Archiv článků od 10.7.2017 do 13.11.2017

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Analysis of the Durability of Industrial Chimneys

13.11.2017 | prof. Ing. Juraj Bilčík, PhD., Ing. Ivan Hollý, PhD., Ing. Natália Gažovičová, Stavebná fakulta STU Bratislava
Industrial chimneys are civil engineering works, which in addition to static and dynamic effects, direct and indirect loads, are also exposed to significant non-stationary environmental loads. Analysis of their durability focuses on the evaluation of vertical cracks, corrosion of concrete and reinforcement, which have a decisive influence on the resistance of the chimney's shaft with regard to the ultimate and serviceability limit states, as well as their durability.

Influence of Build-Up around Fireplace Inserts on the Time Course of Heat Output

6.11.2017 | Ing. Petr Kubesa, Ing. Jiří Horák, Ph.D., Ing. Kamil Krpec, Ph.D., Ing. František Hopan, Ph.D., VŠB-TU Ostrava, Výzkumné energetické centrum, Břetislav Holešínský, Cech kamnářů ČR, Časopis Vytápění, větrání, instalace
This article aims to broaden knowledge about behaviour of different types of local wood-burning heaters in term of time course of heat delivery into the room. The article presents a comparison of performance of the selected heater – fireplace insert, which was gradually rebuilt and tested as stove with/without accumulation heat exchanger and closed fireplace with accumulation in different stoking regimes. In the end of the article, the measured results are compared with previously obtained hea t output course of individually built stoves.

Unrenewable primary energy

30.10.2017 | Ing. Jiří Novotný, Ústav techniky prostředí, Fakulta strojní, ČVUT v Praze, doc. Ing. Tomáš Matuška, Ph.D., Univerzitní centrum energeticky efektivních budov, ČVUT v Praze
Assessing energy performance of the building is also done from the point of view of the need for non-renewable primary energy. A common layman probably does not know what this means. At the same time, the need for non-renewable primary energy fundamentally influences the design of energy sources for heating, cooling, hot water preparation, etc. for a particular building. The need for non-renewable primary energy is one of the three main energy performance indicators of a building, and if it is assessed as too large, the building can not be validated.
9 comments, last 08.11.2017 14:31

Low-boiling liquids for heating systems

23.10.2017 | Ing. Jiří Matějček, CSc.
Heating systems, solar systems, primary circuits of heat pumps, etc. can be installed in the environment or exposed to operating conditions where their function must be guaranteed even at temperatures below zero degrees Celsius. In this case, pure water cannot be used to transmit heat energy. Low-setting (non-freezing) liquids consisting of a mixture of water and other substances are used to reduce the resulting freezing point to negative temperatures.
1 comment, 23.10.2017 21:25

What parameters must be met by stoves, fireplaces and solid fuel stoves? Legislation in the Czech Republic and Europe – situation in 2017

16.10.2017 | Ing. Jiří Horák, Ph.D., Ing. Lubomír Martiník, Ing. Kamil Krpec, Ph.D., Ing. Petr Kubesa, VŠB-TU Ostrava, Výzkumné energetické centrum, Ing. Jiří Dvořák, Milan Holomek, Ing. Stanislav Buchta, Strojírenský zkušební ústav, s.p., BRNO, www.szutest.cz
Because of the emission of pollutants during the combustion of solid fuels in local household heaters (fireplaces and stoves) tightening requirements (emissions and efficiency) are gradually adopted in individual EU countries. The requirements are mainly aimed at manufacturers or importers of incinerators who have to prove their fulfillment when placed on the market. This is a different approach than hot-water boilers, where requirements are targeted not only on manufacturers and importers, but also on operators. This partly changes for the Czech Republic, where the Air Protection Act also introduces obligations for local furnace operators with a hot-water coil (part of the heat is supplied to the heating water from the source). The aim of this article is to provide an overview of valid and planned requirements and also to compare them.

