ZEMCH 2015 - International Conference Proceedings | Page 78

Introduction
“Energy Performance of Buildings Directive” (EPBD) in 2002 had set a framework which forced all
member states to determine their national required building performance. Later in 2010, EPBD
recast requested member states to ensure that their minimum energy performance requirements
for buildings must be complied with a view to achieve cost-optimal levels. Main purpose of this
type of study is to make a proper link between financial targets and building energy performance.
This economical assessment shall be done in accordance with a comparative methodology described by EU No 244/2012.
The most common method to assess cost efficiency of energy performance requirements of
buildings is Life Cycle Cost (LCC) analysis. In this regard, European standard EN 15459:2008 presents the detailed method of buildings global cost calculation which considers all types of cost
during building life time including investment costs, energy costs, maintenance costs, operational costs, replacement costs, and added costs. All the future costs are calculated in their value at
the starting year by means of the method “Net present value” (NPV) which is a tool for financial
assessments of long term projects.

Literature review
There is a great number of researches which has performed LCC analysis of an entire building(Badea et al. 2014:542–555)(Corrado, Ballarini, & Paduos 2014:443–452)(Fabbri, Tronchin, &
Tarabusi 2010:3064–3071)(Ferrara, Fabrizio, Virgone, & Filippi 2014:442–457)(Ganiç & Yılmaz 2014:94–
107)(Han, Srebric, & Enache-Pommer 2014:223–231)(Kapsalaki, Leal, & Santamouris 2012:765–778)
or specific building elements e.g. energy supply systems(Aste, Adhikari, & Manfren 2013:615–624)
(Georges, Massart, Van Moeseke, & De Herde 2012:452–464)(Leckner & Zmeureanu 2011:232–241)
in various building types, commercial buildings (Kneifel 2010:333–340) and office buildings (Pikas, Thalfeldt, & Kurnitski 2014:30–42) in different contexts in order to determine the cost optimal
solutions. In Italy, Corrado (Corrado et al. 2014:443–452) studied a typical apartment block taken
from “National Building Typology” as a reference building and applied a sequential technique in
which energy efficiency measures (EEMs) for the building envelope as well as technical systems
and renewable technologies were applied. Results showed that the optimal level gets an annual
primary energy use for heating, cooling and domestic hot water of 115 kWh/m2yr corresponding
to an actualized global cost of 676 €/m2.
Some studies demonstrated that within different assumptions, different cost optimal levels are
obtained. In a study in Turkey (Ganiç & Yılmaz 2014:94–107) EU methodology framework for cost
optimal calculations were adapted in the national level according to Turkish factors and implemented on an exemplary office building under two different climatic zones and regarding different time periods in order to find the lowest LCC under a limited number of retrofit packages. By
considering various time scales, this study found out that lowest global costs varies in short-term
(e.g. 5 and 10 years) or long-term (e.g. 20 and 30 years) periods. Results also showed that cost optimum point in temperate dry or hot-humid climates doesn’t belong to the same retrofit scenario
as a consequence of higher cooli