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Energies, Volume 7, Issue 6 (June 2014), Pages 3512-4053

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Open AccessArticle An Intelligent Fuzzy Logic Controller for Maximum Power Capture of Point Absorbers
Energies 2014, 7(6), 4033-4053; https://doi.org/10.3390/en7064033
Received: 13 March 2014 / Revised: 29 May 2014 / Accepted: 13 June 2014 / Published: 24 June 2014
Cited by 8 | PDF Full-text (4215 KB) | HTML Full-text | XML Full-text
Abstract
This article presents an intelligent fuzzy logic controller (FLC) for controlling single-body heaving wave energy converter (WEC) or what is widely known as “Point Absorber”. The controller aims at maximizing the energy captured from the sea waves. The power take-off (PTO) limitations are
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This article presents an intelligent fuzzy logic controller (FLC) for controlling single-body heaving wave energy converter (WEC) or what is widely known as “Point Absorber”. The controller aims at maximizing the energy captured from the sea waves. The power take-off (PTO) limitations are addressed implicitly in the fuzzy inference system (FIS) framework. In order to enhance the WEC power capturing bandwidth and make it less susceptible to wave environment irregularities and the system parametric uncertainties, the controller is built to have a self-configurable capability. This also eliminates the need to repeatedly run in-situ tuning procedure of the fuzzy controller or switch between several controllers based on the operating conditions. The fuzzy membership functions (MFs) are optimally tuned using particle swarm optimization (PSO) algorithm. To alleviate the computational burden associated with performing on-line optimization, the fuzzy controller is tuned at a rate significantly lower than the system sampling time. The suggested PSO-FLC has shown promising results compared with the fixed structure fuzzy logic controller (FS-FLC) and other passive control strategies. Several computer simulations were carried out to evaluate the controller effectiveness by applying different sea-states and analyzing the resultant WEC dynamics. Full article
Open AccessArticle Investigation of Process Variables in the Densification of Corn Stover Briquettes
Energies 2014, 7(6), 4019-4032; https://doi.org/10.3390/en7064019
Received: 27 March 2014 / Revised: 6 June 2014 / Accepted: 17 June 2014 / Published: 24 June 2014
Cited by 4 | PDF Full-text (1237 KB) | HTML Full-text | XML Full-text
Abstract
The bulk density of raw corn stover is a major limitation to its large-scale viability as a biomass feedstock. Raw corn stover has a bulk density of 50 kg/m3, which creates significant transportation costs and limits the optimization of transport logistics.
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The bulk density of raw corn stover is a major limitation to its large-scale viability as a biomass feedstock. Raw corn stover has a bulk density of 50 kg/m3, which creates significant transportation costs and limits the optimization of transport logistics. Producing a densified corn stover product during harvest would reduce harvest and transportation costs, resulting in viable pathways for the use of corn stover as a biomass feedstock. This research investigated the effect of different process variables (compression pressure, moisture content, particle size, and material composition) on a densification method that produces briquettes from raw corn stover. A customized bench-scale densification system was designed to evaluate different corn stover inputs. Quality briquette production was possible using non-reduced particle sizes and low compression pressures achievable in a continuous in-field production system. At optimized bench settings, corn stover was densified to a dry bulk density of 190 kg/m3. Corn stover with a moisture content above 25%wb was not suitable for this method of bulk densification, and greater cob content had a positive effect on product quality. Full article
(This article belongs to the Special Issue Renewable Energy for Agriculture)
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Open AccessReview Evaluation of the Wave Energy Conversion Efficiency in Various Coastal Environments
Energies 2014, 7(6), 4002-4018; https://doi.org/10.3390/en7064002
Received: 8 April 2014 / Revised: 11 June 2014 / Accepted: 16 June 2014 / Published: 24 June 2014
Cited by 31 | PDF Full-text (1543 KB) | HTML Full-text | XML Full-text
Abstract
The main objective of the present work was to assess and compare the wave power resources in various offshore and nearshore areas. From this perspective, three different groups of coastal environments were considered: the western Iberian nearshore, islands and an enclosed environment with
