Livscykelanalys för koldioxidutsläpp från flerbostadshus

Sammanfattning: Today, about 15 to 20 percent of Sweden’s total emission of carbon dioxide can be traced to the household sector. By examining apartment blocks in a life cycle perspective, the origin of the carbon dioxide emission has been charted and analyzed. This information has been used to create a computational model that calculates the total emission of carbon dioxide from a specific apartment block. The results from the analyzed apartment blocks indicate that both the use of energy and the emission of carbon dioxide have been reduced since the 1960s.   Through the examination of building materials, it is possible to lower the emission of carbon dioxide that origins from the construction phase of an apartment block. However, the largest contributing factor to the emission of carbon dioxide is the usage of the apartment block. Within this phase of the life cycle a large amount of energy is being used, mostly because of heating and electricity, and this results in emissions of carbon dioxide. It is the source of the energy that decides the quantity of the emission. The choice of ventilation-system and lighting in the apartment block can also have an effect on the total emission of carbon dioxide.   Construction, usage and demolition of six apartment blocks in Stockholm have been analyzed to calculate the emission of carbon dioxide in a life cycle perspective. Calculations have been executed in the created computational model and the result shows that the emission has decreased during the last decades. The emission of carbon dioxide is mostly affected by the building’s energy performance, but also the relationship between district heating and electricity. The energy performance depends on the construction of the apartment blocks and the mentioned relationship depends greatly on the choice of ventilation system. An obvious difference in the percentage of district heating can be noticed when the apartment block uses a ventilation system with heat recovery.   It is possible to examine changes in construction and usage of the apartment block in the computational model, in order to analyze how large impact a specific change has on the total emission of carbon dioxide. According to the examination of changes of a passive house that was built in 2010, installation of sun heating is a possible way to reduce the emission of carbon dioxide.