Configuration C1 Research Articles

Numerical investigation on thermal performance of three configurations of solar thermal collector integrated with metal hydride

This study investigates the optimal configuration of a Metal Hydride-based Solar Thermal Collector (MH-STC) by developing a transient 3D mathematical model to simulate three distinct configurations: C1, C2, and C3. These configurations differ in the placement of water pipes within the metal hydride bed C1 features pipes in the top region, C2 in the core zone, and C3 at the bottom. The performance of these configurations was rigorously compared based on hydrogen charge state, outlet water temperature, useful energy output, and thermal efficiency across varying water flow rates. Results reveal that configuration C1 achieves superior thermal performance during daytime operation, producing outlet temperatures up to 10 °C higher than the other configurations. Conversely, configuration C3 excels at nighttime heating, delivering water temperatures approximately 11.5 °C higher than C1. Furthermore, the analysis indicates that hydrogen desorption pressure significantly impacts outlet water temperature; for instance, increasing the pressure from 2.41 bar to 6 bar enhances the average outlet temperature of the C3 design by about 20 °C during the day and reduces it by approximately 15 °C at night. These findings highlight the critical need for optimizing solar collector designs to effectively meet the thermal demands of both daytime and nighttime applications.

Optimization and analysis of Si/SiGe strained vertically stacked heterostructure on insulator FeFinFET for high performance analog and RF applications

As semiconductor technology advances, the exploration of novel materials and device architectures becomes imperative to meet the growing demands of integrated circuits for analog and radio-frequency (RF) applications. In this paper, various advanced technologies have been amalgamated such as integration of ferroelectric layer in multigate FinFET along with the adaptation of SOI technology. Further strain technology is also used which employs a tri-layered strained-silicon channel system with the help of SiGe to form Vertically Stacked Heterostructure on Insulator Ferroelectric based FinFET (VS-HOI-FeFinFET) and on comparison with baseline FeFinFET, it is found to show remarkable improvements in terms of various measured parameters such as drain current, switching ratio, threshold voltage and subthreshold swing. Subsequently, gate stacking architecture is incorporated in VS-HOI-FeFinFET to further optimize the device performance. The four different configurations C1 to C4 are taken in terms of four different combinations of gate stack materials considered for gate oxide such as C1(SiO2+Al2O3), C2(SiO2+HfO2), C3(Al2O3), and C4(Al2O3+HfO2). It is found that the static and analog performance of VS-HOI-GS-FeFinFET enhance sequentially from configuration C1 to C4 such as switching ratio is enhanced upto around 5 times, DIBL and quality factor are improved by around 41% and 58% respectively along with significant improvement in device efficiency, early voltage, intrinsic gain, output conductance and output resistance. Subsequently performance optimization of VS-HOI-GS-FeFinFET with variation in mole fraction of germanium is also explored for various analog metrics. Further, several RF parameters are also explored and it is observed that the gain frequency product (GFP) and gain transconductance frequency product (GTFP) are augmented by around three times in magnitude along with 16% reduction in the unity gain cut off frequency in C4 configuration, exhibiting its ability of high frequency amplification with minimized noise distortion thus makes the device suitable for various high performance Analog and RF applications.

Effects of location of nano-enhanced PCM-packed bed on the process of heat transfer and phase transition in a nonuniform magnetic field

The phase change and thermal process intensification under nonuniform magnetic field (MGF) effects during hybrid nanofluid (NF) convection are investigated in this study using various arrangements of phase change material (PCM)-packed bed (PB) in a vented cavity. The PCM-PB is is considered as a triangular shape. The numerical research is done using the finite element method for different Reynolds numbers (Re between 200 and 600), inlet port sizes (between 0.5 and 2.5), Hartmann numbers (Ha between 0 and 60), nonuniform MGF component amplitudes (between 0 and 1), and different locations of the triangle PCM-PB zone. The process of phase change is accelerated by increasing the Re and port size, and the entire transition time (tf ) is reduced by 63% and 76%, respectively, when mix/max Re and min/max port sizes are considered. By using NF, the phase change is improved even further, and tf is further reduced by 17.6%–31.5%. When MGF strength and amplitude of the nonuniform component are increased, tf is reduced by about 13% and 6%. At the highest Ha, the average heat transfer (HT) drops by about 59%. The flow patterns, phase transition, and thermal performance are all significantly impacted by the placement of the PCM-PB zone. In terms of phase change process, configuration C2 by using NF at Ha = 60 is the best case while case at Ha = 0 by using only water is the worst case. The tf value is reduced by about 82.6% at the best case. When phase change and HT processes are considered, the optimal design of triangular PCM-PB zones alters.

