The paper presents the results of the energy analysis of the conversion of solar radiation energy into electrical energy in Polish weather conditions. The effect of sunlight and working temperature on the photovoltaic module on its power curve P = f(U) is shown. STC and NOCT conditions are described for which the manufacturers specify the parameters of the photovoltaic modules. The manufacturers of photovoltaic panels should give the PPV = f(E) characteristic for the different values of the operating temperature of the modules. An analysis of the economic efficiency of a photovoltaic power plant investment of 1 MWp taking the current legal regulations for the three variants into account was presented. Variant I – the investor benefits from the support of public aid of operational only, Variant II – the investor benefits from the support of public aid for investment in the amount of PLN 1 million, Variant III – the investor benefits from the support of public aid for investment in the amount of PLN 2 million. For all variants, indicators for assessing the economic effectiveness of the investment and the value of the auction price from the maximum price to the price at which the project loses its profitability are determined.
A low drop-out [LDO] voltage regulator with fast transient response which does not require a capacitor for proper operation is proposed in this paper. Recent cap-less LDOs do not use off chip capacitor but instead they use on chip capacitor which occupy a large area on the chip. In the proposed LDO, this on chip capacitor is also avoided. A novel secondary local feedback technique is introduced which helps to achieve a good transient response even in the absence of output capacitor. Further an error amplifier that does need compensation capacitor is selected to reduce the on chip area. Stability analysis shows that the proposed LDO is stable with a phase margin of 78°. The proposed LDO is laid out using Cadence Virtuoso in 180 nm standard CMOS technology. Post layout simulation is carried out and LDO gives 6mV=V and 360µV=mA line and load regulation respectively. An undershoot of 120 mV is observed during the load transition from 0 mA to 50 mA in 1 µs transition time, however LDO is able to recover within 1:4 µs. Since capacitor is not required in any part of design, it occupies only 0:010824 mm2 area on the chip.
To improve bioremediation of arsenic (As) contamination in soil, the use of microorganisms to efficiently reduce As and their assessment of genetic erosion by DNA damage using genomic template stability (GTS) evaluation and using RAPD markers were investigated. The five sites examined for microorganisms and contaminated soils were collected from affected gold mining areas. The highest As concentration in gold mining soil is 0.72 mg/kg. Microorganism strains isolated from the gold mining soil samples were tested for As removal capacity. Two bacterial isolates were identified by 16S rRNA gene sequence analysis and morphological characteristics as Brevibacillus reuszeri and Rhodococcus sp. The ability to treat As in nutrient agar (NA) at 1,600 mg/L and contaminated soil samples at 0.72 mg/kg was measured at 168 h, revealing more efficient As removal by B. reuszeri than Rhodococcus sp. (96.67% and 94.17%, respectively). Both species have the capacity to remove As, but B. reuszeri shows improved growth compared to the Rhodococcus sp. B. reuszeri might be suitable for adaptation and use in As treatment. The results are in agreement with their genetic erosion values, with B. reuszeri showing very little genetic erosion (12.46%) of culture in As concentrations as high as 1,600 mg/L, whereas 82.54% genetic erosion occurred in the Rhodococcus sp., suggesting that Rhodococcus sp. would not survive at this level of genetic erosion. Therefore, B. reuszeri has a high efficiency and can be used for soil As treatment, as it is capable to tolerate a concentration of 0.72 mg/kg and as high as 1,600 mg/L in NA.
Compared with the robots, humans can learn to perform various contact tasks in unstructured environments by modulating arm impedance characteristics. In this article, we consider endowing this compliant ability to the industrial robots to effectively learn to perform repetitive force-sensitive tasks. Current learning impedance control methods usually suffer from inefficiency. This paper establishes an efficient variable impedance control method. To improve the learning efficiency, we employ the probabilistic Gaussian process model as the transition dynamics of the system for internal simulation, permitting long-term inference and planning in a Bayesian manner. Then, the optimal impedance regulation strategy is searched using a model-based reinforcement learning algorithm. The effectiveness and efficiency of the proposed method are verified through force control tasks using a 6-DoFs Reinovo industrial manipulator.
