Transcript Ανάπτυξη των ΑΠΕ στην Ελλάδα

Laboratory of Heat Transfer and Environmental Engineering
Department of Mechanical Engineering
Aristotle University Thessaloniki
The European Directive on the
Energy Performance of Buildings
and the need for enhanced Thermal Insulation
Professor Agis M.Papadopoulos
Tirana, 07.04.06
The role of a building with respect to climate
and its inhabitants
A building’s design should aim to provide comfort to its inhabitants,
whatever the ambient conditions are.
The balancing
of climatic conditions
in the
indoor environment
can be implemented
either
through an energy
conscious design
or/and
by energy consuming
devices (HVAC systems)
Summer Sun
Rain, snow, etc.
Protection
Wind exposure
Decrease
Ventilation
Control to provide cooling and IAQ
Humidity
Disposal
Winter Sun
Temperature
Isolation from ambient
environment
Daylighting
Increase
Solar Radiation
Increase solar gains
during winter
Decrease solar gains
during summer
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Relation of indoor comfort and a building’s energy demand
A building’s design should aim to provide comfort to its inhabitants,
whatever the internal loads are.
Solar gains &
daylighting
Shading
Cooling
Natural
ventilation
Heating
Infiltration
Heat transfer
Lighting
Mechanical
ventilation Internal
gains
Comfort:
Thermal
Air quality
Lighting
Acoustic
………….
3
Indoor comfort and the human reaction
A building’s design should aim to provide comfort to its inhabitants,
keeping in mind the human needs.
4
Energy consumption in buildings
40% of energy consumption in the EU is in buildings of all kinds.
25% of CO2 emissions result from buildings.
Electricity consumption is expected to double between 2000 and
2020
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This is the main reason and philosophy behind…
The new
European Directive on the Energy Performance of Buildings
(EPBD) or 2002/91/EC
This is the main reason and philosophy behind…
The new
European Directive on the Energy Performance of Buildings
(EPBD) or 2002/91/EC asks for four main things:
- A detailed methodology to determine energy consumption
- Final and primary energy consumption statement
- Inspection of heating systems and air-conditioning systems
- Energy certification of buildings
EPBD: a systemic, generic approach
A holistic and integrated consideration of the building:
We determine the primary energy demand of the building!
EPBD: a systemic, generic approach
A whole set of new CEN standards to implement it
EPBD: a systemic approach towards reducing energy consumption
A four-phase approach
EPBD: New CEN standards on Thermal Losses Calculations
A typical construction practice in Greece. Up till now the
calculation of the transmission heat transfer coefficient was
calculated not taking into account the thermal bridges
H D   i Ai U i   k lk k   j  j
Thus, the transmission heat
transfer coefficient was
calculated according to
H D   i Ai U i
EPBD: New CEN standards on Thermal Losses Calculations
A new constructional approach will be required to cope with
the implementation of the new standards and the following
regulations.
According to standard ISO 14683 the
transmission heat transfer coefficient is
calculated by
H D   i Ai Ui   k lk k   j  j
EPBD: New CEN standards on Thermal Losses Calculations
6m
10 m
For the simple two
storey building with
the thermal bridges
R, B, C, F the new
calculation procedure
determines …
5m
R
B
C
F
EPBD: New CEN standards on Thermal Losses Calculations
… HD = 148.15 W/K
instead of
* It is noted that the calculations
were conducted for common
material properties and included
only the linear thermal bridges
(and not the point)
HD = 106 W/K
Thus, linear thermal bridges account for the 28.5% of the
total transmission heat transfer coefficient of the building.
Otherwise, the inclusion of thermal bridges in the
calculation increases the heat transfer coefficient of the
building by almost 40%.
EPBD: Indoor comfort and new CEN standard CEN/TC 156 WG 12
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Free-running buildings, line A
32
Heated or cooled buildings
C
o
Tc = 13.5 + 0.54 To
30
Neutral or comfort temperature
For not
air-conditioned
buildings
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A
26
24
B
22
20
18
Tn = To
16
14
12
-24 -22 -20 -18 -16 -14 -12 -10 -8
where
Τc is the thermal comfort,
and
Το the ambient air temperature
-6
-4 -2
0
2
4
6
8
10 12 14 16 18 20 22 24 26 28 30 32 34
Monthly mean outdoor temperature
o
C
EPBD: Indoor comfort and new CEN standard CEN/TC 156 WG 12
For fully
air-conditioned
buildings
EPBD: Taking care of real life conditions
Introducing the inspection of heating and A/C systems
EPBD: Certifying the energy performance of buildings
Who has to comply?
All new buildings
bigger than 1.000 m2
All public buildings
All buildings to be
sold or rented
And how?
