ENERGY EFFICIENCY PLANS IN SLOVENIA

by Nika Jutraž &Slovenian Comenius group

Vižmarje Brod Primary School

SITUATION IN SLOVENIA

Slovenian government has offered financial assistance (subventions) and co-financing for alternative ways of heating homes, that is, for energy efficient ways of heating.

Energy efficient houses are passive houses. Therefore such financial assistance has been offered for constructing such a house.So let us introduce you to our study on passive houses.

WHAT IS A PASSIVE HOUSE?

Passive house is energy-efficient construction, it is construction of the future. The concept of the passive house represents the highest energy standards.The passive house and very good low-energy house offer maximum comfort and minimal costs of energy. In economical house the costs of construction are 10 – 15% higher, costs of living are 75 – 80% lower as in usual house.The passive house is well insulated and air-tight building. It is mainly heated by passive solar gain and by internal gains from people, electrical equipment, etc. Energy losses are minimized.

Kinds of energy economic houses

• USUAL HOUSE (energy consumption is more than 70

kW/m2 per year)• ENERGY STANDARD BUILDING HOUSE • ECONOMIC HOUSE • LOW-ENERGY HOUSE • PASSIVE HOUSE• NO-ENERGY HOUSE • PLUS ENERGY HOUSE• ENERGY INDEPENDENT (SELF-SUFFICIENT) HOUSE

DIFFERENCES BETWEEN USUAL AND ECONOMIC HOUSE

Economic houses are carefully designed, well insulated, maximize air-tight, with as few as possible thermal bridges. For heating they use renewable energy from environment.Each "spare", "bio" and "eco" material must be properly installed and it must combine with other materials. The criterion of economy is the annual primary energy consumption per square meter. If usual house uses up to 10-25 l of oil on square meter annually, then economic house uses up to 3-5 l and passive house less than 1,5 l per year.

DIFFERENCES BETWEEN USUAL AND ECONOMIC HOUSE

USUAL HOUSECONSUMPTION 10 – 25 L OF OIL / m2 PER

YEAR

ECONOMIC HOUSECONSUMPTION 3 – 5 L OF OIL / m2 PER

YEAR

THERMAL BRIDGES - balconies insulated badly or uninsulated, connected with construction - formation of thermal bridges - the house has extensions, dormer windows ...

- balconies hanged, separated from the construction - the house is designed very simple, the outside surface of the walls is as small as possible according to the volume of the interior

AIR TIGHTNESS

- slots between the bricks are not tight- contact between the wall and windows is bad - windows and front door don’t tight

- quality realisation of construction provides the required degree of air tight- super-insulated doors and windows

DIFFERENCES BETWEEN USUAL AND ECONOMIC HOUSE

THERMAL LOSSES - airing by opening windows, warmth is being lost - insulating envelope of the building is too small

- forced ventilation (always fresh air) - insulating envelope of the building is correct, loss of warmth is minimal

THERMAL PROFITS - no - the energy of sun is exploited with

large windows on southern side and fewer windows on northern side

SOURCES OF PRIMARY ENERGY- it uses primary energy (gas, petroleum)

- beside electricity it uses renewable sources of energy (sun, air, water, land)

WAY OF HEATING - heating with radiators - heating with heat pumps

DIFFERENCES BETWEEN USUAL AND ECONOMIC HOUSE

USUAL HOUSE ECONOMIC HOUSE

cistern for oil/ gas no

stove for oil/ gas or solid-fuel stove heat pump, solar collectors

chimney no

radiators floor/ ceiling/ wall heating

air conditioning no / cooling through the heating

system no ventilation system (use of waste heat)

DIFFERENCES BETWEEN USUAL AND ECONOMIC HOUSE

USUAL HOUSE ECONOMIC HOUSE

usual windows well insulated windows

usual front door well insulated front door

windows can be anywhere maximum window areas are on southern side, as little as possible on northern side

orientation of house is not important orientation of house to south

a thin layer of insulation against the ground, round outside walls and on roof

thicker layer of insulation

PASSIVE HOUSE CONCEPTS AND STANDARDS

PASSIVE HOUSE

The Passive house is not an energy performance standard, but a concept to achive highest thermal comfort conditions on low total costs. Passive houses do not require active heating system. In winter a comfortable temperature is achieved without a special system for central heating and in summer without air-conditioning systems.

Passive house is only low energy building. In passive house we can live as in any normal house. Higher living standards are provided with technical improvements in good thermal insulation and in-house technique.

The building is situated of its axis and follows the daily movement of the sun, Heliotrope, Freiburg, Germany

PASSIVE HOUSE

HEAT LOSSES = HEAT GAINSHEAT LOSSES = HEAT GAINS

HEAT RECOVERY OF PASSIVE HOUSE

HEAT LOSSES

The building is losing heat in two ways: through the envelope,

• with ventillation (the exchange of air between the building and the surrounding area through the windows and through the gaps).

HEAT GAINS

Heat gains are very important and they are from various sources:

• the solar radiation through the windows (so called passive solar energy), the energy of the electricity supply, which is converted into "internal heat sources" in the building. This adds to the heat radiated from persons inside the building.

MAJOR FEATURES OF ARCHITECTURE DESIGN

• SAVING OF SOLAR ENERGY

In the building the heat is stored in order to use it later, when solar irradiation is no available. Because of this the need of heat is reduced.

• ORIENTATION

The correct orientation of the building allows yield of solar radiation. In summer the south facade is shined less than the east and west facade, but in winter the south facade is shined more than east and west facade. South facade is much more suitable for the use of solar energy.

MAJOR FEATURES OF ARCHITECTURE DESIGN

• FORM OF BUILDING

In a passive house it is very important that the external surfaces are in relation to the volume of the building as little as possible. The relationship between surface area and volume is expressed by form factor, which should be close to 1.00, this is when the object is compact and simple. Especially favorable factor has the building with square and round forms.

MAJOR FEATURES OF ARCHITECTURE DESIGN

• THERMAL INSULATION

Thickness of thermal insulation depends on the composition of the wall and is 25-40 cm. It is very important that thermal-insulative layer goes on continuously all around the house and overlaps frames of windows and doors, which are also the thermal insulation.

• TECHNOLOGY OF CONSTRUCTION

For the construction of passive houses they mainly use solid and lightweight construction. The most widespread method of construction is masiv construction from block of brick, brick block, filled with perlit and block from the light concrete. Outside insulation must be thick enough. The most frequently used material is wood.

EXAMPLES OF ECONOMIC AND PASSIVE HOUSES

SOURCES AND REFERENCES:

• http://www.passiv.de/

• http://www.pasivna-hisa.com/

• http://live.pege.org/2005-plus-energy-village/

• Delo, annex Delo in dom, 24.09.2008