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The paper focuses on the operation analysis of the photovoltaic chain in condition of partial shading. For the needs of this analysis, the model of this PV system was implemented in the MATLAB/Simulink. This model corresponded to the structure of the real photovoltaic system on which experiments were carried out. The model consists of seven PV modules connected in series, where each of them can receive a different irradiance. Two cases were analyzed, the first when each of the seven modules had a bypass diode and the second when there were no bypass diodes in the system. The model was validated by identifying parameters based on two experiments carried out under different conditions, so that the model corresponds to the actual installation on which the experiments were conducted. The operation of the model was analyzed for various configurations of partial shading and the presence or absence of bypass diodes.
Wojciech Kreft; Estera Przenzak; Mariusz Filipowicz. Photovoltaic chain operation analysis in condition of partial shading for systems with and without bypass diodes. Optik 2021, 247, 167840 .
AMA StyleWojciech Kreft, Estera Przenzak, Mariusz Filipowicz. Photovoltaic chain operation analysis in condition of partial shading for systems with and without bypass diodes. Optik. 2021; 247 ():167840.
Chicago/Turabian StyleWojciech Kreft; Estera Przenzak; Mariusz Filipowicz. 2021. "Photovoltaic chain operation analysis in condition of partial shading for systems with and without bypass diodes." Optik 247, no. : 167840.
According to the Sustainable Development Scenario, the power generated by concentrating solar systems will be multiplied by 12 times by 2030 and will achieve nearly 184 TWh. To make it possible it is necessary to combine the concentrating solar systems with other technologies such as photovoltaics, sorption chillers, Stirling engines, etc. The total efficiency of hybrid systems is significantly higher than standalone ones. This paper analyzes the possibility of upgrading the existing concentrating solar thermal system with two-focal points located in Cracow, Poland. So far, this installation was used only for water heating applications. To estimate the possibilities of upgrading this system, numerical simulations with the use of Ray Tracing methods and Computational Fluid Dynamics were provided. Data obtained from the ray-tracing analysis allowed to determine the distribution of irradiance for various locations of the receiver. The CFD methods enabled to find the dependencies between the initial parameters of the working fluid, irradiance distribution, and heat transfer efficiency. Obtained results allowed to conclude that it is possible to use generated heat (354 K) for absorption chiller purpose. Moreover, this system may be used for simultaneous heat and electricity production, but firstly some changes in receiver geometry should be introduced.
Karolina Papis-Frączek; Maciej Żołądek; Mariusz Filipowicz. The possibilities of upgrading an existing concentrating solar thermal system — Case study. Energy Reports 2021, 1 .
AMA StyleKarolina Papis-Frączek, Maciej Żołądek, Mariusz Filipowicz. The possibilities of upgrading an existing concentrating solar thermal system — Case study. Energy Reports. 2021; ():1.
Chicago/Turabian StyleKarolina Papis-Frączek; Maciej Żołądek; Mariusz Filipowicz. 2021. "The possibilities of upgrading an existing concentrating solar thermal system — Case study." Energy Reports , no. : 1.
Microscale heating devices are mandatory for users located in areas lacking of heating networks, especially in the rural ones. An interesting option for schools, farms, houses, and other users is to increase the functionality of heating devices with the power generation option. Such systems may operate on the basis of a simple Rankine Cycle fired by biomass. In this paper, the energy and economic parameters of a prototype micro-cogeneration system based on a 100 kWth straw-fired boiler with a thermal oil jacket and a 14.8 kW steam engine were investigated. During the experimental tests, the power at a level of 1.1 kWel was obtained by the prototype installation when steam pressure was equal to 4.3 bars and steam mass flow was about 105 kg/h. The relatively low electric power resulted from a limited heat exchange surface of the evaporator and, undersized nominal power of electricity generator and piping heat and pressure losses. On the other hand, the maximum measured pressure was 10 bars, when steam temperature was ca. 200 °C, pointing out that the installation has a significant potential of improvement from the power generation point of view. A dynamic simulation model was developed using TRNSYS software in order to investigate the system capabilities. This model was calibrated using experimental investigations, and further technical improvements of the installation were analyzed from energy and economic points of view. The possibility of integrating an absorption chiller in the system was also considered. As a result, the operation of the existing micro-cogeneration system was simulated and the operation parameters of the proposed micro trigeneration system were analyzed.