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The main objective of the present work was to assess and compare the wave power resources in various offshore and nearshore areas. From this perspective, three different groups of coastal environments were considered: the western Iberian nearshore, islands and an enclosed environment with sea waves, respectively. Some of the most representative existent wave converters were evaluated in the analysis and a second objective was to compare their performances at the considered locations, and in this way to determine which is better suited for potential commercial exploitation. In order to estimate the electric power production expected in a certain location, the bivariate distributions of the occurrences corresponding to the sea states, defined by the significant wave height and the energy period, were constructed in each coastal area. The wave data were provided by hindcast studies performed with numerical wave models or based on measurements. The transformation efficiency of the wave energy into electricity is evaluated via the load factor and also through the capture width, defined as the ratio between the electric power estimated to be produced by each specific wave energy converters (WEC) and the expected wave power corresponding to the location considered. Finally, by evaluating these two different indicators, comparisons of the performances of three WEC types (Aqua Buoy, Pelamis and Wave Dragon) in the three different groups of coastal environments considered have been also carried out. The work provides valuable information related to the effectiveness of various technologies for the wave energy extraction that would operate in different coastal environments. Full article
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Open AccessArticle Efficacy and Efficiency of Italian Energy Policy: The Case of PV Systems in Greenhouse Farms
Energies 2014, 7(6), 3985-4001; https://doi.org/10.3390/en7063985
Received: 14 May 2014 / Revised: 11 June 2014 / Accepted: 17 June 2014 / Published: 24 June 2014
Cited by 41 | PDF Full-text (589 KB) | HTML Full-text | XML Full-text
Abstract
The production of energy from renewable sources is a form of energy production that has less impact on the environment than the traditional one. For the farmer this new form of production represents an opportunity, especially for the economic benefits that can produce,
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The production of energy from renewable sources is a form of energy production that has less impact on the environment than the traditional one. For the farmer this new form of production represents an opportunity, especially for the economic benefits that can produce, both in terms of the incentives provided by the public operator and for higher revenues, deriving from the sale of energy back to the grid and/or the savings generated by self-consumed energy, that help to increase the farmer’s income. In this paper, we analyzed a case study of a farm that has realized a grid-connected photovoltaic (PV) system on a greenhouse. In particular, firstly the farm profitability has been estimated and subsequently, in order to assess the efficiency of the energy policy adopted by the Second Conto Energia in Italy, the minimum incentive tariff at which the entrepreneur has an economic advantage to realize a PV system has been determined. Results show that PV system relegates to a marginal role the cultivation of agricultural products compared to energy production and that government PV remuneration policies far outweigh the minimum threshold that makes the investment advantageous. Full article
(This article belongs to the Special Issue Energy Transitions and Economic Change)
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Open AccessArticle Investigation of a Five-Phase Dual-Rotor Permanent Magnet Synchronous Motor Used for Electric Vehicles
Energies 2014, 7(6), 3955-3984; https://doi.org/10.3390/en7063955
Received: 21 April 2014 / Revised: 12 June 2014 / Accepted: 17 June 2014 / Published: 24 June 2014
Cited by 8 | PDF Full-text (3888 KB) | HTML Full-text | XML Full-text
Abstract
This paper presents a novel five-phase permanent magnet synchronous motor (PMSM), which contains dual rotors and a single stator, equivalent to two five-phase motors working together. Thus, this kind of motor has the potential of good fault tolerant capability and high torque density,
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This paper presents a novel five-phase permanent magnet synchronous motor (PMSM), which contains dual rotors and a single stator, equivalent to two five-phase motors working together. Thus, this kind of motor has the potential of good fault tolerant capability and high torque density, which makes it appropriate for use in electric vehicles. In view of the different connection types, the inside and outside stator windings can be driven in series or parallel, which results in the different performances of the magnetomotive force (MMF) and torque under open-circuit fault conditions. By decomposing the MMF, the reason that torque ripple increases after open-circuit faults is explained, and the relationship between MMF and torque is revealed. Then, the current control strategy is applied to adjust the open-circuit faults, and the electromagnetic analysis and MMF harmonics analysis are performed to interpret the phenomenon that the torque ripple is still larger than in the normal situation. The investigations are verified by finite element analysis results. Full article
(This article belongs to the Special Issue Advances in Hybrid Vehicles)
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Open AccessArticle A Systematic Method for Designing a PR Controller and Active Damping of the LCL Filter for Single-Phase Grid-Connected PV Inverters
Energies 2014, 7(6), 3934-3954; https://doi.org/10.3390/en7063934
Received: 3 March 2014 / Revised: 13 June 2014 / Accepted: 17 June 2014 / Published: 24 June 2014
Cited by 31 | PDF Full-text (1895 KB) | HTML Full-text | XML Full-text
Abstract
The Proportional Resonant (PR) current controller provides gains at a certain frequency (resonant frequency) and eliminates steady state errors. Therefore, the PR controller can be successfully applied to single grid-connected PV inverter current control. On the contrary, a PI controller has steady-state errors
[...] Read more.
