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ZBAŠNIK SENEGAČNIK, M.
POTENTIAL ENERGY SAVINGS IN BUILDINGS
KOMUNALNA ENERGETIKA / POWER ENGINERING, 1
The energy efficiency of buildings is becoming increasingly important and represents a great energy-saving potential. Today it is possible to build a house that requires 10 times less energy for heating than it would have done a quarter of a century ago. This is known as a passive house. The passive house standard was created in 1996 in Germany and spread rapidly, first in Austria and Switzerland and then in other European countries. By the end of 2011 there were 39,390 passive houses in Europe, with the number predicted to grow to 143,000 by 2016. Passive houses have been built on every continent and are suitable both for moderate climates and for hot and cold regions.
A passive house demands a maximum of 15 kWh/(m2a) for heating. It has an extremely high-quality airtight thermal envelope, without thermal bridges, and features a controlled ventilation system with heat recovery. As a result of all these measures, specific heat losses (transmission heat losses and ventilation heat losses) in a passive house are less than 10 W/m2. The building therefore has such low heat needs that traditional heating systems are no longer necessary. Passive houses use a "warm air" heating system.
A passive house is an optimal house – with costs that are around 5% higher, its heat needs are at least three times lower than those of houses built in compliance with current legislation. This legislation will become even stricter in a few years. The Energy Performance of Buildings Directive (EPBD) and the Rules on Energy Use in Buildings (PURES) introduce the concept of the nearly zero-energy house, which will apply to all public buildings from 2018 and to all other buildings from 2020. Precise definitions of permitted energy use are not yet available, but the values will undoubtedly be very similar to those of the passive house, if not even lower. The components and know-how already exist, so there is no reason for less ambitious requirements.
The passive house standard is suitable for new buildings and renovations, for different construction technologies and for all purposes of use: single-family and multi-family dwellings, business and manufacturing premises, schools and nurseries, museums, churches, recreational facilities, prisons, etc. As well as residential buildings, offices, schools, etc., a number of centuries-old listed buildings have already undergone renovation to passive house standard.
Almost 500 energy-efficient houses were built in Slovenia between 2008 at the end of 2012. Just over 160 of these are passive houses. This high number is due in part to grants provided by the state via the Eco Fund. The majority of passive houses are new buildings. Despite the incentives offered, the number of renovations is currently very small. Their number will shortly have to increase, however, in order for Slovenia to be able to meet its 20-20-20 by 2020 obligations. We need to be renovating 3% of the country's building stock every year, since the number of new buildings in Slovenia is too small to enable us to meet the requirements.
Reducing the amount of energy used to heat buildings therefore represents a considerable proportion of energy savings in the near future. Buildings need energy throughout their life cycle – for the production of raw materials, manufacture of building materials, construction, operation and, finally, removal. Throughout most of history, it is the operation phase that has accounted for the largest percentage of energy use. By increasing the energy efficiency of buildings, however, the share of energy for heating is reduced and the share of embodied energy increases. In the future, potential energy savings from the operation phase of a building will be transferred to the construction phase and to the search for materials and construction technologies with low embodied energy.
SENEGAČNIK, A., ZBAŠNIK SENEGAČNIK, M.
ENERGY EFFICIENT BUILDINGS ARE ALSO AN ENERGY STRATEGY
KOMUNALNA ENERGETIKA / POWER ENGINERING, 13
Passive house is an energy optimal building. It has very low energy demands for heating the building and sanitary water, with affordable expenses. In the paper a comparison of energy savings between buildings, built by Regulations about isolation and energy efficient use in buildings from 2002 and buildings, built by passive house standard. The calculations are based on new buildings built between 2003 and 2008. The same buildings, built by passive house standard would consume a lot less energy for heating, but electric energy consumption would increase a bit because of the heating pump usage.
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