Comparison of Three Calculation Methods of Energy Performance Certificates in Slovenia

Abstract

Apstrakt:Kako bi dobili ovlaštenje za izradu energetskih certifikata u Sloveniji, kandidati moraju pohađati propisanu obuku i položiti ispit. Pojednostavljena metoda proračuna toplotnih gubitaka koja se podučava na ovoj obuci zanemaruje toplotne mostove, što pouzdanost rezultata čini upitnim. U ovom radu uporedili smo tri metode proračuna toplotnih gubitaka kod "tipične" porodične kuće. Prva metoda predstavlja prethodno pomenuti pojednostavljeni proračun koji koristi korekcijski faktor; druga uzima u obzir toplotne mostove, koristeći numerički dobijene vrijednosti linijskih koeficijenata prolaza toplote, a treća koristeći zadane vrijednosti ovih parametara. Uzimajući u obzir da druga metoda daje najpreciznije rezultate, utvrdili smo da su rezultati prve metode preveliki, ali ipak manji nego rezultati dobijeni trećom metodom. Abstract:In order to get the authorization for issuing energy performance certificates in Slovenia, the expert candidate has to attend the prescribed course and pass the exam. The simplified method for heat losses calculation that is taught at this course neglects the thermal bridges, raising concerns whether the calculation results are reliable. In this paper we have compared three methods for calculation of thermal losses for a "typical" family house. The first is the above mentioned simplified calculation using a correctional factor; the second takes into account the thermal bridges, using linear thermal transmittances obtained by numerical calculation, and the third takes into account the thermal bridges, using default values for linear thermal transmittances. Noting that the second method returns the most exact values, we have found that the first method results are too large, yet still smaller than the third method results.