Dalarna University's logo and link to the university's website

This thesis investigates the technical, environmental, and economic viability of transitioning a Swedish residential building cluster from the conventional high-temperature district heating (DH) systems to the low-temperature and decentralized energy configurations. Using a case study of Rymdgatan in Borlänge, the research simulates three future climate years: 2020, 2050, and 2080 under various both light and deep energy efficiency retrofit scenarios. The City Energy Analyst (CEA) program was employed to evaluate building energy demand, carbon emissions, system performance, and lifecycle costs, while integrating renewable potentials from ground-source heat pumps (GSHPs), photovoltaic-thermal (PVT) modules, and solar thermal systems.

The findings reveal that deep energy efficiency retrofitting combined with decentralized energy systems can reduce winter peak loads by up to 42% and operational carbon emissions by nearly 90%, while achieving up to 60% reductions in total annualized costs compared to the baseline in 2018. Solar energy utilization increased from 98 MWh/year in the baseline to over 240 MWh/year in the optimized scenarios, demonstrating the impact of strategic technology deployment. Among all configurations, the 2050 deep retrofit scenario emerged as the most techno-economically balanced, offering strong alignment with Sweden’s 2045 climate neutrality targets using commercially available technologies.

The study concludes that integrated energy efficiency retrofit, and supply system planning implemented before mid-century is critical for achieving energy resilience, cost-efficiency, and net-zero emissions in this Swedish residential building cluster. The research also provides policy and planning guidance for scalable deployment of fifth-generation DHC systems in cold climates.