P.H. D. Thesis

Ms Roza Vakilnezhad will present his P.H.D thesis on "Effect Of Building Envelope and Natural Ventilation Patterns on Energy Consumption of Residential buildings   " on July 2013 under the guidance of Dr. S.M. Mofidi, Dr. F. Mehdizadeh Seraj .

Abstract

Natural ventilation has been considered as one of the most important cooling methods used in buildings for many years. The spread of modern air conditioning systems led to design of isolated buildings and using of natural ventilation has been forgotten. In the 70’s energy crisis and environmental problems became the reason for renewed attention in renewable energy sources such as ventilation cooling. On the other hand, application of air conditioning systems caused the sick building syndrome, inappropriate indoor air quality and health problems of residents therefore made a desire for application of natural ventilation. Nowadays the design of naturally ventilated buildings requires theoretical studies based on the new knowledge about feasibility and design of related components used for natural ventilation. Despite rich history of the application of natural ventilation in Irainian architecture, there is no contemporary applied research in this field in order to design contemporary naturally ventilated buildings. Most studies have reported a descriptive aspect or a holistic approach analyzing specific components used for ventilation such as wind catcher from the fluid dynamics viewpoint. Since much of the world's energy consumption is used for heating and cooling of buildings, it is necessary to research in this field particularly in relation to urban and architectural design. On the other hand, due to the extent of related fields it is important to define the variables and limits of the study based on the research scope. This study is organized to provide design guidelines for architects in order to create energy sufficient buildings provided by natural ventilation. In the most previous studies, the effect of design variables on energy consumption had been evaluated regardless of natural ventilation performance (for air-conditioned buildings) just considering sun radiation. Therefore, in the present study, the effect of the most important design parameters on natural ventilation efficiency and energy consumption of a building has been analyzed. Based on the literature, window to wall ratio, shading, orientation and balcony have been selected as the most important factors defining thermal behavior and energy consumption of buildings. In order to achieve the desired aims, various research methods have been used such as literature review, comparative comparison, case study and computer simulation. Final data analysis has been done using statistical methods and logical argumentation. Based on the results, the impact of design parameters on building energy consumption depends on the of ventilation type. The results show that thermal performance of naturally ventilated buildings differs from the air-conditioned ones. Therefore it is necessary to choose design parameters according to the ventilation patterns (no ventilation, day ventilation, night ventilation, day and night ventilation) in early design stage. The results of the study help architects to choose the optimum combination of the design parameters using potential of natural ventilation in order to design energy efficient building. In the second part of the research the effect of balcony on building thermal performance and energy consumption has been analyzed. The results show the effect of provision of balcony and its type on the efficiency of various natural ventilation patterns.

Keywords: Natural Ventilation, Architectural Design, Thermal Comfort, Building Energy Consumption.