Average Conversion Efficiency Research Articles

Enhance the Performance of CZTSSe Solar Cells Through Inhibiting the Cu2+, Tu, and (─COOH) Association Reaction.

The Sol-gel precursor solution reaction mechanism has a significant impact on the Cu2ZnSn(S, Se)4 (CZTSSe) solar cells. It is discovered that in the Cu2ZnSnS4 (CZTS) precursor solution (CZTS-PS) in the preparation, there is an association reaction among Cu2+, thiourea (Tu), and carboxyl (-COOH), which is an important reason for the undesirable CZTSSe solar cells. The strong association reaction generates excessive Cu2+ ions, forming the CuxSe secondary phase on the surface of the CZTSSe absorber. The secondary phase causes a short circuit and deterioration of gadget performance. Following a 6-h aging period for the CZTS-PS, the average photoelectric conversion efficiency (PCE) of the device is enhanced to 8.02%, and there is also an improvement in device uniformity, as evidenced by a decrease in the standard deviation to less than 1. To inhibit the association reaction and eliminate the aging time phenomenon, a strategy is developed using hydrochloric acid to regulate the CZTS-PS environment. This strategy shifts the REDOX reaction in Cu2++Sn2+ toward the formation of Cu1++Sn4+, leading to a decrease in the defect concentrations of VSn(-/0) and CuSn(-/0), which increases the carrier concentration and reduces the impact of band tailing. The average power conversion efficiency (PCE) of the devices improved from 7.45% to 9.26%, the PCE of the best-performing CZTSSe solar cells increased from 9.25% to 9.83%, and the consistency among the devices is further enhanced, as indicated by a reduction in the standard deviation from 0.98 to 0.44. Ultimately, the device performance of the Cu2++Sn2+-DMF system improved by 11.01% (without the MgF2 layer) after optimization. This study serves as a reference for regulating the environment of the CZTS-PS to further enhance the CZTSSe devices' performance, and the photoelectric conversion efficiency is improved by ≈30%.

Effect of supplementation of cactus (Opuntia ficus-indica) cladodes, Acacia saligna, wheat bran and cotton seed cake on feed intake, digestibility, growth and carcass characteristics of goats

The objective of this study was to evaluate the effect of supplementation of cactus (Opuntia ficus-indica) cladodes, Acacia saligna, wheat bran and cotton seed cake on growth, digestibility, intake and carcass characteristics of goats. A randomized complete block design was used in the experiment with 24 yearling central highland goats with an initial body weight of 15.6 - 16.1kg. The same amount of grass hay (GH) + 150 gDM/head/day wheat bran (WB) was given to all animals. The experimental diets consisted of 80 cotton seed cake (CSC) as treatment 1 (T1), 45CSC +160 cactus cladodes (CC) as T2, 45CSC+ 80 Acacia saligna (AS) as T3, and 45CSC+80CC+40AS as T4 (gram dry matter: DM, per day per goat), Data were gathered on the goats' growth, digestibility, intake, and carcass of major organs, edible and nonedible organs. The consumption of dry matter and organic matter was higher in goats fed T2 and T4 than in the T1 group. The DM, organic matter (OM) and crude protein (CP) digestibility, average daily body weight gain and feed conversion efficiency were higher in T4 and T3 goats when compared to T2 goats. Goats fed on T4 had higher hot carcass weight and dressing percentage on slaughter body weight basis than T2, T3, and T1 supplemented goats. Generally, the experimental diets improved goats’ performance in descending order (T4 > T3 >T1 >T2). Supplementation of T4 (replacement of 35 g DM of cotton seed cake per day by 40g of Acacia saligna and 80g of cactus cladodes on dry matter bases) could be recommended to improve goat performance.

