Embodied Energy in Buildings - Solar Thermal | IEA-SHC

Transcription

Dipartimento dell’Energia
Prof. Maurizio Cellura
Universitàdi Palermo
Embodied Energy in Buildings
Prof. Maurizio Cellura – Dipartimento dell’Energia Università di Palermo
Ph. +39-091-23861931; e-mail: mcellura@dream.unipa.it;
Building Energy Life Cycle Assessment
Life Cycle Approach
 the Life-cycle approach aims to the computation or evaluation of all the
input and output flows that occur into the product cycle, from the extraction
of raw materials to the final disposal.
 the approach has been standardized by the Life Cycle Assessment (LCA)
methodology in the standards of series ISO 14040.
 The environmental Impact are generally synthesized into global energy
and environmental idexes as:
- GER – Global Energy Requirement
- GWP – Global Warming Potential
- Total hazardous and not hazardous wastes
-…
Life Cycle Approach: buildings
Raw materials
Construction
Energy
Use
End-life &
disposal
Materials
Maintenance
 Full cycle should be considered
 Normally analysis are restricted to
in order to have a global “view” of
the building performances
the use phase, and mostly only on the
energy consumption assessment
Life Cycle Approach: buildings
Partial and side analysis are generally developed because the aim to give to
the consumer information about final energy consumption and other
consumables (mainly addressed to economic considerations on the working
phase)
The LCA is furthermore basic for the future
The new approach of the European Union legislation is, instead, to focus the
development of the building legislation
attention to the global approach, because it avoids wrong actions whose effect is
(energy
certification
only to shift the impacts
from
one life-cycleof
stepconstruction
to another.
or the Ecolabel applied to the buildings)
For example, the use of some
Raw materials
materials instead of others, could
reduce the energy consumption during
the use, but on the other side to
increase greatly the problems during
the building dismantling (as asbestos)
End-life &
disposal
Life Cycle Approach and Ecodesign
The future legislation and directives will more and more focus on the
ecodesign of products, and buildings in particular
In fact the European Integrated Product Policy
(IPP) supposes that “once a product is
commercialized, there are few opportunities to
improve their energy and environmental
performances”
EcoDesign
Introduction of environmental life-cycle
consideration in the Early design processes
Life Cycle Approach: advantages
Assessing, on the basis of a internationally agreed scientific procedure, the
components and the life cycle steps that are responsible of the most significant
environmental impacts
Identifying the most efficient and cost effective options to increase the
environmental performance of the building, more desirable to consumers
Assessing the company's operations and production processes to identify
opportunities for efficiency improvements, while reducing financial costs
Reducing greenhouse emissions and other environmental burdens throughout
every life-cycle step, in accordance with national and international laws and
agreements
Utilising the LCA results as the basis to develop an Environmental Management
System (EMS) or to obtain environmental label and product certifications
Comparing the performances of replaceable products in terms of environmental
performances or life cycle costs
Life Cycle Approach: disadvantages and problems
Lack of information: difficulty and shortage of consistent, verified and reliable
data
Data collecting is often a time consuming, difficult and expensive process
Lack of expertise: inadequate number of analysts able to proceed in the
assessment
Tools for the environmental design of building are often simplified, with
restricted available information, not related to the design not adequate for the
complex design process
Specific tools for LCA are instead often too difficult and not intuitive for
designers
Legislation is often inadequate, pointing only on requirements about the use
phase, and not stressing or inducing to life-cycle considerations
LCA of building: Benchmark
Distribution of house
types in EU-19
Anyway, Nordic buildings are generally
characterized by higher construction
standards and the number of buildings is
relatively small compared to countries of
the central and southern Europe
Eurostat, 2005
Life cycle impacts of all building types, comparing new building types
(blank symbols) and existing building (full signs)
LCA of building: Case Study
Similar trends are observed for the other
environmental impacts
POCP
ODP
AP
EU
[kg C
H4 eq/(m2 a)]
2 2a)]
GWP
[kg CFC11eq/(m
2 a)] [kg SO2 eq/(m2 a)]
[kg
PO
eq/(m
2
4
[kg CO2 eq/(m a)]
GER
Consumi energetici
specifici degli edifici
Comparative assessment for Swiss
constructions
It was estimated that the construction sector
is responsible of the consumption of about
50% of the primary energy in Swiss.