The article raised issues related to the design and execution of low-energy objects in Polish conditions. Based on the designed single-family house, adapted to the requirements of the National Fund for Environmental Protection and Water Management ("NF40" standard), the tools to assist investment decisions by investors were shown. An economic analysis and a multi-criteria analysis were performed using AHP method which had provided an answer to the question whether it is worthwhile to bear higher investment costs in order to adjust to the standards of energy-efficient buildings that fulfil a minimal energy consumption's requirements contained in Polish law. In addition, the variant of object that had optimal characteristics due to the different preferences of investors was indicated. This paper includes analysis and observations on the attempts to unify that part of the building sector, which so far is considered to be personalized, and objects in accordance with the corresponding idea are designed as "custom-made".
The energy efficiency of photovoltaic modules is one of the most important aspects in energetic and economic aspects of the project related to system installations. The efficiency of modules and the electricity produced by photovoltaic conversion in solar modules is affected by many factors, both internal, related to the module structure itself and its technical and external factors related to the energy infrastructure, which includes: cabling, inverters, climate conditions prevailing at the micro-installation location and the orientation and angle of inclination of the solar modules. The installation of photovoltaic modules should be preceded by an energy efficiency analysis, which will help to indicate the optimal solution adapted to the given conditions. The article presents a comparative analysis of the amount of energy produced under real and simulated conditions. Analyzes were made on the basis of research carried out in the Wind and Solar Energy Laboratory located at the AGH University of Science and Technology, data from solar irradiation data-bases and computer software for estimating energy resources. The study examined the correlation of the solar irradiation on the modules and the amount of electricity generated in the photovoltaic module. The electricity produced by the module was compared under real conditions and simulated based on two sources of data. The comparison and analysis of the amount of energy of the module were also made, taking simulated different angles of the module’s inclination into account.
This publication presents an assessment of the economic efficiency of a hypothetical installation for the gasification of the municipal and industrial waste for the production of syngas used subsequently for the production of energy or chemical products. The first part of the work presents an example of a technological system for the energo-chemical processing of coal mud and municipal waste, based on the gasification process using a fluidized bed reactor. A hypothetical installation consists of two main blocks: a fuel preparation unit and a gasification unit. In the fuel preparation installation, reception operations take place, storage, and then grinding, mixing, drying and transporting fuel to the gasification unit. In the gasification installation, fuel gasification, oxygen production, cooling and purification of raw process gas and ash treatment are carried out. The following key assumptions regarding the gasification process, as well as the capital expenditures and operating costs related to the process, were estimated. Consequently, based on the method of discounted cash flows, the unit cost of generating energy contained in the synthesis gas (cost of energy, COE) was determined and the results were interpreted. In order to obtain an acceptable efficiency of the gasification process for waste fuels for the production of alternative fuel (process gas), it is necessary to supplement the mixture of waste coal and coal mud with the RDF. In this case, the unit cost of fuel measured by the PLN/GJ index is lower than in the case of hard coal and comparable with brown coal. The use of coal mud for the production of process gas in an economically efficient way is possible only in the case of changes in the legal system allowing for charging fees for the utilization of industrial waste – coal mud.
The Stirling engine type alpha is composed of two cylinders (expansion space E and compression space C), regenerator that forms the space between the cylinders and the buffer space (under the pistons). Before the start-up and as a result of long-term operation, the average pressure in the working space (above the pistons) and in the buffer space is the same. However, in the initial phase of operation, the average pressure in the working space is different then the average pressure in the buffer space depending on the crankshaft starting position (starting angle). This, in turn, causes a large variation in the starting torque. An additional unfavorable factor caused by a large variation in the course of the indicated torque is the rotational speed variation and the formation of torsional vibrations in the drive system. After some time, depending on the quality of the engine piston sealing, the average pressure in the working and buffer space will equalize. The occurrence of the above-described phenomenon affects the selection of the starting electric motor, which can be significantly reduced, when the crankshaft starting position is optimized (the starting torque is several times greater than the average torque occurring in the generator operation mode). This paper presents the analysis of the impact of the crankshaft starting position on the course of the indicated torque and the resulting start-up energy. Starting the engine at an unfavorable position of the crankshaft may, in extreme cases, increase the starting torque even three times.