A Multiplicative-Exponential function to correct precipitation for distributed hydrological modeling in Poorly-gauged basins

Given the greater spatial and temporal variability in precipitation and the absence of rain gauges at mountainous regions, it is challenging to accurately estimate precipitation, consequently impeding the predictive capability of hydrological models. Here, we developed a nonlinear precipitation correction method in the SWAT (Soil and Water Assessment Tool) model to correct gridded (remote sensing or reanalysis) precipitation data for better distributed hydrological modeling. The precipitation correction module is featured by a multiplicative-exponential equation with two parameters, a multiplicative coefficient (PCP_COE) and an exponent (PCP_EXP). We proposed three configurations to determine PCP_COE and PCP_EXP, i.e., curve fitting between gridded and gauge precipitation data pairs (Configuration C1) or using gridded precipitation from multi-grids within an elevation range of the gauge (Configuration C2), and the calibration of the SWAT model against observed streamflow (Configuration C3). We applied the proposed method to a typical poorly-gauged alpine inland basin, the Xiangride River Basin of Northwest China, with only one rain gauge and streamflow station. Results show that Configuration C1 outperformed C2 and C3 by significantly improving streamflow modeling in both model calibration and validation, particularly when the GPM (Global Precipitation Measurement) precipitation datasets were used. We also argue that Configuration C3 is promising in ungauged basins with only streamflow available, since this configuration does not require gauge precipitation. This study puts forward a feasible method to derive more accurate spatiotemporal precipitation estimate based on gridded precipitation products, hence improving distributed hydrological modeling in poorly-gauged and ungauged basins.

Triboelectric Nanogenerators (TENGs) Based on Various Flexible Polymeric Materials Along With Printed and Non-Printed Electrodes

Four designs (D1-D4) of flexible triboelectric nanogenerators (TENGs) were successfully fabricated in three different configurations for energy harvesting applications. Typically, TENG consists of anode layer, cathode layer, and electrodes. Combination of materials were investigated in this study using polyethylene terephthalate (PET), thermoplastic polyurethane (TPU) and a flexible fabric as top triboelectric (cathode) layers; Kapton and polydimethylsiloxane (PDMS) as bottom triboelectric (anode) layers. Copper (Cu) tape and screen-printed silver (Ag) were used as electrodes. Each of these designs (D1-D4) has three configurations C1, C2 and C3 in which the top substrate (cathode layer) was different from one configuration to other. In order to determine the best material combination that would provide better TENG performance, different configurations were considered. The capability of the TENGs in terms of open circuit voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">oc</sub> ) and short circuit current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sc</sub> ) were demonstrated by subjecting them to ~5 to 6 N force at 10 Hz operating frequency. A maximum V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">oc</sub> of 21.61 ± 2.27 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pp</sub> , 35.32 ± 0.89 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pp</sub> , 31.21 ± 1.43 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pp</sub> and 45.75 ± 5.09 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">pp</sub> resulted in a power density of 0.29 μW/cm², 1.12 μW/cm², 0.47 μW/cm² and 0.91 μW/cm² from the D1, D2, D3 and D4 designs, respectively. The TENG fabricated using screen printed Ag flake on PDMS and fabric (D4) exhibited the highest open circuit output and a good repeatability after six months of re-testing with a maximum difference of ~ 7.39 % change(ΔV/V) in the output signal. In addition, a cyclic test was performed on D4, the results obtained demonstrate a good durability of the TENG sensor over 1000 cycles. The fabricated TENG device has a simple design, compact size, and demonstrated a better performance in comparison with some of the other works in terms of output voltage.

