Life cycle primary energy use of nearly-zero energy building and low-energy building

Panel: 5. Buildings and construction technologies and systems

This is a peer-reviewed paper.

Authors:
Ambrose Dodoo, Linnaeus University, Sweden
Leif Gustavsson, LNU, Sweden
Uniben Tettey, LNU

Abstract

Energy legislations are increasingly driving towards buildings with very low operation final energy use, as part of efforts to reduce energy use and climate impact of the built environment. In this study we analyse the life cycle primary energy use of a recently constructed Swedish multi-story building and compare it to variants designed as nearly-zero energy building or as low-energy building with a combination of improved thermal envelope and passive design strategies. Our study is based on a reference conventional 6-storey apartment building recently built in Sweden. We maintain the architectural design of the reference building and improved the thermal envelope properties of the walls, windows and roofs to achieve a low-energy building and also nearly-zero energy building including photovoltaic panels and solar thermal collectors. We consider scenarios where the building versions are heated with renewable energy using cogenerated district heating, also complemented with solar heating system. We follow the life cycle of the building versions and analyse their total primary energy use, considering the production, retrofitting, operation and end-of-life phases. The results show that the production phase accounts for a large share of the total life cycle primary energy use for the nearly-zero energy and low-energy building variants. For the nearly-zero energy building, the production phase constitutes 33% of the total primary energy use for a 50 years lifespan. For the reference and low-energy buildings, the production phase account for 17 and 31% of the total primary energy use for a 50-year lifespan, respectively.