Renewable Energy Sources: Engineering, Technology, Innovation

The subject of the work concerns the design of a hybrid solar system to maintain mesophilic conditions in the process of anaerobic biomass decomposition. The main purpose of the work was to design a hybrid heating installation for a biomass utilizer. It was assumed to simulate the use of three energy sources: photovoltaic panels, solar collector and heat from biogas combustion. It was assumed that the results of the analysis will be supported by evaluation of biogas yield for substrates containing food and feed ingredients. The quasi-continuous and periodic operation of the rendering chamber was tested in relation to the energy demand for maintaining the mesophilic conditions in the fermentation process. As a result of the objective of the work, biogas productivity tests of the selected substrate mixture were carried out. A general design of the utilization plant (microbiogas plant) was also carried out, including thermal insulation and the design of the heating system. In order to determine the heat losses of the digester, the methodology based on the heat transfer coefficient by individual partitions was used. The level of biogas production was determined using a test stand complying with the requirements of DIN 38 414 S.8. On the basis of the volume of biogas production, thermal deficiencies resulting from its combustion were determined. Biogas deficiencies constituted more than 30% in the worst computing conditions for the periodic system and about 6% for the quasi-continuous system. The designed heating installation, which uses additional solar energy, will allow, in the case of a periodic system, to cover 100% of the summer heat demand. In winter, the coverage of heat demand was around 90% for average monthly temperatures in December and January and 80% for the worst computing conditions. Identified energy shortages can be limited by optimizing the control of the biological process and optimizing the parameters of thermally insulating layers.

Demand for energy, which is largely produced from fossil fuels, is increasing together with civilizational development. Using this type of fuels contributes to considerable pollution of the natural environment, and results in the increase of the average temperature worldwide. Another problem is that the deposits of fossil fuels will likely run out in the next century. In order to limit the greenhouse effect and other adverse effects of using fossil fuels, an attempt was made to find renewable resources of energy to replace them. One of such fuels that may successfully replace hard and brown coal, crude oil or even natural gas, is biomass, one type of which is nutshells. This work contains results of research on energy properties of nutshells of selected nut species. The following properties were examined: the nutshell share in the total mass of the nut, water content (u), moisture and ash content as well as calorific value of nutshells. The results of the conducted examinations indicate that the outer shells of nuts are characterized by very good energy properties, due to low moisture and small ash content as well as high calorific value.

The production of microglons for energy purposes is difficult and costly. One of the important parameters influencing the efficiency of photosynthesis in photobioreactors is light radiation. In order to obtain information on the distribution of intensity of photosynthetic active radiation PAR in the PBR space measurements of the photon flux (PPFD) were measured at the nodes of the measured mesh. The tests were made for two cylindrical LEDs in designed photobioreactors. The measurements were made during the culture inside the culture medium using a Quantum MQ-200 Apogee Instruments Quantum Digital Meter. The tests were performed for the different intensity of light, light colour and the length of exposure time. Preliminary lighting studies have spearheaded the first stage of the modeling and lighting optimization process in the designed photobioreactors. They allowed the following conclusions: No statistically significant differences were found between the instantaneous intensity of PAR radiation for the analyzed photobioreactors, The increase in biomass of alga results in a change in the intensity distribution of photosynthetic active radiation PAR in photobioreactors, The increase in optical density in the photobioreactor causes a decrease in light intensity within the reactor.

In recent years, biomass is one of the most important renewable energy sources. Most often it is a material with a high water content, which reduces its energy potential. Therefore, it is necessary to carry out the preliminary drying phase. The purpose of the work was to analyze the kinetics of drying of waste resulting from the production of juices obtained by extrusion. Drying process (forced convection, medium flow rate 1.5 m s−1 are, initial relative humidity 5–10%) were carried out at various temperatures of 45, 76, 96 °C, for apple pomace, formed in the form of cuboidal cubes. The influence of process parameters on the drying kinetics was determined. The drying curves and the drying rate over time and the water content in the sample at a given process temperature were analyzed.

Fuel combustion optimisation in compression-ignition engines with multi-stage HPCRS injection is the main direction of research in the area of the thermodynamic stability of fuels with FAME addition, also including the formation of PM. This paper presents stages of multi-aspect diagnostic inference in relation to the causes of failures of an engine’s functional systems as a result of PM deposits. The engine operating parameters were evaluated using a dedicated tester, showing the significance of diagnostic procedures during the vehicle servicing periods, which prevent the occurrence of emergency states signalled by the MIL warning lamp. The diagnostic procedure showed a gradual injector dysfunction which contributed to PM formation, necessitating an earlier service intervention. XRF spectrum analysis in relation to the determination of elements forming the PM along with IR spectroscopy showed the presence of organic FAME compounds in the PM deposit.

In this article, we report on the dehydration of bioethanol over solid acid catalysts―0.1 mmol g−1 of phosphotungstic acid loaded on activated carbon carriers obtained from waste biomass. An ethanol vapor showed a selective transformation, catalyzed by the phosphotungstic acid, into diethyl ether at between 120 and 150 °C. At the temperature range of 180–205 °C, the ethanol conversion reaches almost 99.7% with 100% selectivity towards ethylene. The adsorption and catalytic studies have shown that the oxygen-containing functional groups on carbon solids act as sites of the immobilization of phosphotungstic acid and of the ethanol adsorption contributing to alcohol dehydration.

The reduction of fossil fuels usage and increase of local agricultural and forest residues for energy purposes belong to the main drivers to face with a climate change in a sustainable and environmentally friendly way. One of the alternative sources of wooden residues from agriculture is biomass generated during a regular fruit trees pruning. In Poland, there is a significant potential of pruned biomass from apple orchards that might be used to produce energy. In the paper the options of pruned biomass harvesting applying baling technology are presented. Next, the possibilities of the bales handling and their optional further treatment to produce energy are described. It was shown that depending on the local market requirements, the energetic use of pruning residues is feasible and may parallel lead to the CO2 emission reduction to the atmosphere.

The work assesses physical properties of pellets produced from wood of coniferous and deciduous trees of different varieties. Four assortments of pellet produced by three main pellet producers, i.e. Duraterm, Ecogold and Happypellet were used for this purpose. Results of research related to specific density, bulk density, calorific value, volatile matter content and ash content of the analysed materials were similar to those provided by producers.

This work examines the impact of pre-treatment of wood biomass with ultrasounds with the frequencies of 21 and 40 kHz on the process of convective drying in a chamber dryer. Convective drying is a relatively cheap and widely used method, characterized by a free flow of heated air by the material being dried. The white willow (Salix alba L.) was used in the research due to its availability and the highest coefficient of use for energy-related purposes in Poland. The goal of the work was to assess the impact of ultrasound pre-treatment of wood biomass on the process of convective drying. Samples of the white willow (Salix alba L.) were pre-treated with ultrasounds with the frequencies of 21 or 40 kHz for the period of 10, 30 and 60 min. After ultrasound pre-treatment, the material was dried in the convective dryer using free convection method, at the drying temperature of 60 °C.

Energy willow planting process requires the use of highly effiecient and productive machines. The analysis of construction of machines for planting energy crops, forest plantations and seedlings and the processes which take place in the process of planting made it possible to systemize the accumulated experience in the design of planting machines, and highlight the most effective technical solutions. The revealed features of planting machines for different types of planting material are compared with the designs of energy willow planting machines. This study found a number of characteristics and advantages of different machine types, which will ultimately lead to an increase in productivity of planting aggregates and will facilitate the work of a planter.

The paper analyses the efficiency of apple pomace production in an enterprise producing dried vegetable and fruit. The dried vegetable and fruit was traditionally produced in drum driers. Pomace it is the pulpy residue remaining after fruit has been crushed in order to extract its juice and constitutes up to 25% of the total processed raw material. The research shows that to produce 1 ton of dried fruit is needed about 3.2 tons of dried pomace and about 400 kg of coal dust is consumed. The economic production efficiency was estimated at over 178% and the profit on sales of 1 ton finished product was 185 PLN. The costs of the enterprise directly related to production were taken into account and expressed in net terms. Investigating energy consumption in the production of dried pomace extracts, it was found that to reduce the humidity 1 of ton of pomace by 1%, it was necessary to use 142 MJ of energy in various forms. Increasing the efficiency of production must be associated with a reduction in the amount of heat for drying and introducing changes in technology.

As of today, petrographic studies on charcoals and charcoal briquettes in Poland are rarely used as a source of information on the quality of fuels used for grilling. It should be noted that, according to the Polish Standard PN -EN 1860-2, petrographic analyzes of coals and briquettes are obligatory before placing the discussed fuels on the market. However, in the case of the majority of coal and briquette producers, these tests are carried out only once in order to receive a long-term certificate for the entire range of products. Most entrepreneurs believe that the process of producing grill fuels is stable and the parameters of wood used for their production are characterized by a very low variability. The same opinion prevails among the producers of charcoal briquette and is the reason why the tests, which should be carried out for each batch of a product entering the market, are rarely performed. Another argument in favor of the mentioned tests is the fact that fine coal and coal dust of both domestic and foreign origin are used in the production of briquettes. The presented article, based on petrographic analysis of coals and charcoal briquettes, pays special attention to the differences in the content of impurities in the analyzed material from different production periods. The research material was obtained from producers at the beginning of the calendar year (previous year’s production) and in autumn of the year in which the analysis was carried out (current-year production). In addition to the petrographic analysis, showing the percentage of solid contaminants, TOC, analyzes were performed for individual coals and briquettes. Furthermore, petrographic examination of grill ash was carried out. Additional examination of the material in terms of carbon content (TOC) has shown differences between the individual batches from different production periods. Supplementary petrographic analysis of ashes was carried out in order to show the amount of remaining solid impurities in the obtained material after the grilling process. The determination of the amount of remaining solid impurities in the ash was aimed at demonstrating their suitability as additives to gardening soil. The ash admixture in soil is associated with its deacidification in the case of an unwanted pH change during the production of gardening soil and with additional mineralization of the product intended for balcony garden.

The paper presents biomass as an alternative renewable energy source for fossil fuels, the combustion of which provides neutral CO2 emission, thereby making it the potential main primary energy medium in Poland. The paper also presents the heat results of combustion, humidity, content of ash, volatile compounds and C,H,N,S in selected dry pellets (straw, hemp willow, wheat straw) with division into fractions: 0.5 mm, 0.25 mm, 0.125 mm and below 0.125 mm. In relation to the analysis of the study results, the paper includes a discussion on the requirements specified in standards regarding biomass quality research and especially concerning the basic parameters determining the energy value of biomass (combustion heat, humidity, volatile organic compounds, ash content, CHNS).

Biomass has been used by humans since immemorial time to obtain heat. The current trend of using biomass and replacing it with coal is mainly related to the implementation of EU targets for reducing carbon dioxide emissions. The aim of the work is the analytical determination of physical properties (including energy) of granular biomass (rice and corn) for their further energy processing. Determination of the properties of crushed biomass, and at a later stage burned, is of key importance in the development of energy and environmental efficiency indicators for preparatory processes, e.g. grinding and, consequently, combustion. Based on the analysis, it was found that rice and corn grains are a valuable source of energy and can be successfully used as alternative, renewable energy sources. The results of experimental studies have shown that corn grains are characterized by better energy properties. The analysis of the literature regarding the properties of rice and corn grains as well as the results of own investigations are the basis for determining the influence of biomass properties on the processes of its further processing (including grinding) and to develop energy and environmental efficiency models and the original CO2 emission indicator.