The Proportional Resonant (PR) current controller provides gains at a certain frequency (resonant frequency) and eliminates steady state errors. Therefore, the PR controller can be successfully applied to single grid-connected PV inverter current control. On the contrary, a PI controller has steady-state errors and limited disturbance rejection capability. Compared with the L- and LC filters, the LCL filter has excellent harmonic suppression capability, but the inherent resonant peak of the LCL filter may introduce instability in the whole system. Therefore, damping must be introduced to improve the control of the system. Considering the controller and the LCL filter active damping as a whole system makes the controller design method more complex. In fact, their frequency responses may affect each other. The traditional trial-and-error procedure is too time-consuming and the design process is inefficient. This paper provides a detailed analysis of the frequency response influence between the PR controller and the LCL filter regarded as a whole system. In addition, the paper presents a systematic method for designing controller parameters and the capacitor current feedback coefficient factor of LCL filter active-damping. The new method relies on meeting the stable margins of the system. Moreover, the paper also clarifies the impact of the grid on the inverter output current. Numerical simulation and a 3 kW laboratory setup assessed the feasibility and effectiveness of the proposed method. Full article
Open AccessArticle Effects of Pretreatment Methods on Electrodes and SOFC Performance
Energies 2014, 7(6), 3922-3933; https://doi.org/10.3390/en7063922
Received: 29 April 2014 / Revised: 1 June 2014 / Accepted: 17 June 2014 / Published: 23 June 2014
Cited by 5 | PDF Full-text (541 KB) | HTML Full-text | XML Full-text
Abstract
Commercially available tapes (anode, electrolyte) and paste (cathode) were choosen to prepare anode-supported cells for solid oxide fuel cell applications. For both anode-supported cells or electrolyte-supported cells, the anode needs pretreatment to reduce NiO/YSZ to Ni/YSZ to increase its conductivity as well as
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Commercially available tapes (anode, electrolyte) and paste (cathode) were choosen to prepare anode-supported cells for solid oxide fuel cell applications. For both anode-supported cells or electrolyte-supported cells, the anode needs pretreatment to reduce NiO/YSZ to Ni/YSZ to increase its conductivity as well as its catalytic characteristics. In this study, the effects of different pretreatments (open-circuit, closed-circuit) on cathode and anodes as well as SOFC performance are investigated. To investigate the influence of closed-circuit pretreatment on the NiO/YSZ anode alone, a Pt cathode is utilized as reference for comparison with the LSM cathode. The characterization of the electrical resistance, AC impedance, and SOFC performance of the resulting electrodes and/or anode-supported cell were carried out. It’s found that the influence of open-circuit pretreatment on the LSM cathode is limited. However, the influence of closed-circuit pretreatment on both the LSM cathode and NiO/YSZ anode and the resulting SOFC performance is profound. The effect of closed-circuit pretreatment on the NiO/YSZ anode is attributed to its change of electronic/pore structure as well as catalytic characteristics. With closed-circuit pretreatment, the SOFC performance improved greatly from the change of LSM cathode (and Pt reference) compared to the Ni/YSZ anode. Full article
(This article belongs to the Special Issue Reacting Transport Phenomena in Solid Oxide Fuel Cells)
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Open AccessArticle Communication Network Architectures for Smart-Wind Power Farms
Energies 2014, 7(6), 3900-3921; https://doi.org/10.3390/en7063900
Received: 11 February 2014 / Revised: 28 May 2014 / Accepted: 9 June 2014 / Published: 23 June 2014
Cited by 7 | PDF Full-text (1669 KB) | HTML Full-text | XML Full-text
Abstract
Developments in the wind power industry have enabled a new generation of wind turbines with longer blades, taller towers, higher efficiency, and lower maintenance costs due to the maturity of related technologies. Nevertheless, wind turbines are still blind machines because the control center
