District heating with low-carbon heat sources and low distribution temperatures: Dissertation

Energy supply sector is the largest source of anthropogenic emissions with a share of more than a third in global greenhouse gas emissions. In terms of energy demand, the heating and cooling sector corresponds to more than a half of the global final energy consumption. Urban areas have been evaluated to be responsible of 76 % of global energy use and 37-49 % of the greenhouse gas emissions. The relevance of cities in the context of climate change mitigation and the significance of the heating and cooling sector imply that solutions for urban areas are an essential part of the mitigation measures needed. This is where district heating and district cooling technologies can play an important role. Both district heating and cooling are energy solutions designed for densely populated areas.

The dissertation focuses on developing DH systems by studying means for improving their efficiency and integrating more low-carbon heat sources for heat supply. The potential impact of low temperature distribution is also assessed. The heat sources considered in the scope of the presented research are heat pumps, solar collectors and nuclear district heating.