Napredna metodologija za vrednotenje okoljskih vplivov prenove stavb v celotni življenjski dobi

Učinkovita in trajnostna obnova obstoječega stavbnega fonda bo pri zmanjševanju toplogrednih emisij na področju gradbeništva v prihodnosti ključna. Okoljski vplivi prenov se določajo z analizo življenjskega cikla (metodo LCA), pri čemer se prenova običajno obravnava kot začetek novega življenjskega cikla stavbe. V okviru doktorske naloge smo razvili napredno metodologijo LCA za ocenjevanje okoljskih vplivov prenov, ki vključuje tudi faze pred prenovo in rabo časovno ustreznih podatkov za analizo življenjskega cikla stavbe (LCA). S tem zagotavlja, da so vključeni vsi vplivi prenove stavb in se eliminira podvajanje vplivov. Napredna metodologija je sestavljena iz dveh delov. Prvi del omogoča prilagajanje trenutno dostopnih podatkov tako, da ustrezajo dejanskemu času proizvodnje. Drugi del metodologije zagotavlja ustrezno razporejanje (alokacijo) vplivov na okolje in preostale vrednosti materialov ter gradbenih elementov v življenjski cikel pred prenovo in po njej. Oba dela metodologije lahko uporabimo tudi ločeno. Vzporedno smo razvili LCA metodologijo za primerjanje ukrepov prenove, ki poleg utelešenih vplivov vključuje tudi okoljske vplive v času rabe stavbe. V nalogi je bilo dokazano, da je uporaba časovno ustreznih podatkov pri analizi okoljskih vplivov izjemno pomembna. Za prenove stavb pa je ključno tudi, da se okoljske vplive alocira na življenjski cikel pred obnovo in po njej, kar je pomembno zlasti kadar se materiali reciklirajo in ponovno uporabijo. Primerjalne okoljske analize prenove fasadnega ovoja so pokazale, da v našem geografskem področju položaj toplotnoizolacijskega sloja ne vpliva bistveno na toplotni akumulacijski potencial stavbe in da je povračilna doba okoljskih vplivov fasadnega ovoja v veliki meri odvisna od okoljskih vplivov same toplotne izolacije. The refurbishment of the building stock is one of the key tasks for reducing future environmental emissions. The environmental emissions are mostly assessed with the Life Cycle Assessment (LCA) method, where the refurbishment is usually considered as the beginning of the new life cycle, and all the impacts associated with the life cycle before the refurbishment are neglected. In order to overcome this inconsistency, in the PhD study an advanced LCA methodology was developed that allocates the impacts between the life cycle before and after the refurbishment, and assures the use of time-corresponding data. In this sense, the neglecting of the environmental impacts before the refurbishment, as well as the double-counting, is eliminated. The developed methodology consists of two sub-methodologies. The first sub-methodology is used for remodelling the input data, in order to make them time-corresponding. The second sub-methodology enables the allocation of environmental impacts before and after a refurbishment and calculation of the residual value of materials. Both sub-methodologies can be used also individually. Additionally, a methodology for the comparison of the environmental impacts of refurbishment measures that also includes operational EI was developed. The thesis proved that the use of time-appropriate data for the analysis of environmental impacts is extremely important. For building refurbishment, it is also crucial that environmental impacts are allocated to the life cycle before and after renovation, especially when materials are recycled or reused. The comparative methodology for the refurbishment measures indicated that in Central Europe the position of the thermal insulation layer does not significantly affect the heat storage capacity of buildings, and that the environmental payback period for the façade refurbishment is mainly dependent on the environmental impacts of the thermal insulation itself.