The presented work presents an analysis of the possibility of obtaining straw from soybean cultivation from Ukraine for energy purposes. The work included obtaining raw material from soy plantations (in the form of yellow straw and gray) and processing them into plots. A number of tests for the determination of quality parameters were carried out to determine the practical potential. It has been shown that straw as a residue from the production of soybeans is a good raw material for the production of plots as renewable fuel. The quality parameters of the analyzed pellets indicate that it is characterized by a quality similar to fuels made from straw from classic cereal crops. The advantage of the raw material in the form of gray straw was also shown in relation to the fresh yellow straw.

The objective of the paper was to determine the energy efficiency of biomass production from Sida hermaphrodita and miscanthus in the selected farm. The paper covered research for the real residential building. Calculation of energy consumption of biomass production were made for theoretical plantations with the surface area of 1.20 and 1.30 ha. Energy needed for biomass production from Sida hermaphrodita is 27 606.1 MJ ha−1, while for the miscanthus it is 30 198.9 MJ ha−1. In the structure of energy consumption of production the highest share is in case of materials and raw materials (37.6% for Sida hermaphrodita and 32.8%—miscanthus), energy carriers (31.5% and 32.8%) and then investment means (17.2% and 20.9%) and human labour (13.7% and 13.4%). In case of Sida hermaphrodita, energy efficiency of biomass production from the acreage of 1.20 ha is 6.5, namely, more than six times more energy will be obtained in the first year of biomass production from Sida hermaphrodita than energy incurred on setting up the plantation. In case of miscanthus, for the surface area of cultivation of 1.30 ha the estimated index is 5.6.

The research was carried out on a SRC willow plantation (Salix viminalis) cultivated in a three-year cycle, established in 2010. Obtained results come from 2013–2015 and cover the second rotation of biomass production. The aim of the study was to evaluate the reaction of two clones of SRC coppice (shrub willow)–Sprint and Boks–to organic and mineral fertilization in light soil conditions. The experiment included two clones–Sprint and Boks, and three fertilizer combinations: without compost 0, 10 and 20 t ha−1 dry mass of compost produced from municipal green waste. Following rates of nutrients in the form of mineral fertilizers were used annually on experimental objects: 100 kg N, 80 kg P2O5 and 120 kg K2O ha−1. Detailed determinations included: number of shoots per plant, shoot thickness at a height of 10 cm from the soil surface and length of shoots as well as fresh and dry weight. On all fertilizer combinations, Boks clone has developed fewer shoots per plant, but with a greater thickness and length compared to the Sprint clone. Boks clone was characterized by a greater production potential in the second production cycle and reacted with a higher increase in fresh and dry matter yield after using compost in doses of 10 and 20 t ha−1, against the background of mineral fertilization.

The mathematical model of the dynamics of thermal processes in a bioreactor was proposed and time of the transition process was determined. The results of theoretical research were presented. The obtained results can be further used for the synthesis of the automatic temperature control system.

The article presents contemporary technical and technological capabilities in the production of biogas from organic substances of various types, including waste products which are a by-product of the operation of wastewater management facilities, as well as by-products of the meat industry and municipal waste management. Alternatives are discussed regarding traditional raw materials (those of the so-called first generation of biofuels), including raw materials obtained from waste materials, from the agricultural and food industries, and from plants with biofuel potential. The latest methods for pre-treatment of raw materials involving digestion of lignocellulosic structures, which are key for the effective use of the biogas potential of these substrates, are also discussed.

The article examines the development of the biomass market in Ukraine. It was noted that for Ukraine, bioenergy is one of the strategic directions of the development of the renewable energy sector, taking into account the high dependence of the country on imported natural gas and the high potential of biomass available for energy production. An analysis of the state of bioenergy development in recent years was shown that the total amount of energy from biomass is increasing. The existing resource potential of biomass and its source and the expediency of growing special energy crops for the production of electric and thermal energy were described. Capacity of biomass objects, the share of biomass among all renewable energy sources, as well as the state of supply of energy from biofuels and wastes were described. Attention was drawn to problems with access to woody biomass resources, as well as biomass of agricultural origin, which negatively affects the attraction of biofuels to the energy balance of the country and requires the creation of a civilized biomass market. To achieve the set goals in the development of bioenergy, the importance of marketing concepts in the management system in this area of activity was disclosed. The model of fuel biomass market development was offered, which takes into account the factors that create obstacles in achieving the necessary level of development of this renewable energy sector. The model emphasizes the use of the concept of interaction, which involves the development of long-term partner relationships. This will solve communication problems in the biomass market.

Although the methane fermentation process has been known for a long time, the use of new agricultural substrates can increases the efficiency of agricultural biogas plants. Therefore, new mono-substrates and co-substrates are still being sought for increasing biogas potential. The use of beet mixed with other substrates can accelerate the fermentation process and improve the quality of biogas produced. The aim of the study was analysis of methane efficiency of sugar beets used as co-substrate in biogas production. Sugar beet mixtures with maize silage and wheat straw were studied. Sugar beet was added in various proportions, and their share was between 10 and 50%. The study was conducted at the Laboratory of Ecotechnologies, in Institute of Biosystems Engineering. To test the biogas efficiency the batch culture method has been used and the process took place in mesophilic conditions. The experiment was carried out in accordance with the German standard DIN 38414-S8. The results have shown that the use of sugar beet as a co-substrate in the production of biogas with other substrates has a positive effect on the methane yield.

Today small-scale wood stoves becoming increasingly popular in Poland, and the use of wood logs in small-scale units stoves is expected to increase substantially towards 2020. Many new constructions are created and numerical modelling of combustion processes is an increasingly important stage in the design work of new constructions. The article presents the numerical study of a combustion process in a wood stove. The computational fluid dynamics (CFD) model include fluid flow, chemical combustion reaction, and heat exchange. The simulation was proceeded by experiment with the commercially produced fireplace by company Kratki.pl. The test bench was designed according to PN-EN 13229 codes requirements. The successful verification of results with experiment was a base to perform a series of simulations to achieve the optimal construction with increased efficiency and reduction of the harmful components of combustion.

As the low emission of particulate matter (PM, or ‘floating dust’) and gaseous pollutants from coal-fired boilers is the main source of air pollution in Poland, more environmental-friendly alternatives for coal combustion should be considered. One of them is the co-combustion of coal and biomass. The following article describes the experimental co-combustion of different coal-biomass blends with the use of Galmet boiler, which is a part of a mobile educational installation designed by the AGH University of Science and Technology and Galmet. The research is concentrated on flue gas composition changes connected to the rising content of biomass in the blends. The flue gas composition was measured with the use of Testo 350 and Testo 380 probes. The combusted coal-biomass blends contained 10 wt%, 20 wt%, and 30 wt% of biomass pellets. The flue gas composition was also compared to the flue gas produced during the coal combustion in the same boiler. The results show that with the rise of the biomass content in the blend, the NO and NO2 content drops significantly, and in the case of blend with 30 wt% of biomass, no NO2 emission was detected. The SO2 content in the case of 10 wt% blend is slightly higher than the SO2 content in flue gas from coal combustion, but its content drops in the case of the 20 wt% and 30 wt% blends. No clear correlation between PM emissions and the biomass content in the blends was observed.

Pellet drzewny, klasyfikowany jako biomasa stała jest uznawany za odnawialne źródło energii. Pellet formowany jest w wyniku mechanicznej kompresji małych części biomasy roślinnej, produktów rolnych, leśnych, a także przemysłowych i odpadów (także tych używanych do produkcji mebli). Celem badań było porównanie jakości pelletów drzewnych używanych w domowych kotłowaniach opalanych pelletem oraz zweryfikowanie, czy istnieją duże różnice między pelletem certyfikowanym, a niecertyfikowanym, a także eksperymentalne oznaczenie pelletu dobrej i złej jakości używając wysokosprawnego kotła domowego. Eksperyment wykazał, że nawet niewielkie różnice w składzie chemicznym mogą mieć wpływ na proces spalania, ale także potwierdził dobrą jakość paliwa z popularnymi na rynku europejskim certyfikatami.

Bioenergy (energy from biomass) is still the most used source of renewable energy in most of countries around the world. Lignocellulosic crops e.g. willow (Salix spp.) grown as short rotation coppice are a valuable option for diversification of biomass sources that provide bioenergy. Such crops should be neutral in terms of CO2 emissions to the atmosphere; therefore, the amount of carbon supplied to the soil (and sequestered) along with residues after harvest must at least balance the amount of CO2 emitted to the atmosphere during cultivation, harvesting and biomass conversion. Therefore, the aim of this study was the theoretical analysis of the amount of willow biomass residues (i.e. above- and below-ground residues, harvest residues) that enter into soil on commercial plantation cultivated in triennial harvest cycle and to determine the carbon sequestration potential in soil. The research was based on actual biomass yields of seven different clones and varieties and post-harvest residues and carbon sequestration theoretically estimated on this basis. In addition, net carbon sequestration was determined based on actual CO2 emissions from crop cultivation on the plantation. Results showed large differences in the amount of estimated biomass residues that stay on the field after harvest (from 2.94 to 14.88 Mg ha−1 y−1 d.m.) and potential net carbon sequestration (from 0.07 to 0.99 Mg ha−1 y−1 C) between analyzed clones and varieties depending on biomass yield and emissions from cultivation. It must be emphasized, that in each case potential net carbon sequestration exceeded emissions from willow cultivation.

One of the methods for optimizing fertilization is the use of slow-release fertilizers, which are characterized by gradual release of fertilizer components to a soil solution, thus reducing their losses. However, slow-release fertilizers available on the market are expensive, and their use is often economically unsubstantiated. The aim of this study was to assess the possibility of absorption fertilizer elements introduced to soil in the form of fertilizer products based on torrefied biomass or biochar as well as mineral valorizing additives. To achieve the set objective, an incubation experiment was conducted. The experiment was based on assessing the capacity of absorbing fertilizer elements under conditions of using fertilizers that contain an organic component (torrefied biomass or biochar) and a mineral component (ammonium nitrate, potassium salt, ammonium phosphate, urea). The soil, along with the fertilizer, was incubated for 30 days. After that the amount of nitrogen, phosphorus, potassium, calcium and magnesium extracted with distilled water was determined. Results of the conducted experiment point to a positive effect of biochar and torrefied biomass on the absorption of nitrogen introduced with mineral fertilizers. Similar relationships were observed in the case of phosphorus and potassium, but to a lesser degree than in the case of nitrogen. At the same time, there was no difference in the effect of biochar and torrefied biomass on the level of nitrogen absorption. Fertilizers based on torrefied biomass or biochar valorized with mineral additives have properties characteristic for slow-release fertilizers.