Energy and exergy analysis of a novel ejector-assisted compression–absorption–resorption refrigeration system

We propose two novel configurations of an ejector-assisted compression–absorption–resorption refrigeration system. In these configurations, an absorption–resorption sub-cycle is cascaded to a compression sub-cycle to deliver two simultaneous refrigerating effects to the end-users. The absorption–resorption sub-cycle utilises waste heat and delivers the refrigerating effect at -5°C, while the compression sub-cycle delivers the refrigerating effect at 7°C. The two novel configurations are categorised as the first configuration (C1) and the second configuration (C2), based on the cascading of the compression sub-cycle. The first and second law coefficients of performance (COP) of the proposed configurations are computed and compared at different compression ratios, generator and absorber temperatures, and ejector pressure ratios. The results indicate that the configuration C2 achieves the highest COP of 0.98 at 25°C absorber temperature and the COP changes from 0.98 to 0.79 as the absorber temperature increases from 25°C to 55°C. For the same refrigerating capacity, the proposed configurations C1 and C2 save electricity consumption by 36 % and 23 %, respectively, as compared with the electricity consumption by the conventional compression refrigeration system. The performance of the cascaded compression sub-cycle using R717, R600, and R290 refrigerants is assessed and compared with the widely used R134a and R410A refrigerants.

Passive Exosuit Emulator for Material Handling Applications

The letter introduces a passive back-assist exosuit (BASE) emulator system for manual material handling applications. The presented emulator has a fabric brace mounted modular moment arm, onboard load cells for measuring device interaction forces, and a synchronized EMG system. The design permits studies for experimenting with different elastic elements and their routing and moment arm configuration to establish biomechanical and physiological understanding before exosuits development. Human trials were conducted to demonstrate the usability of the presented emulator during the lifting/lowering task. Three different moment arm configurations (C1, C2, and C3) were tested for their effect on the muscle activity, device-to-body forces, and perceived discomfort during a lifting/lowering task. The configuration C2 was found to produce the least device-to-body forces (at shoulder and waist). While the maximum reduction of 16.7% in erecter spine muscle activity was observed for C3 configuration compared to when no Exosuit was used. The emulator could be used to understand biomechanics for different exosuit configurations during manual handling tasks. The understanding from the emulator will aid the development of future passive back assist devices for rehabilitation and occupational use.

Thermal management and performance improvement by using coupled effects of magnetic field and phase change material for hybrid nanoliquid convection through a 3D vented cylindrical cavity

In this study, effects of using magnetic field and packed bed phase change material (PCM) system in a 3D cavity having ventilation ports on the performance improvements are analyzed during hybrid nanoliquid convection. Two different locations of inlet port is considered while the numerical study is conduced for various values (Reynolds number (Re, between 250 and 750), Hartmann number (Ha, between 0 and 100), size of the inlet (wd, between 0.15H and 0.85H) and nanoparticle loading amount (between 0.02% and 0.1%). When PCM is used in the vented cavity, 13% and 16.5% enhancements of average Nusselt (Nu) number are obtained as compared to no-PCM case at Ha=0 and Ha=100. A critical Ha is obtained beyond which the phase transition time (tc) is reduced and the value depends upon the inlet port location. The location of the inlet port has significant impacts on phase change dynamics and transition time. When it is closer to the wall (case-C2), tc is reduced. 65% and 80% of reductions in the tc are observed at the highest Re for configurations C1 and C2. The higher port size resulted in fast phase transition while reduction of 89% in tc is obtained at Re=750 for case C1. Nanoparticle loading accelerates the phase transition and tc is reduced by 10.4% and 9% for cases C1 and C2. However, the average Nu variation with PCM shows different behavior for cases C1 and C2. At the highest particle loading, 11% (t=52 min) and 13% (t=250 min) increments in the average Nu are achieved C1 and C2. A polynomial type correlation for tc is obtained in terms of Ha and nanoparticle amount in the heat transfer fluid.

Hydrodynamic Evaluation of Five Influent Distribution Systems in a Cylindrical UASB Reactor Using CFD Simulations

