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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.
KOKOT KRAJNC, M., DOMJAN, A.
Performing Energy Efficiency Policy in Slovenia
KOMUNALNA ENERGETIKA / POWER ENGINERING, 1
Energy efficiency is one of the key pillars of the EU's climate and energy policy, as it pursues the awareness that only the energy that we don’t use is the cheapest, cleanest and the most reliable. This awareness was the basis for amendments of existing Directive on energy efficiency, which extends the energy savings targets by 2030. In this article, we present novelties that Slovenia will have to take into account regarding energy efficiency. We also introduce the results of energy savings that were reported for 2015, as well as new measures, which will contribute to achieving the objectives set out in the amended Directive.
THALER, S., HECHL, T., ZARBAKHSH, J.
ENERGY SAVINGS THROUGH THE USE OF BIOMIMETIC ARCHITECTURES
KOMUNALNA ENERGETIKA / POWER ENGINERING, 16
Absorbers in solar collectors are used to collect the heat from sunlight for heating and hot water production. The use of solar energy will continue to increase in the future due to the rising cost of fossil fuels such as oil and gas. The aim of this work is to optimize the pipework system in the absorber plate of a solar thermal collector in relation to uniform flow and a lower decrease in pressure for modern solar heating systems inspired by nature. The other parts of the collector like housing, insulation, and the transparent cover should be the same as in common flat plate collectors using the existing production equipment and maintaining the production line. It is essential to tag the problems of common solar panels and to define the parameters meaningful for the fluid mechanics evaluation.
The evaluation of different natural channel structures should help to find a suitable network with good characteristics in utilization and flow resistance. The chosen examples will be presented, simulated, and analyzed with appropriate software to demonstrate their flow characteristic. The resulting new pipework model will be integrated in the existing pipework design of the absorber to obtain the first bionic-optimized pipework design.
BELIČ, E., DEŽAN, K., LUKAČ, N., ŠTUMBERGER, G.
EVALUATION OF ENERGY SAVINGS ACHIEVED WITH OPTIMUM PHOTOVOLTAIC SYSTEMS REACTIVE POWER GENERATION IN LOW VOLTAGE DISTRIBUTION NETWORK
KOMUNALNA ENERGETIKA / POWER ENGINERING, 32
This paper deals with the evaluation of energy savings that can be achieved in low voltage distribution network by photovoltaic systems (PVS) reactive power generation according to the network needs. Whole analysis is done on the model of real low voltage distribution network, where two 50 kWp PVS are installed. For evaluation of energy savings, time frame of one year is considered. Active powers of PVS are determined on the basis of average measured solar irradiance in half hour intervals and loads active powers on the basis of load profile. Since installed photovoltaic systems are relatively large, the analysis is also performed for smaller PVS with rated power of 5 kWp. The presented results shows, that energy savings can be achieved with existing PVS when they generate optimal reactive power. However, savings can be even improved if instead of big, smaller PVS are installed at sites where consumption is present.
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