Waste-heat re-use from commercial sources in urban environments - identification of potentials and assessment of supply-demand matches, a Vienna case study

The mitigation of Global Warming triggered by accelerated greenhouse gas (GHG) emissions requires changes in the energy supply towards renewables. Thus in this paper possibilities are identified to improve the energy supply system using waste heat as an additional energy source in the City of Vienna as case study. As no observation data for waste heat and heating demand is available this data has to be derived from proxy data for estimating waste heat potential and heating demand patterns. Commercial heat consumption as a waste heat source is mapped based on the distribution of industries and services within the urban area, estimated via employees and turnover as proxy numbers. Waste heat share and temperature ranges are reviewed from literature. Heating demand is mapped based on floor space distribution related to building age, class, type and heating demand factors per m2. The difference of both maps shows the local heat supply deficit or surplus pattern to be eventually covered through local waste heat sources. The distribution of new housing developments and the retrofitting potential of existing housing has been identified to examine the possibilities of local waste heat reuse.