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Paweł Drąg
Faculty of Electronics, Department of Control Systems and Mechatronics, Wroclaw University of Science and Technology, 27 Wyspiański st., 50-370 Wroclaw, Republic of Poland

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Journal article
Published: 22 July 2021 in Energy Conversion and Management
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This paper presents the concept of a Rotary Indirect Evaporative Cooler (RIEC) which the operation principle is based on implementation of evaporative cooling in rotary exchanger to increase its cooling effectiveness. The RIEC unit can operate in two modes: standard and regenerative. The mathematical model of RIEC, based on the ε–NTU method, is presented. The operation of RIEC is compared to the traditional Counter-flow Indirect Evaporative Cooler (CIEC) which also operates in two modes: standard and regenerative. Different performance indicators are introduced i.e. Energy Efficiency Ratio (EER), indicators relating the cooling capacity to cooler's length, cooler's inlet cross-section, and to cooler's overall volume. Additional two indicators are introduced to describe RIEC and CIEC operation principles by relating the cooling capacity to the rate of heat or mass transfer occurring in the wetted part of the cooler. The performance of RIEC and CIEC is compared under different climate conditions following Köppen-Geiger climate classification system. It was found that the values of performance indicators calculated for RIEC are higher than for CIEC under various operational parameters and climatic conditions. It was stated that choosing RIEC instead of CIEC allows increasing EER on average by 63% in standard mode and 88% in regenerative mode. It was concluded that RIEC is a competitive solution for cooling purposes due to its lower electricity demand and smaller dimensions.

ACS Style

Demis Pandelidis; Aleksandra Cichoń; Anna Pacak; Paweł Drąg; Marlena Drąg; Korneliusz Sierpowski; William Worek; Sabri Cetin. Performance analysis of rotary indirect evaporative air coolers. Energy Conversion and Management 2021, 244, 114514 .

AMA Style

Demis Pandelidis, Aleksandra Cichoń, Anna Pacak, Paweł Drąg, Marlena Drąg, Korneliusz Sierpowski, William Worek, Sabri Cetin. Performance analysis of rotary indirect evaporative air coolers. Energy Conversion and Management. 2021; 244 ():114514.

Chicago/Turabian Style

Demis Pandelidis; Aleksandra Cichoń; Anna Pacak; Paweł Drąg; Marlena Drąg; Korneliusz Sierpowski; William Worek; Sabri Cetin. 2021. "Performance analysis of rotary indirect evaporative air coolers." Energy Conversion and Management 244, no. : 114514.

Journal article
Published: 31 December 2020 in Energy Conversion and Management
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This paper presents the first numerical analysis of a novel Dew Point Desalination unit (DPD), which utilizes the phenomenon of the evaporative cooling process to minimize energy consumption. The proposed solution is based on a modular structure, which allows it to obtain any required water production capacity. The analyses for various operational parameters and various climatic conditions are based on the numerical simulations conducted using a validated mathematical model. The system performance was described with different factors, including specific energy consumption (SEC) and daily water production rate respected to 1 m^3*s^-1 of passing air stream (DWP). It is shown that the DPD system can operate in almost every climate zone, and the desalinated water production consumes less than 1.5 kWh*m^-3 of electric energy It is noted the best performance of the DPD system is achieved in the semi-arid, desert and subtropical climate zones. In these climate zones, the 2-stage DPD system allows the production of desalinated water with an electric energy consumption SEC lower than 0.5 kWh*m^-3. The additional benefit of the DPD system is its modularity. The presented DPD system stands as a module, that can be multiplied as needed to achieve the desired size of the desalination plant.

ACS Style

Demis Pandelidis; Aleksandra Cichoń; Anna Pacak; Paweł Drąg; Marlena Drąg; William Worek; Sabri Cetin. Water desalination through the dewpoint evaporative system. Energy Conversion and Management 2020, 229, 113757 .

AMA Style

Demis Pandelidis, Aleksandra Cichoń, Anna Pacak, Paweł Drąg, Marlena Drąg, William Worek, Sabri Cetin. Water desalination through the dewpoint evaporative system. Energy Conversion and Management. 2020; 229 ():113757.