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Developments in the wind power industry have enabled a new generation of wind turbines with longer blades, taller towers, higher efficiency, and lower maintenance costs due to the maturity of related technologies. Nevertheless, wind turbines are still blind machines because the control center is responsible for managing and controlling individual wind turbines that are turned on or off according to demand for electricity. In this paper, we propose a communication network architecture for smart-wind power farms (Smart-WPFs). The proposed architecture is designed for wind turbines to communicate directly and share sensing data in order to maximize power generation, WPF availability, and turbine efficiency. We also designed a sensor data frame structure to carry sensing data from different wind turbine parts such as the rotor, transformer, nacelle, etc. The data frame includes a logical node ID (LNID), sensor node ID (SNID), sensor type (ST), and sensor data based on the International Electrotechnical Commission (IEC) 61400-25 standard. We present an analytical model that describes upstream traffic between the wind turbines and the control center. Using a queueing theory approach, the upstream traffic is evaluated in view of bandwidth utilization and average queuing delay. The performance of the proposed network architectures are evaluated by using analytical and simulation models. Full article
(This article belongs to the Special Issue Wind Turbines 2014)
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Open AccessArticle Gas Hydrate Occurrence Inferred from Dissolved Cl Concentrations and δ18O Values of Pore Water and Dissolved Sulfate in the Shallow Sediments of the Pockmark Field in Southwestern Xisha Uplift, Northern South China Sea
Energies 2014, 7(6), 3886-3899; https://doi.org/10.3390/en7063886
Received: 19 February 2014 / Revised: 26 May 2014 / Accepted: 3 June 2014 / Published: 20 June 2014
Cited by 1 | PDF Full-text (832 KB) | HTML Full-text | XML Full-text
Abstract
Deep-water pockmarks are frequently accompanied by the occurrence of massive gas hydrates in shallow sediments. A decline in pore-water Cl concentration and rise in δ18O value provide compelling evidence for the gas hydrate dissociation. Mega-pockmarks are widely scattered in the
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Deep-water pockmarks are frequently accompanied by the occurrence of massive gas hydrates in shallow sediments. A decline in pore-water Cl concentration and rise in δ18O value provide compelling evidence for the gas hydrate dissociation. Mega-pockmarks are widely scattered in the southwestern Xisha Uplift, northern South China Sea (SCS). Pore water collected from a gravity-core inside of a mega-pockmark exhibits a downward Cl concentration decrease concomitant with an increase in δ18O value at the interval of 5.7–6.7 mbsf. Concentrations of Cl, Na+, and K+ mainly cluster along the seawater freshening line without distinct Na+ enrichment and K+ depletion. Thus, we infer that the pore water anomalies of Cl concentrations and δ18O values are attributed to gas hydrate dissociation instead of clay mineral dehydration. Moreover, the lower δ18O values of sulfate in the target core (C14) than those in the reference core (C9) may be associated with the equilibrium oxygen fractionation during sulfate reduction between sulfate and the relatively 18O-depleted ambient water resulting from gas hydrate formation. The gas hydrate contents are estimated to be 6%–10% and 7%–15%, respectively, according to the offset of Cl concentrations and δ18O values from the baselines. This pockmark field in southwestern Xisha Uplift is likely to be a good prospective area for the occurrence of gas hydrate in shallow sediments. Full article
(This article belongs to the Special Issue Coastal Ocean Natural Gas Hydrate 2014)
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Open AccessArticle Production of Ethanol and Biomass from Thin Stillage Using Food-Grade Zygomycetes and Ascomycetes Filamentous Fungi
Energies 2014, 7(6), 3872-3885; https://doi.org/10.3390/en7063872
Received: 22 April 2014 / Revised: 17 May 2014 / Accepted: 17 June 2014 / Published: 20 June 2014
Cited by 17 | PDF Full-text (431 KB) | HTML Full-text | XML Full-text | Correction
Abstract
A starch-based ethanol facility producing 200,000 m3 ethanol/year also produces ca. 2 million m3 thin stillage, which can be used to improve the entire process. In this work, five food-grade filamentous fungi, including a Zygomycete and four Ascomycetes were successfully grown
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A starch-based ethanol facility producing 200,000 m3 ethanol/year also produces ca. 2 million m3 thin stillage, which can be used to improve the entire process. In this work, five food-grade filamentous fungi, including a Zygomycete and four Ascomycetes were successfully grown in thin stillage containing 9% solids. Cultivation with Neurospora intermedia led to the production of ca. 16 g·L−1 biomass containing 56% (w/w) crude protein, a reduction of 34% of the total solids, and 5 g·L−1 additional ethanol. In an industrial ethanol production process (200,000 m3 ethanol/year), this can potentially lead to the production of 11,000 m3 extra ethanol per year. Cultivation with Aspergillus oryzae resulted in 19 g·L−1 biomass containing 48% (w/w) crude protein and the highest reduction of the thin stillage glycerol (54%) among the Ascomycetes. Cultivation with Rhizopus sp. produced up to 15 g·L−1 biomass containing 55% (w/w) crude protein. The spent thin stillage had been reduced up to 85%, 68% and 21% regarding lactic acid, glycerol and total solids, respectively. Therefore, N. intermedia, in particular, has a high potential to improve the ethanol process via production of additional ethanol and high-quality biomass, which can be considered for animal feed applications such as for fish feed. Full article
