Comparative Solar Access Analysis on Building Surfaces, Determination of the Relationship Between Solar Radiation, SVF, and Sunlight Duration

Abstract

Urbanization is a rapidly accelerating total phenomenon, particularly in developing countries. This trend is largely driven by factors such as rural-urban migration, natural population growth and the attraction of economic opportunities in cities. According to the latest data from the United Nations, more than half of the world's population lives in urban areas, which is 57% (Anonymous, 2022). This proportion is expected to increase to 66% by 2050. In 2045, there will be approximately 6 billion city dwellers (World Bank, 2023). Considering these statistics, it is evident that measures need to be taken for future urban development strategies across several domains. In this context, energy in the urban environment is a crucial aspect and warrants significant attention. One of the most important challenges associated with energy consumption in urban areas is the need to balance energy demand and supply. With more people living and working in cities, there is a greater need for energy to power homes, businesses, and transportation. The energy consumption of buildings in urban areas is a significant issue that requires attention due to the high demand for energy and the resulting environmental impact. Buildings account for a significant portion of the world's energy consumption. Buildings contribute to roughly 32% of global final energy consumption, 17% of direct CO2 emissions, and account for one-third of indirect emissions (Skillington et al., 2022). In particular, buildings in urban areas consume more energy than those in rural areas, making the urban building sector a crucial area for energy efficiency improvements. One of the primary reasons for the high energy consumption of buildings in urban areas is the need for heating and cooling systems. According to a study by the International Energy Agency, the energy used for heating and cooling buildings in urban areas accounts for approximately 60% of total building energy consumption (Anonymous, 2017). The energy consumption of buildings in Turkey has been a major concern for the country due to its increasing population and urbanization. The construction industry in Turkey accounts for roughly 34% of the nation's total energy consumption and the energy usage in this sector is steadily rising each year (Anonymous, 2021). Consequently, endeavors aimed at boosting energy efficiency in the construction sector are becoming increasingly crucial. Heating accounts for 55% of the total energy consumption in housing in Turkey. The remaining distribution of energy consumption is as follows: 19% for hot water production, 4% for cooking, 3% for lighting, and 19% for household appliances (Anonymous, 2018). The predominant source of energy consumption in housing is derived from fossil fuels. For instance, in 2018, natural gas consumption in Turkish households accounted for 25.7% of the total consumption (Kabakçı, 2018). Turkey, under the scope of the "Climate Change Action Plan 2011-2023," aimed to ensure that at least 20% of the annual energy demand of new buildings from renewable energy sources starting from the year 2017 (Kabakçı, 2018). Despite this action plan, the objectives have not been fully achieved. The utilization of renewable energy sources, such as solar and wind energy, in the energy consumption of buildings, has not yet reached sufficient levels. Among renewable energies, solar energy holds significant potential for utilization in buildings. The simplest method, known since antiquity, is the passive method. Utilizing solar energy passively does not necessitate advanced technology. Passive solar systems are designed to maximize the amount of solar radiation entering a building while minimizing heat loss. At the building scale, passive solar design strategies primarily aim to harness solar energy to achieve thermal comfort in buildings by minimizing the need for electrical or mechanical equipment (Stevanović, 2013). Active solar systems are another type of solar energy system that can be used in buildings. Unlike passive solar systems, active solar systems require the use of mechanical and electrical components to capture and store solar energy. In both cases, the buildings must have sufficient access to sunlight during the day. In the urban environment, the performance of building solar systems is strongly linked to urban density. In the present study, solar access in urban areas was analyzed on building façades in Konya, Turkey. The solar gain potential of a point on a façade differs according to the urban context. To compare the solar gains of different locations and draw conclusions, the selection of points was based on the characteristics of the immediate urban environment. The objectives of the study are as follows: To determine the total solar radiation received at the selected points on the building façades, which have different urban contexts, and to compare and understand the reasons for the differentiations between these points. The second objective of this study is to define a mathematical model based on the results obtained regarding solar gains. This mathematical model can precisely define the relationship between the built context and the total solar radiation received. It can be used in built-up areas with the same climatic context as Konya. Additionally, it could be valuable for acquiring fundamental knowledge about the potential for solar gain, particularly in the early stages of urban and architectural design.