Long-term operation and dynamic response of dissimilatory nitrate reduction to ammonium process under low-frequency infrared electromagnetic field

Dissimilatory nitrate reduction to ammonium (DNRA) received more attention for its ability to recover ammonium. This study investigated the possibility of low-frequency infrared electromagnetic field (IR-EMF) to improve DNRA. The optimal IR-EMF intensity of 0.04 μT could effectively improve DNRA activity of nonwoven fabric membrane bioreactors. In the long-term operation, the average ammonium conversion efficiency was enhanced by 117.7% and 62.5% under 0.04 μT and 0.06 μT IR-EMF, respectively. The highest nrfA-gene abundance and potential DNRA rate were obtained under 0.04 μT IR-EMF exposure. Bacteroidetes fragilis, Shewanelle oneidensis MR-1, and Thauera sp. RT1901 were selected to investigate the dynamic response of nitrogen transformation and energy metabolism to IR-EMF. The transcriptome sequencing and RT-qPCR results suggested that IR-EMF could enhance both denitrification and DNRA process, mainly by improving ATP synthesis to boost metabolic activity. This study provided an efficient method for the nitrogen recovery via DNRA process by applying IR-EMF.

Effect of nonstructural carbohydrates on production performance, rumen metabolism and rumen health in lambs fed with isocaloric and isonitrogenous complete diets.

Nonstructural carbohydrates (NSC) are readily fermentable in the rumen and, are a critical factor while preparing protracted feed for higher animal performance. Four isocaloric and isonitrogenous complete feeds were prepared for this investigation to contain varying levels of nonstructural carbohydrates viz., 40.13 (NSC1), 45.21 (NSC2), 50.00 (NSC3) and 55.85 (NSC4) per cent, respectively. The four isocaloric and isonitrogenous complete feeds were tested in 32 Mecheri ram lambs (around three months of age) in a completely randomised block design (n = 8), and the lambs were fed their respective feed for six months. The study revealed that the increased NSC level in the complete diet increased the body weight and weight gain linearly (P < 0.05). The dietary NSC level affected the dry matter consumption in a quadratic manner (P < 0.05) and the lambs of the NSC4 group consumed significantly (P < 0.05) less DM compared to other dietary groups. The overall average feed conversion efficiency differed significantly (P < 0.05) among dietary groups. The correlation between dietary NSC level and faecal score was quadratic (r2 = 62.7, P < 0.05). The rumen pH, total nitrogen and NH3-N concentration were linearly decreased (P < 0.05) and the molar proportion of total short-chain fatty acids and propionic acid were increased (P < 0.05). The energy loss expressed as methane production was significantly (P < 0.01) lower for the high NSC diet-fed lambs. The lambs fed on a low NSC diet had significantly (P < 0.05) lower carcass weights, dressing percentage and loin eye area. The per cent share of rumen weight in the total fore stomach and the rumen papillae measurements length, width and surface area were significantly (P < 0.05) higher in high NSC diet-fed lambs. Increased levels of NSC in the diet increased (P < 0.05) fat deposition in the internal organs. The saturated fatty acids content in the meat was significantly (P < 0.05) lowered, whereas, the oleic acid and linoleic acid were increased (P < 0.05) as the NSC level increased in the diet. The study revealed that as the level of NSC increased in the complete diet there was a concomitant improvement in the final body weight, ADG and feed efficiency of post-weaned Mecheri lambs. It can therefore be recommended that the complete feed with 50 per cent NSC levels would be optimum to reap maximum returns from fattening Mecheri lambs.

Study on the active regeneration characteristics of DPF in diesel-methanol dual-fuel engine under different exhaust oxygen concentrations