Small solar systems for preparation of hot water (PWH) in family houses

9.10.2017 | doc. Ing. Tomáš Matuška, Ph.D., Univerzitní centrum energeticky efektivních budov, ČVUT v Praze
The author provides a basic overview of technical information on the issue of small solar systems suitable for family houses.
1 comment, 14.10.2017 00:10

Experimental measurement of toxic substances in indoor air before and after renovation of residential building and its heating

9.10.2017 | Ing. Imrich Sánka, Stavebná fakulta STU Bratislava, Katedra Technických zariadení budov
This study investigates the impact of energy renovation on the indoor air quality of apartment building during heating season. The study was performed in one residential building before and after its renovation. Energy audit was performed and energy certificate was calculated for the renovated and the non renovated condition of the dwelling. Objective measurements of CO2 concentration have been used for the evaluation. The average concentrations was much higher after the refurbishment. The air exchange rate was calculated, which was higher in the unrenovated apartments. This study shows that energy renovation of the residential buildings in Slovakia may reduce the quality of the indoor environment in the apartments especially in winter season.
Maintaining a healthy indoor environment requires much more intense air exchange after the reconstruction of the house as it is achieved. Although this is related to energy consumption, it is otherwise endangered by the health of the user. Reducing the thermal energy consumption of the house to the detriment of the quality of the indoor environment and the health of the users of the dwellings can not therefore be considered as a saving and can not be calculated when assessing the energy savings of the building's heating system after reconstruction.

Utilization of overproduction of electricity from a photovoltaic power plant for heating and hot water production in a production area, part 1.

2.10.2017 | Ing. Petr Bican, Ph.D., Zdeněk Lovicar
The authors compare the measured data on the production and use of electricity produced by the solar photovoltaic power plant with the total electricity consumption in the production area of the company. The second part of the article is based on considerations about the use of overproduction of electricity for heating and hot water preparation and its economy.

Utilization of overproduction of electricity from a photovoltaic power plant for heating and hot water production in a production area, part 1.

25.9.2017 | Ing. Petr Bican, Ph.D., Zdeněk Lovicar
The authors compare the measured data on the production and use of electricity produced by the solar photovoltaic power plant with the total electricity consumption in the production area of the company. The second part of the article is based on considerations about the use of overproduction of electricity for heating and hot water preparation and its economy.

Reduced investment costs for heating in a residential building

18.9.2017 | Dr. Ing. Petr Fischer
Investments in heating systems of apartment houses are large and still growing. New modern components of the heating system are coming to market, which are further increasing the investment. Systems become more complex and therefore more susceptible to malfunctions. One solution can be the single-pipe hot water system.

Case study of heating savings due to glazing with increased solar factor

11.9.2017 | prof. Ing. Ivan Chmúrny, Ph.D., Stavebná fakulta STU Bratislava, Katedra konštrukcií pozemných stavieb
Case study of the energy need for heating of a family house depending on the thermal and optical properties of windows with triple glazing and the quantification of heat demand for heating.
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Law and expert: Microorganisms in the heating system

4.9.2017 | Ing. Jiří Matějček, CSc.
Although the heating water is in a non-life-saving environment, it contains a minimum of nutrients and has an elevated temperature, microorganisms can be propagated under certain conditions. Depending on their type and amount, problems with excessive occurrence of gases in the heating system, smell and corrosion may occur. The most frequent cause of the introduction of microorganisms into the heating system is the storage of pipes in the outdoor environment without their ends being blocked, and then, of course, the purity of the water that is impregnated into the system.

Testing the heat loss of the hot water tank

28.8.2017 | doc. Ing. Tomáš Matuška, Ph.D., Univerzitní centrum energeticky efektivních budov, ČVUT v Praze
The paper deals with the experimental determination of heat losses of reservoirs (hot water storage tanks, heaters, heat reservoirs). It shows how the thermal loss of the tank itself, determined by the correct procedure in accordance with the standard, can be different from the loss of the reservoir connected to the thermal system.

