Residential buildings of Esch-sur-Alzette under scrutiny

The Luxembourg Institute of Science and Technology (LIST) recently presented the results of case studies deployed in the town of Esch-sur-Alzette. Based on energy consumption and the environmental impacts of residential buildings, the case studies were carried out in the framework of two projects co-funded by the National Research Fund (FNR): OptiHeat and Daedalus. While the former aims to implement an optimization methodology to minimize costs and environmental impacts through heat recovery, the second aims to develop an integrated geo-spatial approach for the analysis of the dynamic life cycle of the renovation of buildings parks on an urban scale.


Supporting the recovery of heat from wastewater



With OptiHeat, the request for residential heating in the town of Esch-sur-Alzette was analysed. Based on the calculation of the current request for heat in residential buildings, established at 189.2 GWh, and after characterization and quantification of both the demand for domestic hot water as well as the waste water heat recovery potential in buildings, the main conclusions are:

• Only 13% of natural gas is used for domestic hot water, which is approximately the amount lost in the inefficiency of functional heaters.
• Domestic hot water has a major impact in residential buildings that are low energy and passive (up to 50% of the heat requirement in passive houses) and its temperature level can be optimized to increase the energy efficiency of heat pumps.
• By recovering heat from greywater, optimizing the temperature level and the use of a heat pump, a decrease from 20 to 40% of the heat requirement of low-energy and passive houses can be achieved. The implementation of these measures could therefore be an important step in meeting the EU objectives of “near-zero energy buildings” from now to 2020.

Buildings refurbishment and waste recovery

With Daedalus, an approach based on geographic information systems (GIS) has enabled an energy analysis of a life cycle assessment (LCA) of urban housing in the town of Esch-sur-Alzette. Through analysis of the buildings’ life cycle, a study of the renovation of buildings and the environmental impacts, as well as a study of waste management from demolition and recovery alternatives, the main conclusions are:

• The refurbishment of buildings offers a potential 35% energy saving and 31% reduction in global warming potential. The production and transportation of materials related to the renovation contributes to this last point, from 4 to 10% over the entire life cycle.
•  The pre-1949 buildings account for nearly 54% of the mass of the materials present in the city, most of which are inert materials.
• Encouraging the downcycling of 70% of the inert materials would allow the reduction of 25% of abiotic depletion potential and nearly 10% of global warming potential compared to current practices.

The building-by-building approach confirmed



This latest study more broadly confirmed the interest of a life cycle analysis of buildings on an urban scale through a building-by-building approach based on geographic information systems (GIS). An approach for which a technology developed by LIST was used: the platform "Smart City and Region Energy platform". This platform makes it possible for planners, governments and utility companies or service providers to access energy maps, display CO2 emissions, identify opportunities for energy trade and monitor the effects of energy saving measures in their town, which leads to more informed decisions.



> To learn more about the OptiHeat project, please visit the dedicated page.

> To learn more about the Daedalus project, please visit the dedicated page.