Optimal Operation of Microgrids Comprising Large Building Prosumers and Plug-in Electric Vehicles Integrated into Active Distribution Networks

Active distribution networks and microgrids will be powerful tools for future power systems in their endeavor to integrate more renewable energy sources, increase distributed generation and optimize their operation. In this paper, a method for the coordinated optimal operation scheduling of active distribution networks that are hosting complex microgrids comprising large building prosumers and plug-in electric vehicle aggregators is proposed. The electrical and thermal power systems of the microgrid are modelled in detail while the examined active distribution network is assumed to be able to optimally shift part of its loads in time and comprises renewable energy sources as part of its local generation. Moreover, the microgrid is assumed to be able to shift part of its load in order to assist the active distribution network in order to satisfy all of the network constraints when this is required. The proposed method was developed in such a way that allows both the microgrid and the active distribution network to optimize their operations without exchanging the internal information comprising their technical characteristics and parameters. To this end, the method is organized into five levels wherein only the absolutely necessary information is exchanged, i.e., the power that is exchanged by the microgrid and the active distribution network and the time periods in which the network constraints are violated

Διαχείριση ενέργειας και λειτουργία πραγματικού χρόνου μικροδικτύων μεγάλων κτιριακών συγκροτημάτων

Summarization: The present and future conditions in the energy market impose extremely high standards to the operation of building energy systems. Moreover, distribution networks face new operational and technical challenges as a result of the rapid penetration of renewable energy sources (RES) and other forms of distributed generation. Consequently, Active Distribution Networks (ADNs) will play a crucial role in the exploitation of smart building prosumers, smart grids and RES. In this work, advanced, fully parametric systems for the optimal energy management and real-time joint operation of large building complex microgrids and the hosting active distribution network is developed. The examined energy systems include buildings scaling from simple residential ones up to mega office or commercial buildings, single Plug-in Electric Vehicles (PEVs) up to large PEV parking lots, local power generators, PVs and wind turbines. The modeling of the examined system’s components is performed, including those of the thermal and electrical loads of the buildings with the latter being divided in critical and non-critical loads that can be shifted in time. Moreover, a dynamic equivalent aggregate battery model for the cluster of PEVs hosted by the parking lots of the microgrid is developed. Finally, building local power generation units modeling is carried out and suitable optimal power flow algorithms are applied to ADNs hosting microgrids of building prosumers. The ADN-microgrid joint operation scheduling is executed with the purpose of minimizing microgrid’s total energy cost on the assumption of the operation under variable electricity price. Specifically, it provides the optimal total electric power demand of the HVAC systems and optimally shifts building non-critical electrical loads. Moreover, the charging of the hosted PEVs and the operation of the local power generation units are optimally scheduled. Efficient optimization techniques are first applied at microgrid scale to facilitate the optimization process and sub-optimization problems are then solved in order to optimally dispatch the total power demand of microgrid to its components. To this end, suitable flexibility indices are developed for each type of microgrid component. At the same time, a large number of constraints including all the operation and technical constraints of the components of the microgrid and the active distribution network it is connected to, are satisfied. Moreover, the microgrid is able to provide frequency support. Frequency support is enhanced and optimized by suitably exploiting the flexibility of building prosumers and PEVs. Frequency is also supported by adjusting the power of the building local generation units and by suitably adjust their non-critical loads in an optimal way according to their flexibility. In addition, the reactive power is optimally regulated in order to maintain the local voltages of the microgrid and the hosting distribution network within the permissible limits. All the developed models at different microgrid integration levels and algorithms are verified through the simulation of realistic case studies.