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Archiv článků od 2.9.2019 do 31.3.2021

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31.3.2021
Ing. Antonín Vojáček

Alternative energy sources are gradually taking a growing share in the worldwide production of electricity. Solar power is perhaps the easiest to implement and least expensive, its use is not too complicated and can you can easily experiment with it even in a small scale. It is easily accessible to anyone interested in environmentally friendly production of energy. To get started with it, it is just enough to buy one solar panel with a few additional components, and place it on a sufficiently sun-lit place and the production of energy can begin. Certainly, an interesting idea for users is that after the initial investment the system for several years basically doesn't have any requirements, and that it will produce energy for free.
A solar panel (photovoltaic panel or module) is a part of several interconnected solar units with a usual output of around 300W, which generated an voltage corresponding to the multiple voltages of the interconnected individual units. The source of higher outputs consisting of several interconnected solar panels is usually referred to as a solar power plant.

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.

28.12.2020
Ing. Viacheslav Shemelin, doc. Ing. Tomáš Matuška, Ph.D., Časopis Vytápění, větrání, instalace

The design of a solar system for the preparation of hot water in an apartment building is analyzed by computer simulation. The analysis shows the effects of the design of the area of solar collectors, climatic conditions, the connection of the circulation circuit and the design of the volume of the solar storage tank on the solar coverage and specific heat gains.

5.10.2020
Ing. Miroslav Urban, Ph.D., ČVUT v Praze, Fakulta stavební, Katedra technických zařízení budov

In connection with the entry into force of Decree No. 264/2020 Coll., On the energy performance of buildings, the method of assessing the energy performance of new buildings is changing. The article on the case study of a family house presents an approach to the concept of technical systems of new family houses from the point of view of current and future requirements (from 1. 1. 2022) for the energy performance of buildings.

1.9.2020
Ing. Pavel Hrzina, Ph.D., FEL ČVUT v Praze, Katedra Elektrotechnologie

One of the important parameters that are monitored when choosing a battery is the so-called cyclic life. How is this parameter determined and what does it express?

23.7.2020
Ing. Petr Wolf, Ph.D., Ing. Pavel Hrzina, Ph.D.

The design of PV systems with regard to the maximum annual yield (total energy obtained per unit of installed capacity) is slowly becoming a thing of the past. Systems with the adaptation of the production diagram to the local consumption consumption diagram and systems with better use of the space required for the installation of the PV array come to the fore.

16.6.2020
Ing. Radek Červín, doc. Ing. Tomáš Matuška, Ph.D.

The subject of the research is a ventilation unit with a heat pump providing vacuum ventilation in a specific family house. The year-round energy balance of the operation was prepared from the obtained parameters. For a total heat loss of 5 kW, the seasonal heating factor SPF of the entire system was evaluated at the level of 2.5.

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.

16.3.2020
Ing. David Pálenský, Ing. Antonín Lupíšek, Ph.D.

This is a case study of a multifamily residential building that has been environmentally assessed in terms of greenhouse gas (GHG) production using a simplified life cycle assessment (LCA) method. The results of total GHG emissions were compared to the emission limit value, which was set based on the climate objectives of the Paris Agreement and the scientific report The Emissions Gap Report. In response to the non-compliance with the emission limit, a number of emission-saving measures have been proposed and have been suitably designed into variants meeting the emission requirement.

9.3.2020
Ing. David Pálenský, Ing. Antonín Lupíšek, Ph.D.

This is a case study of a multifamily residential building that has been environmentally assessed in terms of greenhouse gas (GHG) production using a simplified life cycle assessment (LCA) method. The results of total GHG emissions were compared to the emission limit value, which was set based on the climate objectives of the Paris Agreement and the scientific report The Emissions Gap Report. In response to the non-compliance with the emission limit, a number of emission-saving measures have been proposed and have been suitably designed into variants meeting the emission requirement.

5.3.2020
Ing. Sebastian Vaculík, doc. Ing. Petr Bača, Ph.D., Ing. Josef Máca, Ph.D.

The main topic of this paper was to count the price for 1 kWh of electric energy in a different battery systems. The prices were determined from the datasheets of the manufacturers. The stationary lead acid batteries and LiFeYPO4 batteries are recommended because of their great properties.

16.12.2019
Ing. Nikola Pokorný, doc. Ing. Tomáš Matuška, Ph.D.

The article acquaints readers with the situation on the European and world market for hybrid photovoltaic-thermal (FVT) collectors. This year, FVT collectors first appeared in the world statistics of solar thermal systems as a significant part of the market. However, their installations are still rare in the Czech Republic.

2.12.2019
Ing. Viacheslav Shemelin, doc. Ing. Tomáš Matuška, Ph.D.

The global market for solar thermal collectors has been steadily declining since 2010, but the decline has come to a halt and, with the current trend, growth can again be expected in the coming years.

14.10.2019
Ing. Jiří Novotný, doc. Ing. Tomáš Matuška, Ph.D., Časopis Vytápění, větrání, instalace

The paper presents an analysis of PV system usage without a battery storage to cover electricity consumption for single family house with 4 persons and heat pump as a heat source for heating and preparation of domestic hot water. The result of the analysis shows the importance of using a sufficiently short time step of load profiles for correct assessment of solar fraction of PV system. Simplifying chart for fast estimation of solar fraction in a given application (heat pump, user energy) has been developed.

9.9.2019
Ing. Viacheslav Shemelin, Ing. Bořivoj Šourek, Ph.D.

The paper deals with simulation analysis of solar system for domestic hot water preparation for apartment building. The analysis shows the influence of climatic conditions on solar system gains. The aim is to verify whether the level of solar gains can be guaranteed in the Czech Republic's climatic conditions. In discussions over the efforts to guarantee the benefits of a designed and installed solar system, another question arises as to how the total solar radiation changes year-on-year and whether its annual fluctuations can be simply passed on to the solar system's profit.

2.9.2019
doc. Ing. Petr Horák, Ph.D., Ing. Jakub Horák

The authors answer the question how to choose a heat source for a family house built with respect to the current thermal technical requirements. An example is new building of a two-storey family house approximately 20 km south of Brno with a residential part of the house with a square plan of 11 × 11 meters. The evaluation results are compared according to five different criteria.


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