UASB reactors are a promising option for environmentally friendly wastewater treatment due to their reduced carbon footprint and their capacity to treat a variety of wastewater strengths, among other recognized advantages over alternative wastewater treatment systems. The Influent Distribution System (IDS) is a critical structure for generating granules in a UASB reactor since it provides the required flow hydrodynamics for their formation. Thus, the objective of this study was to evaluate and compare the efficiency of five IDS configurations to generate ideal granulation conditions using Computational Fluid Dynamics (CFD) simulations. The IDS configurations were as follows: (C1) single radial inflow, (C2) upward axial inflow, (C3) downward distributed axial inflow, and two novel configurations in the form of (C4) double opposite radial inflow and (C5) downward tangential inflow. The hydrodynamic response of configuration C1 was validated in a physical model with dynamic Froude similitude. The granulation measurement was velocity-based in the reactor reaction zone using steady-state CFD simulations. The novel IDS configuration C4 was the one that resulted in the highest granulation volume, with up to 45.5% of the potential granulation volume of the UASB reactor, in contrast to the IDS C2 that obtained the lowest granulation with only 10.8%. Results confirm that the IDS directly impacts the hydrodynamics of the reactor and that model-based design can be used to ascertain IDS configurations that better promote granulation in UASB reactors.

Improving the performance of vertical flow constructed wetlands by modifying the filtering media structure.

The aim of this research was to study the influence of the bed media configuration and particle size on the treatment efficiency of subsurface vertical flow (VF) constructed wetlands (CWs) treating municipal wastewater. Two outdoor pilot units (VF1 and VF2, planted with Phragmites australis) with the configuration C1 were operated in parallel for 2 years at similar surface loading rates of 9.7 ± 3.2 (VF1) and 10.1 ± 3.3 (VF2) g biological oxygen demand (BOD5)/m2·day (19.5 ± 6.4 (VF1) and 20.4 ± 6.2 (VF2) g chemical oxygen demand (COD)/m2·day). A different configuration C2 was used during the third year at 16.9 ± 4.6 (VF1) and 18.2 ± 3.0 (VF2) g BOD5/m2·day and 26.0 ± 7.2 (VF1) and 28.0 ± 4.7 (VF2) g COD/m2·day. Two different filtering materials (1-3-mm sand for VF1 and 2-6-mm fine gravel for VF2) were used for configuration C1. The same units were modified after 2 years of operation by adding a 10-cm layer of fine sand (0-2 mm) on the top (configuration C2). In C1 conditions, the unit with the coarse material VF2 showed significantly (p < 0.05) lower removal efficiencies of total suspended solids (TSS) and BOD5 than VF1, and both units failed to meet the BOD5 discharge limit. In C2 conditions, removal efficiencies reached 82% TSS, 97% BOD5, 76-81% ammonia, and 60-66% TN, without significant differences between VF1 and VF2 units. Removal efficiencies were significantly higher for configuration C2 than that for C1, due to the positive effect of the upper fine sand layer. The presence of this fine sand layer doubled the water retention time and increased the removal rates, while the infiltration rates were high enough for an operation free of clogging.

Architected material analogs for shape memory alloys

Architected material analogs for shape memory alloys

Effect of tab parameters on the near-field mixing characteristics of a Mach 1.5 elliptic jet

The effect of delta-tabs with its apex leaning downstream on the jet mixing characteristics of a Mach 1.5 elliptic jet of aspect ratio (AR) 3.37 is reported in this paper. The delta-tabs were placed along the minor and major axes of the elliptic nozzle, referred to as tab configuration C1 and C2, respectively. For each tab configuration, four different orientation angles varying from θ= 90∘ to 150∘ were studied, where θ= 90∘ is the tab positioned normal to the nozzle exit and θ= 150∘ is the tab oriented in the downstream direction at the nozzle exit. The tab effects on jet manipulation were investigated via shadowgraph visualization, and the mean Pitot pressure was measured along the jet centerline and along the orthogonal planes of the jet. The non-dimensonalized supersonic core length Lc*, average shock-cell spacing Ls¯*, and the axis-switching location xas* were examined in detail to understand the jet characteristics of the natural and manipulated jets. The mixing capability of the manipulated jets quantified based on the reduction in supersonic core length ΔLc* depends strongly on the ideally expanded jet Mach number Mj, tab configuration (C1 and C2), and θ. As such, the ΔLc* for the manipulated jet at θ= 135∘ is the largest, revealing the optimal tab orientation for jet mixing enhancement, as also observed for the circular jet [Zaman et al., “Control of an axisymmetric jet using vortex generators,” Phys. Fluids 6(2), 778–793 (1994)]. The relationship between ΔLc* and ΔLs* is presented to understand the correlation between the jet mixing and noise characteristics of the manipulated jet. Discussion is conducted based on the dependence of ΔLc* and ΔLs* with θ, which provides useful insight into the jet flow physics. With suitable placement of tabs C1 and C2, the axis switching could be either stopped or augmented. The superior mixing characteristics of an elliptic jet relative to a circular jet, which were found in previous works on the supersonic over-expanded jet [Kumar and Rathakrishnan, “Characteristics of a supersonic elliptic jet,” Aeronaut. J. 120(1225), 495 (2016)] prevail in the supersonic jet under-expanded jet as well.