Either as designed
Or as built
Valid for 10 years
EPBD: Certifying the energy performance of buildings
and setting the goals for an efficient policy
If 200 kWh/m2 is the average consumption of the current building stock (class C),
then 125 should be the aim for 50% of the buildings after 2005 (class A)
If 100 kWh/m2 is the average consumption of a good current building (class C),
then 75 should be the aim for 50% of the buildings after 2005 (class A)
EPBD: Certifying the entire performance
of the buildings’ indoor environment
EPBD: A partial success is not enough
Up till now, a building with poor thermal comfort conditions, due to the lack of thermal
insulation could be “improved”, by means of higher energy consumption.
Up till now, a building with poor indoor air quality could be “improved”, by means of
increased ventilation and, therefore, higher energy consumption.
Up till now, a building with high energy consumption could be “improved”, by reducing
the heating or cooling provided, and hence reducing thermal comfort.
This is no longer possible.
Buildings have to be “honest” to their users, and this officially certified.
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EPBD and thermal insulation
Thermal insulation is still the most economic and efficient way to design and construct
an energy thrifty building.
Insulation materials are the key tool in that sense.
This is demonstrated by the increasing thicknesses used in buildings,
which also reflects in the growing sales of the branch.
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EPBD and thermal insulation: The potential
The greatest potential, also for existing buildings, lies within the reduction of thermal
losses through the building’s shell – and also in the improvement of heating systems.
Exploitable potential 60 kWh/m2 a
.
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EPBD and thermal insulation: the case study
A real case study: 41 buildings in Northern Greece,
with a climate almost identical to Albanian zones 1 and 2.
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EPBD and thermal insulation: the case study
Energy consumption
with respect to the date of construction.
.
Heating and cooling consumption
with respect to the heated surface
25 .
EPBD and thermal insulation,
not forgetting thermal comfort
Thermal comfort conditions in winter are by and large good or acceptable –
yet the energy cost is very high. Without it, comfort would be poor.
In summer we have both problems: lack of comfort and high energy costs.
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EPBD and thermal insulation: The real saving potential
The average achievable saving on the average specific annual consumption
is some 40 kWh or 20% of the current condition.
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EPBD and thermal insulation: The economic aspect
The latest increase in energy prices is a good reminder of how short-sighted the policy of the last
years has been.
20% of the Greek population spends more than 10% of its income for energy – tendency rising!
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Had the measures been carried out, their reduced pay back period would now become apparent.
EPBD and thermal insulation: The problems
The unsuitability of the densely built urban environment
(An only partially existing problem)
Lack of legislative obligations and incentives, complex legislative
framework
Lack of financial incentives
(The two most frequently mentioned barriers)
Lack of proven expertise and qualified professionals
Unwillingness to abandon the ‘business as usual’ approach
(The two less easily acknowledged reasons)
Low energy prices (not anymore?)
Lack of energy and environmental consciousness
(The truly socio-political problems)
All points mentioned are result of a FORESIGHT study carried out in
Greek SMEs in 2004
EPBD and thermal insulation,
not forgetting the exploding air-conditioning demand
Estimated growth of Air Conditioning (cooling) in the EU (EECCAC study)
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EPBD and thermal insulation,
not forgetting the exploding air-conditioning demand
Estimated growth of Room Air Conditioning in the EU (EERAC study)
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EPBD and thermal insulation,
not forgetting the exploding electricity demand
In July 2005 the absolute peak monitored was 9,620 MW.
At the same time the cost for providing the ‘upper 600’ MWs, that are used only
for 20 days per year was estimated at something like 3,800 Euros / MW, compared
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to the 1,300 of the base load.
EPBD and thermal insulation,
not forgetting the exploding electricity demand
According to the Green Paper on energy efficiency (June 2005):
The production of an electric kWh costs on average 0,12 €
The production of an electric kWh peak load costs between 0,15 and 0,25 €
The cost of saving this same kWh is only between 0,026 and 0,039 €
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EPBD and thermal insulation,
not forgetting the exploding electricity demand
EPBD, thermal insulation and a rational, realistic policy
Average energy consumption is increasing rapidly, due to increased
thermal comfort demands, black and white appliances and electronic
equipment.
300
250
kWh / m2 a
200
150
100
50
0
Consumption
in 1985
Consumption Forecast 2005 Forecast 2005
(RUE)
(BAU)
in 1995
Space Heating - DHW
Lighting
A/C
Equipment
The most effective way to absorb this increase is
to exploit the saving potential in
space heating, A/C and DHW demand of new and older buildings.
EPBD, thermal insulation and a certain goal
This is the minimum aim that we must set,
in order to be able
to establish and maintain
high living standards
affordable by everyone.