Papers by Kostas Kalaitzakis
Applied Reconfigurable Computing. Architectures, Tools, and Applications
We survey the Proportional-Integral-Derivative (PID) controller variants and we switch them in ru... more We survey the Proportional-Integral-Derivative (PID) controller variants and we switch them in runtime via reconfiguration, as the control requirements change. Depending on the PID variant, e.g. P, I, PI, PD, PID, PI-PD, the involved computations to produce the control output are different. We rely on a previous published design to shorten the execution cycle of each controller variant, by increasing the number of arithmetic units operating concurrently. Furthermore, we incorporate a design based on multiplexers that allows for eliminating frequent reconfigurations, which were required in the previous work. Finally, we evaluate our approach in terms of resource utilization and reconfiguration time.
The proposed technique a) provides both charge and discharge equalization and supports battery op... more The proposed technique a) provides both charge and discharge equalization and supports battery operation even with damaged cells b) ensures a uniform battery cell voltage fall, thus protecting cells from reverse polarization, and c) maximizes the energy delivered by the battery. The operation has been verified both by simulation and by experimental results.
Sustainability
Measurement and verification (M&V) has become necessary for ensuring intended design performance.... more Measurement and verification (M&V) has become necessary for ensuring intended design performance. Currently, M&V procedures and calculation methods exist for the assessment of Energy Conservation Measures (ECM) for existing buildings, with a focus on reliable baseline model creation and savings estimation, as well as for reducing the computation time, uncertainties, and M&V costs. There is limited application of rigorous M&V procedures in the design, delivery and operation of low/zero energy dwellings and settlements. In the present paper, M&V for four pilot net-zero energy settlements has been designed and implemented. The M&V has been planned, incorporating guidance from existing protocols, linked to the project development phases, and populated with lessons learned through implementation. The resulting framework demonstrates that M&V is not strictly linked to the operational phase of a project but is rather an integral part of the project management and development. Under this sc...
2018 IEEE International Conference on Imaging Systems and Techniques (IST)
The inspection of power transmission lines is an important task that enhances the reliability of ... more The inspection of power transmission lines is an important task that enhances the reliability of Electricity Distribution Network Operators. This task can be performed in a low-cost way using unmanned aircrafts. At the present study, we examine the effectiveness of using basic image processing methods on image data of the power lines acquired by an unmanned aerial vehicle (UAV). The specific UAV was assembled for the present work under the considerations that arise from the purpose of the inspection of power transmission lines. Two methodologies are proposed differing on the preprocessing required in order to detect the location of the lines on the video images. Both proposed methodologies were tested in real-world cases, with the image background in each case to be characterized of non-uniform texture, i.e., the natural terrain is rugged at some locations, wooded land at some other or it is road that appears at the same hue as the aerial power lines. We examined the case of a broken line where the methodologies result in successful detection of the power lines before and after the discontinuity of the power line. The proposed work offers a robust and low-cost way for the inspection of power transmission lines and so an effective way to detect the location where a cable fault has occurred.
Applied System Innovation
In this article, a method for the efficient charging of electric vehicles (EVs) at the parking lo... more In this article, a method for the efficient charging of electric vehicles (EVs) at the parking lot (PL) level, including V2G operation and taking into account lifetime of EV batteries, distribution network and local transformer loading, is proposed. The main targets of the method are to minimize the total charging cost of the PLs hosting the EVs and to satisfy all technical and operation constraints of EVs and PLs. The proposed method exploits particle swarm optimization (PSO) to derive the charging schedule of the EVs. The proposed method is compared with conventional charging strategies, where the EVs are charged with the maximum power of their charging power converter or the average power required to achieve their state-of-charge target, and a conventional charging scheduling method using the aggregated behavior of the plug-in EVs. Real-world data series of electricity price and parking lot activity were used. The results obtained from the study of indicative operation scenarios ...
