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Archiv článků od 14.5.2019 do 24.4.2023

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24.4.2023
Dr. Ing. Libor Čapla, doc. Ing. Václav Koza, CS.c.

The composition of natural gas in the Czech distribution system, or the Czech part of the former Czechoslovak system, has not changed too much over time to date. Almost all of the gas was that supplied from the former Soviet Union and, following its disintegration, from Russia mainly to western European countries and met their requirements. The situation completely changed in 2022 when gas supply from Russia to the EU was reduced and large quantities were replaced with LNG. In this context, the contribution discusses the changes in the composition of the natural gas distributed in the Czech Republic.

Model tepelného čerpadla v Malmo (Zdroj: GEA)
3.1.2023
Ing. Erika Langerová, Ing. Nikola Pokorný, Ph.D., doc. Ing. Tomáš Matuška, Ph.D.

High-temperature water-to-water compressor heat pumps with different refrigerants and configurations can be used in district heating systems operating at temperatures between 60 and 120 °C. Part 1 describes the development of installations in Europe and the current state of development, including an overview of the market offer.

2.1.2023
Ing. Erika Langerová, Ing. Nikola Pokorný, Ph.D., doc. Ing. Tomáš Matuška, Ph.D.

High-temperature water-to-water compressor heat pumps with different refrigerants and configurations can be used in district heating systems operating at temperatures between 60 and 120 °C. Part 1 describes the development of installations in Europe and the current state of development, including an overview of the market offer.

28.11.2022
doc. Ing. Miroslav Škopán, CSc., VUT v Brně, asociace ARSM

The article provides an overview of the development of construction and demolition waste recycling in the Czech Republic in the period between 2007 and 2020. Waste group 1701 concrete, bricks, tiles and ceramics analyzed in more detail. Recycled C&DW from this group are assessed in terms of the possibility of their use as concrete filler. Attention is also paid to group 170504 – soil and stones without hazardous substances. A significant increase in recycling has been demonstrated for this group in recent years. In conclusion, the ratio of recycled C&DW and extracted natural mineral raw materials in the construction industry is analyzed.

23.6.2022
Ing. Zdeněk Reinberk, Ph.D., redakce

A nuclear power plant is a powerful and stable source of electricity. Full replacement of such source with photovoltaics is not easy. We calculated how much PV panels and batteries would be needed for replacement and how much it would cost. The calculation in the article is interactive and the individual calculation parameters can be modified.

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31.5.2021
doc. Ing. Michal Stehlík, Ph.D., Mgr. Jana Knapová, Ing. Vojtěch Kostka

The paper deals with the possibilities for use of glass recyclate from photovoltaic panels for concrete masonry units. It compares partivular recipes and its physical and mechanical properties with the main focus on the compressive strength. It then compares the values of these recipes with the values of commonly used composite materials for masonry units without recyclates.

19.4.2021
Ing. Kristina Fořtová, Ph.D., Ing. Diana Mariaková, Ing. Jakub Řepka, Ing. Tereza Pavlů, Ph.D.

This article deals with the possibility of using masonry aggregate from construction and demolition waste. The article summarizes the properties of concrete with a laboratory-optimized recipe with a full replacement of natural aggregate with recycled masonry aggregate. Testing of concrete samples was carried out according to valid standards. The result is a mixture with optimized properties for the production of construction parts.

15.3.2021
Ing. Josef Fík, Dr. Ing. Libor Čapla, Ing. Jiří Žahourek, CSc.

The authors analyze the possibility of burning natural gas with an admixture of hydrogen in gas appliances. The positive and negative aspects of the hydrogen content in natural gas and recommendations for its mixing into the natural gas distribution system are presented.

The contribution describes the effect of hydrogen content ranging from 0 to 25 mol% in a mixture with natural gas on burning in household appliances. Gaseous fuels with similar combustion characteristics, in particular Wobbe index and burning velocity, can only be used in a particular household appliance as a substitute. The various chapters describe the effect of hydrogen content in natural gas on the following: Wobbe index, composition of exhaust gases; emissions of CO2, CO and NOx; burning velocity; output of burners/energy demand of appliances, efficiency of appliances; flame stability; and temperature of combustion. Recommendations on hydrogen content in natural gas for household appliances, accepted from reference literature, are set out there. In conclusion, the authors discuss the pluses and minuses of hydrogen content in natural gas and offer recommendations for hydrogen injection into natural gas distribution systems from the perspective of burning these mixtures in household appliances.

