Peter Pilát’s research while affiliated with University of Žilina and other places

This study investigates the effects of hydrogen addition on the laminar flame speed of natural gas using computational simulations performed with Cantera. The calculated laminar flame speed of hydrogen-enriched natural gas mixtures was simulated across a range of equivalence ratios (0.6-2) and hydrogen fractions (0-25% by volume). The modified GRI-Mech 3.0 mechanism was employed. Results demonstrate a significant increase in laminar flame speed with increasing hydrogen content, with the effect more pronounced at higher equivalence ratios. The peak flame speed was observed in stoichiometric conditions with increasing hydrogen fraction. The highest speed is achieved with a 25% hydrogen concentration in a natural gas mixture, reaching 45.219 cm/s at an equivalence ratio of 0.9. This study provides insights into the combustion characteristics of hydrogen-enriched natural gas and demonstrates the utility of Cantera for such simulations.

The article deals with the optimization of biomass combustion in a small heat source using the optimal distribution of combustion air. Uneven distribution of combustion air was observed during certification tests and in real operation of the used heat source and has an impact on uneven combustion of biomass in the gasification chamber, on increasing emissions and combustion losses. In the first phase of the research, optimization was carried out using CFD simulations, then a transparent model of a real heat source was created, on which the real distribution of combustion air in the gasification chamber was observed using the Particle Image Velocimetry (PIV) method. The results of CFD simulations and the PIV method led to the optimization of the cross-sectional profiles of the four supply channels for gasification air supply. CFD simulations and subsequent PIV measurements on the experimental device were carried out without real combustion, only the air flow in the empty gasification chamber was investigated. This approach was chosen in order to simplify calculations and experiments and on the assumption that with optimal distribution of combustion air in the empty chamber, there will be an optimal even during real combustion. The flow of primary air in the gasification chamber in real operation is influenced by the size and shape of the inserted biomass and its location in the chamber, and this influence is random and difficult to verify. After optimization, the distribution of the primary combustion air in the gasification chamber is uniform and the same amount of air flows into the chamber through the four combustion air inlets.

Human life is inextricably linked to the generation of waste, whether at the municipal or industrial sphere. Waste is an important source of secondary raw materials and stored energy, which nowadays is advantageous to use. The most suitable way of waste recovery is its recycling and reuse. The share of waste that is unsuitable for recycling for various reasons is high, it currently exceeds the processing capacity of the Slovak Republic and is therefore deposited in landfills. The energy stored mainly in chemical bonds is therefore not used. The share of energy stored in this way is considerable, and its use would help not only in the field of rational waste management, but also in the field of power industry. The simplest way of energy recovery of waste is its direct combustion, more complex technologies are its gasification and pyrolysis. All technologies are called as Waste to Energy systems. Combustion of waste releases stored chemical energy, which is converted into heat, which is used for the production of electricity and heating. The products of gasification and pyrolysis are gaseous and liquid fuels that can be directly used in heat sources for the production of electricity and heat for heating, but also as an input material for the creation of high-grade fuels and for the chemical industry. The article deals with the conceptual design of a small facility for the recovery of waste, especially plastics, from the automotive industry and sorted municipal waste. The concept discusses the technical possibilities of preparing the input material, the technical ways of using it by gasification or pyrolysis, and the possibilities of using the resulting products of processing plastic waste. The assumptions for the design of a small waste recovery facility are verified on an experimental pyrolysis waste treatment device, the article contains the results of laboratory pyrolytic waste treatment and the properties of the resulting products.

The car is now a consumer product and its use has significantly decreased over the last decades. According to the sources of the Ministry of the Internal Affairs of the Slovak Republic, is to 31 January 2020 registered 3.286.258 motor vehicles and of which 2.395.362 are passenger cars, which means that per slovak citizen there is something below 0.5 of passenger vehicle. Used passenger cars make up the largest part of the car waste. This paper deals with how the waste from cars after their lifecycle in currently operating energy facilities.

The article deals with the optimization of biomass combustion in a small heat source by means of an optimal distribution of combustion air. The uneven distribution of combustion air has been observed in certification tests and in real operation of used heat source and it has an influence on uneven combustion of biomass in the gasification chamber, on increase emissions and combustion losses. At this stage of the research, optimization of the combustion air distribution is performed by CFD simulations, which will be later verified by PIV measuring of the velocity fields in gasification and combustion chambers of the experimental heat source. CFD simulations and subsequent PIV measurements on the experimental device are realized without real combustion, only the air flow in the empty gasification chamber and in the combustion chamber is investigated. This approach has been chosen to simplify calculations and experiments, and on the assumption that when the combustion air distribution is optimal in empty chambers, it will be optimal even during real combustion. The primary air flow in the gasification chamber is in real operation affected by the size and shape of the inserted biomass and its placement in chamber and this effect is accidental and difficult to verifiable.

For achieving of low emission in compliance of required performance parameters of small heat source affects a number of factors. It’s not just about redistribution and intensity of combustion air or flue gas temperature in the chimney. An important role in the combustion process also have a combustion chamber shape, size of embers, placing of the fuel in the chamber, positioning, distribution and temperature of combustion air entering into the combustion process, the tightness of the measured heat source or temperature of the combustion chamber. The bigger problem with the achievement of low emission limits occurs at the operation of gasification heat source in lower performance. The article discusses about the effects on the combustion process is simple structural adjustment of heat source - removal of water grate during operation at reduced performance. On measuring were used identical small heat sources (with and without lambda probe oxygen sensor, with water and without water grate), which uses principle of biomass gasification.

It is relatively complicated to effectively burn biomass. Combustion of biomass fuel itself as a renewable energy source does not automatically ensure the best use of its energy content with low emission production. Biomass combustion with bad settings of combustion conditions can be ineffective and with a high production of emissions. The article discusses the impact of humidity on the thermal technical parameters of the heat source. The influence of the relative humidity of combustion air and the fuel moisture on thermal power and emission production in automatic boiler for combustion of wood pellets were specifically determined. The results show that these properties of combustion air and biofuel have an effect on the thermal and emission parameters of biomass heat source. Biofuel moisture had higher impact on thermal power and emissions production in comparison with relative humidity of combustion air impact.

The article deals with design and construction of solar adsorption cooling device and with heat transfer problem in adsorber. The most important part of adsorption cooling system is adsorber/desorber containing adsorbent. Zeolith (adsorbent) type was chosen for its high adsorption capacity, like a coolant was used water. In adsorber/desorber occur, at heating of adsorbent, to heat transfer from heat change medium to the adsorbent. The time required for heating of adsorber filling is very important, because on it depend flexibility of cooling system. Zeolith has a large thermal resistance, therefore it had to be adapted the design and construction of adsorber. As the best shows the tube type of adsorber with double coat construction. By this construction is ensured thin layer of adsorbent and heating is quick in all volume of adsorbent. The process of heat transfer was experimentally measured, but for comparison simulated in ANSYS, too.

This article deals with possibility of solar system connection with adsorption cooling system. Waste heat from solar collectors in summer is possible to utilize in adsorption cooling systems, which desorption temperatures have to be lower than temperature of heat transport medium operation temperature. For verification of work of this system was constructed on the Department of power engineering on University of Zilina solar adsorption cooling device.