Eutrophication is a very undesirable process, because the lake in which this process takes place losses most of its amenities. The deterioration of the water quality in the case of eutrophicated reservoirs is caused by the inflow of biogenic compounds that accelerate the development of plankton and higher forms of plant life. A perfect example of such a reservoir is Winiary Lake, located in the city of Gniezno in the Wielkopolska Voivodeship. The lake is located in the city centre, so it is exposed to strong anthropogenic pressure, which led to the degradation of the reservoir. There have been several attempts to restore the Winiary Lake, with various results. Currently, the condition of the lake has improved and it is overgrown with macrophyte, Potamogeton crispus—Curly-leaf pondweed. This pondweed is regularly pruned to extend its vegetation period. In this work the preliminary results of heating value and heat of combustion of the collected biomass will be presented.

The aim of the research and laboratory work was to determine the energy potential of raw materials obtained as a residue after harvesting of beans. Raw materials for research were obtained from farms cooperating with State Agrarian and Engineering University in Podilya. The material was harvested after harvest in October 2017. Analysis of quality parameters showed that the quality of obtained fuel granulates, both pellets and briquettes, is at a good level, placing them between a typical grain straw fuel and wood biomass fuel. The specific gravity and pellet dump density as well as mechanical durability indicate that the pellets as well as the briquettes are characterized by good parameters comparable to fuels found on the market.

The paper presents a preliminary analysis of the possibility of using residues from the production of maize grain for energy purposes. The physical characteristics of the analyzed raw materials were made together with the production of pellets. The quality assessment of obtained pellets and analysis of ash fusibility were carried out. The obtained results allowed to show that the use of residues from maize production for the production of solid biofuels is highly justified both for agrotechnical reasons and due to the parameters of the obtained fuels. The growing interest of agricultural producers in this type of crops in Ukraine means that the potential of these raw materials should be taken into account in balancing energy resources.

This article presents the results of research on biomass combustion process of vegetable origin in a 23 kW SAS boiler. The research material was prepared from sawdust and fruit pomace. The assembly of thermocouples in the experimental boiler allowed the reading of temperature values at individual levels of the combustion chamber. In addition, the composition of waste gases was monitored using the GASS 3000 flue gas analyzer. The obtained emission level was compared with the limit values in accordance with the Regulation of the Minister of Development in force. The physical parameters of the mixtures that were subjected to the combustion process were also examined. The analysis of static and dynamic material characteristics of biomass aims at finding a low-emission and at the same time high-efficiency renewable fuel, adapted to V class boilers.

The aim of the paper was to assess the efficiency of using fertilizer produced from FGD gypsum and fluidized bed combustion ashes (as combustion by-products at coal power plants) in crop production. The scope of work included laboratory analyses to examine the material for the content of macro- and microelements, and a vegetation experiment to determine its effect on the amount and quality of spring wheat yield and spring rape yield. Moreover, the study determined the impact of the analyzed material on selected physicochemical and chemical properties of soil. The research goal was accomplished through a vegetation experiment conducted in 2016 on brown soil made of loess. The experiment comprised five treatments which were repeated four times for each cultivated plant. The test plants included spring wheat cv. Monsun and spring rape cv. Belinda. The experiment scheme included the following treatments: control treatment I—without fertilization, II—with mineral fertilization, and three treatments with different levels of the fertilizer and a constant level of NPK fertilization. Calcium content in the investigated product was at the level of 34.2% CaO, sulfur—23.8% SO3, and iron—1.1%. The heavy metal content was below critical values for fertilizers or plant growth promoters specified in the Polish Act of 10 July 2007 on fertilizers and fertilization. The test results did not show any effects of the investigated product on soil reaction or on the content of available forms of calcium, phosphorus, potassium, magnesium and total content of nitrogen and carbon. However, in the treatments where the analyzed material was applied, we found an over three times higher sulfate sulfur content in the soil compared to the control treatment I and II. The investigated material did not influence the amount of plant yield. In the treatments with successive levels of the mixture of FGD gypsum and fluidized bed combustion ashes, we found a 20% increase in sulfur content in the wheat grain compared to the control treatments. In the case of rape, we found a 40% increase in sulfur content. The obtained results showed great fertilizing potential of the examined coal combustion by-products.

The article is concerned with the research results is to determine the energy value of straw buckwheat as another type of alternative fuel, because straw of agricultural crops is one of the main sources of bio-fuel in Ukraine. The conducted research has shown that it is possible to produce quality pellets for energy purposes. Obtained granulates are characterized by high mechanical strength, which promotes extended storage periods and the possibility of transport to distant places in Europe.

Jerusalem artichoke (Helianthus tuberosus L.) becomes a perspective plant that can be cultivated to obtain a large amount of shoots as energy biomass and tubers for the production of biofuels and valuable raw material in the food and medical industry and human diet. Because it grows well in a wide range of field conditions, the researchers are looking for biological preparations which would increase the biomass yield and at the same time would be an alternative to synthetic fertilizers contaminating the environment and plants. It is believed that one of such biological preparation can be Stymjod, which is the nano-organic-mineral fertilizer and produced by PHU Jeznach Sp.J. Because of scant information in literature, the objective of the presented research was to assess the impact of this stimulant on growth dynamics in field, biomass yield, photosynthesis parameters and activity of enzymes affecting plant development. The obtained results show that the foliar application of this preparation, added to one liter of tap water at dosages of 1–30 ml, increased activity of phosphohydrolases (pH = 6.0) and (pH = 7.5), ribonuclease and total dehydrogenase and also metabolic activities in leaves measured by index of photosynthetic dye (chlorophyll a + b), transpiration, net photosynthesis, stomatal conductance and decreased concentration of intercellular CO2. These enhancements were resulted in the increased dynamics of shoot growth and their yield of fresh and dry mass. The most effective in accelerating plant growth and yield was the twice plant sprayings with the studied biostymulator, at three week interval and at dosage of 15–30 ml L−1 (water). The Stymjod stimulating influence on growth and yield of plants designates its usefulness in Jerusalem artichoke production, as a partial alternative to artificial fertilizers and therefore favoring the reduction of toxic substances in plants used for energy, medical and human diet purposes.

The multifunctional use of macrophytes including production of biofuels, reduction of post-industrial waste, animal feed, phytoremediation and bioindication of toxicity, are developing directions that support the energy industry, including RES. The ash from Sorghum contains large amounts of macroelements, including phosphorus, nitrogen, potassium, calcium, as well as many micronutrients. The aim of the research was to determine the possibility of using ash from Sorghum as a media supplement for the cultivation of aquatic macrophytes. Plant cultivation was carried out in a phytotron room at 24 °C, 40 W light on a liquid medium supplemented with various concentrations of ash coming from the Sorghum combustion and control series. For all experimental series, Lemna minor L. plant growth analysis was performed by counting the number of fronds, determination of chlorophyll index, gas exchange (net photosynthesis, transpiration, stomatal conductivity of the cells and intercellular CO2 concentration), chlorophyll fluorescence, fresh and dry mass of plants as well as of important physical and chemical parameters of the medium i.e. COD, PO43− phosphates, NO3− nitrates. The energy value for L. minor L. biomass was determined. The experiments showed high sensitivity of plants grown on a medium supplemented with different concentrations of Sorghum ash compared to the control series, and depending on the concentration, the plant biomass increased proportionally. The medium supplemented with ashes was characterized by high physico-chemical parameters. The above studies indicate the possibility of using waste ashes and their management in supplementation of breeding media for macrophytes Lemnaceae, which constitute a new source of energy biomass.

Energy recovery from municipal and agricultural wastes is a major element of waste treatment. Refuse-Derived Fuel (RDF) is produced from Municipal Solid Waste (MSW) as an alternative fuel for power plants. Briquetting increases homogeneity and density of RDF, reducing costs of handling, transport and storage. In present studies, the properties of 1:1 RDF:wheat straw blend briquettes were investigated. Samples were manufactured in lab-scale EDZ-20 hydraulic press using die set of 50 mm diameter at 56, 66, and 77 MPa, at temperatures of 100 and 120 °C. Density, net calorific value (NCV), fixed carbon, volatile matter, ash content, and resistance to compression of the briquettes were analyzed. Moreover, structural parameters of RDF, wheat straw, and the briquettes’ ashes were examined by X-ray diffraction, using a high-resolution X-ray Diffractometer (Empyrean, Panalytical) with CuKα radiation and a Ni filter at generator voltage and current of 40 kV, 30 mA. Proportional detector was used. Samples were investigated at room temperature in θ-2θ geometry, from 10 to 70 deg with step size of 0.01 deg and counting time 6 s per point. Source divergence and detector slit were 1/2, with Soller slits. Crystalline phases were identified using HighScore Plus software package. Studies have demonstrated that the RDF and wheat straw mixture can be compressed to a density of 770–850 kg/m3. Also, heating rate of the die appears to affect density and durability of the briquettes. Consequently, RDF-wheat straw blend is feasible for feedstock in briquetting and can be used for waste management for energy purposes.

The presented work involves the issues of analysis of physical properties of residues from the production of fennel for grain. The basic properties essential for the quality assessment of solid biofuels such as pellets and briquettes were determined. The results of laboratory tests confirmed the preliminary assumptions that these raw materials are a good material for the production of solid biofuels. The quality of pellets and briquettes.

Energy crops and waste coming from agricultural production have the most promising perspective from all kind of renewable energy sources in Poland. Biomass is most often subjected to a compaction process in order to facilitate its energy use. Currently, intensive works on the process of biomass torrefaction are being carried out. In this paper author presents research results which are the optimum parameters of the torrefaction process. The most important information about torrefaction process are temperature and residence time. Both parameters are essential to designing and construction of industrial biomass torrefaction installations. In this investigation, authors examined the torrefaction process of two types of energy crops: cane, millet. Those types of biomass were dictated by the indicators: both biomass grow in low-grade soils and have increase in HHV. In this paper author has chosen thermogravimetric analyses and a setup with a batch reactor. Using thermogravimetric analyzer and installation with special design batch reactor for torrefaction process, cane and millet were investigated to obtain an optimal torrefaction process temperature, residence time and best fuel characteristic. Installation with batch reactor ensured the stability of energy crops torrefaction process and continues conditions. New founding’s about torrefaction process done by the authors were done using two types of analyzes: thermogravimetric and second using experimental setup with batch reactor to find best operation condition for carbonization of energy crops which is 30% of mass loss and the highest caloric value with that loss. Proper torrefaction process temperatures are a temperature in a range of 242–244 °C, and a residence time in a range of 12–13 min. These parameters could be used as a constraint in the design of torrefaction installations and also maintenance.

Ability to perform a simulation with reliable results require experimental verification of the numerical model and simulation methodology. To be able to make verification the test bench was designed and build according to PN-EN 13240 codes requirements with the additional data acquisition system. The bench data collected system consist of exhaust gas analyzer with a probe placed in the chimney which measures CO+, CO2, O2, NO, thermal imaging camera which monitors the temperature distribution outside the stove. To be able to monitor the heat distribution inside the combustion chamber the array of 36 thermocouples were placed inside. The data were recorded during entire wood burning cycle according to codes. Tested fireplace insert was the commercial product by company Kratki.pl. The successful verification of results with experiment was a base to perform a series of simulations to achieve the optimal construction with increased efficiency and reduction of the harmful components of combustion.