8.3.2021
Ing. Josef Fík, Dr. Ing. Libor Čapla, Ing. Jiří Žahourek, CSc.

The authors analyze the possibility of burning natural gas with an admixture of hydrogen in gas appliances. The positive and negative aspects of the hydrogen content in natural gas and recommendations for its mixing into the natural gas distribution system are presented.

13.4.2020
Ing. Miroslav Havrlent, RACEN, spol. s r. o., Piešťany, Slovensko

Achieving the criteria set for effectively district heating will be a precondition for the development of central heat supply in the coming period. Heating companies are therefore looking for suitable alternative solutions. In this paper it is the view of the designer on a concrete example of the combination of the use of geothermal water and CHP.

9.4.2020
Mgr. Dana Stejskalová, Doucha Šikola advokáti s.r.o.

This article describes a long-term Renewables Power Purchase Agreement under which a consumer purchases renewable electricity directly from an electricity producer. Signing a renewables PPA ensures that the producer acquires the long-term revenue stream through the sale of energy and the costumer gets the fixed electricity price for the entire period of the contract.

21.10.2019
Ing. Jan Blažíček

Decree No. 269/2015 Coll. I consider it one of the worst regulations I have ever encountered. I start from the experience of people who asked me for advice on what to do when they have winter at home and yet the highest share of heating costs in the whole house. At first I bet on the effect of heat parasitizing unoccupied neighboring apartments, but then I thought of looking at positional coefficients.

10.10.2019
Ing. Zdeněk Burdek, ČEZ Distribuce

The article describes various offgrid operation modes as an option for mitigating consequences of a power outage - blackout.

7.10.2019
Ing. Jan Blažíček

Unfortunately, the fairness in the allocation of the cost of heating flats in multi-dwelling buildings is most often taken by people who have no idea on what principles the heating of these houses is based. Out of ignorance they then create a problem where it is not at all, and to build a “solution” to construct a bizarre structure. The problem is that the field of heating revolves around the physical quantities of heat and temperature, whose names sound very similar in Czech, and therefore people often confuse them, even though they are completely different in meaning.

25.7.2019
Ing. Jana Veverková, Ph.D., Ministerstvo průmyslu a obchodu

The article focuses on the introduction of renewable energy sources (RES) in the energy balance as primary energy sources, during the transformation process and their use for final consumption. The first part is devoted to basic terminology and primary energy sources, the second part focuses on the transformation process and final consumption.

15.7.2019
Ing. Jiří Tichý, UETE FEKT VUT v Brně

The article describes currently used types of lithium based accumulators. Basic principles, parameters, advantages and disadvantages are listed in the article.

24.6.2019
Ing. Jiří Cigler, Ph.D., Feramat Energies, s.r.o.

The paper deals with the problem of optimal sizing of battery-powered hybrid power systems for HV extraction installations, where electricity consumption diagrams are available and it can be assumed that the nature of the operation will not change when photovoltaic technology is installed with battery storage. This is a difficult task, as each installation is specific to its nature of consumption, energy prices, location and investor requirements. The article outlines how to solve this problem by using the numerical optimization methods implemented in MicrOpt Design, the use of which is shown in a specific example.

4.6.2019
doc. Ing. Vladimír Zmrhal, Ph.D., ČVUT v Praze, Fakulta strojní, Ústav techniky prostředí, Časopis Vytápění, větrání, instalace

Data centres are a significant energy consumer, which is related to both the operation of IT technology and its cooling. It is the part of the consumed energy intended for the cooling of data centres, which, in some cases, has the potential for saving measures. The paper targets the possibilities of using outdoor air for free cooling of data centres and tries to financially quantify possible savings. Several analyses were carried out based on a real example of an existing data room equipped with a cooling circulation system.

14.5.2019
Mgr. Iva Zvěřinová, Mgr. Milan Ščasný, Ph.D., Mgr. Zuzana Martínková, JUDr. et Mgr. Vojtěch Máca, Ph.D.

The largest market share of new registered passenger battery electric vehicles in Europe is in Norway (31 %), the Netherlands (5 %), Sweden, Austria and France (2 %). The share of electric vehicles in new vehicles registrations remains low in the Czech Republic, reaching 0.27 % in 2018. Policy measures can significantly support adoption of electric vehicles by consumers. Based on a literature review, we discuss a wide range of policy measures to support battery electric vehicles (BEV), including effectiveness of these measures. Further, we describe support measures in the Czech Republic. Last, we aim at the expected trends in BEVs and a policy design that may support to increase market share of BEV technology when undesirable side effects on inequality, public finance and the environment are minimised.


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