This study proposes a method to control exhaust oxygen (O2) concentration by adjusting the intake throttle valve, achieving intake throttling, and reducing intake airflow. The impact of exhaust O2 concentration at the inlet of the diesel oxidation catalyst (DOC) the diesel particulate filter (DPF) performance during active regeneration in diesel engines is investigated. Experiments are conducted under methanol substitution rates (MSR) of 0% and 20% to investigate how different exhaust O2 concentrations affect the performance of the DOC and DPF during active regeneration. A comparative analysis of fuel consumption and cumulative CO2 emissions during DPF active regeneration under different exhaust O2 concentrations is performed. Research results indicate that decreasing exhaust O2 concentration reduces exhaust flow, raising DOC inlet temperature. This enhancement improves catalytic conversion efficiency, accelerating the rise in DPF inlet temperature. The average conversion efficiency of DOC to unburned methanol exceeds 98.07%. After initiating DPF active regeneration, O2 concentration sharply drops, leading to elevated CO2 emissions. As soot combustion advances, the required O2 diminishes, resulting in a gradual rise and eventual stabilization of O2 emissions. Economically and environmentally, irrespective of MSR (20% or 0%), there exists an optimal exhaust O2 concentration that minimizes effective regeneration time during DPF active regeneration, achieving minimal fuel consumption and the lowest CO2 mass emissions. This study offers theoretical support for optimizing energy-saving and emission-reduction processes during DPF active regeneration.

Rainfall partitioning characteristics by two sand‐binding shrubs and their impact on shallow soil moisture replenishment in the Northwestern desert steppe of China

AbstractRainfall partitioning by the vegetation canopy into stemflow (SF) and throughfall (TF) plays a crucial role in soil infiltration and the local water balance. This study aims to quantify the differences in SF and TF between two sand‐binding shrubs, Caragana liouana and Salix psammophila, in the desert steppe, clarify the effects of biotic and abiotic factors on them using the boosted regression trees (BRT) model, and compare soil moisture replenishment during the growing seasons of 2021 and 2022. Under identical rainfall conditions, the canopies of C. liouana and S. psammophila can lead to differences in rainfall partitioning. The SF percentage ranged from 0 to 23.70% for C. liouana and from 0% to 3.3% for S. psammophila, respectively, while the TF percentage ranged from 42.12% to 90.07% for C. liouana and from 52.39% to 94.87% for S. psammophila. The funnelling ratio for C. liouana (69.59) is 1.19 times higher than for S. psammophila (58.36). Rainfall amount is the primary variable affecting rainfall partitioning. The average soil moisture replenishment and soil moisture conversion efficiency under the C. liouana canopy are 11.02 mm and 58.39%, respectively, which are significantly higher than those for S. psammophila (4.84 mm and 24.33%, respectively). These findings suggest that C. liouana, with its relatively higher SF and soil moisture conversion capability compared to S. psammophila, plays a significant ecohydrological role in water‐limited ecosystems. This study provides a reference for species selection and ecological management in vegetation restoration efforts in desert steppes and similar regions.

Metabolic performance and feed efficiency of black soldier fly larvae.

The black soldier fly (BSF), Hermetia illucens, is used in entomoremediation processes because its larvae can use a variety of organic residues with high efficiency. However, feed efficiencies are variable and characterized by uncertainties. Recently developed growth and metabolic performance models have predicted across different studies that BSF larvae have used 53%-58% of the feed components they have assimilated, in terms of carbon equivalents, for growth throughout their lifetime when reared on chicken feed. This is termed their average net growth efficiency. The remainder of the carbon has been lost as CO2. However, mass balances made under similar conditions show that the weight gained by BSF larvae corresponds to only 14%-48% of the feed substrates removed, indicating substrate conversion efficiency. Both performance indicators show even greater variability if more feed substrates are considered. Feed assimilation and growth rates, costs of growth, maintenance, and larval lifespan have been shown to affect how efficiently BSF larvae convert feed into growth. The differences between average net growth efficiencies and substrate conversion efficiencies further indicate that feed is often not used optimally in entomoremediation processes and that the overall yield of such processes is not determined by larval performance alone but is the result of processes and interactions between larvae, substrates, microbes, and their physical environment. The purpose of this study is to illustrate how quantification of the metabolic performance of BSF larvae can help improve our understanding of the role of the larvae in entomoremediation processes.