Περίληψη: Οι σημερινές και μελλοντικές συνθήκες στην αγορά ενέργειας επιβάλλουν εξαιρετικά υψηλές προδιαγραφές στη λειτουργία των ενεργειακών συστημάτων των κτιρίων. Επιπλέον, τα δίκτυα διανομής αντιμετωπίζουν νέες λειτουργικές και τεχνικές προκλήσεις ως αποτέλεσμα της ταχείας διείσδυσης των ανανεώσιμων πηγών ενέργειας (ΑΠΕ) και άλλων μορφών κατανεμημένης παραγωγής. Συνεπώς, τα Ενεργά Δίκτυα Διανομής θα διαδραματίσουν κρίσιμο ρόλο στην εκμετάλλευση των έξυπνων καταναλωτών-παραγωγών κτιρίων, των έξυπνων δικτύων και των ΑΠΕ. Στην παρούσα διατριβή αναπτύσσονται προηγμένα, πλήρως παραμετρικά συστήματα για τη βέλτιστη διαχείριση ενέργειας και την κοινή λειτουργία σε πραγματικό χρόνο του ενεργού δικτύου διανομής και των μεγάλων κτιριακών μικροδικτύων που φιλοξενούν. Tα ενεργειακά συστήματα που εξετάζονται περιλαμβάνουν κτίρια που κλιμακώνονται από απλές κατοικίες μέχρι πολύ μεγάλα κτίρια που στεγάζουν γραφεία ή εμπορικά κτίρια, μεμονωμένα ηλεκτρικά οχήματα μέχρι μεγάλους χώρους στάθμευσης ηλεκτρικών οχημάτων, τοπικές γεννήτριες, φωτοβολταϊκά και ανεμογεννήτριες. Πραγματοποιείται η μοντελοποίηση των στοιχείων του εξεταζόμενου συστήματος, συμπεριλαμβανομένων αυτών των θερμικών και ηλεκτρικών φορτίων των κτιρίων με τα τελευταία να χωρίζονται σε κρίσιμα και μη κρίσιμα ηλεκτρικά φορτία που μπορούν να μετατοπιστούν χρονικά. Επιπλέον, αναπτύσσεται ένα δυναμικό ισοδύναμο μοντέλο μπαταρίας για την ομάδα των ηλεκτρικών οχημάτων που φιλοξενούνται στους χώρους στάθμευσης του μικροδικτύου. Τέλος, πραγματοποιείται η μοντελοποίηση των κτιριακών τοπικών μονάδων παραγωγής ηλεκτρικής ενέργειας και εφαρμόζονται κατάλληλοι αλγόριθμοι βέλτιστης ροής ισχύος σε ενεργά δίκτυα διανομής που φιλοξενούν μικροδίκτυα καταναλωτών-παραγωγών κτιρίων. Ο προγραμματισμός της κοινής λειτουργίας ενεργού δικτύου διανομής-μικροδικτύου εκτελείται με σκοπό την ελαχιστοποίηση του συνολικού ενεργειακού κόστους του μικροδικτύου με την παραδοχή της λειτουργίας υπό μεταβλητή τιμή ηλεκτρικής ενέργειας. Συγκεκριμένα, παρέχει τη βέλτιστη συνολική ζήτηση ηλεκτρικής ισχύος των HVAC συστημάτων και μετατοπίζει βέλτιστα τα μη κρίσιμα ηλεκτρικά φορτία των κτιρίων. Επιπλέον, η φόρτιση των ηλεκτρικών οχημάτων, καθώς και η λειτουργία των τοπικών μονάδων ηλεκτροπαραγωγής προγραμματίζονται βέλτιστα. Εφαρμόζονται αρχικά αποτελεσματικές τεχνικές βελτιστοποίησης σε κλίμακα μικροδικτύου για να διευκολυνθεί η διαδικασία βελτιστοποίησης και στη συνέχεια επιλύονται υποπροβλήματα βελτιστοποίησης προκειμένου να κατανεμηθεί βέλτιστα η συνολική ζήτηση ισχύος του μικροδικτύου. Για το σκοπό αυτό, αναπτύσσονται κατάλληλοι δείκτες ευελιξίας για κάθε στοιχείο μικροδικτύου. Ταυτόχρονα, ικανοποιείται ένας μεγάλος αριθμός περιορισμών, συμπεριλαμβανομένων όλων των λειτουργικών και τεχνικών περιορισμών των στοιχείων του μικροδικτύου και του ενεργού δικτύου διανομής στο οποίο είναι συνδεδεμένο. Επιπλέον, το μικροδίκτυο έχει τη δυνατότητα στήριξης της συχνότητας. Η στήριξη συχνότητας ενισχύεται και βελτιστοποιείται με την κατάλληλη αξιοποίηση της ευελιξίας των κτιριακών συγκροτημάτων και των ηλεκτρικών οχημάτων. Η συχνότητα στηρίζεται επίσης με τη ρύθμιση της ισχύος των τοπικών μονάδων παραγωγής, καθώς και με την κατάλληλη προσαρμογή των μη κρίσιμων ηλεκτρικών φορτίων των κτιρίων με βέλτιστο τρόπο ανάλογα με την ευελιξία τους. Επιπλέον, η άεργος ισχύς ρυθμίζεται βέλτιστα ώστε να διατηρούνται οι τοπικές τάσεις του μικροδικτύου και του ενεργού δικτύου διανομής εντός των επιτρεπτών ορίων. Όλα τα μοντέλα που αναπτύχθηκαν σε διάφορα επίπεδα του μικροδικτύου και οι προτεινόμενοι αλγόριθμοι επαληθεύονται μέσω προσομοίωσης ρεαλιστικών σεναρίων λειτουργίας

