IMPACT OF MUTUAL SHADING ON ENERGY CONSUMPTION IN A MID-RISE RESIDENTIAL BUILDING

Abstract

Human population increase and economic growth agendas (e.g. MBIE, 2015) increase the pressure on natural resources and ecosystems around the world (MEA, 2005). Even more, production needs to be realized from the same finite amount of natural resources. At the same time, environmental conditions need to be improved or at least maintained. One of the major natural resource for development is land. The land values around the urban areas, which has easy access to a number of resources for a comfortable lifestyle, are very high because the demand of land is much more then the supply. To solve this issue of land reduction, densely built urban spaces with multi-storeyed buildings started coming up, because more and more people are migrating to the urban areas in the need of a better life, resulting in the demand of more number of dwelling units. The buildings in these densely built urban spaces suffer lack of solar radiation due to shading from the adjacent buildings. This hugely impacts the energy consumption of a building. The study is sought to develop a systematic approach to quantify influence of mutual shading within a network of buildings, and what measures can be taken to optimize the building envelope for energy efficient design, keeping in mind the shading effect from adjacent buildings. The shaded areas of the building require different guidelines for lesser energy consumption as compared to areas that are not shaded, as these are prone to less amount of solar radiation throughout the day. The guidelines provided for the energy efficient building design such as ECBC (in India), does not consider the impact of shading from the adjacent buildings. In the recent studies conducted by BEEP India while preparing the guidelines for Energy Efficient multi-storey residential buildings in Composite & Hot-Dry areas, the need for increasing the WWR for the rooms existing at the lower floors of the building is mentioned to meet the desired day light factor, as these floors are shaded by adjacent buildings and does not have direct solar access. In the guidelines, only WWR is talked about while there are other parameters that can be influenced as well. There are several parameters which are to be considered while studying the impact of mutual shading on a building’s energy consumption. These can be classified into two: 1. Building Exterior Parameters (Surrounding Environment), that impact the area of the building envelope exposed 6 to solar radiation & 2. The Building Envelope Parameters. Firstly these parameters are identified through in depth literature study. Then different building layouts of the adjacent buildings around the subject building are prepared and tested in different climates of India. Hot-dry climate is impacted by mutual shading the most. The further study is carried out for hot-dry climate. The simulations are carried out by varying the parameters for the selected network of buildings. Based on the outcome of the simulations, recommendation and suggestions, considering mutual shading, for the building envelope parameters are provided for the energy efficient design of a building are provided. The recommended values of the envelope parameters are more lenient and easy to comply as compared to the general energy efficient design guidelines provided by BEEP India.