, 26.43⁰C and 26.64⁰C respectively for the year 2004, 2005, 2006, 2007 and 2008 respectively. Annual mean minimum and maximum relative humidity are high ranging from 76.80% (2006) minimum to 81.5% (2005) as maximum. The annual mean value of solar radiation are high and constant while the average outdoor wind speed for those periods are generally low between (1.5 – 2.0 m/s). The control potential zone (CPZ) constructed on the psychometric chart of Ogbomoso showed that the length of overheated  period (Lo) is greater than length of underheated (Lu) with thermal implications of hot and humid conditions. It also shows that air movement alone cannot provide adequate thermal comfort for the occupants. Other passive controls like the mass effect with night ventilation can be combined with the air movement to produce the required comfort.

Keywords: Climatic pattern, Indoor comfort, Control Potential Zone (CPZ), Bioclimatic chat, Warm humid condition.