Numer 14 (3-4) 2021
Redaktor: Józef Zasadziński
Spis treści
Strony
Pobierz
Grzegorz Szerszeń,
Damian Zygadło
Falownik trójfazowy ze zmiennym algorytmem sterowania
DOI: https://doi.org/10.5604/01.3001.0015.6741
1 – 11
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Słowa kluczowe

przemiennik częstotliwości |falownik |modulacja PWM |sterowanie skalarne

Streszczenie

W pracy przedstawiono budowę trójfazowego przemiennika częstotliwości z możliwością wyboru typu modulacji PWM oraz płynną zmianą częstotliwości sygnału modulowanego. W praktyczny sposób zrealizowano różne algorytmy sterowania falownika w tym samym układzie sprzętowym z wykorzystaniem procesora STM ARM Cortex M3. Zastosowanie modulacji THIPWM pozwoliło zmniejszyć zawartość harmonicznych w sygnale wyjściowym i efektywnie wykorzystać możliwości źródła zasilania. Układ posiada możliwość wyboru jednego z dwóch algorytmów sterowania skalarnego, z opcją kompensacji wpływu rezystancji stojana na moment obrotowy wału silnika w początkowym zakresie charakterystyki sterowania liniowego przy stałym stosunku napięcia do częstotliwości. Badania potwierdziły, że najkorzystniejszym typem modulacji PWM w tym układzie jest modulacja jednobiegunowa dwubrzegowa. Wykorzystanie metody THIPWM, skutkowało zyskiem amplitudy podstawowej harmonicznej napięcia wyjściowego dla trójfazowego trybu pracy falownika względem metody SPWM. Uzyskano także odpowiednią precyzję kroku regulacji częstotliwości, a rezultaty badań potwierdziły funkcjonalność przemiennika.


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Grzegorz Szerszeń
Akademia Tarnowska


Damian Zygadło
Akademia Tarnowska
Péter Hermanucz,
Gábor Géczi,
István Barótfi
Modeling and measurement methods for multi-source heat pumps
DOI: https://doi.org/10.55225/sti.314
12 – 17
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Słowa kluczowe

multi-source heat pump |heat pump modelling

Streszczenie

Multi-source heat pumps are gaining prominence as energy prices rise and environmental efforts intensify. This type of heat pump system can be used for industrial processes as well as for heating. However, it is a challenge to properly model the two heat sources, possibly operating in parallel, to provide the appropriate input parameters for the design process. The aim of our work is to compile a system that is suitable for the parallel operation of two heat sources. We can compare the measured data with the results of the software used for modeling.


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Péter Hermanucz
Węgierski Uniwersytet Rolnictwa i Nauk Przyrodniczych

Gábor Géczi
Węgierski Uniwersytet Rolnictwa i Nauk Przyrodniczych


István Barótfi
Węgierski Uniwersytet Rolnictwa i Nauk Przyrodniczych
Rajab Ghabour,
Péter Korzenszky
Effect of in series and in parallel flow heater configuration of solar heat system for industrial processes
DOI: https://doi.org/10.55225/sti.315
18 – 26
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Słowa kluczowe

solar thermal |industrial processes |in series |in parallel |process heat

Streszczenie

The boiler is an enclosed vessel that transfers the energy from fuel combustion or electricity into hot water or steam. Then, this hot water or pressurized steam is used for transferring the heat to a certain heat process. Usually, the required hot water or steam keeps on varying throughout the day which also may be implied on the daily or monthly load. Therefore, several configurations of connecting the boiler into the solar heating system ensure the temperature of the final output. The boiler can be connected in series or parallel to improve the efficiency of the overall process as well as to reduce the running costs. This paper presents a simulation study of a solar heating system for industrial processes. Two flow-heater system configurations are designed for covering the heat demand of a pasteurising factory existing in Budapest, Hungary. The configuration “A” consists of a solar heating system for hot water preparation using in series flow heater configuration. While configuration “B” consists of the same solar system but with a parallel flow heater configuration. These system configurations are modelled using T*sol software for evaluating the system performance under the Hungarian climate from five different aspects: required collector area, glycol ratio, volume flow rate, relative tank capacity, and tank height-to-diameter ratio. According to the optimum design parameters, in series configuration is better than parallel by 3.14% at 45 m² collector area, 0.45% at 25% glycol ratio, 0.42% at 50 l/h · m² volume flow rate, 2.05% at 50 l/m² relative tank capacity, and 0.42% at 1.8 tank height-to-diameter ratio respectively. The results show that in series configuration is better in terms of solar fractions than parallel configuration from all five aspects.