The article deals with the subject of an important component of energy management, which is the performance of energy efficiency audits in companies. Using the case study analysis, the role of the energy audit was analyzed in the context of improvement of energy efficiency in selected production companies. The essence of legal requirements following from the implementation of the amended Energy Efficiency Act was presented. Specifically, problems and challenges, which refer to the method of implementation of the audit obligation in economic practice, were discussed. Furthermore, the issue of quality and usefulness (in the decision-making process) of prepared reports was raised. It was found that there were indications to claim that the obligatory energy audit of companies is not an instrument for the improvement of energy efficiency, which is always used optimally. The fault in this situation is partly attributable to the state, audit bodies and the company management. In this case, not only is the ineffective communication an issue here, but also the insufficient level of knowledge regarding energy management, as well as haste. The amendment of the Energy Efficiency Act (within just one year) imposed the necessity to conduct an energy audit on a specific group of companies. In principle, because all the entities, to which the obligation referred, had to take actions almost at the same time, numerous issues appeared. Some managers learned about the obligation to conduct the audit from companies who themselves had come out with a proposal to carry it out. This proves the lack of the proper information flow between the government administration authorities and the companies. Again, it turned out that practitioners did not keep pace with the implementation of actions, which were a consequence of numerous (and not always well thought-out) changes in the law. Haste in the fulfillment of the statutory obligation affected a high price spread of the bids sent during tenders, related to the performance of an energy audit. Bureaucratic regulations regarding tenders became another obstacle in the correct performance of the tasks. The entrepreneurs themselves, without clear guidelines on what to expect after the performed energy audit and what a report should look like, on many occasions, selected the “cheapest” bid – not always thinking too much about the qualitative consequences of such a decision. Some certifying bodies – taking advantage of an opportunity and the satisfactory combination of circumstances – offered unprofessional audit services of questionable quality. In the presented conditions, it is difficult to expect real, systemic and desirable results (economically, ecologically and socially) with regards to the energy efficiency both in the micro-, meso- and macr-economic scale. It is worth considering changes in the Energy Efficiency Act and spread the obligation to perform audits over different years according to clearly defined (in cooperation with business) criteria. If relevant actions are not taken, the situation of a temporary Eldorado on the market of energy audits will repeat in 4 years. Again, the consequence may be the poor quality and questionable usefulness of reports from energy audits of companies both at the business level and the ecological-political level. It is necessary to counteract all forms of unfair competition to interdisciplinary and specialist bodies which take actions to improve the energy efficiency of organisations. The creation of appropriate business conditions will have a positive impact on the improvement of energy efficiency. In this context, it is necessary to take actions, which enable the optimization of both the process of the implementation of obligatory legal regulations and voluntary (industry) norms and standards.
Recently, the search for new effective energy production solutions has been focused on the production of electricity using renewable and environmentally friendly carriers. This resulted in an increased interest in PV cells and cogeneration systems. The article looks at the main factors affecting their operational parameters against the background of the development history of subsequent generations of PV cells. Average daily solar radiation and wind velocity in Lodz were characterized. The research was done on a static and tracking system with a total peak power of 15 kWp and a 30 kW microturbine. PV panels are installed on the building of the Institute of Electrical Power Engineering of the Lodz University of Technology and they work as part of DERLab. A microturbine is inside the building. Energy measurements were carried out in 2016 giving grounds for the analysis of energy efficiency and financial analysis of the energy supply in buildings. Energy yields in the static and tracking system as well as percentage coverage of electricity from PV cells and microturbines were assessed. The distribution of monthly savings, annual savings of energy costs and the payback time of the investment costs of the systems subject to the test were determined. The research we have done allows us to say that the energy produced by follow-up modules is about 3 times greater than that generated in stationary modules. On the other hand, the annual savings of energy costs using gas micro-turbines are about 10 times higher than those of lagging panels. The analysis shows that it is possible to determine the profitability of the microturbine and photovoltaic panels use despite large financial outlays. The payback period of investment outlays is about 12 years when using the installation throughout the year.