GJ/(m2 anno)
LCA of building: benchmark
1,6
M ateriali e costruzione
1,4
En. elettrica
1,2
Riscaldamento-Acqua
calda
1,0
0,8
0,6
0,4
0,2
0,0
Residential
Residenziale
(multi
house)
(multifamiliare)
Residential
Residenziale
(single
house)
(monofamiliare)
Offices
Uffici
[Zimmermann et. al., 2005]
Specific average energy consumption for different building typologies are: monofamiliar houses resulted the most energy consuming (1.5 2GJ ), followed by multim year
familiar houses (1.15 2GJ ) and offices (0.82 2GJ ).
m year
m year
Consumptions are mainly related to the indoor air-conditioning and sanitary warm
water demand (50%-70% of the global consumption), and to the production of
building materials (10% - 20%).
Sixth semi-detached house typologies
commonly employed in the central Europe,
with a living surface are from 176 m2 to
185 m2, have been analysed, supposing an
average useful life of 80 years.
12
10
[10 3 GJ]
Comparative study among different
residential buildings in a study
funded by the European Commission
Consumo energetico globale
(Vita utile : 80 anni)


8

6
4
2
0
R
A
B
C
D1
D2
E
Tipologia di abitaz ione
[EC, 2003]
It is shown that respect to a common reference building, the adoption of high
efficiency design solutions (with better insulations, high efficiency plants, low energy
materials, etc.) sensibly decrease the global energy demands. Global primary energy
consumption can sensibly vary from 6 ∙ 103 GJ to 12 ∙ 103 GJ.
Worst performances are generally related to bad insulated construction or to the use of
electricity for the building heating.
Analysis of performances of
buildings in Sweden
[Thomark, 2003]
Improving the energy and environmental performances of buildings, the
incidence due to consumption during the Production and Maintenance of the
building is growing, up to represents almost 40%- 50% of the building GER.
A detail of a good performing
building
The analysis included the energy
for material’s production (initial
materials), building installation
(spillage) and maintenance and
replacement (renovation), compared
to the energy consumption due to
heating
[Thomark, 2003]
the energy consumption due to embodied energy of materials could be
sensible decreased by employing recycled materials and about 35%-40 % of
the building embodied energy can be saved through the recycling.
The Dipartimento dell’Energia (ex DREAM), joined the projects research
“Genius Loci” concerning the role of building sector into global greenhouse
gases emission in Italy.
The research included a life-cycle energy performances of constructions
Main aims of the LCA study were:
to evaluate the global environmental impacts of exemplary single-familiar house
to assess peculiarities of houses into the Mediterranean area (mostly the available
references are related to North and Central Europe case studies)
to locate components that are responsible of largest impacts (key issues)
to assess incidence of each life-cycle steps and, in particular of phases generally
not adequately investigated (incidence on the global environmental balance of
construction materials, maintenance cycles, transports, etc.);
to focus the attention on components that are responsible of significant impacts in
a prospective of an environmental design of the residential buildings
The case-study house can be considered as a representative Italian construction of
the Mediterranean area.
The house (108 m2) is located in
Palermo (Sicily) at 270 m. above the
sea level, and is occupied by a three
member family.
The studied area is characterized by:
 a temperate climate, with mild winters and hot summers;
 no neighboring constructions that modify the direct sun radiation of the case
study building;
 a typical residential area;
The
has been
built
in the last decade and it is characterized by:
LCAbuilding
of building:
Case
Study
 reinforced concrete pillars and body bolsters;
 external walls include 20 cm bricks with a 9 cm cavity filled with
insulating expanded vermiculite;
 wooden
double-glazed
insulated
windows;as
The
building can
be considered
a relatively modern
following
the prefabricated
actual standard
 floors construction,
(20 cm width), designed
with perforated
brick and
reinforced
concrete and
rafters;with average solutions for the energy
performance
 roof constituted
by aimproving.
wooden structure with composite materials and
clay roof tiles cover;
Theplaced
case onstudy
is representative
of the
basement
a reinforced
concrete structure
and average
a layer of cave
construction techniques.
crushed stones;
 water proof barriers realized with bitumen;
 Liquid Petroleum Gas boiler as heating system
radiators and insulated steel pipes.
with steel radiant
The LCA of a building have been developed according to the following scheme:
1.
