Increasing the energy conversion efficiency for shrouded hydrokinetic turbines using experimental analysis on a scale model

The objective of the paper is to study the influence of certain shroud types suitable for horizontal axis hydrokinetic turbines using experimental testing in order to increase the energy conversion efficiency. The scale model of the shrouded hydrokinetic turbine is tested on a dedicated experimental bench for axial hydraulic turbine models. Two types of shrouds were tested in order to be compared: convergent shroud and divergent shroud. The rotor and shroud were made using 3D printer technology and were tested at a water velocity of 0.9 m/s on the closed-circuit testing bench. The testing facility allows the determination of the power extracted for each shroud at five distinct positions. Thus, the rotor can be moved within the shroud from inlet to outlet in order to establish the proper operating position. The mechanical power is measured using a torque transducer and an electromagnetic particle brake. The testing results will be analysed based on the variation of power curves obtained for different shroud types and operating positions. The optimum design and the best operating position will be recommended by comparing the testing result with the data collected from the bare turbine using the same rotor placed directly in free flow

Efficient energy use and storage practices within residential facilities for compliance with the nZEB criteria

Solar energy, today, is the leader in renewable energy and the world's increasing new energy source. In 2016, for the first time, newly installed photovoltaic capacity has increased by more than 50%, exceeding the new coal-fired power stations capacity established worldwide. At the beginning of the year, the European Parliament agreed the target that 35% renewable sources by 2030. Studies show that by 2050 approximately 45% of all the households in the EU could produce their own renewable energy and more than a third of them could be part of a renewable energy cooperative, despite the worries of the distribution companies. Furthermore, the EPBD directive (EU) - Energy Performance of Buildings pushes towards new and more performing buildings - nearly zero energy buildings (nZEB) - where energy efficiency and energy flexibility are essential to achieve the required performance targets. Nearly zero-energy buildings (NZEBs) have very high energy performance and could be achieved through the integration of renewable and decentralized energy sources, continuous grid optimization and the inclusion of increasing numbers of consumers becoming producers, so called prosumers. So far, the photovoltaic system is the single technology that can combine data from utility networks with household consumption and therefore should be considered a starting point for streamlining the electricity consumption and production which will be imposed by strict regulations

Analysis of a low-voltage operating microgrid located in a residential area

The paper aims at providing the analysis of domestic energy generation and consumption within residential areas. The topic of this study is twofold: theoretical and experimental by addressing aspects related to the operation of a microgrid connected to the low-voltage distribution grid. In order to achieve the power quality analysis for various scenarios, an appropriate testing stand was developed by using the Chauvin Arnoux CA 8435 analyser. There is envisaged the modelling and design of a mixed microgrid characterized by two line sections established by three main energy consumption nodes. There have been integrated several connection points related to the distributed generation sources and to the photovoltaic power plants, respectively, and also several supply points for the household end-users. 13 operation scenarios have been developed and recorded by analysing the voltage variation within the microgrid. Furthermore, the paper envisages the stabilization impact of the microgrid voltage variation in the presence of distributed generation sources

Increasing the energy conversion efficiency for shrouded hydrokinetic turbines using experimental analysis on a scale model

The objective of the paper is to study the influence of certain shroud types suitable for horizontal axis hydrokinetic turbines using experimental testing in order to increase the energy conversion efficiency. The scale model of the shrouded hydrokinetic turbine is tested on a dedicated experimental bench for axial hydraulic turbine models. Two types of shrouds were tested in order to be compared: convergent shroud and divergent shroud. The rotor and shroud were made using 3D printer technology and were tested at a water velocity of 0.9 m/s on the closed-circuit testing bench. The testing facility allows the determination of the power extracted for each shroud at five distinct positions. Thus, the rotor can be moved within the shroud from inlet to outlet in order to establish the proper operating position. The mechanical power is measured using a torque transducer and an electromagnetic particle brake. The testing results will be analysed based on the variation of power curves obtained for different shroud types and operating positions. The optimum design and the best operating position will be recommended by comparing the testing result with the data collected from the bare turbine using the same rotor placed directly in free flow

Efficient energy use and storage practices within residential facilities for compliance with the nZEB criteria

Solar energy, today, is the leader in renewable energy and the world's increasing new energy source. In 2016, for the first time, newly installed photovoltaic capacity has increased by more than 50%, exceeding the new coal-fired power stations capacity established worldwide. At the beginning of the year, the European Parliament agreed the target that 35% renewable sources by 2030. Studies show that by 2050 approximately 45% of all the households in the EU could produce their own renewable energy and more than a third of them could be part of a renewable energy cooperative, despite the worries of the distribution companies. Furthermore, the EPBD directive (EU) - Energy Performance of Buildings pushes towards new and more performing buildings - nearly zero energy buildings (nZEB) - where energy efficiency and energy flexibility are essential to achieve the required performance targets. Nearly zero-energy buildings (NZEBs) have very high energy performance and could be achieved through the integration of renewable and decentralized energy sources, continuous grid optimization and the inclusion of increasing numbers of consumers becoming producers, so called prosumers. So far, the photovoltaic system is the single technology that can combine data from utility networks with household consumption and therefore should be considered a starting point for streamlining the electricity consumption and production which will be imposed by strict regulations