Application of immobilized biological fillers for the hydrolytic acidification and denitrification of sulfide-containing tannery wastewater

This study investigated the application of immobilized biological fillers in the hydrolytic acidification (HA) and denitrification (DN) of actual sulfide-containing tannery wastewater (TWW) through pilot-scale systematic experiments, which provided technical insights for the engineering application of immobilized bio-filler in practical TWW treatment. HA fillers and DN fillers could effectively realize the enrichment and maintenance of functional flora even under long-term inhibition of high sulfide concentration. The HA fillers demonstrated efficient conversion of organic nitrogen. At a hydraulic retention time (HRT) in the range of 3–6 h, the HA reactor achieved an average organic nitrogen conversion concentration of about 100 mg/L, accounting for 56.2 %-68.5 % of the total organic nitrogen in the TWW. Under this condition, the highest average organic nitrogen conversion and mean chemical oxygen demand (COD) degradation efficiencies were achieved, at 32.95 mgNH4+-N/(L·h) and 179.42 mgCOD/(L·h), respectively. Free ammonia (FA) may contribute to pH stabilization in the HA reactor. Denitrification fillers could utilize the endogenous organic matter in the actual TWW hydrolyzed acidified solution, and realize stable biological nitrogen removal effect with no additional carbon source. The denitrification rate reached 76.3 mg NO3--N/(L·h) and the ΔC/ΔN of the denitrification ranged from 3 to 4.

The surface effect of chlorinated mesoscopic TiO2 in printable carbon-based perovskite solar cells

Printable HTM-free (HTM = hole-transporting material) mesoporous carbon-based perovskite solar cells (C-PSCs) are one of the most promising technologies. In this study, a high-quality chlorinated mesoscopic TiO2 (m-TiO2) film was obtained by hydrochloric acid (HCl) wet chemical process and applied in C-PSCs based on TiO2/ZrO2/(5-AVA)x(MA)1-xPbI3/C structures. Experimental results show that the PCE of chlorinated m-TiO2 C-PSCs greatly improved. Based on (5-AVA)x(MA)1-xPbI3, C-PSCs with TiO2 ETL treated with HCl aqueous solution achieved an average photovoltaic conversion efficiency of 9.36 %, which is an increase of 7.96 % in comparison with the efficiency of the device using unmodified TiO2 ETL, while the Voc and the Jsc were increased by 3.63 % and 2.63 %, respectively. In a 30-day aging test, C-PSCs based on (5-AVA)x(MA)1-xPbI3 and TiO2-HCl 1 exhibited excellent stability under ambient air conditions.

A novel dynamic/adaptive K-nearest neighbor model for the prediction of solar photovoltaic systems’ performance

The inherent variability in solar Photovoltaic (PV) systems motivates developing dynamic and adaptive data-driven models capable of accurately predicting the systems’ performance. A dynamic/adaptive K-Nearest Neighbor (K-NN) model to estimate the conversion efficiency of a solar PV system is proposed in this work. The proposed model estimates the conversion efficiency of a test pattern based on three steps: (i) identifying the similar historical operational conditions experienced by the system, (ii) assigning a weight to each condition based on its similarity to the test pattern at hand, and (iii) computing the weighted average conversion efficiency of the test pattern. Thus, the proposed model is adaptive and dynamic as the nearest neighbors and the associated weights vary from one test pattern to another. The proposed model is applied to a 7.98 kWp rooftop grid-connected solar PV system at the Hashemite University in Jordan. Its effectiveness is evaluated by resorting to the Mean Square Error (MSE), Accuracy, Coefficient of Determination (R2), and Adjusted R2 (R2adjusted), and comparing the results with the traditional K-NN and other techniques adequately developed in the same context, such as Artificial Neural Network (ANN), Extreme Learning Machine (ELM), and Multiple Linear Regression (MLR). Results show that the proposed model exhibited superior performance across all metrics, with a performance gain reaching up to 45.2 % and 6.8 % for the MSE and R2adjusted, respectively, compared to the base MLR. Further, the simplicity and computational efficiency of the proposed model validate its practical deployment in predicting PV system performance.