Chicago/Turabian Style

Demis Pandelidis; Aleksandra Cichoń; Anna Pacak; Paweł Drąg; Marlena Drąg; William Worek; Sabri Cetin. 2020. "Water desalination through the dewpoint evaporative system." Energy Conversion and Management 229, no. : 113757.

Journal article
Published: 17 December 2020 in Applied Sciences
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In this article, an optimization task with nonlinear differential-algebraic equations (DAEs) is considered. As a main result, a new solution procedure is designed. The computational procedure represents the sequential optimization approach. The proposed algorithm is based on a multiple shooting parametrization method. Two main aspects of a generalized parametrization approach are analyzed in detail: a control function and DAE model parametrization. A comparison between the original and modified DAEs is made. The new algorithm is applied to solve an optimization task in heat and mass transfer engineering.

ACS Style

Paweł Drąg. A Direct Optimization Algorithm for Problems with Differential-Algebraic Constraints: Application to Heat and Mass Transfer. Applied Sciences 2020, 10, 9027 .

AMA Style

Paweł Drąg. A Direct Optimization Algorithm for Problems with Differential-Algebraic Constraints: Application to Heat and Mass Transfer. Applied Sciences. 2020; 10 (24):9027.

Chicago/Turabian Style

Paweł Drąg. 2020. "A Direct Optimization Algorithm for Problems with Differential-Algebraic Constraints: Application to Heat and Mass Transfer." Applied Sciences 10, no. 24: 9027.

Journal article
Published: 14 December 2020 in Applied Sciences
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This paper presents the characteristics of the operation of the system for recovery of water from exhaust air in moderate climates in the years 2010–2019. The proposed system for water recovery uses the phenomenon of condensation in a cross-flow heat exchanger operating as an element of the air conditioning system. The parameters of exhaust air behind the heat exchanger have been determined using a mathematical model of the so-called black box. The mathematical model considers the risk of the cross-freezing of the heat exchanger. The calculations carried out for variable parameters of external air during the analyzed period confirm that the system allows to cover the demand for water for lettuce irrigation during the cold and transitional period, which is a major part of the year. It has been noted that the effectiveness of the system is very high (av. 67.12% per year) due to the specific parameters of the internal air in which the lettuce must be grown and the need for continuous air exchange in such facilities. This means that air is a stable source of water recovery, where the recovery rate depends on the parameters of external air.

ACS Style

Anna Pacak; Anna Jurga; Paweł Drąg; Demis Pandelidis; Bartosz Kaźmierczak. A Long-Term Analysis of the Possibility of Water Recovery for Hydroponic Lettuce Irrigation in Indoor Vertical Farm. Part 1: Water Recovery from Exhaust Air. Applied Sciences 2020, 10, 8907 .

AMA Style

Anna Pacak, Anna Jurga, Paweł Drąg, Demis Pandelidis, Bartosz Kaźmierczak. A Long-Term Analysis of the Possibility of Water Recovery for Hydroponic Lettuce Irrigation in Indoor Vertical Farm. Part 1: Water Recovery from Exhaust Air. Applied Sciences. 2020; 10 (24):8907.

Chicago/Turabian Style

Anna Pacak; Anna Jurga; Paweł Drąg; Demis Pandelidis; Bartosz Kaźmierczak. 2020. "A Long-Term Analysis of the Possibility of Water Recovery for Hydroponic Lettuce Irrigation in Indoor Vertical Farm. Part 1: Water Recovery from Exhaust Air." Applied Sciences 10, no. 24: 8907.