Today’s energy industry is currently facing an increasing demand for electricity. Besides to the use of coal, oil and gas, in recent years renewable energy sources have also are used. One of devices using renewable energy sources is fuel cell (FC). The most commonly used fuel for fuel cells is hydrogen. But, problems with storage of this fuel causes, that the finding new fuels for FCs are very desirable. One of these fuels can be linseed oil. Powering high efficiency power sources (like FCs) with renewable fuels (like linseed oil) will allow development of renewable energy sources and elimination or reduce of toxic substances emissions. The paper presents the research of linseed oil electrooxidation. The work shows possible electrooxidation of linseed oil emulsion (with Syntanol DS-10 detergent) on a smooth electrode (Pt). The maximum current density obtained during the measurements was equal 4 mA·cm−2. Thus, the possibility of using linseed oil to direct electricity production has been proved.

The porosity and bulk density of granular materials are closely related to the issues connected with the transport and storage of this type of materials. The article discusses the basic factors determining porosity and bulk density. Additionally, the influence of the two of these factors (moisture, shape factor) on the obtained values of bulk density and porosity was investigated. Non-linear estimation was performed in order to obtain an influence model of the analyzed factors. With respect to bulk density, the model was well fitted to the input data; yet, for porosity, the goodness-of-fit failed to be satisfactory.

The paper presents results of preliminary tests of selected biomass types on the basis of which it is possible to assess their agglomeration properties. The research material was the biomass commonly used as a raw material for the production of compacted solid biofuels. Used raw materials was widely considered as: easy to a pressure agglomeration (softwood—pine), difficult, straw kind raw material (miscanthus), and relatively little studied, in the context of the pressure agglomeration, raw material (cup plant). Has been developed and presented a course of action which allows in a parametric manner to classify a different kind of biomass in terms of its agglomeration potential. The presented method allows to assign the tested type of biomass to the proposed groups. This should give information which of the tested types of biomass has best features of the material promoting compaction and which of them has the characteristics of the material which made it hard to agglomerate. The developed method allows to assess the pro-agglomeration potential of a given type of biomass, omitting in this assessment the impact of moisture content and the degree of fragmentation of the raw material. It allows to parametrically indicate whether a given biomass can be used in the compacted solid biofuels production process as a binder, basic material or difficult material requiring the addition of a binder.

Existing machines for planting energy crops cuttings are characterized by the low productivity because of the speed restriction to hand stowing into a plant setter. Therefore, establishment of mechanisms for the cutting auto-stowing into a plant setter is a current scientific and production task. The research is set against the analysis of the known planting machine constructions that are used for setting the potted plants and forest seedlings. In this research, the methods of structural and factorial analysis with regard to the mechanisms’ arrangement were used, as well as peculiarities of the working processes occurring at each stage of the overall technological process of the cutting relocation from the reservoir to the land area were highlighted. In the issue of analysis, possible ways of different methods implementation into the technological process were singled out. This can be seen in the structural and logical scheme of the process. The promising solutions for planting automation of the energy crop cuttings were provided.

A simple and green visual method for determination of Total Acid Number (TAN) is proposed for analysis of different engine fuels, especially biodiesel, its raw materials and blends with petroleum fuels. Two 4-hydroxystyryl N-octylpyridinium bromides dyes: 4-[-2-(4-hydroxy-3-methoxyphenyl) ethenyl]-1-octylpyridinium bromide and 4-[-2-(4-hydroxy-3,5-dymethylphenyl) ethenyl]-1-octylpyridinium bromide were used as indicators. Determination of TAN in butanol medium in the presence of 10−5–10−4 mol/L of the indicator have shown a high color contrast. Well-marked transition from pale yellow to blue/violet merocyanine form provides for determination of more than 0.01 mg/g of free fatty acids and more strong acids with RSD 1–5%. For the vast majority of samples, the value of the acid numbers found by the proposed method is in good agreement with the data obtained according to the standard ASTM D664-11 method. The optimal conditions for analysis of TAN in diesel samples were found. Particular attention is paid to the FTIR-spectrometric determination of biodiesel content in commercial diesel fuel samples. The content of biodiesel with a characteristic peak in the region that is responsible for the carbonyl group (1730–1750 cm−1) can be seen on the IR spectra.

Geothermal energy, the internal heat of the Earth, has a tremendous energetic potential. As a renewable source of energy, it is an excellent alternative to conventional raw materials in the context of acquiring thermal energy and generating electricity. It can be also intended for recreational and balneological purposes. However, the use of geothermal energy is possible mainly due to deep boreholes, which at the present stage of technology development, remain the only rational solution. Since the stage of wellbore drilling is the largest financial burden of any geothermal investment it is a matter of great importance to properly design a borehole. The expected operating conditions should be considered, among which the pressure - artesian or subartesian, plays a crucial role. Also, the possibility of a justified adaptation of old explorative or abandoned petroleum wells for geothermal purposes is a preferable or even desirable solution of current years. Thus, the most important issues related to the construction of geothermal wells, in dependence on the expected artesian or sub-artesian pressure, are discussed throughout the paper. The existing examples of reconstructed (Mszczonów IG-1), dedicated or suggested for reconstruction (Poręba Wielka IG-1, Wiśniowa-1) wells located in Poland are characterized.

The rapid progress in photovoltaics increases the availability of inexpensive and reliable electricity for individual, industrial and commercial users. Photovoltaic installations convert solar energy into electric energy, thus reducing fossil fuel use and lowering greenhouse gas emissions. The Polish photovoltaics market began to develop rapidly in 2013, and the installed capacity of solar-powered systems continues to increase every year. According to the Institute for Renewable Energy, the total installed capacity of photovoltaic systems reached around 199 MW at the end of 2016. More than 101 MW was installed in 2016 alone, including 73 MW in micro-generation systems. Polycrystalline installations are most popular, and they are followed by monocrystalline modules. Solar panels covered with amorphous silicon and thin film are less popular solutions. The growth of the Polish photovoltaics market is driven mostly by high levels of consumer awareness rather than a cohesive energy policy. Solar panels have an estimated life of 20–30 years, which means that expired modules will have to be effectively managed in the near future. Recycling appears to be the most cost-effective and environmentally-friendly solution, and it can be used to recover more than 90% of the components and materials in solar panels. Recycling delivers a host of environmental benefits by saving energy and raw materials, minimizing the release of harmful chemical compounds, and reducing the space for storing expired and damaged panels. The article discusses various solutions for recycling photovoltaic modules as part of a strategy promoting the sustainable management of waste from expired PV systems.

In recent years the production of energy for own purposes from photovoltaic panels enjoys growing interest in Poland. In 2016 and 2017, more than a dozen thousand micro-installations (in the vast majority the photovoltaic) have been yearly connected to the network. However, the share of micro-installations in the total electricity production in Poland is still very small. Total power below 200 MW gives a share in the order of tenths of a percent. Comparing the installed capacity in photovoltaic sources in our country with the average of the European Union (over 3550 MW) we can expect it to grow in the coming years. Will this increase be generated by prosumers and their micro-installations? Yes, if they would find that it is just profitable.This paper discusses the key parameters—which are responsible for the profitability of investment in photovoltaics from the point of view of an individual customer—the owner of a detached house.

Currently built PV power plants are included in the national energy system, giving the opportunity to “store” energy in this system, provided that they are power plants with pico power or below 40 kWp. The concept of storage refers to the fact that excess energy is put into the energy system, and in the later period we can take from the grid less than 80% of what was given depending on the age of installed power of the PV plant. The operation of the power plant is settled on a semi-annual basis. The purpose of the work was to develop a simple methodology to determine the efficiency of energy use generated from a photovoltaic micro electric plant for the needs of users of prosumer installations. The research was carried out in a vegetable farm located in the Kazimierza Wielka poviat on three independent photovoltaic installations, which were used to cover the energy needs of the household and vegetable store, respectively. Regardless of the oversizing of the PV installation on the DC voltage side, the operating point is very rigidly maintained, and its changes are in the range of 747 ÷ 760 V DC of direct voltage, which is unfavorable. Oversizing the PV installation on the DC side results in a proportional increase in unit costs without the effect of an increase in the unit efficiency of the electricity produced.

The analysis and synthesis of mathematical model of double channel heliocollector to heat air as drying agent during drying agricultural crops and materials were made. The simulation of thermal processes for the quasi-stationary mode of the collector was carried out. The analytical dependences of the degree of air heating and the coefficient of efficiency from the regime parameters were obtained. Data matching temperature distribution in the direction of the coolant and collector efficiency depending on the profile, determined little difference theoretical and experimental data (error is 5%).

When assessing the amount of energy produced, it is necessary to consider the scope of changes in parameters of PV modules guaranteed by the manufacturer during their operation. In addition, the production of energy during the use of the PV plant is also dependent on the conversion efficiency of the generated DC voltage to sinusoidal voltage in inverters, as well as on many other factors. Based on the conducted tests, the actual amount of available solar radiation energy and its structure in particular months of the analysed years were determined. This analysis was supplemented by the characteristics of the variability of the daily amount of available solar radiation energy at the location of the PV plant in individual months. For the same period of time, calculations of the amount of energy produced in the PV power plant were made based on the indications of the AC energy meters. The structure of the actual amount of electricity produced in polycrystalline modules for individual months in a two-year cycle was also determined and the characteristics of the variability of daily electricity production in individual months were presented. The analysis shows that in a two-year research cycle, both the average daily amounts of available solar energy in a given month as well as energy yields from polycrystalline modules do not differ significantly between 2016 and 2017. However, statistically significant differences between the amount of available solar radiation energy and the amount of generated energy in PV modules in particular months were observed.

The aim of article was to examine the issue of detached house heating costs depending on the type of heating system chosen. The demand for heat was defined by means of the Audytor OZC software. Based on the results obtained, the heating device was selected: a heat pump and an automatic solid fuel boiler with a coal feeder. The heat pump was chosen by means of Vito-WP software, where the seasonal performance factor was calculated. The role of selected devices was to heat and prepare hot domestic water for a family of four. Costs of energy purchase and heat generation were calculated for each solution on the basis of current market prices for eco-pea coal and electricity supply to the area. The results of the quantifying were summed up and compared with each other. Furthermore, the amount of annual operating costs usage permit the definition of economic effect and simple payback time out for the investment. Financial analysis also took into account the different prices of purchasing heating devices. Based on choice of heat source, the ecological effect was also demonstrated, permitting the amount of harmful substances emitted during normal use for each of analysed systems to be determined.

The article deals with the potential and development prospects of hydroelectric objects of the river Smotrych within the city of Kamianets-Podilskyi, Khmelnytskyi region. The analysis of information on hydropower is carried out. The potential of the region is characterized, the existing and new hydroelectric power stations are defined.

As part of the search for effective ways of obtaining energy, a model of a ground heat exchanger was built. It is an element of the ventilation system of a residential building. In order to develop methods for designing ground heat exchangers, it was necessary to build a model to simulate the operation of such an exchanger in laboratory conditions. This article presents a data acquisition system dedicated to cooperate with a laboratory simulator of a ground heat exchanger. The data acquisition system uses a spatial grid of temperature sensors that allow obtaining information on the temperature distribution in the space of the simulator test chamber. The second set of measured parameters is the distribution of pressure drops along the porous bed filling the simulator test chamber. The data obtained from the sensors are registered in a system developed for the needs of the simulator with a one chip microcontroller with a Cortex core. The microprocessor system also performs simulator operation control functions. The design of the system provides the possibility of autonomous simulator operation with the simultaneous acquisition of measurement data that will be used to validate the simulation model used for computer simulation of ground heat exchanger operation.