Performance Evaluation of Lohman Brown Commercial Layer Chicken Breeds Under On-Station Management at Pawe, Benishangul Gumuz, Ethiopia

This study was undertaken to evaluate the performance of Lohman Brown under on-station conditions at Pawe Agricultural Research Center. To evaluate the breed production performance and to generate information for private commercial farms and multiplication centers. A total of 100 (sixty-day-old) chicks and commercial layer feed were purchased from Alema poultry farm in Bishoftu. Vaccinations were administered to the chicks while bio-security measures were employed throughout the experimental period (83 weeks). Daily feed intake, body weight, feed conversion rate, egg production, egg weight, egg mass, and mortality, were recorded. Data were analyzed using descriptive statistics free R-4.0.4 software. Average feed intake during the growing period (10-20 weeks) 59.29g/head and in the layer period (21-72weeks) 117.26g/head/day. The average feed conversion rate at12, 16 and 20weeks of age was 8.85, 8.23 and 7.35 respectively. Average body weight at age at first egg lay and peak egg production were 1368.6 and 1553.9g/head respectively. Average daily weight gain at 10-12, 12-16, and 16- 20 weeks of age was 5.43, 7.22 and 11.09g/bird respectively. Age at first and 5% egg-laying were recorded at the beginning of 21weeks (141days). Age at 50% and peak egg production were recorded at 22 weeks (151 days) and 36weeks. The average HHEP (90.71) and HDEP (92.03) were recorded at peak production, while the overall percentage of lay from 21-72(52) weeks of age were HHEP (74.77%) and HDEP (78.28%). The total amount of egg production from 21-72(52) weeks of age in terms of HHEP and HDEP was 272.2 and 284.93egg/hen/year. Average egg weight at age at first egg lay, 50% egg lay and peak egg production were 47.43, 51.5 and 57.03g. Overall mean egg weight from 21-72(52) weeks of age was 57.81g. The average daily egg mass at the age of first egg lay, 50% egg lay and peak egg production were 7.59, 25.68, and 52.48g. On the other hand, the overall mean daily egg mass from 21-72(52) weeks of age was 45.38g. The average feed conversion rate and feed conversion efficiency for egg mass from 21-72 weeks were 2.64 and 0.387. There was no mortality record up to 28 weeks but, the overall mortality rate was 10% up to 83 weeks. The higher egg production and lower mortality record showed that the breed is adapted in the study area. Lohman Brown is recommended for users with basic input packages and on-farm evaluation of chickens should be done.

Performance optimization of interleaved boost converter with ANN supported adaptable stepped-scaled P&O based MPPT for solar powered applications

Solar energy is the most promising among many renewable energy sources to meet the increasing demand. Photovoltaic (PV) based power generating solutions are expected to gain popularity as a power source for different applications, including independent and grid connected loads, due to their cleanliness, high performance, and high dependability. The efficacy of photovoltaic systems is impacted by several elements, including geographical location, positioning, shadowing effects, and local climate conditions. In order to fulfil the demands of loads, an interleaved boost converter is utilized, which has a reduced number of filters with less stress on the devices. Solar powered systems employ several maximum power point tracking (MPPT) methodologies. However, when there is partial shading, many power peaks arise, which complicates the identification of the overall peak. Although MPPT approaches are designed to measure and maintain the global maximum power point (GMPP), there are still significant oscillations observed around the GMPP with subpar settling time, tracking efficiency, and conversion efficiency. In this work, novel hybrid MPPT technique called artificial neural network supported adaptable stepped-scaled perturb and observe (ANN-ASSPO) method and water cycle optimization based perturb and observe (WCO-PO) have been proposed. Artificial neural network (ANN) has been used to determine the best scaling factor in ANN-ASSPO MPPT. Performance is enhanced in ANN-ASSPO MPPT by using the optimum scaling factor, particularly in situations when the irradiance is rapidly changing/partial shading conditions. Similarly, in WCO-PO MPPT water cycle optimization is used to determine the peak power when the PV panel is subjected to partial shading conditions. The performances of proposed hybrid MPPT ANN-ASSPO and WCO-PO techniques have been compared in terms of power generated, output voltage, average settling time and conversion efficiency. The MATLAB/Simulink tool is employed to carry out the experiment for this study.

