From the phase of architectural studies, the building process goes through steady changes. The expert "forecast" of the thermal behaviour of these buildings will almost always be hampered by the lack of input data. However, even in such cases there are ways to provide valuable information about future features of the project. The information doesn't need to be always accurate. For example, if we asked if the building will be low-energy, it would be enough to know, among other things, if the resulting heat needed for heating will not exceed a certain threshold. We are able to identify this already at the stage where we have a clear idea about, for example, the properties of windows or the exact shape of the building. In this case, it is appropriate to extend the standard calculation procedures to be able to describe not only one chosen object, but a number of variations that may occur depending on what the we know about the building at a given moment. This presents a method for design and estimation of thermal-technical properties of family houses with very low energy requirements. The method uses the creating of variants with the Monte Carlo simulation applied to the parametric model house (monthly calculation according to EN ISO 13790 and 730329 DESERT). The results show the influence of individual characteristics of the building on the heat balance and makes it possible to optimise the overall building.
Archiv článků od 12.10.2009 do 18.1.2010
This completes a series of articles dealing with modifications in heating systems in residential buildings. It contains thus far unpublished data on the impact of setting valves for heat savings, explains the causes of insufficient performance in heating systems and provides completely new project documents.
The following contributions, which deal with this problematic, consider the impact of high heat resistance of the walling on the thermal comfort and the design of heating ventilations systems, which are still perceived, as it is the case in buildings with classical walling, therefore, to have lower thermal resistance. For instructions to formulate the effect of walling on the thermal comfort and technical equipment, a general comparison of both the following cases is made, which is simply called building with high thermal resistance of external walls for a low-energy house, and a building with classical walling parameters (e.g. housing estate from the past) as a standard house. The articles are not of exact technical nature and deal with regularly updated dependencies and sometimes refer to previously applicable legal provisions.
The author draws attention to the deterioration of the quality of indoor environments in flats where the original windows have been replaced by modern, tight windows, which although improve the flat's energy balance, they also limit the possibilities for ventilation. Moisture that has not been ventilated accumulates in the flat, which leads to mould growth, and in the case of gas appliances, there are also exhaust gases, which are are toxic substances that lead the health problems, intoxications and even death. In the Czech legislation there aren't sufficient basis for an unambiguous determination of the requirements for the quality of the indoor environment of flats, including the requirements for their security, i.e. ventilation. The information can be found in selected European Standards, the author cites ČSN EN 15251.
New systems with many advantages are constantly being developed for the construction of gas pipelines. They include, for example, easy installation, specially in inaccessible areas; time saving installation with a minimum number of connections, corrosion resistance, bends without fittings or a complete system of elements for a sepcific technology. The following article deals with the ALPEX system.
We can observe in the Czech press a significantly higher frequency of expressions suchs as passive house or energy-efficient construction, specially in connection with the subsidy program “Zelená Úsporám”. However, the reality is that the number of passive houses built is very low, moreover, in some of the so called passive houses there can certainly be doubts about their actual properties.
Many safety devices are used on gas pipelines and appliances. They are devices that control various parameters and respond in the event of non-compliance. The following section will describe only those devices that have a major impact on the safety of gas appliances, about which every operator and user should have at least basic information.
The concentration of greenhouse gases in the atmosphere has been dramatically rising for the past 150 years. This fact and the possible link between GHG concentration and rising temperature of the Earth caused that the reduction of greenhouse gases has recently emerged as widely discussed issue.
First step to cut CO2 emissions is to identify countries with the highest contribution to the worldwide emissions. From this point of view the emissions of China and USA are very similar.
However the information about absolute CO2 emissions per country is not fully correct for most of comparisons. Much better is to compare CO2 emissions per capita. From this point of view, which comes from idea that every people have the same right to consume the natural resources and produce waste, the emissions of China are much lower than that of the USA.
Information about CO2 emissions is relatively simple indicator. There are more complex indicators that should be used in case of sustainable development assessment.
In the 1970's the interest in renewable energy sources increased considerably due to the energy crisis. At that time, the fist extensive and reputable studies were published, which talked seriously about the fact that conventional energy sources are exhaustible. The Czech republic adopted its first energy policy in 1992 in agreement with the regional environmental limits of coal.
The article deals with real experiences of growing of an energetic crop - the sorrel. There are described four selected locations concerning the crop production and applied treatment, including future outlook. The article also includes the price estimation of energy of 1 GJ from the sorrel, based on available data.
The second article on heat saving when adjusting heating systems is focused on the importance of good transfer of heat between external and internal networks. including the effect on the activation of temperature sensors and economical operation of dynamic heating systems, including the effect on the activation of temperature sensors and high-economy operation of the dynamic heating systems (thermostatic valve reverse curve, the dependence of operating parameters on the system differential pressure and problem solving of the central heating supply thermal hydraulics)
The article contains supporting evidence for the treatment of heating systems, describes the effect of adjustments to the internal wiring and piping on the outside heat supply network of central heating (CPP), analyzes the causes of low heat savings and provides information on the best solution practices for actual adjustments.
Air conditioning and ventilation systems show big energy consumption in buildings. Measure of the consumption of electrical energy for the conveyance of air is SFP. SFP is defined as the total consumption of electrical energy by the all of fans in the air-distribution systems, defined by the total volumetric air flow through the operated space under nominal loads. The article presents influence of design equipment on energy consumption.
Products resulting from the combustion of gas that contain harmful substances (carbon monoxide CO, carbon dioxide, CO2, water vapor, H2O) can penetrate into a room during the activity of Type A gas appliances. The concentration of oxygen, O2, also decreases during the combustion of gas. Water steam should also be considered harmful. The results of calculations show that the rate of humidity is most important for determining the minimum volume of the room or the minimum volumetric flow rate of ventilation air.
Lately, the Czech Association of Technical Equipment has been approached by several manufactures who wanted to know whether it is possible, in accordance with Czech legal practices, to have their products certified by a variety of accredited certification bodies, and very often applied to products that have already been certified by an authorised person. These additional certifications are very often a condition for the use fo some products in the field of gas equipment.
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