Performance investigation of metal hydride reactors adopting multilayer bed with graded content of expanded natural graphite for thermochemical heat storage

Metal hydrides (MHs) are promising materials for thermochemical heat storage. However, poor heat transfer limits the hydrogen absorption/desorption processes in MH reactors. In this study, a modified multilayer MH bed configuration with graded content of expanded natural graphite (ENG) was proposed. A mathematical model was established to obtain the distributions of temperature and reacted fraction within the MH beds during hydrogen absorption. Two comprehensive indices, gravimetric heat storage rate (GHSR) and gravimetric exergy-output rate (GEOR), were adopted to evaluate the heat discharging performance of the MH reactors. The simulation results show that a configuration in which the direction of the ENG content gradient (β) is consistent with the direction of heat flow can improve the performance of the MH reactors. Furthermore, increasing steepness of the ENG content gradient can increase both of the GHSR and the GEOR. The configuration with the squared graded ENG contents (C5-7, β = 3.5 wt%) exhibits the highest GHSR and GEOR values (16.98 and 16.16 W kg−1, respectively), whereas the configuration C1 which employs a uniform ENG content exhibits much lower values of these parameters.

Field Performance of a Solid Set Canopy Delivery System Configured for High-Density Tall Spindle Architecture Trained Apple Canopies

HighlightsVariants of a solid set canopy delivery system were evaluated in a high-density apple orchard.A pair of hollow-cone nozzles installed in three tiers had optimum spray performance for studied crop growth stages.A shower-down arrangement of emitters was the simplest design but had lesser deposition on abaxial leaf surfaces.Abstract. Optimally configured solid set canopy delivery system (SSCDS) based spraying has potential to improve tree-fruit crop pest and disease management by reducing application time and eliminating dependence on ground conditions. In such an effort, this study attempted to optimize SSCDS variants. Four different emitter types (E1 to E4) installed in different mounting configurations (C1 to C4) were evaluated for spray deposition and coverage in a high-density apple orchard trained in tall spindle architecture. Emitters E1, E2, and E4 had full circle spray patterns, and E3 had a hollow-cone pattern. Configuration C1 had a pair of E1 emitters spraying in a vertical plane and installed between two trees at 1.5 m above ground level (AGL). Another E1 emitter spraying in a horizontal plane was mounted atop each tree at 3.3 m AGL. Configurations C2 and C4 had emitters (E2 and E4, respectively) mounted atop each tree at 3.3 m AGL, and C3 had a pair of E3 emitters installed in a three-tier arrangement between two trees in the crop row. During field trials, a tree canopy about 3.0 m tall was divided into three zones (0 to 1.4 m, &amp;gt;1.4 to 2.2 m, and &amp;gt;2.2 to 3.0 m AGL) as bottom, middle, and top canopy zones, respectively. Mylar cards were used to quantify spray deposition using fluorometry, and water-sensitive papers (WSPs) were used to quantify coverage using image processing. Configuration C3 with 80° hollow-cone nozzles in a twin-emitter, three-tier arrangement had the highest overall spray deposition (581.1 ±77.8 ng cm-2, mean ± standard error) and coverage (18.4% ±4.1%). Moreover, C3 also had a significantly higher coverage on the abaxial surfaces of leaves compared to the other configurations. Configurations C1 was non-optimal because it lacked abaxial surface coverage as the canopy grew in the middle and late growth stages. Moreover, significant spray runoff from leaf surfaces was observed visually in the middle zone for C1 during the middle and late stages. This may be attributed to canopy growth around the emitters. Configurations C2 and C4, with emitters in a shower-down arrangement, had the highest deposition and coverage in the top canopy zone compared to the middle and bottom zones. Configurations C2 and C4 also had significantly higher spray coverage on the adaxial surfaces of leaves compared to the abaxial surfaces. Overall, despite the complex design of configuration C3 with six emitters per tree, it may be the most ideal arrangement for agrochemical application in an apple orchard trained in tall spindle architecture. For commercial feasibility, we recommend exploring this three-tier SSCDS configuration with low-cost emitter alternatives. Pertinent continuing efforts have been published by our group in which we successfully modified low-cost irrigation emitters, and the resulting three-tier SSCDS configurations had improved spray performance over expensive hollow-cone nozzles. Keywords: Fixed spray system, High-density apple orchard, Solid set canopy delivery system, Spray coverage, Spray deposition, SSCDS.