Wind turbines can operate at fixed or variable speeds. The manner in which the rotational speed of a wind turbine is controlled is an important consideration. The power output of a wind turbine can be controlled with the involvement of two mechanisms, active stall and passive stall, and six major control methods (yaw control, active pitch regulation, etc.). A fuzzy model was used to describe a wind turbine whose output is controlled by changing the blades’ angle of attack and rotating the nacelle to a position facing the wind. The input parameters in the developed control model were: wind speed, power demand. The output parameters were: angle of attack, nacelle yaw from the wind direction and generated power. The values of input and output parameters were described in fuzzy terms, and the rules of a fuzzy system were developed. The model was described in the LabView environment, and it was tested with the use of various defuzzification methods. The results of LabView simulations revealed that a model for controlling the power output of a wind turbine was successfully developed based on fuzzy logic. The control model responded appropriately to changes in the values of input parameters. An increase in power generation was observed when the angle of attack was increased to a given threshold value under stable weather conditions. Power generation decreased when that threshold value was exceeded. The developed wind turbine model can be used to predict the electric power output of a wind turbine under various weather conditions.

The state of lakes cleanliness has not been optimistic for many years. A good example of this is Góreckie Lake, which is one of the most valuable natural objects of the Wielkopolski National Park, it has interesting landscape values, which undoubtedly makes it the most famous place in the Park. In spite of the fact that many point sources of pollution were cut off many years ago and that a part of the lake was made a strict protection area, the trophy of the lake’s waters remains at the consistently high level. In December 2009 the restoration of Góreckie Lake was started by placing a pulverizing aerator powered by wind turbine on the lake. During the pulverizing aeration half of the available energy is devoted to removing gases that often saturate the water in the hypolimnion layer. The purpose of the work was to determine the effect of wind speed on oxygenation of lake zones, especially hypolimnion waters. The research was carried out from May to October in the Wielkopolski National Park on Góreckie Lake. The samples were taken at one point of the lake at the pulverizing aerator. It has been shown that the wind speed has an influence on the oxygen content in the waters of Góreckie Lake, which proofs the validity of the use of the restoration using the pulverizing aeration method with wind turbine. The results of the research and observations has been presented in this work.

The AGH-UST Educational and Research Laboratory of Renewable Energy Sources and Energy Saving in Miękinia utilizes shallow geothermal heat by means of heat pumps. The article describes efficiency tests regarding two shallow geothermal systems based on borehole heat exchangers. Temperature parameters and power exploited from the ground was checked during two heating seasons. Additionally, the performance factor of the installations was monitored. In the second testing season effective length of borehole heat exchangers was reduced in two installations. It enabled checking changes of the seasonal performance factor of the system and the possibility of stable heat pump operation using only one of three borehole heat exchanger. Both tests brought positive results.

This scientific paper work presents the results of research related to development of a new refractory material used as a furnace lining inside the built-in fireplaces as well as freestanding stoves. Ten different mixtures have been developed, including raw materials such as corundum, cement, ground biscuit, andalusite and chamotte. The said mixtures were enriched with relevant oxides, quantities of which have been respectively 2%, 5%, 8% and 10% of the entire sample weight.

The Region of Warmia and Mazury in north-eastern Poland is situated at a distance from conventional energy sources. Therefore, the Region is a Polish leader in power generation from renewable energy sources. This study investigated the efficiency of a heat pump system for heating a single-family house based on an energy balance and a cost-benefit analysis. Recent years have witnessed a growing interest in the use of heat pumps for heating purposes in the residential housing sector. Due to their lower running costs, heat pumps can provide considerable savings over other energy sources and contribute to mitigating adverse environmental impacts. The University of Warmia and Mazury in Olsztyn has developed, in collaboration with the Warmia and Mazury Energy Agency, a renewable energy strategy for 2010–2020 in the Region of Warmia and Mazury. The strategy is consistent with the Polish Energy Policy and the national plan for the use of renewable energy sources, based on the results of studies investigating the use of heat pumps in 2000–2010. In 2010, total energy consumption in the analyzed area reached 71,827.5 TJ. Renewable energy consumption was determined at 7743 TJ, which accounted for 10.78% of total energy consumption, including all sectors and energy carriers. Heat pump power generation was 7.2 TJ, i.e. 0.093% of renewable energy consumption and 0.01% of total energy consumption. According to the proposed strategy, heat pumps with heating output ratings of 3.77 MW will be installed by 2020, and the total amount of HP power will reach 40.68 TJ, thus implying an increase of 33.48 TJ (over 446%) relative to 2010.

The article presents the results of the changes measurements in the temperature distribution of the lower heat source during operation of the brine-to-water type heat pump. The lower source for heat pumps with a heating capacity of 234.4 kW and cooling power of 191.8 kW installed in the building of the Bialystok University of Technology, Faculty of Civil and Environmental Engineering is a vertical ground heat exchanger with a total length of 5.200 m (52 wells of 100 m each). The results of tests carried out in the coldest months of the ground heat exchanger operation in north-eastern Poland in two heating seasons 2015–2016 are presented. Obtained measurements results in openings with working vertical probes in individual years of work were compared with the base profile of the soil to a depth of 100 m with unloaded operation of vertical ground heat probes of the same length. It also presents the amount of heat generated in this period by heat pumps and the amount of electricity consumed by it along with the heat pump performance factor (PF) in the next weeks of its operation. The average annual heat pump efficiency coefficient was also determined in two heating seasons. Due to the high costs of drilling wells and their measurement, this type of research is unique. There are practically no measurements of the temperature distribution in 100 m vertical ground probes loaded with heat pump operation in buildings in continuous operation. Computer simulations or smaller research stands are made more often.

The article discusses the efficiency of monocrystalline and polycrystalline photovoltaic installations under the real-world conditions of north-eastern Poland in autumn and winter. The experiment was performed on photovoltaic panels with a combined power rating of 276.66 kWp, supplied by 3 different manufacturers, installed in different locations with different orientation. In the analyzed period, the combined energy output of the evaluated systems reached 33,842 kWh. Energy gains were lowest in December and highest in March. The energy output registered in March was seven-fold higher than in December. The energy gains of south-west-facing panels were 35–56% higher than those of south-east-facing panels. An analysis of the energy gains per 1 kWp in successive months of the experiment indicates that the orientation of PV panels is a very important consideration during months with low solar elevation.

The paper tackles the problems related to the assessment of the possibility of exploitation of identified geothermal resources. The conditions of geothermal waters extraction in the Lower Jurassic complex (formation) in Polish Lowland have been determined. Utilization of identified geothermal water resources is conditioned by the cost of completion of a geothermal installation, amount of recovered heat and efficiency of its exploitation. The specificity of the variations in the geological setting of the given study area required sound analysis of structural, lithological, petrophysical, hydrogeological and hydrochemical conditions in order to appropriately select a geothermal system both in its underground and aboveground parts. A geothermal installation based on a two-well geothermal system (the so-called geothermal doublet), in which the first well operates as a production well and the other as an injection well, was presented. A concept of a single-well geothermal installation with production-injection technological systems was proposed as a competitive solution that significantly reduces installation costs. Technological schemes of the aboveground and underground parts were presented with regard to doublet systems and single-well systems. The specific character of the technology of thermal water extraction from the Lower Jurassic complex was taken into account. In the discussed complex there is usually observed subartesian pressure, which negatively affects the wells and aboveground part of the geothermal installation and, as a consequence, creating unfavourable hydrochemical phenomena that have an impact on the water flow process. Based on the available data, the ranges of the basic values of geological parameters which can be related to the basic technical parameters of geothermal wells are listed.

This paper presents the results of a one-year study investigating the efficiency of a photovoltaic system installed on a flat roof of a residential building in north-eastern Poland. The analyzed system, with a peak power rating of 4.77 kWp, comprised 18 polycrystalline photovoltaic modules and an inverter. This on-grid PV system was connected to the electrical grid in the building. In the analyzed period, the PV system generated 3966.54 kWh of energy, and the average monthly power output was 330.55 kWh. The total power output of the analyzed solar system could cover the annual electricity demand of a residential building in 94.4%. The monthly electricity gains from the analyzed PV installation would be sufficient to cover the energy needs of the building in 100% only from the beginning of April to the end of August. The electrical energy gains from the analyzed PV system were compared with those from similar PV installations in Germany, located at similar latitudes.

The solar radiation is a commonly available source of renewable energy. This means that the use of energy of this type does not reduce its resources. The light plays a very important role in buildings. This factor ensures the comfort of use and staying in rooms, and has a beneficial influence on people’s mood and productivity. To achieve a higher energy efficiency of buildings, the solar radiation is most commonly used to produce hot water and electricity. Studies show that significant savings in energy consumption can also be achieved by appropriate control of lighting in rooms with access to the daylight. The solar energy is commonly used to produce electricity, which then can be used to power, e.g., air conditioning devices. The solar radiation resources are large enough to significantly reduce energy consumption at facilities. In some cases, systems using energy of the solar radiation can be used to ensure a complete energetic autonomy of a facility by covering its total demand for electricity. This article discusses issues related to the energy efficiency of buildings and the use of the solar energy to reduce the consumption of final energy—heat and electricity. A particular attention was paid to possibilities for savings in electricity consumption for lighting by appropriate control of lighting using daylight.

Geophysical methods are widely applied in geothermal water reservoirs prospection as well as in recognition of its resources and geological conditions of occurrence. There could be distinguished in Poland three areas of radically different geological characteristics that demand separate methodology of geological surveys with use of geophysical methods. These are: Polish Lowlands with predominant sedimentary formations of relatively simple geological structure, Flysch Carpathians with intensive fold and thrust type tectonics and Sudetes region with predominant role of crystalline rocks in geological structure. Hydrogeothermal reservoirs usually occur inside crystalline massifs in Sudetes area, the most frequently as fractured zones accompanying faults. The Sudetes Region is characterized by diverse and highly complex geological structure. High level of geological structure complexity causes strong difficulties in prospection works. Recently, magnetotelluric surveys were made in the Sudetic area in small scale but with good results. Four basic methodological variants of the method were applied: deep magnetotelluric soundings (MT/AMT), audiofrequency magnetotelluric soundings (AMT), continuous MT and AMT profilings as well as soundings and profilings with use of artificial source of primary field (CSAMT). Results of survey with use of magnetotelluric methods in recognizing of thermal and mineral water illustrate works made in Cieplice Śląskie-Zdrój, Polanica-Zdrój, Lądek Zdrój and Nysa areas. The mentioned above investigations as well as other surveys made on the commission of individual private investors confirm effectivity of MT methods in recognition of relatively deep (up to 3–4 km) fault zones as prospective for thermal and/or mineral water occurrence.

This work deals with the development of stable perovskite solar cell structure. In the research, two sets of perovskite photovoltaic cells were manufactured with a different way of their production. In the first series, an active perovskite layer CH3NH3PbI3-xClx was applied in a glovebox with N2 atmosphere. In the second series was used glove box filled with air with controlled 15% relative humidity. Perovskite solar cells were analyzed for the most frequent degradation mechanism, which is moisture. XRD measurements revealed decomposition of the active perovskite structure with lead iodide increase. XRD measurements, along with EDS analysis, have also confirmed that chlorine is not in the perovskite structure and applies only during the manufacturing process. According to the output parameters of the cells, along with the changes in the perovskite structure, it was found that solar cells manufactured in the controlled humidity environment are more stable. However, they do not achieve such conversion efficiency as cells produced in an inert atmosphere.