Βέλτιστος προγραμματισμός λειτουργίας μικροδικτύων μεγάλων κτιριακών συγκροτημάτων

Περίληψη: Microgrids constitute a developing area of the energy industry, representing a paradigm shift from centralized power plants to more localized, distributed generation, particularly in cities, communities and campuses. Microgrids provide efficient and low-cost energy, improve the local robustness and the regional electric grid operation and stability. Moreover, plug-in vehicles (PEVs) are expected to play an important role in the operation of electric power systems as electric vehicle technology is rapidly developing. In this thesis, a method for optimal operation scheduling of microgrids of large building complexes is proposed. It is based on a hierarchical multi-agent system (MAS) comprising a group of large office buildings, considering their thermal and electrical loads, and plug-in electric vehicles (EVs). A significant advantage of the proposed algorithm is that at the time periods of the day that the electric grid is not available, the microgrid is able itself to supply a satisfactory percentage of the buildings’ electric power demand exploiting only the hosted PEVs. The main target of the method is to minimize the total operation cost of the microgrid while satisfying at the same time a large number of technical and operation constraints. The examined optimization problem is solved using the particle swarm optimization (PSO) method. The efficiency of the method is proved by detailed simulation results of different operation scenarios, showed that cost savings in range of 27% can be achieved.Περίληψη: Τα μικροδίκτυα αποτελούν έναν αναπτυσσόμενο τομέα της ενεργειακής βιομηχανίας, αντιπροσωπεύοντας ένα παράδειγμα απομάκρυνσης από τις κεντρικές μονάδες παραγωγής ηλεκτρικής ενέργειας προς μια πιο τοπική, κατανεμημένη παραγωγή, ιδίως σε πόλεις, κοινότητες και πανεπιστήμια. Τα μικροδίκτυα παρέχουν αποδοτική και χαμηλού κόστους ενέργεια, βελτιώνουν την τοπική ευρωστία και τη λειτουργία του περιφερειακού ηλεκτρικού δικτύου. Επιπλέον, τα διασυνδεδεμένα ηλεκτρικά οχήματα (PEVs) αναμένεται να διαδραματίσουν σημαντικό ρόλο στη λειτουργία των συστημάτων ηλεκτρικής ενέργειας, καθώς η τεχνολογία των ηλεκτρικών οχημάτων αναπτύσσεται με ταχείς ρυθμούς. Στην παρούσα διατριβή προτείνεται μια μέθοδος για τον βέλτιστο προγραμματισμό λειτουργίας μικροδικτύων μεγάλων κτιριακών συγκροτημάτων. Βασίζεται σε ένα ιεραρχικό σύστημα πολλαπλών πρακτόρων (MAS) που περιλαμβάνει μια ομάδα μεγάλων κτιρίων αποτελούμενα από γραφεία, λαμβάνοντας υπόψη τα θερμικά και ηλεκτρικά φορτία τους, καθώς και ηλεκτρικά οχήματα (EVs). Ένα σημαντικό πλεονέκτημα του προτεινόμενου αλγορίθμου είναι ότι στις χρονικές περιόδους της ημέρας που το ηλεκτρικό δίκτυο δεν είναι διαθέσιμο, το μικροδίκτυο είναι σε θέση να καλύπτει το ίδιο ένα ικανοποιητικό ποσοστό της ζήτησης ηλεκτρικής ενέργειας των κτιρίων του με μοναδική μονάδα παραγωγής τα διασυνδεδεμένα ηλεκτρικά οχήματα. Ο βασικός στόχος της μεθόδου είναι η ελαχιστοποίηση του συνολικού κόστους λειτουργίας του μικροδικτύου και η ταυτόχρονη ικανοποίηση ενός μεγάλου αριθμού τεχνικών και λειτουργικών περιορισμών. Το πρόβλημα βελτιστοποίησης που εξετάζεται, επιλύεται με τη χρήση του αλγορίθμου particle swarm optimization (PSO). Η αποτελεσματικότητα της μεθόδου αποδεικνύεται από λεπτομερή αποτελέσματα προσομοίωσης διαφορετικών σεναρίων λειτουργίας, τα οποία έδειξαν ότι μπορεί να επιτευχθεί εξοικονόμηση κόστους της τάξης του 27%

