Urban form and energy demand- Impact of height and density height and density for low-energy design in Tropical climate

Background

Accounting for almost 50% of the total energy supply in urban areas, buildings offer great potential for minimizing the energy demand in these areas. The energy consumed in a building is a function of climate, envelope design, and the form of the built environment. The spatial interactions between buildings and their form characteristics lead to variations in building energy usage through shadowing, radiation, and mutual reflections. Their arrangement and form, particularly the height, density, and street width, affect cooling loads and indoor thermal sensation. The effect of urban form on the warming up of urban areas, microclimate, and outdoor thermal comfort is well documented. However, limited efforts have been made to capture the combined effect of variations in urban form and envelope design, predominantly in terms of varying typologies, on cooling demand.

Aim and methodology

This study examines the relationship between urban form, particularly height, and variations in climate and envelope design on cooling demand in buildings for different neighbourhood typologies in hot climates. It employs the local climate zone classification to select representative urban forms in two Indian cities with different climatic zones. Datasets related to urban form features, including building location, footprints, height, number of floors, intermediate distances, are extracted from Google Earth images. Consequently, real weather data, instead of a typical meteorological year, is employed for calculating the energy demand. The collected spatial data are organized in ArcGIS and exported to CEA for conducting energy simulations.

Potential findings

The results reveal that urban form and climate play a key role in shaping space cooling demand. The variations in inter-building distances and heights in compact typologies strongly correlate with energy demand. In contrast, high-rises exhibit a more consistent profile. A building that does not exhibit a strong correlation individually may become significant in the presence of others.

These findings underscore the importance of developing climate-contextual typologies for building design. Integrating climate-based strategies into building regulations offers significant potential for energy conservation.