Analysis of design plants: collection of structural information and calculation
and assessment of the quantity of used construction materials;
Qualitative and quantitative analysis of building components including the main
construction materials and the main equipments
Analysis
of building
components: technical sheet of building components
was
analyzed
technical
have beenplanimetry
analysed in order
documents,
and to detail their composition and performances;
structural
of case and
studytransports, the use of construction machineries,
Analysis ofdatamaterials
building.
installation steps;
2.
It
B
PORTICATO
m q. 15,90
LETTO
mq . 18,40
WC
mq . 7,20
L ETTO
mq. 1 2.50
Detail
of main construction
materials
and have been consulted in order to acquire
3. Reference
survey: LCA
databases
components
information regarding the eco-profile of construction materials, components
and plants;
DISIMP.
mq. 1 0.60
A
POR TIC ATO
mq. 21 ,30
SOGGIORNO
mq. 41,75
C UC INA
PR ANZO
mq . 19,25
B
PIANTA
A
4. Inventory of construction phase: A similar mono familiar house in
construction has been studied, in order to estimate main impacts due to
construction machines and transports;
Reference analysis to collect information regarding the construction materials and
plant’s components.
5.
Use phase: electricity, LPG
and water
consumptions
of the case-study
It was
analyzed
the Construction
phase of house
similar
have been monthly monitored
for two years.
mono-familiar
house in the same area.
Detailed analysis of the use phase, computing the yearly energy employed for
consumption
Itfood
was cooking,
submitted
a questionnaire at
lighting, air conditioning, Average
sanitary annual
water heating,
etc.;
the builders considering:
6. Maintenance: the consumptions due to materials,
the renovation of plants and house
submitted a questionnaire
components have been calculated.It was construction
machinery,
about a survey of habits of the
dump
site,
of maintenance
operations.
We
referfamily
to
experiences
previous
7.Analysis
Demolition
and Disposal:
the life-time
of
theon
building
supposedbuildings
to be 50
house’s
use ofofisequipments
demolition,
and years.
to local and national statistics
and appliances
transports,
That include the energy and the environmental
etc.impacts related to the building
demolition and the exhausted materials disposal or recovery
It is possible to observe that:
The GER amounts to about 4.58
·103 GJ of primary energy.
Yearly specific consumption per
unit of area is 0.63 GJ/(m2 year)
less than half of other European
referenced value (1.50 GJ/(m2 year).
Use phase is responsible of 75 %of
the GER;
The incidence of the construction phase is considerable, moving about 20% of
GER, while the other phases are responsible of about 6% of the GER.
The GER consumption is mostly represented by non renewable energy sources.
Small quantity of renewable energy are related to the use of electricity, following
Italian power energy generation mix, and to the utilization of renewable materials
into the construction components.
It
is possible
to observe
that:
Detail
of energy
life-cycle
consumption during the use phase
The largest impacts are due
to the use of electricity.
The utilization of electricity
is dominant, followed by the
use of LPG for house winter
heating, warm water demand
and cooking.
The consumptions for the winter heating and for the sanitary warm water demand
are almost the same.
From a more detailed analysis, it was assessed that the energy consumption for
summer air conditioning is about 20% of global summer electricity input,
corresponding to about 7% of the yearly consumption, as about 157 GJ of primary
energy consumption during the life-cycle of the building. This low consumption is
also related to energy-saving habits of occupants.
The energy and the environmental impacts have been assessed on the basis of
declaration scheme and characterization factors utilized in the Environmental
Product Declaration system:
Data regarding each life cycle step have to be processed in order to obtain global
environmental indexes that synthesize the environmental performances.
Life Cycle Impacts
The
These
impacts
figuresfor
show
eachthat:
phases are:
Use is the phase that causes the largest impacts. It is responsible, for each
environmental index, of about 50-70% of the global impacts;
Maintenance and Demolition are comparable and not insignificant although always
below 10%;
Concerning ODP, impacts are almost negligible. The highest incidence is related to
the production and transport of construction materials;
The energy classification of the case study was carried out by the application of
the main italian software ( Bestclass - Docet).
Primary energy demand for heating
[kWh/(m2 year)]
124,44
ENERGY CLASS “E”
23
The performance analysis has highlighted the critical performance of the building.
Retrofit Actions:
To decrease the U value of walls (Expanded polystyrene EPS) [Scenario A];
Of roof (rock wool panels); [Scenario B];
Of the ground floor (Extruded polystyrene insulation boards (XPS) - [Scenario
C];
Improving the efficiency of the heating system by replacing traditional
boilers with high efficiency condensing boiler [Thermal plant scenario];
24
kWh/(m2 year)
2 year)
Reduced energykWh/(m
demand
for heating[%]
Scenario C (insulated floor) best performances
Reduction of the Epi (-45.84%). This action
are not able to reach the compliance with
the regulatory limit of Epi.
