ENERGY EFFICIENCY IN RESIDENTIAL BUILDINGS

Abstract

Despite having abundant natural resources, Afghanistan is not an energy-self-sufficient country; and relies on imported electrical energy from neighboring nations. Increasing population and urbanization further contribute to the rise in energy demand and energy deficiency. Metropolitan areas consume about 70% of Afghanistan’s energy accounting for 50% of the country’s CO2 emissions. Moreover, extreme weather conditions trigger more usage of fossil fuels for generating electricity and biomass for indoor heating, which produce higher CO2 of the total building energy consumption in Afghanistan, residential buildings are the major consumer, with a proportion of 71 %. Due to extreme climatic conditions in the country, especially the arid climatic zone, a large proportion of energy is consumed for cooling and heating in residential buildings. Such energy consumption practice is further affected by the non-consideration of scientific principles and energy efficiency in building designs. This thesis argues that there is significant scope for improving the energy efficiency of buildings to reduce energy consumption and substantially influence national energy consumption levels. Hence, the research proposes technically feasible energy-saving solutions by improving the energy efficiency of buildings through the design and analysis of realistic and practical approaches. The research also considers the unique challenges regarding awareness, construction practices, and affordability for building energy efficiency in Afghanistan. The research began by assessing Afghanistan’s energy situation and analyzing the climate conditions of the selected regions to outline the external context for the research on energy-efficient building solutions. For this, data were collected from open source and climate portals and analyzed using Climate Consultant and ArcGIS-Earth tools. vi Subsequently, five research objectives were identified, covering – (i) identification of characteristics of urban residential buildings and energy consumption patterns; (ii) Determining adaptive summer thermal comfort levels for residents, (iii) Passive solar radiation control strategy for reduction of heating and cooking requirements, (iv) Sustainable energy retrofit plan for apartments, and (v) Analysis of building envelop in the early design stage for improving energy efficiency. Due to the muti-facet research problem, each objective required a different research method. For the first two objectives, questionnaire surveys combined with statistical analyses, SPSS, and CBE thermal comfort tools were used to understand the external environment, energy consumption patterns, dwelling characteristics, and determining parameters that support building energy efficiency analysis. The last three objectives focused on building energy simulations using the latest energy modeling tools to produce measures for enhancing the energy efficiency of buildings. Different modules of DesignBuilder with EnergyPlus simulation engine were used for simulations. In simulations, the values of the thermal properties of construction materials such as brick and indoor plaster from Afghanistan were obtained through Lab testing in India. All the location-specific data were collected from the city of Mazar-I-Sharif, including case studies of a seven-story residential building and the typical house. The findings indicate that energy usage in households is affected by dwelling types, and the bulk of the energy is consumed for indoor heating and cooling. The result revealed the neutral temperature in summer was about 27.8C and the comfort zone (responses in the range of -1 and +1) from 23.6 - 32.1C. The south has been found to be the optimal orientation to face the building’s glazed façade, saving up to 7.4% of cooling and 9.7% of heating energy. Movable shading devices installed on the building’s openings in the vii summer can reduce the building energy load by up to 19%, with a total energy cost saving of AFN 188448 (USD 2447) annually. The thesis also proposes potential combinations of building retrofit measures. The research concludes that retrofitting existing apartments can provide substantial advantages and increase buildings' energy efficiency. Further, the study highlights the potential for increasing the energy efficiency of housing by up to 53% by adopting energy-efficient measures for building envelopes in the early design stage. The energy modeling and simulations demonstrated in this study will be a valuable resource for building designers in Afghanistan. The findings from this study will aid in the energy efficiency of Afghanistan’s residential sector and provide valuable references for future building thermal retrofit research and efficient design and innovation. The thesis makes a novel contribution to the body of knowledge, especially for Afghanistan, by demonstrating energy modeling and simulations in the local context. Practitioners may readily use the thermal properties of local construction materials.