Maciej Żołądek; Rafał Figaj; Krzysztof Sornek. Energy analysis of a micro-scale biomass cogeneration system. Energy Conversion and Management 2021, 236, 114079 .
AMA StyleMaciej Żołądek, Rafał Figaj, Krzysztof Sornek. Energy analysis of a micro-scale biomass cogeneration system. Energy Conversion and Management. 2021; 236 ():114079.
Chicago/Turabian StyleMaciej Żołądek; Rafał Figaj; Krzysztof Sornek. 2021. "Energy analysis of a micro-scale biomass cogeneration system." Energy Conversion and Management 236, no. : 114079.
Energy needs of air conditioning systems are constantly growing worldwide, due to climate change and growing standards of buildings. Among the possible systems, solar heating and cooling based on reversible heat pumps and thermally driven chillers are a viable option for ensuring space heating and cooling for different users. The high installation costs are a limit to their diffusion, however, under specific circumstances (climate, type of the building, type of the user, etc.), the investment in this technology can be profitable in a long term. The presented paper describes an energy-economic assessment of a solar heating and cooling system integrating a solar dish concentrator with thermal collectors coupled with a reversible heat pump and an absorption or adsorption chiller. The system integrated with a household building is developed and dynamically simulated in the Transient System Simulation (TRNSYS) environment under different circumstances –adoption of absorption or adsorption chiller, use of auxiliary thermal energy to drive the sorption chillers, and locality. The results show that space cooling demand in Cracow is matched by solar energy, in a range between 49.0 and 97.6%, while for Naples the space cooling demand is provided by solar heat from 46.1 to 99.1% depending on the adopted sorption chiller and or the use of auxiliary heat for a natural gas boiler. The proposed system is not profitable in case Cracow, since a Simple Pay Back period of about 20 years is achieved. Conversely, case of Naples, the same index achieves a value between 8 and 12 years showing that the proposed system may be a viable solution for heating and cooling installation.
Rafał Figaj; Maciej Żołądek. Operation and Performance Assessment of a Hybrid Solar Heating and Cooling System for Different Configurations and Climatic Conditions. Energies 2021, 14, 1142 .
AMA StyleRafał Figaj, Maciej Żołądek. Operation and Performance Assessment of a Hybrid Solar Heating and Cooling System for Different Configurations and Climatic Conditions. Energies. 2021; 14 (4):1142.
Chicago/Turabian StyleRafał Figaj; Maciej Żołądek. 2021. "Operation and Performance Assessment of a Hybrid Solar Heating and Cooling System for Different Configurations and Climatic Conditions." Energies 14, no. 4: 1142.
Renewable energy sources, such as solar, wind, biomass, and geothermal energy, are being more and more adopted in small and micro-scale distributed generation systems. In this context, different hybrid configurations and layouts that may adopt, lead to different energy and economic performance of energy generation systems. In micro-scale applications, biomass and solar energy sources are more frequently investigated in literature compared to other combinations as biomass and wind energy. The analysis of the performance of a novel small-scale trigeneration system is presented in this paper. The system includes biomass boiler, water steam turbine, absorption chiller, and wind turbine, and it is linked to the electric grid by means of a bidirectional connection, allowing to the store virtually the electrical energy produced in excess, and use when needed. For the proposed system, a zootechnical farm and a residential building are considered as case study, including different scenarios for the reference energy system. The Transient System Simulation (TRNSYS software is used to model, simulate, and investigate the system performance under realistic operation conditions. Energy and economic performance of the system is assessed by means of a daily, weekly, and yearly analysis. The effect of the main design parameters, as steam and wind turbine power on the system performance, is investigated by means of a sensitivity analysis. The investigations show that the Simple Pay Back time of the proposed system is below 6 years, when the biomass is free, capacities of steam and wind turbines lower than 4 kW are selected, and a reference system with a natural gas boiler and electrical grid is considered. The system allows one to achieve satisfactory energy and economic performance under the considered conditions, when a proper design of the system component capacities is adopted.