Work on increasing the efficiency of heat exchangers used in car air conditioning systems may lead to a partial change in the construction of refrigeration systems. One of such changes is the use of smaller gas coolers, which directly translates into a reduction in the production costs of the entire system. The article presents the use of computational fluid dynamics methods to simulate the impact of changing the shape of an internal heat exchanger on the cooling efficiency with R744 as the refrigerant. Internal heat exchangers with different geometry of the outer channels were subjected to numerical analysis. The obtained results of calculations show temperature changes in inner and outer channels on the length of the heat exchanger.
The purpose of this article was to discuss the use of adsorption chillers for waste heat recovery. The introduction discusses the need to undertake broader measures for the effective management of waste heat in the industry and discusses the benefits and technical problems related to heat recovery in industrial plants. In addition, heat sources for adsorption chillers and their application examples were described. The principle of operation of adsorption chillers is explained in the next chapter. Heat sources for adsorption chillers are indicated and their application examples are described. The above considerations have allowed the benefits and technical obstacles related to the use of adsorption chillers to be highlighted. The currently used adsorbents and adsorbates are discussed later in the article. The main part of the paper discusses the use of adsorption chillers for waste heat management in the glassworks. The calculations assumed the natural gas demand of 20.1 million m3 per year and the electricity demand of 20,000 MWh/year. As a result of conducted calculations, a 231 kW adsorption chiller, ensuring the annual cold production of 2,021 MWh, was selected. The economic analysis of the proposed solution has shown that the investment in the adsorption chiller supplied with waste heat from the heat recovery system will bring significant economic benefits after 10 years from its implementation, even with total investment costs of PLN 1,900,000. However, it was noted that in order to obtain satisfactory economic results the production must meet the demand while the cost of building a heat recovery system shall not exceed PLN 1 million.
According to the European Environment Agency (EEA 2018), air quality in Poland is one of the worst in Europe. There are several sources of air pollution, but the condition of the air in Poland is primarily the result of the so-called low-stack emissions from the household sector. The main reason for the emission of pollutants is the combustion of low-quality fuels (mainly low-quality coal) and waste, and the use of obsolete heating boilers with low efficiency and without appropriate filters. The aim of the study was to evaluate the impact of measures aimed at reducing low-stack emissions from the household sector (boiler replacement, change of fuel type, and thermal insulation of buildings), resulting from environmental regulations, on the improvement of energy efficiency and the emission of pollutants from the household sector in Poland. Stochastic energy and mass balance models for a hypothetical household, which were used to assess the impact of remedial actions on the energy efficiency and emission of pollutants, have been developed. The annual energy consumption and emissions of pollutants were estimated for hypothetical households before and after the implementation of a given remedial action. The calculations, using the Monte Carlo simulation, were carried out for several thousand hypothetical households, for which the values of the technical parameters (type of residential building, residential building area, unitary energy demand for heating, type of heat source) were randomly drawn from probability distributions developed on the basis of the analysis of the domestic structure of households. The model takes the coefficients of correlation between the explanatory variables in the model into account. The obtained results were multiplied so that the number of hypothetical households was equal to 14.1 million, i.e. the real number of households in Poland. The obtained results allowed for identifying the potential for reducing the emission of pollutants such as carbon dioxide, carbon monoxide, dust, and nitrogen oxides, and improving the energy efficiency as a result of the proposed and implemented measures, aimed at reducing low-stack emission, resulting from the policy. The potential for emissions of gaseous pollutants is 94% for CO, 49% for NOx, 90% for dust, and 87% for SO2. The potential for improving the energy efficiency in households is around 42%.
