Climate responsive building design in warm and humid climates

Sammanfattning: This study assess the climate consideration in building designs and aims to explore the extent of passive house performances in warm and humid climates. Previous studies have shown significant correlation between climate conscious building designs and meaningful improvements in indoor climate. The study uses a number of indices that are used to summarize indoor climatic parameters that describes human thermal comfort. Fanger’s Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) comfort model in conjunction with Gagge’s Standard Effective Temperature (SET) are used as a reference for the indoor thermal comfort. According to the Intergovernmental Panel on Climate Change, (IPCC), the building sector was in the year 2010 responsible for 24% of the global greenhouse gas emissions. As the developing countries of the world keep industrializing and evolving economically, the global energy use will fatefully increase. A big part of the increased energy usage will undoubtedly come from all the new houses that are going to be built as well as the increasing usage of air conditioning units and other electrical home appliances. The rate of urbanization is growing rapidly, particularly in developing countries as increasing number of people move to urban areas in search for opportunities. Today, one out of four people live in urban areas and this number is expected to increase. Due to the shortage of affordable housing, lack of opportunities and the high cost of living in major urban areas has resulted in the rise of informal settlements, so called slums. For instance, two third of close to five million inhabitants of Dar es Salaam live in informal settlements according to the 2013 government census. Generally, building designs in developing countries follow international trends or the architecture of temperate countries neglecting the prevailing local climate conditions. This results in buildings that are designed for a wrong climate at a wrong place. In order to fix the indoor climate requires the use of mechanical ventilation which further increases the cost for housing, energy use and maintenance. This remains huge challenge in developing countries such as Tanzania where resources are limited. Comparative housing studies were carried out on traditional, contemporary and modern housings in terms of building design, orientations and construction materials. Parametric model simulations were generated and used to determine the influence of various design features on indoor climates in terms of the human thermal comfort and cooling energy demand whenever necessary. According to the simulations, buildings in warm and humid climates have the potentials of obtaining and maintaining the human requirements for adequate indoor thermal comfort given the buildings are properly designed according to prevailing climatic conditions. From the analysis of the parametric model simulations, the study concludes that design parameters have significant influence on the indoor thermal comfort and potential to reduce the need for mechanical ventilation. The use of various design parameters in buildings in warm and humid climate is highly recommended as a means to regulate the indoor thermal comfort, lower the building costs and eliminate or significantly reduce the need for mechanical ventilation systems.