Rafał Figaj; Krzysztof Sornek; Szymon Podlasek; Maciej Żołądek. Operation and Sensitivity Analysis of a Micro-Scale Hybrid Trigeneration System Integrating a Water Steam Cycle and Wind Turbine under Different Reference Scenarios. Energies 2020, 13, 5697 .
AMA StyleRafał Figaj, Krzysztof Sornek, Szymon Podlasek, Maciej Żołądek. Operation and Sensitivity Analysis of a Micro-Scale Hybrid Trigeneration System Integrating a Water Steam Cycle and Wind Turbine under Different Reference Scenarios. Energies. 2020; 13 (21):5697.
Chicago/Turabian StyleRafał Figaj; Krzysztof Sornek; Szymon Podlasek; Maciej Żołądek. 2020. "Operation and Sensitivity Analysis of a Micro-Scale Hybrid Trigeneration System Integrating a Water Steam Cycle and Wind Turbine under Different Reference Scenarios." Energies 13, no. 21: 5697.
The adoption of micro-scale renewable energy systems in the residential sector has started to be increasingly diffused in recent years. Among the possible systems, ground heat exchangers coupled with reversible heat pumps are an interesting solution for providing space heating and cooling to households. In this context, a possible hybridization of this technology with other renewable sources may lead to significant benefits in terms of energy performance and reduction of the dependency on conventional energy sources. However, the investigation of hybrid systems is not frequently addressed in the literature. The present paper presents a technical, energy, and economic analysis of a hybrid ground-solar-wind system, proving space heating/cooling, domestic hot water, and electrical energy for a household. The system includes vertical ground heat exchangers, a water–water reversible heat pump, photovoltaic/thermal collectors, and a wind turbine. The system with the building is modeled and dynamically simulated in the Transient System Simulation (TRNSYS) software. Daily dynamic operation of the system and the monthly and yearly results are analyzed. In addition, a parametric analysis is performed varying the solar field area and wind turbine power. The yearly results point out that the hybrid system, compared to a conventional system with natural gas boiler and electrical chiller, allows one to reduce the consumption of primary energy of 66.6%, and the production of electrical energy matches 68.6% of the user demand on a yearly basis. On the other hand, the economic results show that that system is not competitive with the conventional solution, because the simple pay back period is 21.6 years, due to the cost of the system components.
Rafał Figaj; Maciej Żołądek; Wojciech Goryl. Dynamic Simulation and Energy Economic Analysis of a Household Hybrid Ground-Solar-Wind System Using TRNSYS Software. Energies 2020, 13, 3523 .
AMA StyleRafał Figaj, Maciej Żołądek, Wojciech Goryl. Dynamic Simulation and Energy Economic Analysis of a Household Hybrid Ground-Solar-Wind System Using TRNSYS Software. Energies. 2020; 13 (14):3523.
Chicago/Turabian StyleRafał Figaj; Maciej Żołądek; Wojciech Goryl. 2020. "Dynamic Simulation and Energy Economic Analysis of a Household Hybrid Ground-Solar-Wind System Using TRNSYS Software." Energies 13, no. 14: 3523.
One of waste heat recovery technologies are thermoelectric generators, which allow direct conversion heat to energy. In the face of shrinking fossil fuels resources, simultaneous increase of global energy demand and level of pollution it is becoming more and more important to introduce technologies enabling fullest utilization of fuels. In the paper, tests of water and air cooled thermoelectric generators mounted on the stove were described. Problems that occurred while operation of the system and its solutions were presented. Analysis of factors influencing incineration process, therefore affecting produced electrical energy was carried out. Power and voltage-current characteristics of generators were drawn up. A possible electrical energy yield in conditions described in this paper was also estimated.
Maciej Żołądek; Karolina Papis; Jakub Kuś; Michał Zając; Rafał Figaj; Kyrylo Rudykh. The Use of Thermoelectric Generators With Home Stoves. E3S Web of Conferences 2020, 173, 03005 .
AMA StyleMaciej Żołądek, Karolina Papis, Jakub Kuś, Michał Zając, Rafał Figaj, Kyrylo Rudykh. The Use of Thermoelectric Generators With Home Stoves. E3S Web of Conferences. 2020; 173 ():03005.