Epi limite
Thermal plants and B Scenarios (condensing boilers and insulation of roof) are less
significant, while significant is the scenario A (vertical walls insulation -27%)
The synergistic action of all retrofit actions (Scenario E) can significantly improve the energy
performance (reduction of 86, 23% of the Epi and compliance with standard limits)
25
Results
Energy demand for heating
[kWh/(m2 year)]
22,35
ENERGY CLASS “A”
26
The aim of the study is to evaluate and quantify the energy and environmental
impacts of retrofit, according to the following scenarios and functional units:
 Scenario A Insulation of walls (224 m²) with EPS ;
 Scenario B Insulation of roof (142 m²) (rock wool panels);
 Scenario C Insulation of ground floor (109 m²) with XPS;
27
Total energy consumption for the retrofit
is 69,767 MJ
98.6% non renewable energy
1.4% (958 MJ) from renewable sources.
The energy consumption for EPS
production is (5.1164 MJ) 73.33%
transport is the less relevant
(502 MJ) - 0.7% of the total.
Specific energy demand per unit area of the building is equal to 636 MJ/m2
28
The total energy
consumption is 38,033 MJ.
96.8% (36,827 MJ) is
from non-renewable sources,
while the 3.2% (1,206 MJ) from
renewable sources.
The
material
that
requires
greater
its production is wool 12,359 MJ (32.5%).
use
of
primary
energy
for
Other materials used (the wooden support strips, the panels of plasterboard lining and steel
anchors) have smaller but significant impact energy (20.6%, 19.4% and 13.7% respectively) .
Specific energy demand per unit area is equal to 437 MJ/m2
29
It involves a total energy consumption
of 110,67 MJ, of which 96.99% (107,33
MJ) from non-renewable sources, while
the remaining 3.01% (3333 MJ) from
renewable sources.
The production of tiles
needs 67,684 MJ of energy (61.16% of
the total) (the raw
material with the greater impact.
XPS panels needs 28,275 MJ of primary
energy (25.55%
of the total). The impact energy of the
other materials is negligible.
Specific energy demand per unit area of the building is equal to 1008,8 MJ/m2
30
The implementation of all Retrofitting
Scenarios involves a total consumption of
primary energy of 218,591 MJ of
which only 2.5% from renewable energy
sources
The insulation of the floor (Scenario C)
is the intervention with greater impact;
energy consumption
amounted to 110,666 MJ of energy,
equivalent to 50.63% of the total
energy used for all interventions.
Scenario A
Scenario B
The consumption of electricity for retrofit
and raw material transportation are
negligible compared to their production.
The second intervention most impactful is
insulation of walls (Scenario
A) with 69,767 MJ of energy
Scenario
C (equal
Scenario
D
consumed
to 31.92%)
followed by
scenario B - insulation of roof (38,033MJ of
total energy equal to 17.40%)
31
The
consumed
the retrofitting
is 218.632%
GJ, of(6%);
is greater than
that it
The energy
construction
phasefor
represents
approximately
total itconsumption
making
used
for the than
demolition
andof building
comparable
to the maintenance of the
more significant
the Ecoprofile
at Pre-retrofitting.
building (respectively 96 and 276 GJ)
The specific energy consumption per unit area of the building (as a result of this
Even the scenario post-retrofitting the use phase is 2 the most energyreduction in Use phase) decreased from 0.85 to 0.54 GJ / (m year) with significant
consuming(approximately 49% of total consumption),
but less significant than in thepre148,55
improvement Ecoprofile of building.
retrofittng Scenario (72% of the total). The implementation of retrofitting leads to a
reduction in the consumption of this stage of 56.5%
ECOPROFILE
ECOPROFILE of
of Building
BuildingPre-Retrofitting
Post-Retrofitting
32
GJ
Comparison between "Use" and "Construction" phases for pre-and
post-Retrofitting scenarios
33
The results of the LCA study of a mono-familiar Mediterranean house showed
that:
 The large incidence of the use phase in almost all the considered energy and
environmental indexes (about 75% of the GER index).
 Other phases, as in particular the use of construction materials and components,
have a significant incidence (from 20% to 40%).
The GER consumption is mostly represented by non renewable energy sources.
