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The full length version of this article is available at the journal website http://www.rehva.eu/en/rehva-european-hvac-journal
Cristina BecchioTEBE Research Group, Department of Energy, Politecnico di Torino, Italycristina.becchio@polito.it | Stefano P. CorgnatiTEBE Research Group, Department of Energy, Politecnicodi Torino, Italy | |
Ilaria BallariniTEBE Research Group, Department of Energy, Politecnicodi Torino, Italy | VincenzoCorradoTEBE Research Group, Department of Energy, Politecnicodi Torino, Italy |
The
present paper reports the first outcomes of the application of the above
described methodology to the national residential building stocks of four
countries representative of the North, Middle, South and East European
Countries. It summarizes the results presented in the TABULA report “Application of Building
Typologies for Modelling the Energy Balance of the Residential Building Stock”.
Building
typologies developed during the TABULA project can be exploited as a basis for analysing the
national housing sector. Specifically, as shown in Figure 1, starting from global statistics at national and regional level and
from the corresponding available residential building samples divided in
classes, some reference building types have been selected in order to obtain a
relevant characterization of the analyzed buildings. They have been chosen as
representative of a large portion of the national residential building stock.
Different modelling approaches were chosen by the partners
depending on the available statistical data. Some defined a set of synthetic
buildings reflecting building stock averages; others applied a set of generic
example buildings from the national TABULA typologies.
For each reference building type two refurbishment measures have been considered: a standard refurbishmentthrough the application of measures commonly applied within the country; an advanced refurbishment through the introduction of measures that reflect the use of the best available technologies. Finallyadditional information about the number and the frequency of each specific building type has made possible the application of statistical models in order to estimate the overall energy performance, energy saving potentialities, carbon dioxide emissions reductions of the building stock at national/regional level.
This paper shows the first outcomes of the
application of the above described Energy Balance Method at the national
residential building stock of four countries:
· Denmark, as a representative of the North European countries;
· Germany, as a representative of the Middle European countries;
· Italy, as a representative of the South European countries;
· Czech Republic, as a representative of the East European countries.
The data presented in this paper have been extrapolated from the TABULA report “Application of Building Typologies for Modelling the Energy Balance of the Residential Building Stock” and from the “National Scientific Report” on the TABULA project of the four analysed countries.
Figure 1.Procedure for Energy Balance Method used in the
TABULA project to predict the potential impact of energy efficiency measures on
national housing sector.
The
energy balance of the Danish residential buildings was calculated using synthetical average buildings. These were split within nine
different construction periods and three building types (single family houses
SFH, terraced houses TH, block of flats AB).
In order to
estimate energy saving potentials the national Energy Balance method was used.
Refurbishment measures were applied only to the envelope and consisted in two different levels of thermal insulation: details about retrofit actions are reported on the full length version of this paper on the web site. Consequently, the energy saving potential was calculated only in term of net energy demand for heating and DHW. The results of the analysis are presented in term of energy saving and CO2 emission reduction in Table 1.
Table 1.Annual energy saving potential (in terms of net
energy demand for space heating and DHW) and CO2
emissions reductions by standard and advanced refurbishment of Danish
residential building stock.
Reference building type | Original State | Standard Refurbishment | Advanced Refurbishment | |||||
QH,W,p | tCO2 | ΔQH,W,p | Δ% savings | ΔtCO2 | ΔQH,W,p | Δ% savings | ΔtCO2 | |
[10³GWh] | [106t] | [10³GWh] | [-] | [106t] | [10³GWh] | [-] | [106t] | |
SFH and TH | 31.5 | --- | 14.6 | -46% | --- | 15.6 | -50% | --- |
AB | 12.1 | --- | 5.3 | -44% | --- | 5.9 | -49% | --- |
43.6 | --- | 19.9 | -46% | 3.1 | 21.5 | -49% | 3.4 |
The
analysis of the German building stock was conducted on a set of six synthetical average buildings. Two building size classes
(single family houses with one or two dwellings and multifamily houses with
three or more dwellings) and three construction periods according to different
levels of energy saving national regulations were considered (see full length
version of this paper on the web site).
The energy
balance model was developed on basis of the available statistical input data.
The energy demand for space heating of the considered six building types was
calculated according to a seasonal energy balance approach. In this way an
estimation of energy saving potentials in the German building stock for heating
and hot water supply was carried out. Details about retrofit actions are
reported on the full length version of this paper on the web site.
Energy
saving potential obtained by retrofitting the German residential building stock
is reported in Table 2.
Table 2.Annual energy saving potential (in terms of primary energy for space
heating and DHW) and CO2 emissions reductions by standard
and advanced refurbishment of German residential building stock.
Original State | Standard Refurbishment | Advanced Refurbishment | |||||
QH,W,p | tCO2 | ΔQH,W,p | Δ%
savings | ΔtCO2 | ΔQH,W,p | Δ%
savings | ΔtCO2 |
[103GWh] | [106t] | [103GWh] | [-] | [106t] | [103GWh] | [-] | [106t] |
661 | 136 | 304 | -46% | 63 | 512 | -77% | 100 |
In Italy,
six reference building types were created to represent the housing stock for
the purpose of Energy Balance analysis (single family house SFH, multi-family
house MFH, apartment block AB; see full length version of this paper on the web
site).
These
reference buildings were chosen according to statistical analysis: they are
representative of a suitable significant portion of the entire national
building stock considering both the construction age and the building size
(i.e. number of apartments, floor area) and they belong to the “Middle Climatic
Zone” (from 2100 to 3000 heating degree days), which is the most representative
of the Italian climate (about 4250 municipalities on a total number of 8100).