Pollution, climate change and energy security are significant problems. Climate-disrupting fossil fuels are being replaced by clean and non-depletable sources of energy. It requires major changes to energy infrastructures and strong support for promotion of the use of energy from renewable sources. Renewable energy is emerging as a driver of inclusive economic growth and reinforcing energy security. Public entities have to promote renewable energy development by implementing cost-effective national support schemes. By acting at national-level, several barriers to public and private investments could be tackled, addressing the lack of coordination between various authorising bodies at national level and stimulatng the administrative capacity to implement energy projects. It should be effective in promoting transparency for investors and others economic operators. In Poland there is a lack of regulatory policies creating incentives for decentralised energy. Market-based support schemes are still needed for small-scale self-consumption system. Currently operating solutions have been shown in the contrast of the ones applied abroad. The development of clean energy technologies depends on many factors. The author identified few most important ones, mainly financial, regulatory issues, social, environmental and characterized them in this work. The article presents the recommendations of regulatory framework and some proposals for energy cluster based policy’s tools, the introduction of which would significantly facilitate the wider renewable energy uses in Poland.
Using renewable energy sources for electricity production is based on the processing of primary energy occurring in the form of sun, wind etc., into electrical energy. Economic viability using those sources in small power plants strongly depends on the support system, based mainly on financial instruments. Micro-installations, by using special instruments dedicated to the prosumer market may become more and more interesting not only in terms of environmental energy, but also financial independence. In the paper, the term hybrid power plant is understood to mean a production unit generating electricity or electricity and heat in the process of energy production, in which two or more renewable energy sources or energy sources other than renewable sources are used. The combination of the two energy sources is to their mutual complementarity, to ensure the continuity of the electricity supply. The ideal situation would be if both sources of energy included in the hybrid power plant continuously covered the total demand for energy consumers. Unfortunately, due to the short-term and long-term variability of weather conditions, such a balance is unattainable. The paper assesses the possibility of balancing the hybrid power plant in daily and monthly periods. Basic types of power plants and hybrid components and system support micro-installations were characterized. The support system is based particularly on a system of feed-in tariffs and the possibility of obtaining a preferential loan with a subsidy (redemption of part of the loan size). Then, an analysis of energy and economic efficiency for a standard set of hybrid micro-installations consisting of a wind turbine and photovoltaic panels with a total power of 5 kW, were presented. Fourteen variants of financing, economic efficiency compared with the use of the method of the simple payback period were assumed.
The role of the hard coal mining sector in ensuring energy security of the country has been presented in the paper. An analysis of its current status was made based on the results obtained by the sector in 2017. Moreover, the determinants which are the precondition for further sustainable and efficient operation in the years to come have been defined.
As a result of introduction of the Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings, all of the EU member states are obliged to introduce legal regulations for energy performance of all newly constructed buildings. The key aim is to achieve close to zero energy use starting from the year 2021. Estimating effectiveness of the actions and the new possibilities requires an analysis of the multiple criteria. They comprise both the current conditions as well as the changes that have occurred in the recent years due to new legislation, the eff ects of the subsidies and the development of the housing stock. This paper presents a broad overview and diagnosis of current situation. The development of the energy-efficient and passive housing in Poland is considered in the context of financial incentives, availability of design knowledge and building technology as well as the role of the green building certification.
Architecture is a discipline combining aesthetics with technology. This paper is focusing on the relationship between aesthetics and energy efficiency in architecture with special interest in solar collectors and photovoltaic panels as technological equipment of the buildings. The paper takes into consideration the present situation and architectural development in northern Poland, with some input basing on European experiences. The paper defi nes aesthetics and effi ciency in the field of architectural design as well as the use of public and urban spaces. Authors present also some case studies regarding the use of solar panels in selected architectural examples. The paper ends with summary and some conclusions including the need for further research in the field of architectural design, technology and product design, as well as the perception of urbanised spaces and the important field of economic and financial factors connected to the topic.
Assumptions of the major political and legal documents of the European Union, dedicated to energy efficiency and energy performance of buildings provide the Member States with relevant instruments supporting improvement of the ambient air qualityby dissemination of measures reducing energy demand and promotion of renewable energysources. Mainstreaming EU legislation into national regulations constitutes initial stage of the long term process of supporting implementation of energy efficiency measures. Experience in the improvement of energy performance of the residential buildings revealslimited efficiency of the measures implemented up to date, which results in significantair pollution of Polish cities. The national Action Plans had adopted a limited scope of recommendations included in the EU directives, hence the process meets significant challenges.The article describes adaptation of the relevant EU directives as well as the National Urban Policy in terms of the potential to effectively address faced challenges.