Rabka-Zdrój is a health resort municipality located in Southern Poland. According to data from the European Commission, the yearly sum of global horizontal irradiation in the health resort of Rabka-Zdrój equals 1100 kWh∙m−2. For this analysis, it was taken into consideration databases from three different sources. It was agreed that the Typical Meteorological Year (TMY) for Kraków city would act as reference data as it was elaborated based on years of observation. This data was compared with PVGIS-CMSAF satellite data as well as with our data received from a ground measurement station (LB-714) located in Rabka-Zdrój. The observations of data from the station LB-714 has shown that 70% of measurements obtained in December falls within the range 0–100 W∙m−2. The results of verification show that differences of distribution of average daily horizontal irradiance are significantly smaller than in the case of an inclined plane at a given angle. The dissimilarity between the PVGIS and TMY data could be a result of the application of the estimated model (for PVGIS) for calculating the values of solar irradiance on the inclined plane and also a reference to another measurement period. Values of total solar irradiance obtained for LB-714 after applying the correction factor, present a similar distribution of values to PVGIS, however, they differ significantly to TMY data. The correction factor for the total solar irradiance on the inclined plane, calculated from TMY data, should be used only for estimated calculations.

The paper presents the application of Data Mining techniques for the assessment of wind energy resources at Lodz Hills (Wzniesienia Lodzkie). The measurements taken at a meteorological station, as well as long-term data from meteorological reanalysis were used as the input data. Linear regression, neural networks and support vector networks were used to obtain a long-term forecast of potential wind energy resources. According to the European and Polish recommendations specifying the suitability of land for wind turbines installation in terms of wind conditions, the obtained forecast confirmed the purposefulness of localization of such installations in the examined area. The purposefulness of applying Data Mining methods for solving problems related to the assessment of wind energy resources was also confirmed.

Ground-source heat pumps are widely applied technology for building heating, cooling and DHW production, which gained considerable development over last years. However, the technology faces number of challenges consequent on the ever-increasing efficiency demand in parallel with environment-friendly usage of low-temperature energy sources, inter alia ground, which is freely available all over the year. The most commonly way of extracting heat accumulated in near-surface layers of the ground is to use vertical heat exchanger, also called borehole heat exchanger, with intermediary agent. The aim of the study was to assess the influence of local geological structure on the efficiency of the ground-source heat pump. Assessment was conducted based on the elementary computational assumptions, the borehole data obtained from the Polish Geological Institute-National Research Institute and the defined thermal coefficients, and consequently the heat transfer rate values in selected measurement points were determined. As a result, the efficiency of selected boreholes were determined in relation to the previously established power demand for selected building. In the most parts of area studied, in selected measurement points, sands, clay gravels and clays dominated with vary thickness of particular types of land. Moreover, more favorable parameters for geothermal installations were specified in locations where the heat transfer coefficient of particular layers were lower, but the average heat transfer coefficient for borehole was higher.

In recent years technological development towards more rational and effective usage of biomass for energy purposes has been observed. A similar tendency has been noted for waste biomass or organic waste from various industries, including agro-food. A good example of such organic waste is coffee grounds, which has been recently generated in increasing quantities and, due to market changes (new commercial networks of coffee-houses), collected separately in significant amounts. The energetic usage of this waste is feasible, yet because of high moisture content (reaching 60%) an appropriate technology has to be applied. One of the possibilities is coffee grounds gasification, which transforms the fuel from solid to gas. The obtained gas can subsequently be combusted in more effective and environmental friendly manner. The article presents an analysis of subjecting used coffee grounds to a gasification process as well as the results of physicochemical tests regarding energetic properties of the material (moisture content, heat of combustion, ash content). Moreover, the article shows the results of applying coffee grounds as an additive to gasification of willow chips, i.a. the influence of the coffee grounds additive on process duration time, temperatures in the reactor as well as energetic effects of the process.

The purpose of the work was to determine the temperature course in the composting box intended for the organic recycling of dead poultry depending on the structure-forming material used. Wheat, barley, oat, rapeseed and maize straw were used as the structure-forming material. The condition for obtaining a compost with appropriate sanitary parameters is to achieve an organic temperature exceeding 70 ℃ during the organic recycling process. The simulation of temperature changes in the compost box was carried out using the Autodesk: Inventor and CFD Simulation programs. In Inventor, a geometrical model of a compost box based on an existing prototype was built. The CFD Simulation program analyzed the operation of the system in the field of air flow in a two-phase bed (air-structure-forming material) and temperature distribution in the bed. The program defines the materials from which the composter is made, the boundary and initial conditions of the deposit work were defined. In order to optimize the bed’s operation, multi-variant scenarios with different initial parameters were designed: changing the temperature and structure-forming material as well as the air flow velocity. Section planes on which visualization of air velocity vectors and additional section planes with temperature field distributions have been defined. The obtained results of temperature fields from the multivariate simulation were compared to the actual temperatures in the deposit. The tests involved the use of a measuring system equipped with a probe with a temperature sensor with an accuracy of ±0.15 ℃, a transducer and a data recorder.

Wastes containing mercury and its compounds are formed in various branches of industry. The biggest environmental toxicity had types of waste—ashes from coal combustion and wastes from used discharge lamps, segregated and separately collected. In order to investigate the possibility of processing the above-mentioned waste, a laboratory installation was designed and constructed: (1) limiting mercury leaching from waste using sulphur and its compounds (sodium sulphide, sodium thiosulphate); (2) solidifying waste using a filter press. Ash samples originating from the thermal treatment of industrial sewage sludge and waste from the recycling process of the discharge lamps were collected for the tests. Mercury leaching tests were performed according to USEPA procedures, using the atomic absorption spectrometry method. The tests showed a decrease in the concentration of mercury in the solution of reagents from 15 to 2 μg · dm−3.

The aim of the study was to determine the effect of fertilization with compost prepared with the addition of litter and dead birds from a poultry farm on potato yield. The studies were conducted on potato Solanum tuberosum L. cv. Vineta in the years 2015–2017. Soil for growing potatoes was fertilized with the mature compost from a poultry farm. Dried wheat straw was used as a structural material. Different combinations of proportions between feedstocks (structural material, litter and dead poultry) were used. The experimental results showed statistically significant differences between these combinations. Soil amendment with compost produced with the addition of litter and dead birds was demonstrated to influence Vineta potato yield.

After the biowaste composting process, not only is wholesome compost or a substance for increasing soil fertility, but also non-composted waste. Non-composted waste is returned to the composting process or is utilized in the recovery process, e.g. in degraded land reclamation. The purpose of the study was to determine the energy potential of composted biowaste. The research was carried out in Composting Plant in Brno on biowaste samples from households supplemented with biochar in the share of 1.5%, 3%, 5% and without the addition of biochar (the control). The analyses included biowaste and the 3 weeks of intensive phase of the composing process. Sampling for analyzes was performed every week for the first three weeks of the process. The samples were divided into those from which it was possible to obtain compost (with granulation below 20 mm) and the process residue that did not meet the requirements for composts (fraction with a particle size of over 20 mm, containing impurities). The study included: moisture content, ash content, carbon content as well as the heat of combustion and calorific value. The research results revealed that the heat of combustion and the calorific value for samples with grains below 20 mm decreased very quickly during the intensive phase of the composting process. Samples with a particle size above 20 mm can be a source of energy for the power industry, due to the heat of combustion above 9 MJ.kg−1 (and with the addition of biochar above 10 MJ.kg−1), but after prior drying of the waste.

Comparative analysis of the accumulation of municipal waste in two selected rural communes in the European Union showed, in a quarterly basis, substantial differences between the number of inhabitants and the amount of non-selective and selective waste collected. A significant increase in waste collected fell on the tourist and agricultural commune with a larger population. Generally, in this commune there was a four times higher amount of non-selectively collected waste in relation to separately collected ones. The occurrence of the highest values of collected waste confirmed the seasonal variability with the dominance of spring and summer. Waste accumulation rates were helpful in the analysis. One of them concerned the overall accumulation of municipal waste rate per capita per year, which showed the highest value of 40.3 kg in the commune with a smaller number of inhabitants. Analysis of another rate of plastic waste accumulation per capita per year showed the possibility of impact of the commune touristic activity on its growth. The fall in the value of the glass packaging waste accumulation rate in two communes, and the lack of accumulation of metal waste and electrical and electronic equipment waste accumulation per capita per year in one of them confirmed the limited recovery of waste with raw material features. This is also indicated by the relatively low share of 1/5 of the municipal waste separately collected “at source” over eight quarters.

The formation of sewage sludge is an inherent effect of the wastewater treatment process. Their composition is characterized by high variability and depends mainly on the properties of wastewater, technologies of their treatment and methods of processing sediments. Without knowing the properties of sewage sludge, it is difficult to choose the appropriate method for their utilization or disposal.The aim of the study was to analyze the physical and chemical properties of sewage sludge from a selected municipal wastewater treatment plant and to assess the possibility of their use in environment. A municipal sewage treatment plant, located in mountainous terrain (Gorlice, Poland, Małopolska Voivodship) was selected for the study. The research were conducted in the years 2011–2016, on dehydrated sludge, after aerobic stabilization.Analysis of the results showed a high variability and a relatively low level of the sludge pH, which could be the result of improperly performed stabilization process. Among the analysed properties of sludge from the wastewater treatment plant in Gorlice, high variability was also demonstrated by the dry matter content and organic compounds. The maximum contents of some of the analysed heavy metals were relatively high, but did not exceed the limits specified for sludge used to fertilize the land, utilized for agricultural purposes, which apply to the most stringent conditions. However, the maximum content of zinc significantly exceeded the limit value at the agricultural use of sewage sludge. This limits the possibility of using sludge and makes it necessary to look for other methods of utilization.

An assessment of the variability of the landfill gas components captured on a used waste landfill site since the 1970s, was presented in the article. The amount of waste deposited in the landfill site has decreased more than 2-times during the period of 6 years, excluding organic waste affecting the productivity of landfill gas. Despite of the variability amount of waste deposited, the composition of landfill gas stood out average concentrations of CH4 and CO2, which exceeded 50% and 30%, respectively. This confirmed that the landfill site was still in the methanogenesis phase. The anaerobic processes were taking place in the deposit to a large extent, which was demonstrated by the low average oxygen content of 1.185%, while the highest variability was confirmed by the result of the standard deviation H2S (35.106 ± 69.915 ppm). In June, the highest values of emissions, CH4, CO2 while the general decrease in values did not relate to emissions.

The prompt development of many industries, including food industry, generates large amounts of waste, the storage of which releases a number of disadvantageous changes in the natural environment. To prevent progressive degradation of natural environment, the efficient neutralisation of waste becomes a serious challenge facing humanity. Due to the possibility of obtaining energy from selected types of waste, their thermal treatment becomes particularly popular. In present paper the possibilities of utilisation of selected municipal packaging waste in the pyrolysis process are discussed: cardboard packaging, two types of multi-layer cardboard packaging—Tetra Pak and Eko Pak and plastic bottles (PET). The basic physicochemical properties of the analysed waste were presented, as well as the calorific value of the resulting pyrolysis gas was determined. The presented research shows that the use of pyrolysis process for the utilisation of waste packaging materials allows their mass to be reduced from 65.5% to 80.5% relative to their original weight. It was shown that, the best results in terms of the quantity and calorific value of the pyrolysis gas were obtained for cardboard materials (extrudates).

