How the roofing morphology and housing form affect energy performance of Shanghai’s workers’ village in urban regeneration

Typologies of the building roof influence the form and the view of a city, and have an impact on its energy performance. “From Flat to Slope Roof” is a governmental project in Shanghai to renovate workers’ villages over the past two decades. The project aimed to change monotonous appearance of the urban roofscape by replacing the flat roof with the slop roof, and to bring benefits of passive cooling through the slide roof to reduce energy demand caused by excessive air-conditioning. However, how different roofing typologies affect the building energy performance requires further investigation. Previous test results have shown that near 6% reduction of total annual building energy consumption could be achieved with the substitution of the polymer material on flat roofs, compared with the reduction by 3% on walls, and the reduction by 2% on floors. In this paper, the numerical modeling with EnergyPlus was applied to test the variation of roofing types and how they would affect the total energy consumption from level of a building to the entire whole community. The results show a connection between the thermal insulation of roof morphology and building energy performance, which conclude an energy reduction strategy through urban design in a neighborhood scale.