For all environmental indicators the use is the most impacting (for the ODP
Construction phase affects more)
The global and specific energy indexes of the studied building are lower than
reference data related to other case-studies in the central and northern Europe .
 The house has good energy performances after RF (mediterrenean climate
conditions sensibly decrease the heating consumptions); user behaviour
increases the energy saving;
The the main source is the electricity, followed by the use of LPG for
heating, domestic hot water and cooking.
A large part of the consumptions are related to the use of households and
other electrical equipments. The eco-profile of a house is strictly depending
from the user behaviour
Retrofit
measures
would
greatly
improve
the building ecoprofile, reducing energy consumption of the management
phase over 50% (86.5% for the Epi - Building Energy Class ”A”).
To increase the energy efficiency of buildings due to the implementation
of retrofit measures implies a higher incidence of the construction
phase (from 20 to 32% of the GER for before and after scenarios ). It is
therefore important that the ecodesign will play a paramount role in the
development of future buildings design (use of eco-friendly materials and
technologies)
LCA of building: Building Management
It is fundamental furthermore the relationship among life-cycle
evaluations and building management
Benchmark analysis and
environmental databases
Design solutions
for new buildings
EcoDesign
Information about
plants, energy sources,
best practices
Operational
Retrofit
Retrofit aspects are often
neglected into tools and
their importance is uderestimated
LCA of building: Building age
Retrofits of building is a more and
more key-issue, being the old
buildings largely dominant in the
market.
Thanks to opportune retrofits actions
it can be possible to improve
significantly the performances of the
constructions and to contribute
therefore to the sustainability
objectives.
About 60%-80% of the building in the EU is older than 25-30 years.
Particularly old the building stocks of Italy, Germany and UK
LCA of building: Retrofit
The Dipartimento dell’Energia has been involved into the “BRITA in
PubS” project
Bringing Retrofit Innovation to Application in Public Buildings
The project aimed to draw
guidelines for retrofit action,
best practices and operative
suggestions
Different buildings in different
climate regions have been used
as operative case studies
Seven case studies have been assessed in:
Life-cycle energy evaluation as been used to assess the adopted initiatives and to
locate, for example, the solutions with the better improvements margins and benefits
Stuttgart: Filderhof (nursery home)
Brno: Brewery
Plymouth: College house
Prøvehallen : school
Borgen: Community Centre
Borgen: Community Centre
Vilnius: University
Structure of the analysis:
The following elements have been included in the analysis:
•Construction materials an components employed during retrofits;
•Main components of traditional and renewable energy based
plants;
•Impacts related to construction works.
The aim of the research was to assess the “environmental quality”
of the engaged actions and, in particular:
•to locate the components and the phases that are responsible of
the greatest impacts;
•to trace a balance of the energy and environmental benefits and
drawbacks concerning the retrofit actions.
Structure of the analysis:
BRITA Partners have been asked to collect and report information
Questionnaires
several
sheets concerning
the following
elements:
about theirincluded
projects
according
to a questionnaire
prepared
by the
LCA research team.
Building materials used for retrofit work, with particular attention to thermal
Questionnaires included both information from the design stage
insulation
and information
collected
during the retrofit implementation. The
Window
typologies and
characteristics
Lighting
equipmentwas intended to guide partners through the data
questionnaire
Innovative
andand
traditional
heating the
systems
collection
to coordinate
LCA results as much as possible.
Photovoltaic (PV) and solar thermal collectors
Ventilation systems
Pipes and ducts
Energy consumption of machinery utilized during retrofit work
Waste produced during construction works.
General Assumptions :
This analysis represents a simplified LCA study concerning the
main benefits and drawbacks related to building energy retrofits.
Compared to the great detail of the previous case study, here data
availability was not so accurate and did not allow the same
procedure.
Anyway the scopes were here different, aiming to a rough
assessment of key issues, and aiming to a flexible instrument able
to drive the choices and the evaluation of the retrofit alternatives
Impact due to construction materials refers to average European data as
presented in the international LCA database (quality of assessment: very good)
Impacts of windows and other building components were assessed by similar
construction typologies included in the environmental databases. Data have
been modified proportionally to their surface (quality of assessment: medium)
Impacts of PV and solar plants were assessed from similar data recorded in the
databases and have been modified proportionally to their surface or installed
power (quality of assessment: rough estimation);
Impacts of heating and ventilation systems have been assessed from
information concerning similar plants (quality of assessment: rough estimation);
Impact due to wastes management refers to disposal processes used in average
European contexts (quality of assessment: medium).