Thermoelectric performance analysis of the novel direct-expansion photovoltaic thermal heat pump/power heat pipe compound cycle system in summer

Photovoltaic thermal heat pump technology has outstanding cogeneration ability by utilizing renewable energy to be accepted as a decarbonization pathway in the residential sector. However, existing photovoltaic thermal heat pumps consume higher energy under better external heat source conditions. To address this problem, a novel direct-expansion photovoltaic thermal heat pump/power heat pipe compound cycle system for heating and power generation as well as refrigeration, whose core equipment was a photovoltaic thermal module with straggled honeycomb fluid channel pattern on the serpentine arrangement, was proposed, manufactured, and studied with the method of experiment. The thermoelectric performance was compared between the heat pump and power heat pipe cycle modes, investigated under typical weather conditions, and discussed in contrast to the literature. The results showed that the average photoelectric conversion efficiency and coefficient of photothermal performance of the PVT modules, as well as COP of the novel system were 10.6%, 51.0%, and 6.19, respectively, at the average ambient temperature of 27.0 °C, average solar radiation intensity of 581 W/m2 and water temperature of 18.3–55.6 °C. And daily average COPs of the novel system under sunny, cloudy, and overcast conditions were 15.12, 7.40, and 3.17, respectively. The conclusion drawn from the experimental results is that the COP of the novel system was 10.0%–60.0% higher than that in the literature under similar outdoor conditions. The payback period of the additional cost of the novel system compared with the existing direct-expansion photovoltaic thermal heat pump was within 2.5 years. The novel system represents a practical response to the need to achieve total decarbonization of the residential sector.

Biodiesel production from the Scenedesmus sp. and utilization of pigment from de-oiled biomass as sensitizer in the dye-sensitized solar cell (DSSC) for performance enhancement

Dye-sensitized solar cell (DSSC) using algal photosynthetic pigments has got rampant attention as it converts sunlight into electricity. Therefore, in this present research, the neutral lipid extracted from the green alga Scenedesmus sp. was used for biodiesel production, and concurrently, pigments extracted from the de-oiled biomass cake were used as a sensitizer in DSSC to evaluate its performance efficacy with and without PVDF (Polyvinylidene fluoride). Initially, neutral lipids extracted from the Scenedesmus sp. were converted to biodiesel with a yield of 72.9%, and the de-oiled biomass was subjected to pigment extraction (17.65 mg/g) to use as a sensitizer in DSSC. This study proposes two DSSC test models, i.e., PVDF (Polyvinylidene fluoride) - bound cell and cell without any PVDF binder. For the PVDF-coated DSSC, the average energy conversion efficiency reached about 14.3%, the open circuit voltage was 0.55 V, and the short circuit current was 144.5 mA. The unbound cells showed a reduction in efficiency, voltage, and current, and notably, efficiency of 10.44% on day 1 was decreased to 3.32%, and the open circuit voltage and short circuit current of 0.38V and 144 mA were decreased to 0.24V and 130 mA after 10 days, under 40 mW/cm2 input power. The PVDF-coated solar cell has maintained its efficiency range of 16.32%–11.22%, which is higher than the PVDF-unbound cell for a tested timeline of 30 days. The fill factor of 0.47 was observed in PVDF- unbound DSSC under 40 mW/cm2 as input power, while it was increased to 0.577 when PVDF was used as a binder. The PVDF-coated cell has low degradation compared with the PVDF-uncoated cell. These results offer dual benefits as the production of biodiesel from microalgal lipids and electricity generation from the DSSC using the pigments of biodiesel-extracted algal biomass.