The article presents the results of experimental research on a heat exchanger type heat pipe for the range of 15 ÷ 50 °C lower source temperature. The emergence of processes occurring inside and related to their work is essential mainly in the era of achieve to demote heat losses and keep off unnecessary dissipation of energy. The need to conduct investigation and studies of heat pipes is also conditioned by the require to rescue primary energy in both construction engineering and manufacture. This work contain the effect of research on a real HEX, a heat pipe made of copper, 1769 mm long, 18 mm in diameter and 1 mm thick wall. This research consisted of placing a heat tube in a tube-type heat exchanger in a pipe in order to supply and collect heat to and from the heat pipe. Previous studies on a heat tube with vacuum and air inside showed that there is a negligible heat flux transmitted through the walls of the heat pipe along its axis. When filling the tube with R404A and R407C, there is a significant increase in the heat flux received and passed through the heat pipe. In addition, the work presents the results of the performed thermographic analysis for the studied working factors.

Phase change materials (PCM) are substances with specific heat that varies in response to the temperature changes and increases rapidly in temperature of phase transition. It means that heat capacity of PCM tank compared to heat capacity of water tank at the same volume is several times higher. This gives the possibility for long-term heat and cold storage. Number of deep charge and discharge cycles—number of phase changes from solid to liquid—is one of the limitation of phase change materials. Therefore, the best solution is to charge and consume energy stored in PCM tank as PCM is in transition phase. This requires developing an adaptive control system enabling evaluation of charge and discharge rate of PCM storage tank. In order to achieve that, it is necessary to perform simulation tests using PCM mathematical model. There was a need to modify this model due to the fact that PCM characteristics in operating conditions are different from classical model described by Eq. (1).

The following work presents the analysis of the potential of renewable energy sources in Września Municipality. Moreover, it gives an insight into the extent of their use and indicates some possibilities of their further development. The conducted analyses stipulate that this area has a great potential in terms of wind and biomass energy. As far as the former is concerned, the existing administrative limitations to all intents and purposes make it impossible to develop a high capacity wind power plant, whereas in the case of latter the barrier stems from inhabitants’ fear of the possible nuisance of biogas plants to be established. There is a great geothermal potential in the area where Września Municipality is located, however tapping into it would require more detailed research. It is useful that the city of Września has an extensive heating network, which would facilitate heat distribution coming from a geothermal facility. The remaining renewable energy sources such as solar batteries, photovoltaic cells, heat pumps and small windmills will probably be developed exclusively depending on individual entrepreneurship and financial resources of inhabitants.

The aim of this study is to identify new opportunities for energy supply in Poland and in the world, on the basis of electric cars (EC). It was assumed that being connected to the local power systems, they can accumulate significant amounts of energy and effectively prevent from occurrence of electric power deficit. To achieve the above mentioned goals the problem has been formulated in the form of the following questions: what are the conditions and technical potentials for energy use in transport? What needs to be done in order to achieve the assumed satisfactory level of energy supply involving improving power availability in the Polish National Power System (NPS) and prosumer use of electric cars, for example in Poland? What are the examples of implementation of different sources of electricity into the electric power system? The innovation involves using mobile (car) prosumer electric power (Ee-Mobile) for battery charging, for example, they can use power from non-renewable sources of energy (RES) and/or renewable energy sources (RES). Environmental compatibility of various ways and means (according to their own evaluation methodologies), as technical solutions for charging and discharging rechargeable batteries for the car own purposes and for the purposes of the local energy systems in case of a deficit, was defined.

The objective of the work was to determine the research trends and carry out a bibliometric analysis of publications concerning the application of the computational intelligence method in the research area renewable energy sources optimization. In this study the Scopus database has been used as a data source. Articles and conference papers published in the years 2011–2017 were analysed. The research consists of two research tasks: bibliometric quantitative analysis and bibliometric thematic analysis of publications. On the basis of the analyses conducted, one can state that: In years 2011–2017, the number of scientific publications regarding RES optimisation, indexed in the Scopus database, increased by 340%. However, it does not mean that optimisation studies become prevailing, since the number of RES-related publications increased as well (by 199%). A percentage share of publications concerning RES optimisation, in relation to all publications dedicated to RES, grew in years 2011–2017 by 177%. The authors of the highest number of publications (in the set of articles and conference materials searched, for years 2011–2017) were researchers from the USA, China, India and Italy. The majority of the studies described in the publications set concerned optimisation of solar energy and wind energy systems, often hybrid systems. For optimisation by means of artificial intelligence computational methods, algorithms belonging to a group of Evolutionary Computations (mainly Genetic Algorithms) and Swarm Intelligence (especially PSO) were applied most frequently. Neural networks and fuzzy systems were applied three times less frequently. The authors suggest new optimisation algorithms combining several artificial intelligence methods.

This work presents statistical analysis of dried wood biomass using Statistica Neural Networks 8.0. program. The goal of the work was to find similarities and possible difference between convective drying of different types of wood biomass. Wood of five different varieties, i.e. poplar, oak, acacia, willow and rosewood, in three different sizes of size reduction: 29-cm shoots, slices and chips was selected for the analysis using Kohonen networks. The material for experiments was dried in the following temperatures: 50, 60, 70 and 80 °C. The analysis of data related to the process of biomass drying using Kohonen network proved correct in the majority of cases. The interpretation of the topological map, developed as the final effect of the analysis, allowed for the assessment of its correctness at the level of 60%.

This work analyses possibilities of applying task prioritization methods in the production of biofuels, based on bibliometric analysis. The results of the bibliometric analysis have shown that studies on applying task prioritization methods in biofuels production have not been conducted on a large scale so far (only 96 indexed works have been published in the Scopus database). In the documents being analysed, the application of prioritization methods concerned mainly production (raw material optimisation and processing, classical and new production technologies, cost reduction, environmental impact reduction, and the like) and logistics (supply chain optimisation, including planting, harvesting, transport, storage, distribution etc.). Mainly advanced task prioritisation methods have been used: MILP (mixed-integer linear programming), Linear Programming Model, Stochastic Sequential Programming and Multi-Objective Genetic Algorithm.

The article presents the teaching and laboratory building Energis as the example of an intelligent building management system (BMS), in which the Department of Environmental Engineering, Geomatics and Energy Kielce University of Technology is seated. BMS in Energis building is equipped with automatic systems and communication networks which allow for the object’s control and full monitoring. The system controls and manages integrated heating systems (heat pumps, heat center MPEC, biomass boiler), installations, ventilation and air conditioning HVAC, lighting inside and outside of the building. The second basic BMS function is continuous monitoring of all telecommunication systems of building automation and security systems (premises access control) with the registration of the individual installation parameters. BMS also allows to generate and send alarms in case of irregularities in each device operation, as well as in case of exceeding the set points. The paper also reviewed selected installations of building automation including the registration parameters possibility by BMS (Building Management Systems). We also performed a detailed analysis of the selected measurement data recorded by the system in terms of energy.

This paper contains description of the smart database with usage profiles and technical data for main thermal energy storage system (TESS) components: solar thermal collectors, compressor heat pump with vertical ground heat exchanger without and with phase change material (PCM) in boreholes, hot and cold PCM tanks, domestic hot water (DHW) tank and building with low temperature heat receivers such as underfloor heating and fan coils. Usage profiles that were created in the database depend on climate data, building type and structure information which are the basis for calculations of building energy demand. The database uses the examples of devices that are available on the market and, most importantly, gives user a smart tool to select solution for the TESS from the technical and economical point of view.

This paper addresses the problem of biomass processing relevance into alternative solid biofuels, related primarily to issues of economic feasibility of agro-industrial production waste recycling, rising prices for fossil fuels, minimizing transportation costs and enhance environmental requirements. It is noted that a new innovative sector of the economy—bioenergetics, based on the production of biomass fuel and energy, but its further development requires improved technology, machinery and equipment used, in order to reduce energy intensity and improve the quality of machines derived products. Analysis of recent researches in this area has shown that reduction of the energy intensity of biomass pressing process with a screw press can be achieved by changing the configuration of the drawing block working surface that will reduce quantities of mass movement harmful resistance in the working channel. The carried out studies of the drawing block working channels wear character and existing curved surfaces made it possible to recommend a curved surface as a working surface a screw press drawing block which is a tractrix. The work imposes the results of the analysis of the tractrix parametric equation and the graphical dependences of the working surface parameters on the tractrix characteristics. The analysis of the displacement nature of the plant mass in the working channel of the drawing block of the proposed design gave an opportunity to obtain the differential equation of the plant mass pressure on the length of the working channel. The paper describes the graphic solutions of the equations in MATLAB environment for various tractrix parameters features and made appropriate conclusions about the nature of relationships and future research directions.

Development of renewable energy sources (RES) is a crucial factor, influencing diversification of energy sector. Popularization of renewable energy projects has a key significance in building energy security system in Poland, therefore most of strategic decisions concerning RES are taken on the country level, and basing on EU directives, general development directions are also formed there. Implementation of assumptions referring to RES is conveyed to administrative organs of lower level. Due to the fact that the most important challenges concerning energy sector transformation, including RES projects, refer to multifunctional urban areas, it is crucial to analyze, what way urban self-government authorities put these tasks of initiating and implementing pro-ecological enterprises of RES sector in practice. Taking into account the fact that renewable energy development in cities is a leading element of urban policy, implementing directives of sustainable development and the fact that actions for RES promoting are indispensable factor influencing low carbon economy development, it is assumed that renewable energy is an important pillar of low-carbon economy in cities. Taking the above into account, the research purpose is to make analyze of initiatives and actions within renewable energy development in big cities, taken up by self-government authorities, outlined in strategic documents. Present research will be carried out in reference to real RES structure and dominant directions of RES development in cities selected for tests. Study results will enable to predict RES sector development in urban areas, as necessary condition of low-carbon economy in Polish cities.

The heat pump as an ecological solution can be an option for using conventional hot water preparation. The article presents an economic analysis of domestic hot water (DWH) preparation using an air-source heat pump. The operation of the heat pump and the consumption of electricity during the one-time heating of the hot water tank were analysed. The test was carried out under real conditions. Basic parameters and test conditions were based on European Standard EN 16147:2017. Fuel and electricity prices have been determined for available energy tariffs and fuel prices in the region. Different configurations of energy tariffs were taken into account to analyse costs of DHW preparation using heat pump. Obtained costs were compared with the costs of DHW preparation using conventional heat sources: a gas boiler and an automated coal-fired boiler. Annual cost comparison were presented. The results show that average Coefficient of Performance (COP) of the heat pump working under real conditions is 2.06. The most expensive heat source for DHW heating is heat pump which works during a 24-h tariff and the best economic solution is heat pump using 100% night tariff. However, annual costs of DHW preparation are still equal to the cost of DHW preparation using gas boiler.

