The European Directive on the Energy Performance of Buildings and the need for enhanced Thermal...

The European Directive on theEnergy Performance of Buildings

and the need for enhanced Thermal Insulation

Professor Agis M.PapadopoulosTirana, 07.04.06

Laboratory of Heat Transfer and Environmental EngineeringDepartment of Mechanical Engineering Aristotle University Thessaloniki

22

VentilationControl to provide cooling and IAQ

Rain, snow, etc.Protection

HumidityDisposal

Wind exposureDecrease

Summer Sun

Winter Sun

Solar RadiationIncrease solar gains

during winterDecrease solar gains

during summer

DaylightingIncrease

TemperatureIsolation from ambient

environment

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)

33

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

InfiltrationHeat transfer

Heating

CoolingLighting

Mechanicalventilation Internal

gainsComfort:Thermal

Air qualityLightingAcoustic………….

Naturalventilation

44

Indoor comfort and the human reaction

A building’s design should aim to provide comfort to its inhabitants, keeping in mind the human needs.

55

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

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 approachEPBD: a systemic, generic approach

A whole set of new CEN standards to implement it

EPBD: a systemic approach towards reducing energy EPBD: a systemic approach towards reducing energy consumptionconsumption

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

Thus, the transmission heat transfer coefficient was calculated according to

iiiD UAH

jjkkkiiiD lUAH


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

jjkkkiiiD lUAH


R B C F5 m

6 m

For the simple two storey building with the thermal bridges R, B, C, F the new calculation procedure determines …


… HD = 148.15 W/K

instead of

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%.

* It is noted that the calculations were conducted for common material properties and included only the linear thermal bridges (and not the point)

12

14

16

18

20

22

24

26

28

30

32

34

-24 -22 -20 -18 -16 -14 -12 -10 -8 -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

Neutr

al

or

comfort

tem

per

ature

o

C Heated or cooled buildings Free-running buildings, line A

B

A

Tn = To

Tc = 13.5 + 0.54 To

where

Τc is the thermal comfort,andΤο the ambient air temperature

EPBD: Indoor comfort and new CEN standard CEN/TC 156 WG 12

For not air-conditioned buildings

For fully air-conditioned buildings

EPBD: Indoor comfort and new CEN standard CEN/TC 156 WG 12

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 buildingsand 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

2121

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.

2222

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.

2323

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

2424

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.

2525

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..

2626

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.

. .

2727

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.

2828

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!

Had the measures been carried out, their reduced pay back period would now become apparent.

The unsuitability of the densely built urban environment(An only partially existing problem)

Lack of legislative obligations and incentives, complex legislative frameworkLack of financial incentives(The two most frequently mentioned barriers)

Lack of proven expertise and qualified professionalsUnwillingness 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: The problems

3030

EPBD and thermal insulation, not forgetting the exploding air-conditioning demand

Estimated growth of Air Conditioning (cooling) in the EU (EECCAC study)

3131

EPBD and thermal insulation, not forgetting the exploding air-conditioning demand

Estimated growth of Room Air Conditioning in the EU (EERAC study)

3232

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 to the 1,300 of the base load.

3333


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 €

Average energy consumption is increasing rapidly, due to increased thermal comfort demands, black and white appliances and electronic 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.

0

50

100

150

200

250

300

Consumptionin 1985

Consumptionin 1995

Forecast 2005(BAU)

Forecast 2005(RUE)

kW

h /

m2 a

Space Heating - DHW Lighting A/C Equipment

EPBD, thermal insulation and a rational, realistic policy

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.

The European Directive on the Energy Performance of Buildings and the need for enhanced Thermal...

Documents

Transcript of The European Directive on the Energy Performance of Buildings and the need for enhanced Thermal...