Performance, carcass characteristics, and meat quality of lambs fed diets containing crude glycerin

The aim of this study was to evaluate the effects of four crude glycerin levels in the diet of feedlot lambs on performance, carcass characteristics, and meat quality. Forty three-month-old crossbred Santa Inês x Dorper lambs weighing 18.2 ± 0.169 kg were used in a completely randomized design, with four diets and 10 replicates per diet. The animals were housed in individual pens. The trial period (42 days) was preceded by 14 days of adaptation to handling and diet. Final body weight (FBW), empty body weight (EBW), average daily weight gain, feed conversion, and feed efficiency did not differ with crude glycerin levels in the diet. Nutrient intake (dry matter (DM), ether extract (EE), crude protein (CP), and neutral detergent fiber (NDF)) did not differ depending on crude glycerin levels. In the evaluation of carcass characteristics, there was a quadratic effect due to crude glycerin levels on hot carcass yield (maximum point- maxP = 9.73%), leg perimeter (maxP = 9.45%), fat thickness (maxP = 7.41%), and leg weight (maxP = 8.69%). Loin weight and conformation showed a linear increase as a function of crude glycerin levels. The other studied variables were not affected by crude glycerin levels in the diet. In the non-carcass components, the full gastrointestinal tract, mesenteric fat, omental, and perirenal fat were not influenced by crude glycerin levels. Regarding meat quality, no effects were observed on the parameters evaluated in the longissimus dorsi. The addition of up to 15% crude glycerin in the lamb's diet does not affect its performance, however, the addition of up to 8% improves carcass characteristics and maintains meat quality.

Designing an energy storage system based on water tower pumping to store the energy generated by the turbo-expander implemented in a gas pressure reduction station

In the present research, an energy recovery and storage strategy for a natural gas pressure reduction station with a capacity of 50,000 Nm3/h has been proposed. Currently, the gas pressure reduction station does not have an energy recovery system; hence, energy of high-pressure natural gas is wasted in it. For this reason, first, the energy recovery system was thermodynamically designed based on the use of a turbo-expander instead of the regulator, and the extracted energy was calculated. The results showed that 1.376 GWh electrical energy can be generated annually using the recovered energy. Then the economic analysis of the use of the proposed plan was discussed. The results of the economic analysis showed that the investment payback period for installing the turbo-expander in the considered station is 2.4 years. In the last part of the research, an energy storage system was designed to store the generated electrical energy. For this purpose, an energy storage system based on water pumping in water towers was designed. Water towers with different classes were investigated. The obtained results showed that the average energy conversion efficiency in the energy storage system varies from about 70 % for small water towers to about 74 % for large ones.

The investigation of V-shaped arrays with non-uniform diameter cylinders for high performance hydrokinetic energy conversion

Harnessing hydrokinetic energy through vortex-induced vibration (VIV) is of great significance. The energy capture efficiency of VIV cylindrical arrays still has great potentials for making further progress. This paper investigates the energy conversion performance of cylinder cluster arrays with non-uniform diameter positioned at the upstream, midstream, and downstream locations, utilizing the downstream VIV enhancement effect. The cylinder arrays consist of five cylinders with non-uniform diameters of 2, 3, and 4 cm, resulting in a total of eight different V-shaped configuration scenarios. Through numerical simulation, it is found that the optimal flow velocity for maximizing the cylinder vibration amplitude is 0.8 m/s. In the condition of 0.8 m/s flow velocity, this study investigates the impact of cylinder diameter and the array arrangement on lift force, amplitude response, vortex shedding frequency, converted power, and efficiency. If the diameter of a cylinder is smaller than that of its upstream cylinder, cylinder experiences an enhanced amplitude, and the magnitude of this enhancement increases with the difference in diameters between the two cylinders. The blocking effect in the cylinder array occurs at a distance of two times the diameter. It has been observed that the small diameter cylinder demonstrates exceptional performance, achieving the highest converted power of 6.58 W (88% higher than the single cylinder) and the highest conversion efficiency of 68 % (75% higher than the single cylinder) in the convergent V-shaped array. The divergent V-shaped array achieves a maximum total converted power of 17.12 W (14% higher than the average conversion efficiency of single 2 cm, 3 cm, 4 cm cylinders), while the convergent V-shaped array achieves a maximum total conversion efficiency of 44% (24% higher than the average conversion efficiency of single 2 cm, 3 cm, 4 cm cylinders). This study presents an innovative perspective on the VIV enhancement effect in energy conversion, specifically focusing on multi-cylinder arrays with non-uniform diameters.