Energies
Demand Response (DR) is a fundamental aspect of the smart grid concept, as it refers to the neces... more Demand Response (DR) is a fundamental aspect of the smart grid concept, as it refers to the necessary open and transparent market framework linking energy costs to the actual grid operations. DR allows consumers to directly or indirectly participate in the markets where energy is being exchanged. One of the main challenges for engaging in DR is associated with the initial assessment of the potential rewards and risks under a given pricing scheme. In this paper, a Genetic Algorithm (GA) optimisation model, using Artificial Neural Network (ΑΝΝ) power predictions for day-ahead energy management at the building and district levels, is proposed. Individual building and building group analysis is conducted to evaluate ANN predictions and GA-generated solutions. ANN-based short term electric power forecasting is exploited in predicting day-ahead demand, and form a baseline scenario. GA optimisation is conducted to provide balanced load shifting and cost-of-energy solutions based on two alt...
IFAC Proceedings Volumes
Abstract Traffic flow is by nature a dynamic process, rendering static, fixed-time signaling syst... more Abstract Traffic flow is by nature a dynamic process, rendering static, fixed-time signaling systems inadequate. A new, adaptive traffic control system is presented in this paper. Traffic load is continuously monitored by loop detectors connected to a microcontroller-based system, which also performs all intersection control functions. Intersection controllers of an area are interconnected with a communication network, passing to each-other traffic load information, and getting synchronized. As a result, the duration and relative phases of each traffic light cycle dynamically change. The new architecture is completely distributed and eliminates the need for a region computer to individually control traffic lights.
Journal of Biomedical Engineering
Energy and Buildings
University campuses can be considered as small towns due to their size, number of users and mixed... more University campuses can be considered as small towns due to their size, number of users and mixed and complex activities, including numerous actions usually met in urban environments. The energy and environmental impact of universities could be considerably reduced by applying organizational, technological and energy optimization measures. The aim of the present paper is to present an efficient web based energy management system for Campuses which manages in an energy efficient way the Campus buildings and spaces of public use, monitors the energy load and performs energy analysis per building and for the Campus as a whole, as well as it interacts with each building's BEMS and each user through questionnaires, e-mails and forms. The existing Campus IP infrastructure is exploited by using sensor networks, where nodes communicate their information using Web services, allowing direct integration in modern IT systems. To guarantee the system scalability and respect consolidated and diffused standards, the logical/architectural level of the whole Campus Energy Management System is linked with the existing infrastructure based on Internet Protocol (IP). The overall installation is tested via on line questionnaires to the building users showing a significant increase of the occupants' satisfaction. Finally, the energy efficiency achieved by the proposed system is almost 20%.
International Journal of Solar Energy
ABSTRACT
Periodica Polytechnica Electrical Engineering and Computer Science, 2016
Solar dish-Stirling technology is the Concentrated Solar Power (CSP) technology that can be more ... more Solar dish-Stirling technology is the Concentrated Solar Power (CSP) technology that can be more easily integrated into Distribution networks due to its small size. However, a disadvantage of this technology is that features shorter thermal inertia and thus, the output is more volatile compared to large scale CSP plants. In this paper, the production of a solar dish-Stirling plant connected to a battery bank forming a Hybrid plant is studied, in order to determine up to what extent the production stabilization can be achieved. A modelling approach of the electricity output of a solar dish system integrated to a lithium-ion battery, is developed. A methodology based on the minimization of the mean square error between the actual and the proposed stabilized production is presented, in order to optimally size the battery bank. Results from the application of the Hybrid plant for typical days of various seasons prove the output capability of such a configuration and the guaranteed power amount of the relevant plant, along with the addition of volatility decrease.
International Journal of Solar Energy, 2001
International Journal of Sustainable Energy, 2015
The aim of this work is to review the current status of photovoltaic (PV) power generation, focus... more The aim of this work is to review the current status of photovoltaic (PV) power generation, focusing on concentrating PVs mainly as regards their typology, market and state-of-the-art feature. The incorporation of a heat recovery system can increase the overall efficiency by exploiting the waste heat. The proposed solution is a Solar Polygeneration System (PROTEAS System) for the simultaneous production of electricity, hot water and airconditioning. The core of the PROTEAS System is the innovative setup of total internal reflection reflectors made of plastic (primary optical system), with the potential to concentrate solar rays up to 5000 suns, while specially designed total internal reflection homogenisers (secondary optical system) later homogenise the radiation to 1000 suns. The engineering of the system is an ongoing task, while some of the subsystems have been successfully developed.