Journal article
Published: 08 December 2020 in International Communications in Heat and Mass Transfer
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A multiple shooting based approach to an optimal control problem for highly nonlinear differential-algebraic systems (DAEs, differential-algebraic equations) is considered. The necessary optimality conditions being a consequence of the theory of variational inequalities are derived in the form of structured nonsmooth equations. A new indirect high accuracy optimization algorithm exploiting the chain structure of the mentioned equations is described. It uses the Chen-Harker-Kanzow-Smale smoothing function for the projection operator. A global superlinear (quadratic) convergence of the new algorithm is proven with using the theory of the smoothing Newton method specialized to the multiple shooting approach. The proposed algorithm is verified on the dynamic optimization of a highly nonlinear heat and mass exchange process. In general, the presented considerations have been motivated by the results of numerical simulations presented in the work Pandelidis et al., “Performance study of counter-flow indirect evaporative air coolers” Pandelidis et al. (2015).

ACS Style

Paweł Drąg; Krystyn Styczeń. A chain smoothing Newton method for heat and mass transfer control with discrete variability DAE models. International Communications in Heat and Mass Transfer 2020, 120, 105056 .

AMA Style

Paweł Drąg, Krystyn Styczeń. A chain smoothing Newton method for heat and mass transfer control with discrete variability DAE models. International Communications in Heat and Mass Transfer. 2020; 120 ():105056.

Chicago/Turabian Style

Paweł Drąg; Krystyn Styczeń. 2020. "A chain smoothing Newton method for heat and mass transfer control with discrete variability DAE models." International Communications in Heat and Mass Transfer 120, no. : 105056.

Conference paper
Published: 07 November 2018 in ITM Web of Conferences
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The main concept of the electrospinning process modeling is to overcome difficulties associated with the experimental-based optimization procedure. Thus, 3-dimensional polynomial models were discussed in this work. Electrospinning process modeling is an approach that supplies the information about wanted concentrations of the electrospinning solution components and will also make it possible to obtain bead-free nonwovens with desired fiber diameter. The application area for described methodology is highly associated with the environmental field of study, where the design of the functionalized nanofibers production is extremely requested (e.g. separation, filtration and purification processes).

ACS Style

Marlena Drąg; Paweł Drąg. Model-based electrospinning process design for nanofibers production. ITM Web of Conferences 2018, 23, 00007 .

AMA Style

Marlena Drąg, Paweł Drąg. Model-based electrospinning process design for nanofibers production. ITM Web of Conferences. 2018; 23 ():00007.

Chicago/Turabian Style

Marlena Drąg; Paweł Drąg. 2018. "Model-based electrospinning process design for nanofibers production." ITM Web of Conferences 23, no. : 00007.

Conference paper
Published: 25 September 2018 in CBU International Conference Proceedings
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In the modern era, information is not only a valuable commodity, but also a potential source of threat, especially when it comes to personal data. The implementation of the General Data Protection Regulation seeks to unify regulations and safeguards in a same manner across the EU. The following paper surveys how the legal aspects of GDPR influence the existing technical framework of databases containing personal data. In this research we want to show if the already existing technical infrastructure and safeguards implemented in databases containing personal data are sufficient and if not, if implementing new ways of protecting of data will require creating entire new system of databases or only changing of existing framework. Therefore, we combine an analysis of legal texts with a technical analysis of existing and newly implemented safeguards. While the GDPR doesn’t answer what safeguards should be implemented (in the spirit of technological neutrality), the notion of pseudonymisation of the data is strongly advocated through the Regulation. In our paper we tried to show the algorithm, which create a pseudonymisation function that can change personal data into generic data with the possibility to reverse that process ad utilise data after de-pseudonymisation. Implementing safeguards based on the following function create a more safe environment for data safekeeping, while give nearly immediate access to data for authorised person, who can reverse pseudonymisation and transform generic data once more into personal data.

ACS Style

Paweł Drąg; Mateusz Szymura. TECHNICAL AND LEGAL ASPECTS OF DATABASE'S SECURITY IN THE LIGHT OF IMPLEMENTATION OF GENERAL DATA PROTECTION REGULATION. CBU International Conference Proceedings 2018, 6, 1056 -1061.