Comparison of different ways of heating in terms of energy consumption

21.8.2017 | Ing. Ondřej Hojer, Ph.D.
This paper describes the method of determining the heat losses resulting from the heat transfer to the space according to ČSN EN 15316-2-1. Based on a detailed comparison of the different heating methods considered for rooms with a room height higher than 4 m, their heat-sharing efficiency is evaluated.

What costs does a zero energy house have?

14.8.2017 | doc. Ing. Tomáš Matuška, Ph.D., Univerzitní centrum energeticky efektivních budov, ČVUT v Praze, Ing. Vilém Ťopek, Fakulta strojní, ČVUT v Praze
The article deals with the analysis of a possible solution of a non-energy residential building. The analysis shows what energy sources help to achieve a zero balance of non-renewable primary energy and what is not. In the contribution, the investment solution and the real operating costs of the energy-zero residential building compared to the current solution are shown for the selected solution and a simple payback period is set.

Law and Experts: Destruction of a double-jacket hot water heater with a reservoir structure tank in tank

7.8.2017 | Ing. Roman Vavřička, Ph.D., ČVUT v Praze, Fakulta strojní, Ústav techniky prostředí
The article presents a concrete example of a real operational problem with the use of so-called double-walled hot water heaters. The example is aimed at destroying the reservoir of the construction system tank in the tank due to a malfunction of the operating mode.
3 comments, last 10.08.2017 17:44
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Boiler Support – Solid Fuels Boilers

31.7.2017 | Ing. Zdeněk Lyčka
The article summarizes the experience, the boiler control issues, boiler operating characteristics and evaluation of the boiler exchanges.

Conversion of Solid Fuel Boilers Specifications (Efficiency and Emissions) as Required by EU Commission Regulation 2015/1189 ("Ecodesign")

24.7.2017 | Ing. Kamil Krpec, Ph.D., Ing. Jiří Horák, Ph.D., Ing. František Hopan, Ph.D., Ing. Petr Kubesa, VŠB-TU Ostrava, Výzkumné energetické centrum, Časopis Vytápění, větrání, instalace
With the advent of the EU Commission Regulation 2015/1189 on the ecodesign of the solid fuel boilers, there are beginning to emerge questions and ambiguities regarding the conversion of the efficiency and emission values reported in the protocols from the testing laboratories. The EU Commission Regulation introduces new evaluation of boilers specifications, which are seasonal efficiency and seasonal emissions. The calculation of the seasonal efficiency takes into account also the electricity consumption and potential production of electricity in a cogeneration boiler. The article mentions the formulas for the conversion of the boilers specifications according to the requirements of the mentioned Regulation. It also includes a model example.
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Effect of Heat Distribution Losses and Cooling of Heating Water on Design of Heating System

17.7.2017 | Ing. Jakub Spurný, Ing. Michal Kabrhel, ČVUT v Praze, Fakulta stavební, Časopis Vytápění, větrání, instalace
The article deals with influence of heat losses in distribution system and related cooling of heating water on the design of two-pipe counter-flow heating system. On the numerical reference model was studied the effect of distribution heat losses and cooling of the heating water on the heating system with mass flow rates designed by conventional calculation. In the following part were compared results from conventional design with design based on the numerical model which considered heat losses of the distribution system and cooling of the heating water. Mass flows rates were chosen as the compared variable, as they affect both thermal and pressure behavior of heating systems.
10 comments, last 25.07.2017 13:23

Law and expert: Aerating of heating systems

10.7.2017 | Ing. Jiří Matějček, CSc.
Revealing the cause of a faulty heating system in a residential building by over-aerating it can be far more complex than it appears at first glance. The impetus for the expert opinion was the complaint to the heating system operator that one riser of the heating system was repeatedly aerated and the heating element on the last floor was decommissioned.
1 comment, 04.09.2017 21:27
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