Study of thermal performance of building envelope of ready made garment factories in Dhaka

Abstract

Primary environmental factors of thermal performance to which the building envelope is exposed, are solar radiation and ambient air temperature that have often been neglected in designing Ready Made Garments factory buildings in context of Bangladesh. It may be also noted that, there is no specific standard regarding green issues of factory envelopes in the current Bangladesh National Building Code (BNBC) or in other building regulations in Bangladesh. The purpose of this study is the determination of thermal performance of building envelope especially exterior walls based on locally available construction materials and commonly used techniques for RMG factory buildings. Another aim of this research is to develop a methodology and a thermal correlation matrix among various types of exterior wall constructions that will help architects and engineers while designing factory buildings while pursuing compliance for energy efficiency. In this work the thermal performance of a factory building envelope has been measured on the basis of previously established indoor thermal comfort range for factory workers in Bangladesh. The thermal condition of production spaces have been recorded consistently by remote data loggers‘ in-situ over a period of time and simulation study has been conducted using whole building dynamic simulation engine. In this study, a three-dimensional model was developed to perform thermal simulations for a typical RMG factory building. In this research, the factory building has been divided into three different zones based on their storey levels and the results have been analyzed by mean of statistical distribution. Two types of variables were considered in the study, these were ‗thickness of the wall‘ and ‗type of the construction materials‘. For the simulation twenty four different envelope constructions behavior have been observed. Prior to the simulation work thermal property local materials were measured in the laboratory. The main focus of this work was to observe that the change of building envelope materials and the design of wall constructions have a significant contribution on indoor thermal environment of a factory building particularly in production spaces. In the research, the overall thermal characteristics of various types of exterior wall constructions have been investigated with respect to local climate which will potentially facilitate the development of design guidelines for RMG factory building envelope in Dhaka, Bangladesh.