The standards ČSN 73 1901 Designing of roofs – basic provisions, ČSN P 73 0600 Waterproofing of buildings – Basic Provisions and ČSN P 73 0606 Waterproofing of buildings – Continuous sheet waterproofing – Basic Provisions have been revised in 2010. What kind of new requirements do these new standards bring? How will their approach change compared to previous regulations? We asked the people behind them about this. The current standards for roof designing have been applied since 1999. According to the proposers of the revision, the many implementations of roofs that have taken place since then have been the source of many new findings, which will be now generalised and reflected in the new standards by clarifying certain provisions or establishing new ones. Developments in European and Czech legislations and standardisations are also necessary to be taken into account.
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Examples of projects in Energy Performance Contracting
First two projects by the Energy Performance Contracting were prepared in the Czech Republic in 1993. From that time about 200 projects were implemented. The investment for the projects footed up to the total amount about 3 billion CZK. The highest number of the projects was implemented in school buildings with investment from one till ten million CZK. A lot of projects were implemented in buildings of healthcare service. On examples of implemented projects are described main features of the EPC projects for hospitals (the biggest project with investment over 100 million CZK), for schools (mostly smaller projects) or for more buildings in one public tender (municipalities or regions).
The EPC and its relations with other activities in connections with energy savings
In 2006 the Directive 2006/32/EC on energy end-use efficiency and energy services was adopted for the support of international activities on development of energy services. The obligation of each EU member state is prepare and submit to the Commission the Energy Efficiency Action Plan in roughly three years cycles. In relation to the Directive other activities were supported by EC under the Intelligent Energy Europe Programme, as projects: the Concerted Action on the ESD, ChangeBest, EESI or Pernament. Internal Czech initiative is under activities of Czech ESCOs, which are preparing Association of energy services companies.
The attenuation of sound wave with bends is mostly used in the design of noise walls, curtains and barriers along ways with intensive traffic (roads, rail and tram). Noise reduction from stationary sources with curtains is less common because it is always better to place the noisy device in the machine hall. This is then ventilated through a system with big enough dimensions so as to absorb sound, which then blocks the source of sound and the fan noise. Let's look at some specific installations seen in this context as well as calculations of the sound attenuation bend.
The problematic of energy savings should not be limited only to thermal insulation and occasional use of alternative energy sources. The energy used not only for heating, but also for ventilation and air conditioning. Significantly affect the consumption requirements, deciding which areas will be heated and at what temperatures. Energy is needed to produce construction materials, their transportation and eventual waste handling. The lifespan of the proposed construction and the complexity of its liquidation should be one of the essential criteria when deciding on contemplated modifications. It is necessary to consider buildings as architectural heritage.
The article deals with the issue of unwanted condensation of water vapour on internal surface of building structures. Building and physical conditions of surface condensation of water vapour is analysed. It discusses possibilities of technical solutions leading to elimination of the mentioned negative phenomenon – change of use, adjustment of peripheral structures, reaching the required parameters of internal air by natural ventilation or through air-conditioning.
The Czech Council for Green Buildings and the British Council, in addition to their other activities, are organising the so-called Biohouse seminars, which include visits to selected buildings. We have attended one of them and we had a look at three interesting buildings in the surroundings of Prague. The first stop of the mini-bus was Pikovice, where an untraditional low energy wooden house, with a gazebo is located. We were expected by the investor, the architect and the projector. The second building, which had almost passive standards, we shown to us by the investor, who personally devised to ideological concept of the house in the outskirts of the village Tehov u Říčan. The third building, located in the garden of the former parish house in Sluštice u Prahy, was shown to us by a representative of the investor, who took us to the world of children. It is a beautiful wooden building projected as a pre-school in a Waldorf style.
What should be respected during renovation works on roofs so as to maintain the architectural quality of the original design? Solar collectors and photovoltaic cells constitute a disruptive element in historical buildings and buildings in historical areas. Among others, the reasons are legal, because the law provides equal access to buildings with a same degree of legal protection. Exceptions can be considered in situations without an indicated conflict. For example, on garage roofs in courtyards or roofs in buildings erected after the WWII. And even in these cases, the installation of panels should be appropriately considered. Of course, even new architectural and artistic works as well as other specific situations will require an individual approach. However, in terms of frequency we are talking about exceptions that confirm the general view of the preservations institutions, that the placement of photovoltaic systems in areas of cultural or historical heritage is not desirable. Let's have a more detailed look at this problematic.
Windows have always been considered a construction surface that had to allow in enough day light and at the same time, protect the interior from wind and rain. Windows protected the house from the outside world, while at the same time enabling communication. The technical capabilities, along with the climatic and economic conditions of different historical periods shaped the appearance of the windows, which also helped create the different architectural styles. The proportions, materials and the segmentation of windows on the façades were also influenced by geographical location, cultural influences and regional aesthetics. The height and width relationships in windows, and their relationship with the total area of the walls, the appropriate width of the interior posts and other similar parameters where basics of the compositional works. Much attention was paid to the fine details. Window openings were framed with various decorative ornaments. The windows of a passive house are among the most complicated structures of the building.
One of the tools for the implementation of a national housing policy is the State Housing Development Fund. Its director, Dr. Jan Wagner, has given TZB-Info an exclusive interview where he speaks about the Czech Housing fund, the possibilities to combine subsidies and the difficulties for investors and developers.
Do you know how to choose a supplier and installers for windows? The article answers to important questions regarding the choice of windows, their frames, glazing, ironwork, sills and accessories such as shadings, etc. The author speaks from personal experiences with suppliers, manufacturers and technical supervisors. The article wants to help people buy windows with the best price/quality ration and ensure their long term satisfaction.
