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Archiv článků od 30.7.2012 do 26.11.2012

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26.11.2012
Ing. Roman Brzoň, Ing. Milan Ostrý, Ph.D.

This paper deals with the issue of comparing simulations for steady and unsteady thermal state at the massive structures. In this paper, computer simulations are compared with real measurements and measurements of climatic data. The evaluation showed that the steady-state temperature can be comparing with real model used after the end of the accumulation phase. It is evident that the requirements for the temperature factor of the internal surface of the solid structures, set by legislation, are a safe assumption.

19.11.2012
Ing. Jiří Horák, Ph.D., Ing. Kamil Krpec, Ph.D., Ing. Lubomír Martiník, Ing. Lenka Michnová, Ing. František Hopan, Ph.D., Ing. Petr Kubesa

It is generally recommended that the wood for quality burning should not have more than 20% by weight of so-called energy moisture. The described method allows a unique determination of moisture content of firewood at home.

12.11.2012
Ing. Vladimír Valenta

The paper describes the management of district heating systems with circulating pumps with variable and controlled speed. It is shown that this control method is compared to systems with circulating pumps with fixed speed very advantageous, by substantially reducing power consumption to drive the pumps.

5.11.2012
J.V.Ráž, DiS.

Evaluated the effectiveness of austerity measures must take into account both external and internal temperature of the object and the value of the average heat gain at which heat consumption was measured. Article analyzes the individual components, and presents the average values.

vrt pro tepelné čerpadlo
5.11.2012
RNDr. Petr Čížek, A až Zet Praha

The article is research on the thermal properties of various construction types of thermal drillings. It focuses on the impact of their installation on their efficacy, duration and cost and to their safety for underground water and water-related ecosystems.

22.10.2012
upravený překlad: Ing. A. Chyba

This paper describes the basic concepts of pumping technology - characteristics of the pump, and resistive characteristics of system, operating point, and deals with the result effect of the series of the circulator in serial and parallel connection.

úspory tepla v panelových domech
15.10.2012
J.V.Ráž, DiS.

Relatively same heat savings can be achieved with thermal comfort by regulation, or without thermal comfort by switching off the radiators. It depends on how the heating is operated and how heat gains are used in the building. The article contains a simplified example that relations between real and purported savings of heat explains.

hybridní solární kolektor
8.10.2012
Ing. Luboš Buchta, ČVUT

The article presents the current state of the issue of flat hybrid photovoltaic-thermal (FVT) collectors, focused on the differences between the basic types of collectors, their advantages and disadvantages. There is also presented an overview of the current global manufacturers. The article aims to highlight the problems but also the opportunities associated with different types of the hybrid FVT collectors.

otopné období
8.10.2012
Ing. Ladislav Tintěra

The heating period 2011/2012 in Prague based on the observation of Prague-Karlov station was 213 days, a little shorter, and with an average temperature of 5,4 ° C, slightly warmer than the long-term average. Year 2012 is leap-year. The basic characteristic is slightly different. Basic characteristic of heat demand for heating is 2 907 D ° (19) degree days, heat demand is much lower than the long-term average of 3 224 D ° (19). It's the second lowest number of degree days of the heating period in the last decade.

1.10.2012
J.V.Ráž, DiS.

Can additionally insulated prefab-panel buildings meet the low-energy standard, or even overcome? The article contains a detailed analysis of the specific parameters of the building and heating system before and after additional thermal insulation of building, supplemented by the results of measuring the actual heat consumption in the period 2010-2011, with output data transferred to the appropriate temperature normal year.

24.9.2012
Ing. Ladislav Tintěra

Energy audit in the Czech Republic has twenty years history. The first decade was a period of searching, others ten years were period of legal obligations. The author is one of our first energy auditors. Features personal experience on the development of the methodology, legislation and practical application.

17.9.2012
Ing. Petr Horák, Ph.D., Ing. Marcel Koňařík, Ing. Iva Ambrožová

Currently the thermography is commonly used for diagnosis of the building envelope quality. Major purpose is the control of construction details, thermal bridge analysis. Thermography can be used for determining the heat transfer coefficient of the building envelope. Though this method of determining heat transfer coefficient is limited and results may not always be exact. It can be caused by variability of boundary conditions and inhomogeneity of building structure. This article describes the methodology for determination of heat transfer coefficient based on thermographic measuring.

10.9.2012
Ing. Tomáš Najbrt, Ing. Josef Lenoch, Ph.D.

At present, it is not easy to find the optimum variant of the energy used for heating, which would be suitable for all types of houses. Economic evaluation of basic options which are offered should be enough for the choice of method of heating. The article gives an example of the selection of appropriate options for heating and hot water of selected house by comparing the technical, economic and geographical possibilities of nine basic and commonly used variants in the Czech Republic.

10.9.2012
Ing. František Vlach

Temperature effects on soil are unexplored and calculations are simplified. This paper deals with the impact of using different soil properties for numerical determination linear thermal transmittance of building foundations. It describes how the numerical calculation react on these soil properties. The analysis was made for real details of foundations and was used to create simple chart for the idea about calculation sensitivity.

3.9.2012
Ing. Jozef Bugáň

Nowadays there is emphasis on energy savings and utilization of renewable energy sources. Therefore, proper selection and design of the heating / cooling system, which should be also able to provide favourable condition of the thermal environment – thermal comfort, is very important.In this article construction systems, compositions and possible solutions of low temperature floor heating / high temperature ceiling cooling are presented.

tepelné zisky
27.8.2012
Ing. Iva Ambrožová, Ing. Petr Horák, Ph.D.

Determination of the energy balance of required building is necessary in energy evaluation, energy audit and energy performance certification of buildings. Key values are heat gains and losses. They are initial for determination of the energy demand and consumption. Calculation of the energy performance should be done in accordance to ČSN EN ISO 13790 standard. This article describes the problematic calculation of glazing solar gains. In the end is enumeration of different methods (current and older) during the heating season.

13.8.2012
Ing. Vít Havlů, doc. Ing. Martin Pexa, Ph.D., Ing. Zdeněk Aleš, Ph.D.

This article is focused on plan optimization issues of preventive maintenance based on risk assessment. The aim is to propose a cohesive system layout which involves the maintenance optimisation as a whole and achieve better results compare to simple applying the individual methods. This system is divided into five fundamental phases which are consequently following one after another and guarantee the order and structure of the process. Every phase consist of individual sections which thoroughly describe particular execution and procedures. The proposed system should help readers to obtain sufficient information in order to understand the different parts of the system and enable them to make their own opinion on synergy of systematic methodology which deals with optimization of maintenance. All these aspects are very important in practice due to the complexity of most ventilation, heating and air conditioning systems.

30.7.2012
J.V.Ráž, DiS.

Commonly practiced simple statistical analysis of heat consumption shows differences of measured values, but not thermal energy savings, for which the buildings are insulated and the heating systems re-regulated. Differences of measured values at different temperatures inside buildings have no practical benefit for the consumer because they say nothing about the actual and they do not allow to adjust the heating mode nor by changing the behaviour of people in apartments, nor by any other instrument. Heat consumers lack information on the relations between the average internal temperature of objects during measurement of heat consumption, on the influence of heat gain and possible heat savings in compliance with the legislation provided average internal temperature of the object.


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