Particular critical are assessed data and estimated data, as assumptions
concerning the useful life length:
Lighting equipment: 3 years;
Small wind turbines: 15 years;
Heating and ventilation plants: 15 years
Solar thermal collectors and plants: 15 years;
PV plants: 20 years;
Building retrofit: useful lifetime 35 years.
Of course these assumptions can not be verified “a priori” but only after the
building will reach its end-life
Table 3: Main Inputs and Outputs of the retrofit action
Example:
Material/component Quantity
Unit
Reference
Materials for insulation and renovation
Roll roofing layers
(bitumen)
Expanded
polystyrene (EPS)
Expanded clay
Stone wool
Vilnius: University
The actions involved mainly the substitution of
old wall insulation with a new and a better
performing envelope, and the installation of
high efficiency windows with selective glasses
(low-e) and low thermal transmittance
The assesses energy savings have been 220,589
kWh/a due to high-efficient windows and
236,672 kWh/a due to insulation of roofs and
facades
Panel (Glued
laminated timber)
Panel ( Particle
board, cement
bonded)
Patterned daub
(base plaster):
Wood board
Profiles (Steel)
12.6
ton
[13]
8.65
ton
[8]
27.7
4.18
ton
ton
[14]
[14]
5.2
m
3
[14]
3.9
m
3
[14]
110.2
ton
[14]
1.72
ton
1
ton
Windows
[[13]
[9]
PVC framed
windows
1001.2
m
Aluminium framed
windows
257.1
m
Electricity
Diesel oil for
construction
machines
Waste production
and disposal
(aluminium, wood,
glass)
2
[7; 8; 14]
2
[7; 9; 13; 14]
Other
1547
kWh
[7]
4.5
m
3
[14]
43.8
ton
[14]
Example:
5.000
4.500
4.000
GER [GJ]
3.500
3.000
2.500
48.4 %
45,5 %
2.000
1.500
1.000
500
5,7 %
0.4 %
Construction
Wastes
treatment
0
Windows
Insulation
Total
The greatest impacts are due to the manufacture of materials. In particular,
insulation and window substitution are responsible each one of about an half of the
global consumptions.
Construction phase represent about 5% of the GER.
Disposal has a low incidence
Example:
Table
ofof
environmental
Impacts & Benefits
Table4:5:Comparison
Comparison
two window typologies
Index
1m
GER [TJ]
GWP
GER[ton
[GJ]CO2-Eq.]
ODP
[kg ]CFC11]
GWP [kg
CO2-Eq.
Acidification [kg SO2]
Eutrophication [kg PO4]
2
Benefits
of aluminiumImpacts2 Net benefits
1 m of PVC window
71.46
4.36
67.10
window
4069.92
217.32
3852.60
3.6
1.2
0.40
0.16
204.7
48.10.24
3206.0
1253.18
1953.52
333.62
111.07
222.55
Environmental
Benefits largelyimpacts
overlook
due
thetoimpacts.
the building
In particular,
retrofit and
the the
primary
benefits
energy
related
saving
haveis
one order of magnitude larger than
been
thecompare.
overall energy consumed during each life
cycle steps of the retrofit materials.
(Environmental benefits have been assessed by calculating the avoided emissions that a
conventional
plant should
have produced.
of heating
plants
Regarding gas
theheating
two window
typologies,
the PVCSpecific
and theemissions
aluminium
framed,
a
refer
to
specific
database)
comparison of specific environmental impacts have been carried out. It resulted
that the aluminium structure causes impacts 3÷4 time larger than the plastic ones
GER
GWP
NP
AP
ODP
POCP
E-PT
EM-PT
ER
[kWh]
[ton CO2-Eq.]
[kg PO4]
[kg SO2]
[kg CFC11]
[kg C2H4]
[year]
[year]
0
Vilnius
Stuttgard
44.898
10
7
56
0,001
6
0,5
0,6
58,0
Proevehallen
399.550
69
53
556
0,03
63
0,6
0,5
37,1
Plymouth
Hol
Index
Brno
Comparison of different
case studies
26.653 914.888 486.983 1.215.899
7
180
101
217
2
91
46
111
32
802
629
1.253
0,07
0,02
0,04
0,16
4
297
105
151
0,7
1,3
0,3
2,0
0,9
1,1
0,3
1,9
22,7
8,9
40,5
16,3
case studies
In order to compare the case studies, the results have been
summarised into 3 synthetic indexes
The Energy Payback Time (EPT), that is defined as the time during which the system
must work to harvest as much energy (considered as primary energy) as it required
for its production and disposal. The harvest energy is considered as net of the energy
expenditure for the system use
The Emission Payback Time (EMPT): the global impacts during the life cycle and the
saved emissions can be summarised by the Emission Payback Time (EMPT). It is
defined as the time during which the avoided emissions thanks to the employment of
the retrofit actions are equal to those released during each life-cycle step of each
component itself.