Malacoplakia of the skin: overview of a rare clinical entity

Background: Malacoplakia is a rare acquired, infection-related granulomatous disorder, that may affect many systems, but typically occurs in the urinary tract. Cutaneous involvement is less prevalent, and most commonly presents with a perianal or genital region localization. Cutaneous malacoplakia is believed to be caused by an acquired bactericidal defect of macrophages in the setting of chronic infections and immunocompromised states. A diagnosis of cutaneous malacoplakia should be considered when encountering non-specific granulomatous lesions that are refractory to treatment. Histologic findings are marked by the presence of foamy macrophages containing the pathognomonic Michaelis-Gutman bodies. Objectives. The aim of this review is to discuss the current perspectives on the pathophysiology, clinical features, diagnosis, and treatment of this disease. We would also like to emphasize that the integration of clinical information, microscopic findings, and exclusion of other cutaneous granulomatous processes is necessary to accurately diagnose this exceedingly rare disease and provide opportunity for therapeutic intervention. Patients/Methods. Data for this work were collected from the published literature and textbooks. Results. Combined surgical excision and protracted antibiotic courses appear to have the highest success rate. Antibiotics should be culture specific, but drugs that easily permeate the macrophages appear to be the best choice

NMR Analysis of Extra Virgin Olive Oil of the Epirus Region of Greece with Emphasis on Selected Phenolic Compounds

Extra virgin olive oil (EVOO) is recognized for its numerous health benefits, attributed to its rich phenolic components. NMR has emerged as a prevalent technique for precisely identifying these compounds. Among Mediterranean countries, Greece stands as the third-largest producer of olives, with the Epirus region notably advancing in olive cultivation, contributing significantly to the dynamic growth of the region. In this study, an NMR method was employed based on the acquisition of a 1H NMR spectrum along with multiple resonant suppression in order to increase the sensitivity. Using the above method, 198 samples of extra virgin olive oil, primarily sourced from the Epirus region, were analyzed, and both the qualitative and quantitative aspects of the phenolic compounds were obtained. In addition, we examined the effects of various factors such as variety, harvest month, and region origin on the phenolic compounds’ concentration. The results revealed an average total phenolic content of 246 mg/kg, closely approaching the EU health claim limit of 250 mg/kg. Approximately 15% of the samples were confidently characterized as high-phenolic olive oil. The highest concentrations were observed in the Thesprotia samples, with several Lianolia varieties exceeding the total phenolic content of 400 mg/kg. Statistical tests demonstrated a significant influence of the olive variety and the month of fruit harvest on phenolic component concentration, followed by the region of origin. A very strong correlation was noted between the total phenolics content and the levels of oleocanthal and oleacein, with a correlation coefficient (r) of 0.924. Upon optimization of all factors affecting olive oil quality, the majority of the EVOOs from the Epirus region have the potential to be characterized as high in phenolic content