Chicago/Turabian StyleMaciej Żołądek; Karolina Papis; Jakub Kuś; Michał Zając; Rafał Figaj; Kyrylo Rudykh. 2020. "The Use of Thermoelectric Generators With Home Stoves." E3S Web of Conferences 173, no. : 03005.
The paper presents the problem of losses of electrical power in photovoltaic chains during partial shading. Photovoltaic modules work best when the illumination is uniform over the entire light-sensitive surface. If a part of this surface is illuminated to a lesser extent, it often ceases to be a part of the electricity generator, but constitutes a resistance. To minimize this phenomenon, PV modules use bypass diodes, e.g. covering several dozen cells in a photovoltaic chain. In addition, parts of the photovoltaic module surface with lower exposure to sunlight may be additionally illuminated with a mirror positioned to reflect light. The analysis uses a photovoltaic chain model implemented in MATLAB/Simulink. The model describes the processes of electrical power generation in photovoltaic modules. The model corresponds to a laboratory photovoltaic system located in AGH in Cracow. In the presented model, each individual part may be illuminated with different light intensity. The light incident on the cells is a direct sunlight or light reflected from the mirror. The model allows for the analysis of the electrical power generated depending on the light profile of the photovoltaic system. The results of the model analysis may be applied in optimization of the PV modules’ configuration.
Wojciech Kreft; Mariusz Filipowicz; Maciej Żołądek. Reduction of electrical power loss in a photovoltaic chain in conditions of partial shading. Optik 2019, 202, 163559 .
AMA StyleWojciech Kreft, Mariusz Filipowicz, Maciej Żołądek. Reduction of electrical power loss in a photovoltaic chain in conditions of partial shading. Optik. 2019; 202 ():163559.
Chicago/Turabian StyleWojciech Kreft; Mariusz Filipowicz; Maciej Żołądek. 2019. "Reduction of electrical power loss in a photovoltaic chain in conditions of partial shading." Optik 202, no. : 163559.
Refrigeration systems are necessary for people living in hot climates. A majority of tropical and subtropical countries uses electrical power as a source of cooling. During the seasons of high ambient temperature there is a significant cooling load due to increased level of energy consumption. Cooling systems are therefore necessary in African countries in order to keep medications and food in safe conditions. Furthermore, there is a power shortage crisis due to the high demand for cooling. TRNSYS software allows to simulate a complete solar-powered absorption cooling system. A model used in an experiment includes PV modules making it advantageous over a conventional cooling system. PV modules of assumed area are sufficient to maintain the temperature inside cooling device below 6°C over the whole year.
Jakub Kuś; Kyrylo Rudykh; Marcin Kobas; Maciej Żołądek; Szymon Sendłak; Maciej Gumułka; Krzysztof Sornek. Solar-driven Refrigerator for off-grid Regions. E3S Web of Conferences 2019, 103, 01001 .
AMA StyleJakub Kuś, Kyrylo Rudykh, Marcin Kobas, Maciej Żołądek, Szymon Sendłak, Maciej Gumułka, Krzysztof Sornek. Solar-driven Refrigerator for off-grid Regions. E3S Web of Conferences. 2019; 103 ():01001.
Chicago/Turabian StyleJakub Kuś; Kyrylo Rudykh; Marcin Kobas; Maciej Żołądek; Szymon Sendłak; Maciej Gumułka; Krzysztof Sornek. 2019. "Solar-driven Refrigerator for off-grid Regions." E3S Web of Conferences 103, no. : 01001.
The worldwide growing demand for energy from renewable sources is observed. This fact is related to a number of factors, especially environmental ones. The renewable energy sector, which can be seen in the most dynamic development is wind energy. This is due to the construction of huge wind turbines, whose power exceeds one megawatts. The main problem that should be solved is to find a proper location for such turbines. Generally, wind turbines are located off-shore and on-shore. The most favourable are off-shore because of better wind condition what relates to power generation. Notwithstanding, it is possible to install smaller turbines in urban areas: so-called wind turbines in built-up areas or integrate wind turbines with buildings (BIWT). However, it is needed to be aware of many problems of above mentioned installations. The article presents an overview and data related to operation of wind turbines integrated with the Center of Energy AGH building.