The article presents current state of the structure of hard coal enrichment plants in Poland, taking the capacity, the range of grain enrichment and the type of equipment used into account. This data were presented in a tabular format for each Polish Coal Company operating on the Polish market. The article was also present simplified: flow sheet of the steam and coking coal enrichment system. Based on the presented data, the planned needs and trends were described in terms of increasing production efficiency, minimizing water consumption and safety of work. A list of research and development works which must be undertaken were also presented as well as factors determining the technological development of the processing plants.
This paper presents the origins of marine steam turbine application on liquefied natural gas carriers. An analysis of alternative propulsion plant trends has been made. The more efficient ones with marine diesel engines gradually began to replace the less efficient plants. However, because of many advantages of the steam turbine, further development research is in progress in order to achieve comparable thermal efficiency. Research has been carried out in order to achieve higher thermal efficiency throughout increasing operational parameters of superheated steam before the turbine unit; improving its efficiency to bring it nearer to the ideal Carnot cycle by applying a reheating system of steam and multi stage regenerative boiler feed water heating. Furthermore, heat losses of the system are reduced by: improving the design of turbine blades, application of turbine casing and bearing cooling, as well as reduction in steam flow resistance in pipe work and maneuvering valves. The article identifies waste energy sources using the energy balance of a steam turbine propulsion plant applied on the liquefied natural gas carrier which was made out basing on results of a passive operation experiment, using the measured and calculated values from behavioral equations for the zero-dimensional model. Thermodynamic functions of state of waste heat fluxes have been identified in terms of their capability to be converted into usable energy fluxes. Thus, new ways of increasing the efficiency of energy conversion of a steam turbine propulsion plant have been addressed.
A formulation developed at the Laboratory of Mechanical Engineering allows robust and efficient simulation of large and complex multibody systems. Simulators of cars, excavators and other systems have been developed showing that real-time simulations are possible even when facing demanding manoeuvres. Hydraulic actuators are presented in many industrial applications of multibody systems, like in the case of the heavy machinery field. When simulating the dynamics of this kind of problems that combine multibody dynamics and hydraulics, two different approaches are common: to resort to kinematically guide the variable length of the actuator, thus avoiding the need to consider the dynamics of the hydraulic system; or to perform a multi-rate integration of both subsystems if a more detailed description of the problem is required, for example, when the objective of the study is to optimize the pump control. This work addresses the inclusion of hydraulic actuators dynamics in the above-mentioned self-developed multibody formulation, thus leading to a unified approach. An academic example serves to compare the efficiency, accuracy and ease of implementation of the simplified (kinematic guidance), multi-rate and unified approaches. Such a comparison is the main contribution of the paper, as it may serve to provide guidelines on which approach to select depending on the problem characteristics.
The paper presents the experimental study of a novel unsteady-statemembrane gas separation approach for recovery of a slow-permeant component in the membrane module with periodical retentate withdrawals. The case study consisted in the separation of binary test mixtures based on the fast-permeant main component (N2O, C2H2) and the slow-permeant impurity (1%vol. of N2) using a radial countercurrent membrane module. The novel semi-batch withdrawal technique was shown to intensify the separation process and provide up to 40% increase in separation efficiency compared to a steady-state operation of the same productivity.
Among the numerous modern, high-efficiency energy technologies allowing for the conversion of chemical energy of coal into electricity and heat, the Direct Carbon Fuel Cells (DCFC) deserve special attention. These are devices that allow, as the only one among all types of fuel cells, to directly convert the chemical energy contained in solid fuel (coal) into electricity. In addition, they are characterized by high efficiency and low emission of pollutants. The paper reviews and discusses previous research and development works, both around the world and in Poland, into the technology of direct carbon fuel cells with an alkaline (hydroxide) electrolyte.