Stratégies de refroidissement urbain (en anglais)

Un rapport fournit des conseils pratiques pour optimiser les projets de développement visant à modérer les microclimats urbains dans les grands centres urbains d'Australie.

According to the World Bank, urban areas contribute as much as 80% of global greenhouse gas emissions, while also becoming increasingly vulnerable to the effects of the changing climate. A new report “Guide to Urban Cooling Strategies” from the Low carbon living CRC provides practical guidance to optimise development projects to moderate urban microclimates in major urban centres in Australia.

Urban cooling as a global approach of temperature reduction in cities had many impacts like less use of air-conditioning involving energy saving, CO2 emission reduction and better life comfort. Existing UHI (Urban Heat Island) mitigation techniques recommend cool materials, urban vegetation, water and shading as potential solutions to moderate temperatures. The effectiveness of each UHI mitigation technique varies according to the location, urban context (density, scale) and climate zone. For example, a high-albedo roof surface with cool white coating can radiate away up to 75% of incident solar energy. This means that it absorbs only 300 W/m2 instead of 900 W/m2 and can reduce surface temperature up to 33 °C compared to conventional roofs. This decreases indoor temperatures in the occupied space directly below the cool roof between 1.2 °C and 4.7 °C. Such temperature reduction can save 18% to 34% energy for air-conditioning during summer in temperate climates. In New York City, a program using cool roofs has contributed to avoid 3.315 metrics tons of carbon dioxide equivalent emissions in the city since 2009. In a warming climate context, such techniques and recommendations will be strategic for cities, especially in hot climate, to minimise their greenhouse gas emissions and improve comfort and life quality of their inhabitants.

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