Optimal operation of microgrids comprising large building prosumers and plug-in electric vehicles integrated into active distribution networks

Summarization: Active distribution networks and microgrids will be powerful tools for future power systems in their endeavor to integrate more renewable energy sources, increase distributed generation and optimize their operation. In this paper, a method for the coordinated optimal operation scheduling of active distribution networks that are hosting complex microgrids comprising large building prosumers and plug-in electric vehicle aggregators is proposed. The electrical and thermal power systems of the microgrid are modelled in detail while the examined active distribution network is assumed to be able to optimally shift part of its loads in time and comprises renewable energy sources as part of its local generation. Moreover, the microgrid is assumed to be able to shift part of its load in order to assist the active distribution network in order to satisfy all of the network constraints when this is required. The proposed method was developed in such a way that allows both the microgrid and the active distribution network to optimize their operations without exchanging the internal information comprising their technical characteristics and parameters. To this end, the method is organized into five levels wherein only the absolutely necessary information is exchanged, i.e., the power that is exchanged by the microgrid and the active distribution network and the time periods in which the network constraints are violated.Presented on: Energie

Levels of Circulating IgM and IgY Natural Antibodies in Broiler Chicks: Association with Genotype and Farming Systems

Naturally occurring antibodies (NAbs), which are major components of innate immunity, exist in circulation under healthy conditions without prior antigenic stimulation and are able to recognize both self- and non-self-constituents. The present study aimed at identifying potential immunological differences between commercial fast- and slow-growth broilers (n = 555) raised in conventional and free-range systems, respectively, through the use of the specificity, isotypes and levels of circulating NAbs. The possible beneficial effect of oregano-based dietary supplementation was also evaluated. To this end, serum IgM and IgY NAbs against self- (actin and DNA) and non-self- antigens (trinitrophenol and lipopolysaccharide) were measured by ELISA and further correlated with genotype, season and performance. Significantly higher levels of IgM NAbs against all antigens were found in slow-growth compared to fast-growth broilers. IgM NAb levels were also significantly increased in dietarily supplemented slow-growth broilers versus those consuming standard feed. Moreover, significantly elevated levels of anti-DNA IgY NAbs were found in fast-growth compared to slow-growth broilers, whereas the opposite was observed for anti-LPS IgY NAbs. Multivariate linear regression analysis confirmed multiple interactions between NAb levels, genotype, season and performance. Overall, serum NAbs have proven to be valuable innovative immunotools in the poultry industry, efficiently differentiating fast-growing versus slow-growing broilers, and dietary supplementation of plant extracts can enhance natural immunity

Monocyte Chemoattractant Protein-1 (MCP-1), Activin-A and Clusterin in Children and Adolescents with Obesity or Type-1 Diabetes Mellitus

Inflammation plays a crucial role in diabetes and obesity through macrophage activation. Macrophage chemoattractant protein-1 (MCP-1), activin-A, and clusterin are chemokines with known roles in diabetes and obesity. The aim of this study is to investigate their possible diagnostic and/or early prognostic values in children and adolescents with obesity and type-1 diabetes mellitus (T1DM). Methods: We obtained serum samples from children and adolescents with a history of T1DM or obesity, in order to measure and compare MCP-1, activin-A, and clusterin concentrations. Results: Forty-three subjects were included in each of the three groups (controls, T1DM, and obesity). MCP-1 values were positively correlated to BMI z-score. Activin-A was increased in children with obesity compared to the control group. A trend for higher values was detected in children with T1DM. MCP-1 and activin-A levels were positively correlated. Clusterin levels showed a trend towards lower values in children with T1DM or obesity compared to the control group and were negatively correlated to renal function. Conclusions: The inflammation markers MCP-1, activin-A, and clusterin are not altered in children with T1DM. Conversely, obesity in children is positively correlated to serum MCP-1 values and characterized by higher activin-A levels, which may reflect an already established systematic inflammation with obesity since childhood