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Rajab Ghabour
Węgierski Uniwersytet Rolnictwa i Nauk Przyrodniczych


Péter Korzenszky
Węgierski Uniwersytet Rolnictwa i Nauk Przyrodniczych

Achraf Qor-el-aine,
András Béres,
Géczi Gábor
The concentration level of PM10 in southern Poland (Katowice, Kraków, and Rzeszów) during the year 2018
DOI: https://doi.org/10.55225/sti.8
27 – 34
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Słowa kluczowe

Kraków |PM10 |Coal Mines |HYSPLIT trajectory frequency analysis |Katowice |Rzeszów

Streszczenie

Human health and food quality are greatly affected by the state of the ambient air. In the European Union, Poland is considered as a country that has the most polluted air. The level of PM10 concentration exceeds the EU limit value in almost all the areas of Poland, but higher concentrations are registered in the southern regions, which are considered as the coal heartlands. Katowice, Kraków, and Rzeszów are three big cities in the southern part of Poland and are surrounded by coal mining industries. High PM10 concentrations are usually registered in these three cities, especially in the winter period. In 2018, the peak PM10 daily concentration occurred in the three cities at the same period (04/03/2018 in Rzeszów, 05/03/2018 in Kraków, and 05/03/2018 in Katowice). The aim was to identify the effect of each of the 8 coal mines that exist in Poland on the level PM10 concentration for the first week and March where the highest daily PM10 concentration for the year 2018 was registered. Using HYSPLIT Frequency analysis, the results showed that 100% of the particles coming from Bełchatów, Bolesław Śmiały, Halemba, Jas-Mos, Pniówek and Marcel Coal Mines hit Katowice region, and 10% from Bogdanka. While for Kraków, it was affected by 100% of the particles that are originated from Bolesław Śmiały, Pniówek, Halemba, and Jas-Mos Coal Mines and 10% Bogdanka, Bełchatów, and Marcel Coal Mines. Moreover, Rzeszów was the least affected city by the coal mines, 10% of the particles coming from Bogdanka, Bełchatów, Jas-Mos and Marcel, Halemba, and Pniówek Coal Mines attributed to high PM10 concentration during the first week of March 2018. Katowice and Kraków are more affected by the coal mines industry, Particulate Matter particles originating from the coal mines sites contribute to the high level of PM10 concentration.


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Achraf Qor-el-aine
Węgierski Uniwersytet Rolnictwa i Nauk Przyrodniczych


András Béres
Węgierski Uniwersytet Rolnictwa i Nauk Przyrodniczych

Géczi Gábor
Węgierski Uniwersytet Rolnictwa i Nauk Przyrodniczych

Robert Toman,
Martina Pšenková,
Ivan Imrich,
Svätoslav Hluchý,
Simona Almášiová
Essential and non-mutagenic elements in raw ewe milk
DOI: https://doi.org/10.55225/sti.316
35 – 45
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Słowa kluczowe

macroelements |microelements |risk elements |metals |non-mutagenic elements |ruminants |ewe milk

Streszczenie

The monitoring of metals and other chemical elements in the basic sources of diet, mainly for children, is very important for preventing health issues. The aim of this work was to determine the concentration of selected essential (Ca, K, Mg, Mo, Na, Zn) and non-mutagenic elements (Ag, Al, Ba, Li, Sb, Sr) in ewe milk from the Orava region in northern Slovakia. Twenty milk samples were analysed in June and August using an inductively-coupled plasma optical emission spectrometry. The differences in elements concentration between the seasonal periods were not significant (p < 0.05), except for lithium (p < 0.05). The essential elements concentration was within the recommended levels, while the non-mutagenic and potentially toxic metals consist was under the permissible limits. However, there were found very strong and significant relationships between the elements which may suggest the synergistic / additive or antagonistic effects of some elements.


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Robert Toman
Słowacki Uniwersytet Rolniczy w Nitrze (Slovenská poľnohospodárska univerzita)


Martina Pšenková
Słowacki Uniwersytet Rolniczy w Nitrze (Slovenská poľnohospodárska univerzita)


Ivan Imrich
Słowacki Uniwersytet Rolniczy w Nitrze (Slovenská poľnohospodárska univerzita)


Svätoslav Hluchý
Słowacki Uniwersytet Rolniczy w Nitrze (Slovenská poľnohospodárska univerzita)

Simona Almášiová
Słowacki Uniwersytet Rolniczy w Nitrze (Slovenská poľnohospodárska univerzita)
Akademia Tarnowska
ul. Mickiewicza 8
e-ISSN 2544-9125
33-100 Tarnów