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Open AccessArticle Aqueous Hybrids of Silica Nanoparticles and Hydrophobically Associating Hydrolyzed Polyacrylamide Used for EOR in High-Temperature and High-Salinity Reservoirs
Energies 2014, 7(6), 3858-3871; https://doi.org/10.3390/en7063858
Received: 1 April 2014 / Revised: 19 May 2014 / Accepted: 9 June 2014 / Published: 19 June 2014
Cited by 27 | PDF Full-text (839 KB) | HTML Full-text | XML Full-text
Abstract
Water-soluble polymers are known to be used in chemically enhanced oil recovery (EOR) processes, but their applications are limited in high-temperature and high-salinity oil reservoirs because of their inherent poor salt tolerance and weak thermal stability. Hydrophobic association of partially hydrolyzed polyacryamide (HAHPAM)
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Water-soluble polymers are known to be used in chemically enhanced oil recovery (EOR) processes, but their applications are limited in high-temperature and high-salinity oil reservoirs because of their inherent poor salt tolerance and weak thermal stability. Hydrophobic association of partially hydrolyzed polyacryamide (HAHPAM) complexed with silica nanoparticles to prepare nano-hybrids is reported in this work. The rheological and enhanced oil recovery (EOR) properties of such hybrids were studied in comparison with HAHPAM under simulated high-temperature and high-salinity oil reservoir conditions (T: 85 °C; total dissolved solids: 32,868 mg∙L−1; [Ca2+] + [Mg2+]: 873 mg∙L−1). It was found that the apparent viscosity and elastic modulus of HAHPAM solutions increased with addition of silica nanoparticles, and HAHPAM/silica hybrids exhibit better shear resistance and long-term thermal stability than HAHPAM in synthetic brine. Moreover, core flooding tests show that HAHPAM/silica hybrid has a higher oil recovery factor than HAHPAM solution. Full article
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Open AccessArticle Batch Growth of Chlorella Vulgaris CCALA 896 versus Semi-Continuous Regimen for Enhancing Oil-Rich Biomass Productivity
Energies 2014, 7(6), 3840-3857; https://doi.org/10.3390/en7063840
Received: 10 March 2014 / Revised: 7 May 2014 / Accepted: 11 June 2014 / Published: 19 June 2014
Cited by 8 | PDF Full-text (1090 KB) | HTML Full-text | XML Full-text
Abstract
The aim of this study was to induce lipid accumulation in Chlorella cells by creating stressful growth conditions. Chlorella vulgaris CCALA 896 was grown under various batch growth modes in basal and modified BG-11 and Kolkwitz culture broths, using a continuous light regimen
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The aim of this study was to induce lipid accumulation in Chlorella cells by creating stressful growth conditions. Chlorella vulgaris CCALA 896 was grown under various batch growth modes in basal and modified BG-11 and Kolkwitz culture broths, using a continuous light regimen of 150 µE/m2/s, at 30 °C. In order to perform the experiments, two indoor photobioreactor shapes were used: a cylindrical glass photobioreactor (CGPBR) with a working volume of 350 mL, and a flat glass photobioreactor (FGPBR) with a working volume of 550 mL. Stress-eliciting conditions, such as nitrogen and phosphorous starvation, were imposed in order to induce lipid accumulation. The results demonstrated that more than 56% of the lipids can be accumulated in Chlorella biomass grown under two-phase batch growth conditions. The highest biomass productivity of 0.30 g/L/d was obtained at the highest nominal dilution rate (0.167 day−1) during a semi-continuous regimen, using a modified Kolkwitz medium. During the pH-stress cycles, the amount of lipids did not increase significantly and a flocculation of Chlorella cells was noted. Full article
(This article belongs to the Special Issue Renewable Energy for Agriculture)
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Open AccessArticle Optimum Peak Current Hysteresis Control for Energy Recovering Converter in CDI Desalination
Energies 2014, 7(6), 3823-3839; https://doi.org/10.3390/en7063823
Received: 28 April 2014 / Revised: 9 June 2014 / Accepted: 11 June 2014 / Published: 18 June 2014
Cited by 2 | PDF Full-text (964 KB) | HTML Full-text | XML Full-text
Abstract
Capacitive De-Ionization (CDI) is becoming a suitable alternative for desalination. The low cost of the materials required and its reduced energy consumption can be critical factors for developing this technique. CDI technology does not require a high-pressure system and the energy storage capability