The Energy Return Ratio (ER): it represents how many times the energy saving
overcomes the global energy consumption
case studies
Payback Times
3
Energy Payback
Emission Payback
[year]
2
1
us
ln
i
Vi
St
ut
tg
ar
d
Pr
oe
ve
ha
lle
n
Pl
ym
ou
th
Ho
l
Br
no
0
The analysis showed significant energy and environmental convenience of the
accomplished retrofits. In particular, the energy and environmental payback times
that resulted were very low, with values varying from 0.3 to 2 years. This means that
in a relatively small time period, the global energy and environmental investments
are fully repaid by the obtained benefits.
Payback Times
3
case studies
Energy Payback
Emission Payback
[year]
2
1
us
ln
i
Vi
St
ut
tg
ar
d
Pr
oe
ve
ha
lle
n
Pl
ym
ou
th
Ho
l
Br
no
0
25
Energy Saving [MWh]
Notes: the largest benefits are generally
related to the insulation of the buildings:
5
high efficiency20windows, mineral wool, and glass wool sheets6 (insulation allows
great energy savings over a long period with a relatively short life-cycle impact).
15
1
Even renovation of heating plants and lighting systems produces large benefits.
10
4
In contrast, the5 use of renewable energy had lower benefits due to the low
productivity of plants,2 with outputs sometimes lower than expected at the design
stage.
0
3
0,0
0,2
0,4
0,6
0,8
1,0
GER [MWh]
1,2
1,4
case studies
Energy Return Ratio
60
50
40
30
20
10
us
ln
i
Vi
St
ut
tg
ar
d
Pr
oe
ve
ha
lle
n
Pl
ym
ou
th
Ho
l
Br
no
0
Results showed an average of about 30 times, with values generally higher than 10
times and an optimum close to 60 times
Prospectives

The current trend of advanced building design is going to the objective of
ZEB (Net Zero Energy Buildings) where the global energy balance is
draw

Missing specialised tools for the support of design in such direction
Specialised tools too difficult to manage for not
specialised and trained analyst

Tools available are in
fact characterised by the
following limits
Support tool too simplified for the design purposes
Reference Databases often with obsolete, or partial, or
not representative data
Short attention to the evaluation of possible alternative,
retrofits, and operating conditions (that play a
dominant role into life-cycle balances)
Prospectives

Designers are expecting global tools able to support the design process of
building into all the steps, including the choice of alternatives, the evaluation
of the quality of the projects, availability of up-to-date and representative
data, concerning not only the energy and the environmental aspects, but
every significant key issues of the design step
Tools should be able to update themselves
automatically, on the basis of European,
National and regional data
The main reference and common base for the future
development of LCA based tool in Europe will be,
for example, represented by the European Platform
on LCA
Other national and local data source could be linked,
in order to improve the set of alternatives
Tools should be able to correlate other
design steps with the assessment of energy
and environmental benefits/drawbacks
For example, modify into the choice of insulation
types or thickness could be related to the calculation
of repercussions of primary energy losses or
variations on the greenhouses emissions
Prospectives

Designers are expecting global tools able to support the design process of
building into all the steps, including the choice of alternatives, the evaluation
of the quality of the projects, availability of up-to-date and representative
data, concerning not only the energy and the environmental aspects, but
every significant key issues of the design step
Tools should be related to local conditions
For example, containing information about local
climate parameters and other significant design data,
that allow the designers to have a realistic view of
the performances of the building
Completeness of the archives concerning
design alternatives, building components,
plants, energy carriers, etc.
The comparison of different alternatives is basic for
a quality building design
Thank you for your
attention
University of Palermo
Ph. +39-091-23861931; fax +39-091-484425
E-mail: mcellura@dream.unipa.it

Embodied Energy in Buildings - Solar Thermal | IEA-SHC

Transcription

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