Journal of Environment and Earth Science www.iiste.org ISSN 2224-3216 (Paper) ISSN 2225-0948 (Online) Vol.5, No.17, 2015 30 Climatic Pattern and Design for Indoor Comfort in Ogbomoso, Nigeria AYINLA, Abdulrasaq Kunle ODETOYE, Adeola Sunday Department of Architecture, Ladoke Akintola University of Technology, 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 26.24 0 C 24.69 0 C, 26.21 0 C, 26.43 0 C and 26.64 0 C 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. 1.0 Introduction Climate is one of the basic properties of the atmosphere that enriches the earth. Understanding how climate occur is not a requisite for building design, but buildings should be designed to respond well to the characteristics of the climate in order to ensure adequate physiological comfort for the occupants. The World meteorological Organization defined climate as a totality of metrological elements that in their usual succession and at a given period, characterize the state of the atmosphere. Boutet (1987), on the other hand simplifies the definition of climate as the prevailing weather conditions of a given region. However, various definitions of climate available recognize climate to be a statistical composite of atmospheric conditions of a place viewed over a given period of time. Several attempts have been made in the past by many scholars to classify climate in to different types (Oliver1980), but all these classification can be broadly divided in to three principal types: those based on climatological data, those founded on the existence of environmental conditions suitable for natural plant growth, and those which evaluate environmental conditions in terms of the ready maintenance of human comfortability. However, the classification of Koppen-Geiger which is based on monthly air temperature, humidity and the potential evaporation rate remain the most generally used classification system (Szokolay 2004) For building design purpose, the classification must have a combined effect of temperature, relative humidity, mean radiant temperature, and wind velocity. However, most building climatologist according to Ajibola (2001), have only been able to combine one or two of the above items, notable among these scholars are Atikson (1954) and Budyko (1956) who based their classification on nature of human thermal problem in a particular location,Fagbenle (1992) who used the national index of dryness for their own classification, Oliver (1980) classification was based on air mass movement and as a result can only account for air movement. In all, the classification of Atikson in Szokolay (2004) forms the basis for other classifications: he recognized only four basic types which he based on the nature of the human thermal problem in a particular location. The climatic types identified are:- i. Cold climate – where the main problem is the lack of heat (under heating) or excessive heat dissipation for all or most of the year. ii. Temperate (moderate) climate, where there is a seasonal variation between under heating and overheating, but neither is very severe. iii. Hot - dry climate, where the main problem is overheating, but the air is dry, so the evaporation cooling mechanism of the body is not restricted. There is usually a large diurnal (day-night) temperature variation. iv. Warm humid climate, where the overheating is not as great as in hot dry areas, but is aggravated by high humidity, restricting the evaporation potential. The diurnal temperature variation is small. brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by International Institute for Science, Technology and Education (IISTE): E-Journals