Advances in multifunctional balanced ventilation technology for dwellings and arising challenge to quantify energy efficiency and renewable generation contributions using international test standards

This paper evaluates the ability of EN16573:2017 to isolate and quantify the energy efficiency and renewable generation contributions of multifunctional balanced ventilation systems. These systems integrate an air-source heat pump with heat recovery ventilation and two similar, yet physically different configurations (C1 and C2) are assessed. Heat pump operation does not influence heat recovery performance for widely used configuration C1 but does influence for novel configuration C2. This study shows that while EN16573:2017 can isolate the energy efficiency (heat recovery exchanger) and renewable generation (heat pump) contributions for configuration C1, it fails when applied to configuration C2. Measurements undertaken using EN16573:2017 on configuration C2 revealed an overall coefficient of performance of 5.07, split 51% heat exchanger with heat pump off (phase 1), and 49% heat pump (phase 2 minus phase 1). If this result were obtained for configuration C1 the respective contributions would be 51% energy efficiency and 49% renewable generation. While these contributions cannot be resolved using EN16573:2017 for configuration C2, it can be achieved using two additional measurement planes in the incoming airstream. These showed an 88%:12% contribution from the heat exchanger and heat pump, respectively. While accurate, this result under-estimates the true heat pump contribution, as its positive impact on the heat exchanger efficiency boosts its contribution from 51% (phase 1) to 88% (phase 2). This paper acknowledges that heat pump operation leverages a 37% increase in heat exchanger performance and proposes a that the respective contributions of the heat exchanger and heat pump should be 42%:58%.

Rational nonlinear analysis of framed structures and curved beams considering joint equilibrium in deformed state

Based on the continuum mechanics principles, a rigorous formulation is presented for the linearized stiffness equation of three-dimensional beam elements with account taken of the joint moment equilibrium in the deformed configuration C2. By sticking to the Bernoulli–Euler hypothesis of plane sections and elasticity definitions for stress resultants, the bending moments and torque of the element are shown to be quasi- and semi-tangential, respectively, in the updated Lagrangian formulation. Further, by invoking the moment equilibrium conditions for structural nodes at C2, the induced moment matrix that first appears to be antisymmetric on the element level turns out to be symmetric upon assembly of all elements on the structural level. The joint equilibrium conditions at C2, as represented by the induced moment matrix, are central not only to the out-of-plane buckling analysis of angled frames, but also to the simulation of curved beams by the straight-beam elements. Examples on the buckling of angled frames and curved beams are provided to support the theory presented.

Performance analysis of ED-PR system with dual expanders and ORC for pressure energy recovery

Natural gas (NG) from the gas factory is delivered with abundant pressure energy to various industrial users and residents. The Throttle Valve Pressure Regulation (TVPR) configuration can only achieve stable downstream pressure. Additional expanders installed could recover the pressure energy, but hard to present a high efficiency and utilize the cold energy. This work innovatively proposes dual expanders and Organic Rankine Cycle (ORC) based on our previous EDNGPR (Expander-Depending Natural Gas Pressure Regulation) configuration. This configuration can not only regulate the NG pressure but harvest more pressure energy than that of the EDNGPR configuration. Thermodynamic analyses are conducted on the ED-PR configuration, the DED-PR configuration, the ORC-ED-PR configuration and the ORC-DED-PR configuration. Results show that the daily round-trip efficiency increased obviously by integrating the dual expander and the ORC. With the same NG volume flow, the daily round-trip efficiency of the configuration C2, C3 and C4 were increased up to 46.73%, 39.79% and 50.48% from 36.91% of the base configuration C1 respectively, while the daily power output was increased by 26.7%, 5.6% and 33.98% from 556.5KW of the base configuration C1 respectively. In addition, the daily exergy efficiency was 50.52%, 39.5%, 55.06% and 42.13% respectively for the configuration C1, C2, C3 and C4. Also, the results show that the contribution of the dual expander is far below that of the ORC cycle powered by solar energy.