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Capacitive De-Ionization (CDI) is becoming a suitable alternative for desalination. The low cost of the materials required and its reduced energy consumption can be critical factors for developing this technique. CDI technology does not require a high-pressure system and the energy storage capability of CDI cells allows it to be reused in other CDI cells, thus minimizing consumption. The goal of the power stage responsible of the energy recovery is transferring the stored energy from one cell to another with the maximum possible efficiency, thus allowing the desalination process to continue. Assuming hysteresis current control is implemented at the DC/DC (direct current) converter, this paper aims to determine the optimum peak current through the inductor in each switching period with a view to maximizing overall efficiency. The geometrical parameters of the desalination cell and the NaCl concentration modify the cell electrical properties. The peak current control of the power stage should be adapted to the cell characteristics so that the efficiency behavior of the whole CDI system can be improved. The mathematical model defined in this paper allows the CDI plant automation using the peak inductor current as control variable, adapting its value to the salt concentration during the desalination process. Full article
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Open AccessArticle Hydrodynamic Effects on Spectroscopic Water Detection in Gasoline Pipe Flow
Energies 2014, 7(6), 3810-3822; https://doi.org/10.3390/en7063810
Received: 17 February 2014 / Revised: 10 June 2014 / Accepted: 11 June 2014 / Published: 18 June 2014
Cited by 2 | PDF Full-text (516 KB) | HTML Full-text | XML Full-text
Abstract
The hydrodynamic effects on spectroscopic water detection were microscopically investigated in a gasoline pipe flow. The effects of the gasoline flow rate and the water content on the water droplet characteristics were investigated experimentally using a phase Doppler particle measurement system. The characteristics
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The hydrodynamic effects on spectroscopic water detection were microscopically investigated in a gasoline pipe flow. The effects of the gasoline flow rate and the water content on the water droplet characteristics were investigated experimentally using a phase Doppler particle measurement system. The characteristics of spectral absorbance of water and gasoline were measured using a spectrophotometer to determine the optimal wavelength of the incident light for spectroscopic water detection. The effects of the droplet size on the light transmittance characteristics were calculated using the light extinction theory of Mie scattering on polydisperse particles and experimental results on the water droplet size in the gasoline flow. The measurement results of spectral absorbance showed that gasoline was almost transparent at 980 nm wavelength of light while water showed peak absorption at this wavelength, therefore, it was appropriate incident light for spectroscopic water detection. It was found that the flow conditions of the gasoline flow rate and the water content influenced the Sauter mean diameter and the volume concentration of water droplets, which influenced the light transmittance. Full article
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Open AccessArticle Pitch Based Wind Turbine Intelligent Speed Setpoint Adjustment Algorithms
Energies 2014, 7(6), 3793-3809; https://doi.org/10.3390/en7063793
Received: 20 March 2014 / Revised: 4 June 2014 / Accepted: 12 June 2014 / Published: 18 June 2014
Cited by 3 | PDF Full-text (527 KB) | HTML Full-text | XML Full-text
Abstract
This work is aimed at optimizing the wind turbine rotor speed setpoint algorithm. Several intelligent adjustment strategies have been investigated in order to improve a reward function that takes into account the power captured from the wind and the turbine speed error. After
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This work is aimed at optimizing the wind turbine rotor speed setpoint algorithm. Several intelligent adjustment strategies have been investigated in order to improve a reward function that takes into account the power captured from the wind and the turbine speed error. After different approaches including Reinforcement Learning, the best results were obtained using a Particle Swarm Optimization (PSO)-based wind turbine speed setpoint algorithm. A reward improvement of up to 10.67% has been achieved using PSO compared to a constant approach and 0.48% compared to a conventional approach. We conclude that the pitch angle is the most adequate input variable for the turbine speed setpoint algorithm compared to others such as rotor speed, or rotor angular acceleration. Full article
(This article belongs to the Special Issue Wind Turbines 2014)
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