Analysis of a low-voltage operating microgrid located in a residential area

The paper aims at providing the analysis of domestic energy generation and consumption within residential areas. The topic of this study is twofold: theoretical and experimental by addressing aspects related to the operation of a microgrid connected to the low-voltage distribution grid. In order to achieve the power quality analysis for various scenarios, an appropriate testing stand was developed by using the Chauvin Arnoux CA 8435 analyser. There is envisaged the modelling and design of a mixed microgrid characterized by two line sections established by three main energy consumption nodes. There have been integrated several connection points related to the distributed generation sources and to the photovoltaic power plants, respectively, and also several supply points for the household end-users. 13 operation scenarios have been developed and recorded by analysing the voltage variation within the microgrid. Furthermore, the paper envisages the stabilization impact of the microgrid voltage variation in the presence of distributed generation sources

Valorizations of Sweet Cherries Skins Phytochemicals by Extraction, Microencapsulation and Development of Value-Added Food Products

Sweet cherries are processed in various ways, leading to significant amounts of underutilized by-products that can potentially be used as a source of bioactive compounds, including antioxidants. The present study focuses on identifying ways to exploit bioactive compounds from sweet cherry skins, namely the extraction, microencapsulation, and functionalizing of some food product to obtain added value. The anthocyanins from skins were extracted and encapsulated in a combination of whey proteins isolate and chitosan by freeze-drying, with an encapsulation efficiency of 77.68 ± 2.57%. The powder showed a satisfactory content in polyphenols, of which anthocyanins content was 14.48 ± 1.17 mg cyanidin 3-glucoside/100 g dry weight (D.W.) and antioxidant activity of 85.37 ± 1.18 µM Trolox/100 g D.W. The powder was morphologically analyzed, revealing the presence of coacervates, ranging in size from 12–54 μm, forming large spheresomes (up to 200 μm). The powder was used as a functional ingredient to develop two value-added food products, namely yoghurt and marshmallows. The powder was tested for its prebiotic effect on L. casei 431® in the yoghurt samples during 21 days at 4 °C, when a decrease in viability was found, up to 6 log CFU·g−1. The anthocyanins and antioxidant activity decreased in yoghurt and increased in marshmallows during storage time. The obtained results support the potential use of extracts from underutilized sources in the development of functional ingredients and value-added food products

Experimental Analysis of a Fish Guidance System for a River Water Intake

This paper describes the experimental study of a behavioural barrier consisting of a bubble curtain placed near an ecological river water intake, aiming to assess the bubble curtain’s influence on the velocity field of water flowing in the water intake proximity. The scientific novelty is given by the water intake solution operating in tandem with the dedicated bubble curtain generator used for avoiding fish entrapment. The water intake solution used in the present research is based on a run-of-river intake without a dam in the riverbed, maintaining the mountain rivers longitudinal connectivity. An experimental setup was designed and built to study the behavioural barrier for ecological water intakes in different operating conditions. Thus, tests were performed for two water velocities (0.33 m/s and 0.535 m/s) in the experimental setup, two water depths (92 mm and 119 mm) and two air flow rates (10.5 LPM and 15 LPM). The results were compared with the case when no air is injected through the bubble curtain generator. The assessment of the bubble curtain influence on the water flow inside the channel was made by measuring and analysing the velocity variation in vertical and horizontal direction. The results showed a significant velocity gradient in the bubble curtain proximity, which can contribute to influencing the behaviour of the fish by deterring them from the water intake area

Experimental Analysis of a Fish Guidance System for a River Water Intake

This paper describes the experimental study of a behavioural barrier consisting of a bubble curtain placed near an ecological river water intake, aiming to assess the bubble curtain’s influence on the velocity field of water flowing in the water intake proximity. The scientific novelty is given by the water intake solution operating in tandem with the dedicated bubble curtain generator used for avoiding fish entrapment. The water intake solution used in the present research is based on a run-of-river intake without a dam in the riverbed, maintaining the mountain rivers longitudinal connectivity. An experimental setup was designed and built to study the behavioural barrier for ecological water intakes in different operating conditions. Thus, tests were performed for two water velocities (0.33 m/s and 0.535 m/s) in the experimental setup, two water depths (92 mm and 119 mm) and two air flow rates (10.5 LPM and 15 LPM). The results were compared with the case when no air is injected through the bubble curtain generator. The assessment of the bubble curtain influence on the water flow inside the channel was made by measuring and analysing the velocity variation in vertical and horizontal direction. The results showed a significant velocity gradient in the bubble curtain proximity, which can contribute to influencing the behaviour of the fish by deterring them from the water intake area