AMA Style

Paweł Drąg, Mateusz Szymura. TECHNICAL AND LEGAL ASPECTS OF DATABASE'S SECURITY IN THE LIGHT OF IMPLEMENTATION OF GENERAL DATA PROTECTION REGULATION. CBU International Conference Proceedings. 2018; 6 ():1056-1061.

Chicago/Turabian Style

Paweł Drąg; Mateusz Szymura. 2018. "TECHNICAL AND LEGAL ASPECTS OF DATABASE'S SECURITY IN THE LIGHT OF IMPLEMENTATION OF GENERAL DATA PROTECTION REGULATION." CBU International Conference Proceedings 6, no. : 1056-1061.

Chapter
Published: 19 September 2018 in Artificial Intelligence: Foundations, Theory, and Algorithms
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In this work a new optimization approach for processes modeled by differential-algebraic equations with variability constraints was presented. The designed procedure was based on the modified direct shooting method, which can transform the dynamic optimization problem into a large-scale nonlinear optimization task (NLP). The first-order KKT optimality conditions with complementarity constraints were obtained. Finally, to solve the optimality conditions with the complementarity constraints, the solution procedure combining SQP algorithm with the filter approach as a globalization procedure was designed. The efficiency of the presented methodology was tested on a production process in chemical engineering.

ACS Style

Paweł Dra̧g; Krystyn Styczeń. The New Approach for Dynamic Optimization with Variability Constraints. Artificial Intelligence: Foundations, Theory, and Algorithms 2018, 35 -46.

AMA Style

Paweł Dra̧g, Krystyn Styczeń. The New Approach for Dynamic Optimization with Variability Constraints. Artificial Intelligence: Foundations, Theory, and Algorithms. 2018; ():35-46.

Chicago/Turabian Style

Paweł Dra̧g; Krystyn Styczeń. 2018. "The New Approach for Dynamic Optimization with Variability Constraints." Artificial Intelligence: Foundations, Theory, and Algorithms , no. : 35-46.

Journal article
Published: 22 April 2017 in Energies
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The aim of this study is to determine which of the heat exchangers is characterized by the highest efficiency in different applications. Various types of evaporative air coolers were compared: a typical counter-flow unit, the same unit operating as a heat recovery exchanger, a regenerative unit and a novel, modified regenerative exchanger. The analysis includes comparing the work of evaporative heat exchangers during summer and winter season. The analysis is based on the original mathematical models. The numerical models are based on the modified ε-NTU (number of heat transfer units) method. It was established that selected arrangements of the presented exchangers are characterized by the different efficiency in different air-conditioning applications. The analysis faces the main construction aspects of those evaporative coolers and also compares two above-mentioned devices with modified regenerative air cooler, which can partly operate on cooled outdoor airflow and on the exhaust air from conditioned spaces. This solution can be applied in any climate and it is less dependent on the outdoor conditions. The second part of the study focuses on winter season and the potential of recovering heat with the same exchangers, but with dry working air channels. This allows establishing their total potential of generating energy savings during the annual operation.

ACS Style

Demis Pandelidis; Sergey Anisimov; Paweł Drąg. Performance Comparison between Selected Evaporative Air Coolers. Energies 2017, 10, 577 .

AMA Style

Demis Pandelidis, Sergey Anisimov, Paweł Drąg. Performance Comparison between Selected Evaporative Air Coolers. Energies. 2017; 10 (4):577.

Chicago/Turabian Style

Demis Pandelidis; Sergey Anisimov; Paweł Drąg. 2017. "Performance Comparison between Selected Evaporative Air Coolers." Energies 10, no. 4: 577.

Book chapter
Published: 16 July 2016 in Artificial Intelligence: Foundations, Theory, and Algorithms
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In the article a new method for control and optimization of the ethanol production process was presented. The fed batch reactor for ethanol production can be described by the system of the nonlinear differential-algebraic equations. The new control approach base on the direct shooting method, which leads to a medium- or large-scale nonlinear optimization problem. In the presented research, three main aims of the optimization with the differential-algebraic constraints are indicated. The first one is the minimization of the cost function, which represents a process performance index. The second and third aims are to provide consistent initial conditions for the system to be solved and to ensure the continuity of the differential state trajectories. For these reasons, the large number of decision variables and equality constraints, connected with both consistent initial conditions for the differential-algebraic system and continuity of the differential state trajectories, was treated using the constraints aggregation technique. The direct shooting approach together with constraints aggregation technique enables us to obtain a new form of the nonlinear optimization task.

