Search

Most popular renewable energy source is biomass. The typical form of biomass is wood. Use of wood for fuel have long tradition in Slovakia. Between a normally trees in Slovakia belongs beech and spruce. This article deals with the energy properties of spruce (Picea Abies). On different parts of the tree have been performed experimental measurements. The measured results show that the parts of the tree have potential for to the next application and processing.

This work deals with the utilization of solar energy using parabolic trough collector. Testing of solar collector manufactured according our own design has taken place in Žilina. Collector consists of firm frame attached to concrete floor, which limits the sun tracking to one axis. Trough of the collector is oriented as east-west position with a small deviation of approximately 10°. To obtain the best performance parameters of the collector, the optimal position of trough to the sunlight must be maintained. The aim of the work is to calculate the tilt angle for specific day and corresponding time of a day.

The fireplace combustion of wood is a significant and largely unregulated source of emission pollution. Therefore article deals about experimental measurements of emission parameters from combustion of biomass in small heat sources. The objectives of the present work are to analyse basic pollutants arising from the combustion process and to define measurement technique applied to characterise particle emissions from biomass combustion. Gravimetric methods are among the most accurate and precise methods of quantitative analysis and therefore was selected for measurement of solid emissions. Conclusion of work focus on evaluation of the tests results, especially concentration of particulate matter (PM) from the combustion of briquettes made from different kinds of biomass. During the combustion of certain briquettes was recorded a high amount of particulate matter and analyser switched to “stand by” mode in several cases. The results indicate that higher concentration of PM was determined in the case of briquettes made from phytomass in comparison to briquettes made of woody biomass.

The work deals with the transformation of solar energy into thermal energy through concentric solar collector. The subject of the research is the parabolic trough collector situated in Žilina. Solar collector including focal absorber was produced according to our own design. The absorber consists of two black coated contradictory pipes serving as inlet/outlet of heat exchanger. The reflector is made of bent polished aluminium sheet. Collector uses automatic tracking system and consists of firm frame attached to concrete floor, which limits the sun tracking to one axis. Trough of the collector is oriented as east-west position with a small deviation of approximately 10°. To determine the required output of collector is necessary to perform optical and thermal analyses. The aim of the work is creating mathematical model to get a theoretical performance of collector. Mathematical model with calculations for specific collector and its geographical position is created in program MS Excel. Although the mathematical model provides theoretical performance parameters it doesn’t include the effect of environment and so the values differ from real conditions. The results of work will serve as an information basis for the following research of cogeneration system using a solar collector.

Straw belongs to heavier combustible fuels as it has low ash melting temperature. This article discusses the properties and effects of various additives suitable for application to straw in order to increase the ash melting temperature. From the laboratory-determined results of the application of various additives, the most suitable additive was chosen to improve the process of incinerating wheat straw in real conditions. This additive was calcium oxide. Testing of the additive was carried out in real conditions on operation of drying system situated near Nove Zamky. The drying system receives the heat from burning straw bales on the heat source. In the combustion process there are various problems due to the low melting temperature of ash straw. For this reason, slags and deposits occur in different parts of the combustion chamber and on the heat exchanger. These deposits must be removed at regular intervals, which cause heat source shutdown and drying. Addition of the additive on the surface of the straw bait was performed manually. The influence of additives on slags formation, thermal performance and emission production were measured during the experiment The results of additive testing have confirmed the positive effect of calcium oxide on the efficiency of the straw burning process.

Temperature as a primary aspect of the environment affects the drying process greatly. The temperature of drying air in a hot air drying depends on the temperature of the ambient air blown into the system. This temperature determines the drying time and energy consumption of the drying process. The work describes the effect of ambient temperature on drying of maize grain in particular drying operation.

Thesis deals with the measurement of performance and emission parameters of small heat source for combustion of biomass in each of its operating modes. As the heat source was used pellet boiler with an output of 18 kW. The work includes design of experimental device for measuring the impact of changes in air supply and method for controlling the power and emission parameters of heat sources for combustion of woody biomass. The work describes the main factors that affect the combustion process and analyze the measurements of emissions at the heat source. The results of experiment demonstrate the values of performance and emissions parameters for the different operating modes of the boiler, which serve as a decisive factor in choosing the appropriate mode.

Application additives into the material for the production of wood pellets achieve an improvement in some properties such as pellets ash flow temperature and abrasion resistance. Additives their properties influence the course of combustion, and have an impact on the results of issuance. The experiment were selected additives corn starch and dolomite. Wood pellets were produced in the pelleting press and pelletizing with the additives. Selected samples were tested for the production of particulate matter (PM) during their direct burn. The paper analyzing a process of producing wood pellets and his effect on the final properties.

Experiment is an operation or procedure carried out under controlled conditions in order to discover an unknown effect or law, to test or establish a hypothesis, or to illustrate a known law. The most important part of the experiment is to evaluate the measured values. Measurement accuracy depends on a number of factors. Deviations of instruments cannot eliminate or influence if it is neglect the possibility of using more precise measuring equipment. Another way for the most accurate results can be calibration. Calibration allows achieve measurement values with relatively high accuracy using less precision instruments. The paper deals about the problematic of thermal power measurement accuracy. Thermal power was measured on heat source with nominal thermal power 2 MW by using direct calorimetric method. There were used ultrasonic flow meter and type K thermocouples. Type K thermocouples are not very suitable for these applications because of their low precision. The paper presents the possibility of using calibrated thermocouples for the thermal power measurement with acceptable accuracy.

Phytomass, particularly wheat straw as a source of energy has countless benefits, but it has many problems in its direct burn too. The worst problem is the ash flow temperature. The aim of study was to analyze and reduce the problems of the wheat straw combustion. The experiment was conducted under realistic conditions. In this paper was implemented analysis of ash features with and without adding additives into the wheat straw. Selected samples were laboratory processed and examined. The result of the work was the impact of additional additives for ash features.

The article deals with the utilizing of solar energy by the means of concentric trough collector based on own design. It focuses on achieving optimal position of the trough with respect to incident radiation during its operation. Due to the collector virtual sun tracking system, which was proved to be ineffective and could not achieve the desired results, the optimum position had to be maintained by manual control of rotation. The measurement of the angle of rotation of the concentric trough is realized using the ARDUINO electronic platform, for which the program was created in the software ARDUINO (IDE) 1.8.4.