Proceedings of the IEEE International Symposium on Industrial Electronics, 1995
... 1 MONITOR UPS AC SIGNAL FOR ONE T CfLCuLATE INCREMENT PERIOD COUhTR VLlHD(./.) t ALARM AND TU... more ... 1 MONITOR UPS AC SIGNAL FOR ONE T CfLCuLATE INCREMENT PERIOD COUhTR VLlHD(./.) t ALARM AND TURN OFF WS J hb-... The design of the system is based on a high-performance microcontroller and includes a number of easily-found ICs. ...
IEEE Power Engineering Review, 1985
linearized decoupled AC load flow technique is selected to solve the global VAR dispatching probl... more linearized decoupled AC load flow technique is selected to solve the global VAR dispatching problem. The reciprocity theorem together with the linearized decou¬ pled Jacobian matrix can handle a large number of contin¬ gency constraints very effectively. The ability of effectively handling a large number of contingency constraints to deal with potential outages is a contribution of this scheme. This scheme has been programmed in FORTRAN IV lan¬ guage on an IBM 4341 computer. A realistic power system
This paper presents an e-learning tool on smart indoor environment and energy management in the b... more This paper presents an e-learning tool on smart indoor environment and energy management in the built environment. The methodology for the syllabus development is presented and justified. Questionnaires are developed and sent to potential trainees as well as to relevant companies to collect information regarding their training needs. Furthermore, the relevant courses offered by universities or professional bodies around the world are investigated. The syllabus is developed according to the results obtained through these two studies. The training tool consists of seven modules covering introduction, the control systems for smart buildings, the communication protocols, sensors and actuators, economic issues and contracting energy management.
In the framework of this study, we present the experience of the Technical University of Crete fo... more In the framework of this study, we present the experience of the Technical University of Crete for the design and construction of "Daedalus", probably the world's first autonomous biodiesel production unit. This innovative unit is already operational in the University Campus, producing biodiesel from different feed-stocks. In additional, this work examines some initial results from the quality tests of the produced biodiesel as well as the advantages and disadvantages of the unit.The data required for the optimum design of this unit were obtained from a wide study on the existing literature and experience on biodiesel units. The goal of this project was the development and operation of a prototype for autonomous small scale biodiesel production. The energy autonomy is based in the exploitation of the solar radiation for the efficient production of heat and electricity. The combination of different renewable energy sources transform this unit to an innovate product whic...
Renewable Energy, 2015
Highlights A methodological tool has been developed for the sustainable siting of wind farms ... more Highlights A methodological tool has been developed for the sustainable siting of wind farms The critical energy issues of insular typology is presented The carrying capacity of the natural systems in wind farms is calculated ABSTRACT The growing energy demand, as well as the supporting European policies of the sustainable development, has strengthened the global interest in wind power installations during the last decade. The interest is higher in areas with promising natural terrain, such as the Greek islands. The region of Crete encourages the siting of wind farms due to the strong wind potential and the insular rough terrain. The aim of this study is to develop and to implement a methodology of comprehensive evaluation and prioritization of areas for site selection of sustainable wind farms at a regional level, which can be used to support the strategic spatial planning of the island. The basic tool used to achieve the study's goals is the Specific Plan for Spatial Planning and Sustainable Development for Renewable Energy applied on Geographic Information Systems and the parallel integration of a systematic and flexible method of multicriteria analysis. The main output of this study is the provision of an objective and realistic overview on wind farm siting issue and the reinforcement of the regional and national policy/decision makers based on a sustainable regional development strategy avoiding fragmented decisions.
Power and Energy Systems, 2011
A Monte-Carlo based, probabilistic power flow method is used to evaluate different power system i... more A Monte-Carlo based, probabilistic power flow method is used to evaluate different power system interconnection options. Suitable indices are proposed to assess the potential profit of each interconnection scenario and the required interconnection rating. Separate investment perspectives are identified and the respective optimal solutions are compared. Indicative results are presented regarding a possible submarine interconnection of the Greek island of Crete with the mainland grid.
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Papers by Kostas Kalaitzakis