New research shows that the compact, taller buildings typical of inner-city areas are often the most heat-energy efficient

A thermal image of the London city skyline. Photograph: Joseph Giacomin/Getty Images/Cultura RF

As the Intergovernmental Panel on Climate Change (IPCC) finalises itsfifth report, cities are again singled out as critical sites for fighting global climate change. Estimates have linked activities in urban areas to as much as 75% of global energy-related carbon emissions.

However, cities can also play a key role in any more prosperous, low-carbon future by taking advantage of their enormous potential for energy efficiency. Heat energy demand in residential buildings presents one such opportunity.

The building sector is the biggest source of urban carbon emissions; globally, it accounts for approximately 33% of all energy-related greenhouse gas emissions. And of all the energy used in buildings, heating is the biggest factor: in Europe, approximately 70% of energy use in residential buildings is heating related. Yet typically there can be an enormous – as big as 20-fold – gap in the heat-energy demand of different contemporary buildings. Why is that?

In principle, there are three main factors that have an impact on heat-energy demand: behaviour, technology and design. New research by LSE Cities at the London School of Economics and the European Institute for Energy Research looked specifically at the role building design can play.

Our research inquired about the impact of the basic configurations of residential buildings (“urban morphology”) on energy demand. This impact is a result of two principal determinants of the thermal performance of buildings: the level of exposure to sunlight, which allows buildings to absorb passive solar heat; and the relative amount of external walls, which lead to heat losses.

The combined effect of sunlight exposure and heat loss is best detected at the neighbourhood level, to fully capture how adjacent buildings impact on each other. Therefore, the study was based on a sample of 100 local areas representing the dominant residential building types in Paris, London, Berlin and Istanbul. For each, a computer simulation based on 3D digital building models calculated the average annual heat energy demand per floor area, and also considered yearly variations in outside temperature, the angle of the sun, and different scenarios for local climate and building insulation....Continue Reading

> via The Guardian