Capital and energy effectiveness in organic production is similar to the one achieved in a traditional system, although it generally has a lower consumption of production and energy means. This consumption depends, however, on the applied technology, size, direction and manner of management. Since, implementation of new technologies and techniques in plant and animal production causes that farms obtain better and better indices of capital and energy effectiveness of their production. In the paper, the production size and consumption of energy carriers and raw materials for production purposes in organic farms was estimated. Effects of the obtained global and commodity production and expenditures incurred thereon presented in energy units enabled determination of capital and energy effectiveness of organic production and its energy consumption. A comparative analysis of the calculated indices was carried out, assuming a division criterion in the form of the surface area of agricultural land.

In the context of the current global economic crisis, the increasing attention of the world community is given to increased structural transformation of fuel and energy complexes of countries. The main content of these processes is to increase the economic efficiency of energy use and reduce the dependence on their imports, which is extremely relevant for Ukraine. Thus, it is evident that there is a need for in-depth scientific consideration of the above-mentioned processes in order to localize existing problems, as well as to develop recommendations for their solution. The article generalizes the tendencies of development of the field of alternative energy in Ukraine and the world, conducted an analysis of the financial state of renewable energy sources, developed recommendations for the improvement and development of this industry. In the course of the study, there were positive changes in the field of alternative energy were discovered, but to date there are still a range of problems that require a state settlement: regulating the alternative energy market needs to be revised by creating new incentive mechanisms for companies active in the alternative energy market and developing effective guidelines; elimination of bureaucratic procedures for obtaining state benefits; activation of bank financing programs for investment in renewable energy projects. Large-scale development of energy from renewable sources will allow to create a new ecologically safe branch of energy, which will help to increase the level of diversification of energy resources and strengthen the energy and ecological safety of Ukraine.

The aim of this study was to analyse the influence of different methods of pre-processing of input data such as moving average, subtraction of the mean and smoothing with the 4253H filter on the quality of forecasts of energy yield from a photovoltaic plant developed on the basis of MLP artificial neural networks. Forecasts were conducted at hourly time intervals for three types of cells; mon- and polycrystalline cells, as well as CIGS thin-film cells. The aim of the study was achieved based on the authors’ own research conducted at a PV plant located in Krakow with a total power output of 12.67 kWp. The assessments of the models developed were made based on the total ratio of energy for balancing in the total energy production (ΔESR) and on an analysis of the mean absolute percentage error (MAPE).

Overheat—it is a negative phenomenon which occurs in solar heating systems due to lack of power consumption. As a result, working fluid, in this case propylene glycol, undergoes phase changes by expanding, which shortens its service life and may unseal the installation and cause an air lock. In practice, there are different methods of preventing the installation to overheat such as shading collector surface, installing additional domestic hot water tanks (DHWT). This article presents an alternative method of protection of solar heating system against the effects of overheat by replacing additional domestic hot water tank with tank filled with phase change material (PCM). The proposed solution gives an extra benefit of higher heat capacity of tank filled with phase change material compared to water tank at the same volume and, moreover, there is no need to initiate anti-legionella cycle.

Control algorithm is the most important element of hybrid energy system while it is in operation. It determines energy effects of each segment of system, which has influence on efficiency of whole system and operating costs. This paper presents the results of research studies which enabled control algorithm of hybrid energy system combining heat pump, solar installation and phase change material (PCM) storage tank to be tested and optimised. Matlab Simulink software was used to perform simulations. A great advantage of this software is the possibility to compile and implement control algorithm in programmable logic controller (PLC). The algorithm that was implemented in PLC is in form of function block diagram, which makes the entire PLC programme very clear.

Among the classical technologies, which apply elevated temperatures for preserving of grain and cereal products, there are two the most effective ones, currently used all over the world. The indicators are storage of cooled fresh raw materials in adjustable or modified gas environment and a long-term storage in a frozen state. The study dealt the first technology which employed active ventilation by the flow of refrigerant. Qualitative parameters for optimization of the investigated process included the mass fraction of gluten, moisture in raw materials, volume of air supplied, and the product processing temperature. On the base of a rootable, central-composite planning of a multifactorial experiment, a mathematical model for the data distribution was obtained. The obtained mathematical models, which are presented in the form of a multiple regression of the second order, allowed to describe the process of grain products storage adequately. As a result, we determined the optimal technological parameters for the equipment operation while studying the humidity of the processed materials, volumetric flow of air as well.

The study of vibrations of the grain pipe drill along which the seeds of cereal crops move and the influence of the main physical-mechanical and geometric characteristics, method of consolidation and the relative velocity of the grain along the tube on the amplitude-frequency characteristic of oscillation is made. The problem of analytical study of dynamic processes of systems characterized by longitudinal movements with regard to their flexural rigidity remains open. To solve the problem we propose the approach takes into account that the number of the relative motion of grain in the grain pipe is a small amount compared to the movement of the pipe during its bending vibration, and the speed of continuous grain flow in the grain pipe is changing slowly. To solve this problem authors used the principle of the single-frequency of the oscillations in nonlinear systems with lumped masses and distributed parameters and asymptotic methods of nonlinear mechanics.

Current furnace waste management is regulated by a number of legal acts largely resulting from the source of waste through a combination with used solid fuel and potential further of their use (recovery) or disposal. The applicable legal regulations refer to physicochemical tests, the results of which determine the further way of dealing with furnace wastes received in this way. An important problem is inaccurate classification of furnace wastes obtained in individual heating devices in relation to their physicochemical properties, especially for cases when the user has made a combustion process, co-combustion of legally admitted solid fuel with municipal waste or other wastes, e.g. hazardous waste. The furnace waste generated as a result of such a combustion process in an individual heating device may pose a threat to human life and health and also the environment, which is confirmed by the results of basic physicochemical tests of waste obtained from individual users with the participation of authorized bodies controlling the application of environmental protection regulations. This paper presents the obtained results of physicochemical tests on furnace wastes in relation to legal acts and an attempt was made to diagnose the phenomenon observed on the basis of own surveys.

Renewable energy installations are known to visually impact the physiognomy of the landscape. They can change its visual resources in many ways, the most important factors being their dimensions and placement. Renewable energy investments are often perceived as visual obstacles which may cause visual pollution in valuable landscape. To prevent this, various visual impact assessment procedures were developed to guide the planning process for such investments. Assessment worksheets, which are proposed as a part of guidelines and good practices are developed to unify and objectify the results of visual impact assessments. In Poland, visual impact assessments should be carried out in accordance with the EIA and SEA procedures. However, there are no detailed regulations of the assessments so far. These policies could incorporate the assessment worksheets for better control of the investment planning process. The aim of this research is to create a comparison of visual impact assessment worksheets based on existing policies and papers published in various countries. Assessment worksheets were also evaluated in scope of their suitability for visual impact assessments done within the EIA and SEA procedures for projects associated with renewable energy investments. Research was based on content analyses of evaluated publications, which contain assessment worksheets as part of the proposed assessment methodologies. The results of this research could be used as a basis for further development of a methodology for conducting visual impact assessments as a part of the EIA and SEA procedures in Poland.

In the paper, for the purpose of a complex assessment of the impact and consequences of the policy carried out by voivodeship local governments on the development of renewable energy, a synthetic measure was constructed which suitably classifies regions and enables interpretation of the situation in voivodeships with regard to the renewable energy sources development. It was stated that in no region of Poland, the situation within this scope is sufficient and only in Kujawsko-Pomorskie Voivodeship and Pomorskie it is mediocre. Moreover, within the recent 10 years, no progress has been visible except for Kujawsko-Pomorskie and Opolskie Voivodeship and in two voivodeships (Mazowieckie and Wielkopolskie) the progress of renewable energy sources is threatened.

Lithium batteries and supercapacitors are a popular scientific topic. This article deals with gel polymer electrolytes, which are a promising replacement for liquid electrolytes. The research reports how different cross-linking agents in the polymer component of gel electrolytes affect their mechanical, electrical and electrochemical properties. For measurements, impedance spectroscopy and linear voltammetry methods were used to calculate electrical conductivity and potential windows respectively. Results indicate, which cross-linking agent is more suitable for further use in gel polymer electrolytes in electrochemical cells.

Heat demand take a large part of energy use in the buildings. The amount of Solar energy is much higher in summer and exceeds heating demands. That is why thermal energy storage technologies are needed to cover the energy supply for winter cold months. Currently available thermal energy storage systems, using water for short-term storage, work well, but it is not enough. For longer storage periods, different technologies are needed. Phase Change Materials (PCM) in the latent heat storage has been taken into account as an energy storage in RES technologies. An example of such a material is sodium acetate CH3COOHNa, which in room temperature is a solid body, and after exceeding the phase transition temperature (TPF ≅ 55 ℃), it turns into a liquid. The substance, when in a liquid state, characterizes with its ability to change into a supercooling state, until it reaches the temperature nearing 0 ℃. It is possible to initiate the process of a phase transition while CH3COOHNa is in the state of undercooling (0 °C ≤ T ≤ 55 °C) by switching on an acoustic generator (20 kHz). The phase transition that has been initiated in this way can be observed through crystallizing the substance, which was used as a specimen; and it indicates a phase transition of the first kind, during which huge amounts of latent heat are released. Therefore, the occurring amorphous substance transition is an exothermic process.

The microbial fuel cell (MFC) is a technical devices that electricity produces during wastewater treatment. One of the problems of MFCs is a low current density. Thus, it is necessary to search for new electrodes for MFC. The comparison of Cu-B alloy and stainless steel as catalyst for MFCs cathode is presented in this paper. The research included measurements of the concentration of COD, NH4+ and NO3− in three types of reactors: without aeration, with aeration and with using a MFC (with Cu-B and stainless steel cathode). It has been shown that effectiveness of MFC with Cu-B electrode is higher than effectiveness of MFC with stainless steel electrode.

The article presents the possibilities of using exhaust waste heat to preheat the combustion air in furnaces for heating steel charge. Calculations illustrating the effect of combustion air temperature on the amount of heat introduced into the heating process were demonstrated. The basic and supporting calculations of the combustion process using authorial computer programs were carried out. The influence of recuperation on the heat economy in heating units was presented. For the selected heating furnaces, analysis of the savings resulting from the use of heated combustion air was conducted.

The strategic goal of Poland’s energy policy is to take actions that will increase the share of energy from renewable sources in the final gross energy consumption to 15% in 2020 and 20% in 2030. The effects of these actions will be: a reduction in greenhouse gas emissions, improvement of the security of energy supply, the development of innovative sectors of the economy and an increase in employment in individual regions of the country. Based on the Central Statistical Office data, the most important renewable energy sources were analyzed. Their consumption in 2006–2016 was compiled in the global system for Poland. It was found that during this period the share of individual energy sources in the total consumption of renewable energy were respectively: 80.7% for solid biofuels, 8.2% for liquid biofuels, 5.3% for wind energy, 2.6% for hydropower, 2% for biogas and 1.2% for other renewable energy sources. In addition, the following indicators were determined in the article: the maximum relative changes in consumption, maximum changes in the share of consumption, as well as the periodic and annual rate of change in the consumption of these energy sources in Poland. The largest increase in energy consumption was noted for solid biofuels and wind energy, while the highest dynamics of change was determined for: wind energy, other renewable energy sources (biodegradable municipal waste and solar energy), as well as liquid biofuels and biogas.