ACS Style

Paweł Dra̧g; Krystyn Styczeń. The Constraints Aggregation Technique for Control of Ethanol Production. Artificial Intelligence: Foundations, Theory, and Algorithms 2016, 179 -192.

AMA Style

Paweł Dra̧g, Krystyn Styczeń. The Constraints Aggregation Technique for Control of Ethanol Production. Artificial Intelligence: Foundations, Theory, and Algorithms. 2016; ():179-192.

Chicago/Turabian Style

Paweł Dra̧g; Krystyn Styczeń. 2016. "The Constraints Aggregation Technique for Control of Ethanol Production." Artificial Intelligence: Foundations, Theory, and Algorithms , no. : 179-192.

Review
Published: 15 July 2015 in Econometrics for Financial Applications
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In the article the main features of direct and indirect approaches for solving optimal control problems were presented. The mentioned methods can be effectively applied in the Model Predictive Control of the complex technological systems in electrical, chemical and aerospace engineering, often described by nonlinear differential-algebraic equations. Among the direct and indirect methods for solving optimal control problems one can mention Euler-Lagrange equations, direct optimization methods and indirect gradients methods.

ACS Style

Paweł Dra̧g; Krystyn Styczeń; Marlena Kwiatkowska; Andrzej Szczurek. A Review on the Direct and Indirect Methods for Solving Optimal Control Problems with Differential-Algebraic Constraints. Econometrics for Financial Applications 2015, 91 -105.

AMA Style

Paweł Dra̧g, Krystyn Styczeń, Marlena Kwiatkowska, Andrzej Szczurek. A Review on the Direct and Indirect Methods for Solving Optimal Control Problems with Differential-Algebraic Constraints. Econometrics for Financial Applications. 2015; ():91-105.

Chicago/Turabian Style

Paweł Dra̧g; Krystyn Styczeń; Marlena Kwiatkowska; Andrzej Szczurek. 2015. "A Review on the Direct and Indirect Methods for Solving Optimal Control Problems with Differential-Algebraic Constraints." Econometrics for Financial Applications , no. : 91-105.

Book chapter
Published: 15 July 2015 in Econometrics for Financial Applications
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In the paper the optimal control of highly nonlinear differential-algebraic systems (DAEs) is discussed. The direct shooting method is seen as an efficient tool for control of the complex real-life technological processes, where dynamics and conservation laws are presented. To stabilize the optimization algorithm, the multiple shooting method was proposed. The multiple shooting approach introduces new decision variables and constraints to the problem, but it can preserve the stability of the process, the continuity of the differential state trajectories and enables parallel computation of the mathematical model. The conditions for the frequency of shots, to establish the well-conditioned optimization problem, are considered. The proposed method was tested on the mathematical model of the fed-batch fermentor for penicillin production process, which is a highly nonlinear multistage differential-algebraic system. The numerical simulations were executed in MATLAB environment using Wroclaw Center for Networking and Supercomputing.

ACS Style

Paweł Dra̧g; Krystyn Styczeń. Direct Shooting Method for Optimal Control of the Highly Nonlinear Differential-Algebraic Systems. Econometrics for Financial Applications 2015, 75 -90.

AMA Style

Paweł Dra̧g, Krystyn Styczeń. Direct Shooting Method for Optimal Control of the Highly Nonlinear Differential-Algebraic Systems. Econometrics for Financial Applications. 2015; ():75-90.

Chicago/Turabian Style

Paweł Dra̧g; Krystyn Styczeń. 2015. "Direct Shooting Method for Optimal Control of the Highly Nonlinear Differential-Algebraic Systems." Econometrics for Financial Applications , no. : 75-90.