The
official national calculation method (Technical Specification UNI/TS 11300 -
National Annex to CEN Standards) for energy certificates was applied for the
evaluation of the energy demand of the selected reference buildings and to
assess the energy saving potential due to energy retrofit actions according to
two different scenarios (standard and advanced refurbishment). Details about
retrofit actions are reported on the full length version of this paper on the
web site.
Energy
saving potentialities obtained applying the mentioned retrofit measures at the
Italian residential building stock are reported in Table 3.
Table 3.Annual energy saving potentialities (in terms of
primary energy for space heating and DHW) and CO2
emissions reductions by standard and advanced refurbishment for Italian
residential building stock.
Reference building type | Original State | Standard Refurbishment | Advanced Refurbishment | |||||
QH,W,p | tCO2 | ΔQH,W,p | Δ% savings | ΔtCO2 | ΔQH,W,p | Δ% savings | ΔtCO2 | |
[103GWh] | [106t] | [103GWh] | [-] | [106t] | [103GWh] | [-] | [106t] | |
SFH
(until 1900) | 50.6 | 10.3 | 38.8 | -77% | 7.9 | 42.8 | -85% | 8.7 |
SFH
(1921-1945) | 22.1 | 4.5 | 17.8 | -81% | 3.6 | 19.4 | -88% | 3.9 |
MFH
(1946-1960) | 127.2 | 25.8 | 98.2 | -77% | 19.9 | 105.5 | -83% | 21.4 |
AB
(1961-1975) | 419.5 | 85.2 | 301.2 | -72% | 61.2 | 349.9 | -83% | 71 |
AB
(1976-1990) | 364.3 | 74 | 204.4 | -56% | 41.5 | 255.4 | -70% | 51.9 |
AB
(1991-2005) | 76.6 | 15.6 | 32 | -42% | 6.5 | 42.3 | -65% | 8.6 |
1060.5 | 215.3 | 692.5 | -65% | 140.6 | 815.4 | -77% | 165.5 |
Six
reference building types were created to represent the Czech Republic housing
stock for the purpose of Energy Balance analysis. This set of buildings was
categorized by size (single family house SFH, multi-family house and apartment
block APT) and age (see full length version of this paper on the web site).
The
buildings are theoretical buildings based on the analysis of available
statistical data and on the knowledge of historical standard requirements for
the U-values of the building envelope and the usual efficiency of the heating
and DHW systems.
The energy
balance model was created on basis of the statistical data. The delivered
energy and the energy demand for space heating of the considered six groups of
buildings was calculated using national calculation method.
In this
case the refurbishment measures were fixed on the basis of recent studies.
Details about retrofit actions are reported on the full length version of this
paper on the web site. The results of the analyses are shown in Table 4.
Table 4.Annual energy saving potentialities (in terms of primary energy for space heating and DHW)
and CO2 emissions reductions by standard and advanced refurbishment for Czech
Republic residential building
stock.
Reference building type | Original State | Refurbishment | |||
QH,W,p | tCO2 | ΔQH,W,p | Δ% savings | ΔtCO2 | |
[103GWh] | [106t] | [103GWh] | [-] | [106t] | |
SFH
(until 1979) | 11.9 | 5.5 | 7.7 | -65% | 3.6 |
SFH
(1980-2001) | 12.7 | 5.9 | 4.8 | -38% | 2.2 |
SFH
(2002-2010) | 5.5 | 2.6 | 1.1 | -20% | 0.5 |
APT
(until 1979) | 6.1 | 2.9 | 3.2 | -52% | 1.5 |
APT
(1980-2001) | 15.2 | 6.5 | 5.3 | -35% | 2.3 |
APT
(2002-2010) | 5.4 | 2.6 | 1 | -19% | 0.5 |
56.8 | 26 | 23.1 | -41% | 10.6 |
The
analysis shows that building typologies can be a helpful tool for modelling the energy consumption of national building
stocks and for carrying out scenario analyses beyond the TABULA project. The
consideration of a set of representative buildings, which reflect the current
state of the building national stock, makes it possible to have a detailed view
on various packages of refurbishment measures for the complete buildings stock
or for its sub-categories. The effects of different insulation measures at the
respective construction elements as well as different system supply measures
including renewable energies can be considered in detail with fast analysis.
As general
rule, when two different level of retrofit were considered it is noted that the
standard refurbishment is associated with high relative percentage of energy
saving (Figure 2): the energy saving due to a
standard refurbishment is bigger than the saving variation between a standard
refurbishment and an advanced refurbishment. In fact, national building stock
is often characterized by low energy performance and even the application of
basic energy renovations may provide significant increases in energy
performance and consequent reduction of CO2 emission (the case of Italy is
exemplificative of this trend). Thereby from an economic point of view it is
more convenient to apply standard refurbishment measures at the national
building stock than advanced ones that are the most expensive.
Figure 2.Comparison between annual energy saving potential by applying a standard refurbishment and an advanced one to the Danish, German and Italian building stock.
It was
highlighted that, even with standard refurbishments, energy saving over 45% can
be achieved. As a consequence of this big saving potential, suitable policies
to address energy retrofit actions of existing buildings are crucial.
Finally,
the quality of future model calculations will depend very much on the
availability of statistical data. For reliable scenario analyses, information
about the current state of the building stock and about the current trends is
needed. The availability and regular update of the relevant statistical data
will be an important basis for the development of energy strategies in the
building sector.
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