Feasibility of a Solid set canopy delivery system for efficient agrochemical delivery in vertical shoot position trained vineyards

Solid set canopy delivery systems (SSCDS) offer advantages such as reduced off–target drift and human exposure to chemicals compared to conventional axial–fan airblast sprayers. In this study, six different SSCDS configurations (C1–C6) with two different emitter types (E1 and E2) were installed in a vertical shoot position (VSP) trained grapevine and evaluated for spray deposition and coverage during early, mid, and late growth stages. Emitters E1 and E2 had full–circle and hollow–cone spray pattern, respectively. Configuration C1 had a pair of E1 emitters installed per vine at 760 mm above the cordon. Configurations C2 and C3 had 2 pairs of emitters (E2 and E1, respectively) installed per vine near the cordon and C4 was a combination of C1 and a pair of E2 emitters at the cordon. Configurations C5 and C6 had two E2 emitters per vine installed near the drip line, and C5 also had E1 emitters 760 mm above the cordon. Overall, configurations with emitters installed close to both the top and bottom canopy zones (i.e., C1, C4 and C5) provided the best coverage and deposition in a VSP trained vineyard. Deposition for C1, C4 and C5 was 588 ± 159 ng cm−2 (mean ± std. error), 653 ± 123 ng cm−2 and 607 ± 114 ng cm−2, respectively. Coverage for respective configurations was 19 ± 4%, 23 ± 4% and 25 ± 4%. Overall, deposition did not differ significantly between upper–and under–sides of leaves whereas deposition and coverage in the top and bottom zones differed significantly among different configurations.

Development of a fiber daylighting system based on a small scale linear Fresnel reflector: Theoretical elements

This paper describes the details of the design of a small scale linear Fresnel reflector (SSLFR) applied to a daylighting system based on optical fiber bundles (OFBs). This study shows the influence of the SSLFR design parameters (mirror width, mirror length, reflector cavity height, and number of mirrors) and the parameters of the optical fiber. A new reflector cavity is designed, consisting of two right trapeziums. Each trapezium collects the incident solar irradiance of the mirrors located at each side of the central mirror. The reflector cavity has two focal points, located in the middle of the aperture of each trapezium. A MATLAB code was developed in order to obtain the optical efficiency of the new reflector cavity and numerical simulations are presented. Two SSLFR configurations, C1 and C2, are studied. C1 is the configuration used in large-scale LFRs and does not consider lateral movement of the OFBs, as is the case in configuration C2. Each of these configurations is analyzed considering the optimal length and longitudinal position of the OFB. Numerical simulations are presented for both configurations using the MATLAB environment. Power consumption based calculations are carried out using the lumen method and the potential electric energy saving is evaluated. The illumination levels obtained are then compared using the lighting design software DIAlux, a free software widely used as a planning tool by lighting designers. The results show a considerable electric energy saving with configuration C2, although configuration C1 also presents good energy savings.

Passage performance of two cyprinids with different ecological traits in a fishway with distinct vertical slot configurations

Adequately designed vertical slot fishways (VSF) mitigate the impact of anthropogenic obstructions on fish migrations. Until now, most studies on VSF were conducted focusing on high priority species, particularly salmonids, while other species, such as cyprinids, have received less attention. In Mediterranean rivers, where water availability is a problem, effective low discharge fishways are desirable. Attempting to contribute towards filling this gap, the present study focuses on the behaviour and passage performance of two Iberian cyprinids with different ecological traits, the Iberian barbel (Luciobarbus bocagei, Steindachner, 1864) and the Southern Iberian chub (Squalius pyrenaicus, Günther, 1868). Fish passage performance was investigated in a full-scale experimental VSF under two different slot configurations (C1 and C2), which require different discharges for equal mean water depths in the pools (Q=110Ls−1, for C1, and Q=81Ls−1, for C2). Results show that the chub, a small-bodied fish that utilises the upper portion of the water column, performed a higher number of upstream movements in C2, while for the barbel, a large-bodied potamodromous bottom-oriented fish, the performance was similar in both configurations. With similar overall passage success, slot configuration C2 requires a lower discharge to operate, making it the more cost-effective geometry, especially in regions affected by water scarcity.