Energy performance and environmental impact analysis of cost-optimal renovation solutions of large panel apartment buildings in Finland

• Published in: Sustainable cities and society Vol. 32; pp. 9 - 30
• Main Authors: Niemelä, Tuomo, Kosonen, Risto, Jokisalo, Juha
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.07.2017
• Subjects: Cost-optimal renovation concept; Energy performance; Greenhouse gas emissions; Large panel apartment building; Multi-objective optimization; Primary energy; Renewable energy source; Large panel apartment building; Primary energy; Multi-objective optimization; Energy performance; Greenhouse gas emissions; Renewable energy source; Cost-optimal renovation concept
• ISSN: 2210-6707; 2210-6715
• DOI: 10.1016/j.scs.2017.02.017

•The nZEB requirements can be achieved cost-effectively also in deep renovations.•The operation phase is dominant in the assessment of the total CO2 emissions.•Modern heat pump system is an excellent solution for deep renovations of apartment buildings.•Investments in energy systems are recommended over investments in the building envelope.•Simulation-based optimization is a recommended method in cost-effectiveness and environmental impact analyzes. The paper presents energy performance and environmental impact analysis of cost-optimal renovation solutions conducted in deep renovations of typical large panel-structured apartment buildings located in cold climate conditions. The main objective of the study was to determine the cost-optimal renovation concepts from both the primary energy performance and the total CO2 emission reduction potential perspectives. The cost-optimal solutions for different main heating systems were determined from over 220 million renovation combinations by using a simulation-based multi-objective optimization (SBMOO) analysis as the main research method. The results demonstrate that the proposed national nearly zero-energy apartment building level can be cost-effectively achieved in deep renovations of large panel apartment buildings, delivering approximately 18–36% return on investment. The results also indicate that up to 90–98€/m2 net savings, 850–930kWh/m2 reduction in the primary energy consumption and 350–390kg/m2 reduction in the total CO2 emissions over the studied 30-year life-cycle period can be achieved simultaneously, when the cost-optimal renovation concepts are selected. Cost-optimally dimensioned heat pump systems deliver significant cost saving and environmental impact reduction potential compared to improving the energy efficiency of the building envelope, as the delivered energy consumption accounts for more than 90% of the total CO2 emissions.