High-efficiency, single-stage tunable optical parametric amplifier for visible photocathode applications.

We present a single-stage optical parametric amplifier (OPA) with an average conversion efficiency up to 38%, tunable between 1.01 and 1.18 µm. The OPA seed is produced by a gain-managed nonlinear fiber amplifier. Numerical modeling of the seed pulse generation shows a linear chirp, a smoothly broadened redshifted spectrum, and a high spectral energy density. When up-converted to the visible through second-harmonic generation, the signal pulses are suitable for visible photocathode excitation.

Superheat matching control method for a roll-bond photovoltaic-thermal heat pump system

In this paper, a superheat matching control method (SMCM) for a roll-bond photovoltaic-thermal heat pump (RB-PVT-HP) system is proposed to achieve adaptive control of the target superheat under different operating conditions. The target superheat was determined based on a comprehensive consideration of the stable running superheat and the optimally performing superheat of the system. The effectiveness of the SMCM was experimentally verified. The trigeneration performance tests of the system under the SMCM were conducted in the summer. Results show that the average deviation degrees of superheat were 0.48 °C and 2.09 °C in the heating and cooling processes, respectively. In the heating process, the average input power of the compressor, heating power and coefficient of performance of the system were 5.40 kW, 17.90 kW, and 3.31, respectively, across four days of continuous operation. The average photoelectric conversion efficiency, comprehensive energy output capacity and comprehensive performance of thermal-and-electrical generation were 14.19 %, 21.29 kW and 34.76 %, respectively, during daytime operation. In the cooling process, the average input power of the compressor, cooling power and energy efficiency ratio of the system were 3.82 kW, 7.72 kW, and 2.02, respectively, during nighttime operation.

TiO2/SiC supported catalyst for efficient thermocatalytic conversion of SF6 waste gas

The harmless treatment of SF6 waste gas is currently a highly concerned focus in the power industry. This article used a new supported catalyst, TiO2/SiC, to study the thermocatalytic conversion of SF6 waste gas. Firstly, the catalytic activity of TiO2/SiC was tested, and it was found that the catalytic efficiency of TiO2/SiC was 3.73 times that of TiO2 at 700 °C; Subsequently, the optimal catalytic conditions for TiO2/SiC were figured out by experiments, which were conducted under different initial pressures and oxygen concentrations. It was found that the catalytic efficiency of TiO2/SiC was highest when the initial pressure was 0.16 MPa and the concentration rate of SF6 and O2 was 1:4. Under these conditions, the total conversion of SF6 by TiO2/SiC reached 288 ml in 6 h, and the average catalytic conversion efficiency reached 33 ml g−1 h−1. It was also found that when the conversion of SF6 reached 110–130 ml, the catalytic activity of TiO2/SiC decreased; the oxygen concentration has a significant influence on the products: the higher the oxygen concentration is, the higher the production of SO2F2 rate in the product, while the lower that of SO2 rate. Finally, in order to know the catalytic mechanism of TiO2/SiC, XPS tests were conducted on the catalysts before and after the experiment. According to the XPS spectrum, gaseous products would react with TiO2 and generate TiF4 and Ti(SO4)2. According to the test results, the catalytic mechanism of TiO2/SiC was summarized in this article. It explained the catalytic effect of TiO2/SiC from two aspects: promoting the defluorination of SF6 and consuming low-fluorinated sulfides. The empirical conclusions of this article provide a theoretical reference for the harmless treatment of SF6 waste gas.