M Filipowicz; W Goryl; Maciej Żołądek. Study of building integrated wind turbines operation on the example of Center of Energy AGH. IOP Conference Series: Earth and Environmental Science 2019, 214, 012122 .
AMA StyleM Filipowicz, W Goryl, Maciej Żołądek. Study of building integrated wind turbines operation on the example of Center of Energy AGH. IOP Conference Series: Earth and Environmental Science. 2019; 214 (1):012122.
Chicago/Turabian StyleM Filipowicz; W Goryl; Maciej Żołądek. 2019. "Study of building integrated wind turbines operation on the example of Center of Energy AGH." IOP Conference Series: Earth and Environmental Science 214, no. 1: 012122.
Nowadays, photovoltaic systems installed in urban areas may be essential for distributed generation and lead to increase energy security and improve economy of building exploitation. Unfortunately, in many cases their operation in urban area is not so efficient. It is connected with shadowing by neighbouring buildings, trees or by the HVAC systems installed on roofs (including such elements as fans, compressors, etc). Moreover, HVAC systems often occupy "the best" place on roofs. Level of shadowing varies during a day, and a year, significantly influencing on the power generation from PV installations. It caused serious difficulties in designing such installations (e.g. choosing position, orientation, number of modules etc.). In the paper a PV efficiency analysis was performed for the case of photovoltaic installation located on the roof of didactic building in Krakow centre. The projected power of the installation was 8.48 kWp (total nominal power of panels), and 7.5 kWp at the output of the inverters used for own building demand and car load station. The available area for PV system was strongly limited and achieving of the optimal tilting angle was impossible. Presented simulations have been conducted using two commercially available software: TRNSYS and Polysun. Results of the simulations were used for improving operation parameters of the installation. A three approaches was considered: avoiding the shadow, tilting angle optimization and redirecting of additional light stream.
Maciej Żołądek; M Filipowicz; K Sornek; R D Figaj. Energy performance of the photovoltaic system in urban area - case study. IOP Conference Series: Earth and Environmental Science 2019, 214, 012123 .
AMA StyleMaciej Żołądek, M Filipowicz, K Sornek, R D Figaj. Energy performance of the photovoltaic system in urban area - case study. IOP Conference Series: Earth and Environmental Science. 2019; 214 (1):012123.
Chicago/Turabian StyleMaciej Żołądek; M Filipowicz; K Sornek; R D Figaj. 2019. "Energy performance of the photovoltaic system in urban area - case study." IOP Conference Series: Earth and Environmental Science 214, no. 1: 012123.
Nowadays, photovoltaic systems installed in urban areas have to be an essential part of distributed generation systems, and lead to improve energy efficiency of buildings. The paper describes the operation aspects of the 7,5 kWp photovoltaic installation located on the roof of the didactic building of AGH University of Science and Technology. The significant part of the roof Is occupied by HVAC installation, so the periodic shading is occurring. It makes, that a level of energy generated in the PV system is lower than expected. The first part of the test was focused on the validating model of the installation and determine its impact on the CO2 emissions. Then, modifications in the arrangement of the panels were considered (redirecting of additional light stream). Moreover, an economic and environmental analysis of proposed improvements were conducted.
Maciej Żołądek; Krzysztof Sornek; Karolina Papis; Rafał Figaj; Mariusz Filipowicz. Experimental and Numerical Analysis of Photovoltaics System Improvements in Urban Area. Civil and Environmental Engineering Reports 2018, 28, 13 -24.
AMA StyleMaciej Żołądek, Krzysztof Sornek, Karolina Papis, Rafał Figaj, Mariusz Filipowicz. Experimental and Numerical Analysis of Photovoltaics System Improvements in Urban Area. Civil and Environmental Engineering Reports. 2018; 28 (4):13-24.
Chicago/Turabian StyleMaciej Żołądek; Krzysztof Sornek; Karolina Papis; Rafał Figaj; Mariusz Filipowicz. 2018. "Experimental and Numerical Analysis of Photovoltaics System Improvements in Urban Area." Civil and Environmental Engineering Reports 28, no. 4: 13-24.
