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Title of the thesis: CO2 emissions reduction of residential buildings with deep renovation and cost-optimal control of an energy community

Thesis defender: Yangmin Wang
Opponent: Prof. Dennis Johansson, Lund University, Sweden
Opponent: Prof. Per Heiselberg, Aalborg University, Denmark 
Custos: Prof. Risto Kosonen,Aalto University School of Engineering

Buildings constitute the largest energy end-use sector in Europe, accounting for approximately 40% of final energy use and 36% of greenhouse gas emissions. Improving building energy efficiency and reducing associated CO2 emissions are therefore essential for achieving European climate neutrality targets. This doctoral thesis investigates the CO2 emissions reduction and cost-effectiveness potential of the European building stock, spanning from building-level novel renovation concepts to the cost-optimal dimensioning and control of community-scale hybrid heating systems. 

At the building level, the research evaluates the impact of novel renovation concepts on CO2 emissions and indoor climate, and also their economic feasibility under different residential buildings, climatic conditions, and heating schedules using dynamic simulations. At the community level, the study compares different control strategies for a hybrid heating system within an energy community under varying electricity and district heating price structures. Besides, it also defines the cost-optimal dimension of thermal energy storage for the community utilizing the proposed simulation-based parametric analysis framework.

This thesis provides practical guidance for accelerating low-carbon heating transitions in Europe. The building-level findings offer recommendations for novel renovation concepts and identify the key barriers that must be addressed to enable wider market uptake and commercialization. At the community level, the results demonstrate the feasibility of economically viable, price-responsive control strategies for future hybrid heating systems that integrate multiple energy carriers. In addition, the proposed simulation-based framework is transferable to other energy communities, supporting decision-making across diverse building types and climates under evolving electricity and district heating tariff structures.

Keywords: Residential energy renovation, Intermittent heating, CO2 emissions, Indoor climate, Energy community, Dual source heat pump, Hydrogen production waste heat, Smart control, Thermal energy storage

Thesis available for public display 7 days prior to the defence at . 

Contact information: yangmin.wang@aalto.fi