The basic importance of the use of inert gas in the space between insulating glasses is its lower thermal conductivity, i.e. the ability to provide greater resistance to heat transfer. Simply put, the inert gasses (argon, krypton, xenon) have this property because in principle their molecules do not create in structure among themselves or with particles from other gasses and strictly occur in monomolecular arrangements, which significantly reduces the transfer of kinetic energy between the molecules, which is the driving force of heat. The paper analyses the variabilities of the heat transfer coefficient of Ug glasses depending on changes in the concentration of inert gases and the width of the space between insulating glasses.
Advantages of the EPC methodology in comparison to other solutions
EPC methodology has a lot of advantages in comparison to other solutions on reconstruction of energy systems. The most important feature is assumption of risks, which customer would have to solve. The most important adoptable risk is guarantee for the savings. Unique feature of the EPC is the same motivation for the ESCO and for the customer, both to invest money by the most effective way (efficient quality equipment) and to reach as high savings as possible. It is very appealing that the ESCO is able to assure financing of the project. The customer needs not spend the investment during implementation of the energy efficient measures and he pays it back during the investment during the contract duration from saved operational costs.
Specific features of the EPC in the Czech Republic
The Energy Performance Contracting was introduced in the Czech Republic in 1992. From that time the EPC methodology was developed enough in the field of documentation for public tendering process and also in the field of text of contracts for the energy services provision. Unfortunately the state support of EPC project development is in the Czech Republic very weak. Nevertheless the situation is from ESCOs effort and interest of customers very good. By number of the EPC projects and size of the projects is the Czech Republic in Europe on the top position, including Germany, France, UK, Austria and Sweden.
Windows, as fillings of peripheral orifices in the structure of buildings, are a construction product, which either must be tested or verified for their compliance with the various Czech regulations and standards. One of the most important criteria that window structures must meet is the one prescribed by ČSN 730540-2 Thermal Protection of Buildings from April 2007 The compliance of the inner surface temperature factor with the standard ČSN 730540-2 must be verified separately for each orifice filling structure. So far, there are no universally applicable rules that determine which edge of glazing units can be applied to with structure. The area of the glazing joints is among the riskiest parts of the whole structure, and that is why two basic design rules were derived in order to provide an increase the internal surface temperature in that area.
More than 15 years TZB-info is focused to perspective equipment for building services with priority in heating. During this period the main question: "how to heat" shifted to question: "how to reduce heat loses". For example France is planning for new buildings only passive standard, and begining 2050 only so-called quasi-zero buildings. In Czech Republic one of significant impulses is subsidy program Zelená úsporám (Green for savings). Technical solutions are widely known in professional community, unfortunately high investment cost and long payback time are the main barriers for broader expansion of the solutions. Folowing article is the first from a serie focused to long time planing of reduction of energy consumption in the Czech Republic. From two ways - to prospect new energy sources or to reduce energy consumption - the second needs no to destroy another villages or towns.
How can heating for Czech homes be assured while at the same time get rid of the dependence on dirty coal and Russian gas? This is answered by the scholarly study by the DUHA movement – Clean Heating. The solution is based on a combination of investments on home insulation, solar collectors and biomass heating plants. Very important are the new standards for developers and provisional supply of coal from the Bílina mine. The calculations are based on those from the Pačes Commission. There are many opportunities. Increasing the energy efficiency of builings – i.e. insultaions – and the heating potential from renewable sources represent more than 300 million gigajoule. This surpasses the total current heating consumption of Czech homes. The possibilities of insulating Czech homes are also five and a half times higher than the controversial expansion of the coal mines around Most, which is linked with a further devastation of the North Bohemian landscape and the demolition of towns.
This article extends the article "Ventilation with heat recovery in flat - yes or no?" and it is concerning with pressure forced ventilation with electric heating coil. This unit includes ventilator, which sucks the external air in from the façade. The electric heating coil with the power of 250 W preheats the external air which is distributed to the rooms with the air distribution system. Nowadays there are a lot of these units on the market that differ in air volume and heating power. The aim of this article is to investigate whether this unit ensures good air quality and what are the costs. The paper was made within the framework of the R&D project performed by the experts in the company EkoWATT, Czech Republic. R&D project VAV-SP-3g5-221-07 is supported by the Ministry of Environment.
Today we have detailed, scientifically based evidence tested in practice, revealing that the construction of new buildings and the renovation of old ones can reduce their energy consumption to values lower than 10% of the current average. This ability of architects, planners, construction workers and companies has arrived just in time to help us avoid the worst consequences of climate change.
Overcoming conservative attitudes is a problem in passive constructions. Sometimes it is necessary to find solutions that are not linked to experiences with the established practice. Moreover, if a structural engineer categorically declares that “such solution can not be signed”, the architect has no other choice than to find a compromise. The article shows some inspiring examples from practice.
The aim of the diurnal lightning proposal is to rectify rooms' access to sunlight, which is dispersed in the atmosphere, and to rectify the visual comfort of the users of the interior during daylight hours; i.e. the appropriate lightning conditions for visual work carried out in the interior. The specifications of diurnal lightning are formulated in IEC-730580-1 to 4. These specifications are binding because the relevant articles mentioned in the standards are determined as binding laws and decrees 268/2009 on the technical requirements for construction, 258/2000 on Public Health, 410/2005 on hygiene requirements for educational facilities and the education of children, Government Decree 361/2007 on sanitary conditions at work. In situations where controls of calculations of measurements are not possible or too difficult, it is then necessary to maximise the transparency of computational procedures. In particular, it is necessary to include all the variables that enter into the calculation (factors of brightness shading barriers, factors of transmission and reflection of light). When assessing the accuracy of the calculations, it is also necessary to require detailed descriptions of the computational models used in determining the individual components of the diurnal lightning factors.
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