Nowadays, the use of wood for cooking and heating has become very popular, especially in rural and suburban areas. Fireplaces and solid fuel stoves with heat accumulation provide both low-cost heating and an aesthetic atmosphere from burning wood. Additional benefits may also be connected with micro-scale power generation, realized using thermoelectric generators. The aim of this study was to examine the selected aspects of integration of a typical wood-fired stove with commercially available thermoelectric generators. Among several aspects included in the carried out analysis, there were e.g. the operation parameters of the tested stove (including temperature variations during combustion process), the efficiency of electricity generation in the tested thermoelectric generators and the requirements for the stove configuration and operation. Three types of thermoelectric generators were tested: two generators designed for mounting on a flat hot surface (cooling respectively by air and water) and one designed for mounting on a flue gas channel (cooling by water). The experiments were carried out using dedicated measuring, controlling, and visualizing systems with a PLC controller as well as an infrared camera. Thermographic analysis allowed determining of the temperature distribution on the rear wall of the stove and selection of the most optimal areas for mounting generators. However, non-homogeneous temperature distribution was observed, identified as one reason for lowering of operational efficiency of the generators. A further problem was identified in the case of the generator mounted on the flue gas channel being too low a cross-section of its gas channels (reducing flue gas flow volume). These problems significantly impacted on the operating characteristics of the thermoelectric generators – meaning they produced no more than 41.7, 31.2, and 7.2% of their nominal power, respectively. The obtained results enabled the proposal of two approaches connected with further development of the micro scale cogeneration systems with thermoelectric generators: These two methods would differ in terms of costs, final product price, and necessary fitting of production lines.
Krzysztof Sornek; Mariusz Filipowicz; Maciej Żołądek; Radosław Kot; Małgorzata Mikrut. Comparative analysis of selected thermoelectric generators operating with wood-fired stove. Energy 2018, 166, 1303 -1313.
AMA StyleKrzysztof Sornek, Mariusz Filipowicz, Maciej Żołądek, Radosław Kot, Małgorzata Mikrut. Comparative analysis of selected thermoelectric generators operating with wood-fired stove. Energy. 2018; 166 ():1303-1313.
Chicago/Turabian StyleKrzysztof Sornek; Mariusz Filipowicz; Maciej Żołądek; Radosław Kot; Małgorzata Mikrut. 2018. "Comparative analysis of selected thermoelectric generators operating with wood-fired stove." Energy 166, no. : 1303-1313.
Nowadays, the worldwide growing demand for energy from renewable sources is observed. This fact is related to a number of factors, especially environmental ones. In the renewable energy sector, the most dynamic development which can be seen is wind energy. This is due to the construction of huge wind turbines, whose power exceeds even a few megawatts. The main problem that should be solved is finding a proper location for such turbines. Generally, wind turbines are located off-shore and on-shore. The most favourable are off-shore due to better wind condition, which relates to power generation. Notwithstanding, it is possible to install smaller turbines in urban areas: so-called wind turbines in built-up areas or integrate wind turbines with buildings (BIWT). This creates an opportunity to develop an integrated system of small energy sources located directly in cities. However, it is necessary to be aware of the many problems connected with the above mentioned installations. The article presents an overview and data related to operation of wind turbines integrated with the Center of Energy AGH building.
Mariusz Filipowicz; Maciej Żołądek; Wojciech Goryl; Krzysztof Sornek. Urban ecological energy generation on the example of elevation wind turbines located at Center of Energy AGH. E3S Web of Conferences 2018, 49, 00023 .
AMA StyleMariusz Filipowicz, Maciej Żołądek, Wojciech Goryl, Krzysztof Sornek. Urban ecological energy generation on the example of elevation wind turbines located at Center of Energy AGH. E3S Web of Conferences. 2018; 49 ():00023.
Chicago/Turabian StyleMariusz Filipowicz; Maciej Żołądek; Wojciech Goryl; Krzysztof Sornek. 2018. "Urban ecological energy generation on the example of elevation wind turbines located at Center of Energy AGH." E3S Web of Conferences 49, no. : 00023.