The energy efficient product can be operated with longer duration.They offer wonderful solutions compared to other conventional water pumping system as it needs less maintenance,simple in installation,zero fuel cost,l...The energy efficient product can be operated with longer duration.They offer wonderful solutions compared to other conventional water pumping system as it needs less maintenance,simple in installation,zero fuel cost,longer operating life,highly reliable and free from production of greenhouse gases.In this paper we analyzed the different topologies of DC–DC converter in terms of their operating region of MPPT,quality of input and output currents.We discussed the MPPT algorithms to address partial shading effects in SPV array,present state of the technology,factors affecting the performance of the system,efficiency improvements and identified the research gaps.Also,the economic feasibility analysis has been done for the real time scenario using the Homer Pro software.The estimation of total dynamic head and horse power calculation has been done to decide the total load capacity.The economic analysis results such as cumulative cash flow over project lifetime of 25 years are presented.It is observed that the capital investment requirement is$7,425 for installing Fronius PV system that has a nominal capacity of 2.47 kW and annualized savings will be$134.93.In the long-term perspective,the return on investment is−2.18%as per the present tariff plan.展开更多
This paper is about the optimized design and analysis of two solar water pumping systems in which one of the systems is designed with a battery bank and other with a cylindrical water tank for a selected site in Pakis...This paper is about the optimized design and analysis of two solar water pumping systems in which one of the systems is designed with a battery bank and other with a cylindrical water tank for a selected site in Pakistan. The design, sizing, cost analysis and steady state analysis of the proposed systems were done in HOMER and dynamic analysis of the designed system with battery bank was performed in MATLAB/Simulink. The simulations performed in HOMER involved proper mapping of the loads which helped to evaluate the PV panel requirement, inverter rating, batteries (in case of battery based solution), modeling of water tank as a deferrable load (in case of solution based of water tank) and detailed cost analysis for a life time of 25 years. To verify the design of the solar water pumping system with battery bank, a simulation in MATLAB/Simulink for study of dynamic behavior of the overall system was performed which involved mathematical modeling of a PV panel, buckboost converter, inverter, battery bank and motor/pump, a perturb and observe maximum power point tracking algorithm based control system. Analysis was conducted based on the economic results that indicate designed solar water pumping system with water tank would be a cheaper solution as compared to solar water pumping system with a battery bank. This work can be taken as a case study for the understanding and optimized designs of solar water pumping system with battery bank and with cylindrical tank in Pakistani conditions.展开更多
Many papers exploiting the various MPPT (maximum power point tracking) techniques in PV (photovoltaic) applications, from the simple to the most complicated, can be found in literature. However, these techniques m...Many papers exploiting the various MPPT (maximum power point tracking) techniques in PV (photovoltaic) applications, from the simple to the most complicated, can be found in literature. However, these techniques may not always be easy to implement in industrial applications. The main challenge of this paper is to model and implement the P & O (perturb and observe) algorithm in a low-cost PV-powered pumping system. To that end, a comparative investigation of the performance characteristics of the most popular MPPT methods, such as FOCV (fractional open circuit voltage), FSCC (fractional short circuit current), FLC (fuzzy logic control), ANN (artificial neural network) and INC (incremental conductance) is presented. This analysis is helpful to highlight the relevance of the P & O technique taking better account of complexity, difficulty of implementation and cost considerations in water pumping applications. The targeted PV-powered pumping system is based on a single-phase induction motor supplied by a three-phase inverter controlled by the DTC (direct torque control) technique. This stand-alone PV system is dedicated to water pumping, especially in rural areas that have no access to national grids but have sufficient amount of solar radiation. Simulation modeling (Matlab/Simulink) and experimental results are presented to demonstrate the relevance of the system.展开更多
This paper investigates the operation and analysis of the photovoltaic water pumping system in detail. Power electronic controllers were designed and developed for the water pumping system using a boost converter alon...This paper investigates the operation and analysis of the photovoltaic water pumping system in detail. Power electronic controllers were designed and developed for the water pumping system using a boost converter along with an inverter followed by an induction motor pump set. The proposed system could be employed in agricultural irrigation under any operating condition of varying natures of solar irradiances and temperatures. The configuration and implementation of the system were described in detail. Further, the detailed method of analysis and simulation characteristics of such PV water pumping system was also presented. With the concern of shortage of fossil fuel, global warming and energy security, the proposed PV based water pumping significant demand of electricity agricultural sector. system can meet the and serve for the展开更多
Based on energy conservation equation and Darcy's law, a model of beach well infiltration intake system applied in a seawater source heat pump system was established. The model consists of the seawater seepage and th...Based on energy conservation equation and Darcy's law, a model of beach well infiltration intake system applied in a seawater source heat pump system was established. The model consists of the seawater seepage and the heat transfer process. A porous medium model in a software named FLUENT was applied to simulate the seepage and the heat transfer process. This model was also validated by field experiment conducted on the seashore in Tianjin, China. The maximum relative error between simulation results and experimental results was 2.1% (less than 5%), which was acceptable in engineering applica- tion. The porosity and coefficient of thermal conductivity of the aquifer soil were determined to be 0.49 W/(m. K) and 1.46W/(m.K), respectively in the simulation. In addition, the influencing factors of pumping water of beach well were also analyzed. The pumping water was found to increase when the distance between the beach well and the impervious boundary becomes longer, when the distance between the beach well and the supplying water source shortens, when the diameter of the beach well enlarges, and the drawdown enlarges.展开更多
In the present work,an assessment of the rural water supply potential by mechanical wind pumping around the floodplains of Lake Chad has been considered.Inside the floodplains around Lake Chad,available surface water ...In the present work,an assessment of the rural water supply potential by mechanical wind pumping around the floodplains of Lake Chad has been considered.Inside the floodplains around Lake Chad,available surface water is largely contaminated and represents health hazards to populations.Access to underground and clean water has increasingly become rare.Moreover,clean water scarcity has led to conflict and territorial pressures,which are contributing factors to poverty in the considered area.Four localities,Baga,Baga-Sola,Makari and Nguigmi,respectively,in Nigeria,Chad,Cameroon and Niger have been selected inside the floodplains around Lake Chad,to evaluate the potential of wind power and prospects of windmills development to provide safe drinking-water supply,livestock watering and small-scale irrigation.Long-term satellite-derived data,obtained through the Prediction of Worldwide renewable Energy Resources have been considered suitable and viable alternative to missing site-specific data from ground stations.Windmill of Multi-blade driven piston pump is the preferred water pumping option for this study because of its higher overall system efficiency.The results of this study indicate that mean wind speeds,at 10 m height above ground level,are 4.64 m/s for Baga,4.76 m/s for Baga-Sola,4.32 m/s for Makari and 4.44 m/s for Nguigmi.In addition,wind speeds for Baga,for instance,are in the range of 2.5–10 m(working range of a wind pump),at 10,15,20 and 25 m height agl,for 79.64,82.80,84.79,and 86.19 per cent of the time.Corresponding values for Baga-Sola,Makari and Nguigmi are in the range of 80.50–87.76 per cent,76.86–85,58 per cent,77.92–86.21 per cent,respectively.For a Windmill with a 2 m-blade,a 25 m-height tower and considering a total dynamic head of 30 m,average monthly discharges for the dry season are 1,330,1,374,1,200 and 1,199 m3,respectively for Baga,Baga-Sola,Makari and Nguigmi.Furthermore,corresponding costs of water are 9.53,9.23,10.56 and 10.57 XAF/m3,for Baga,Baga-Sola,Makari and Nguigmi,in that order.展开更多
For surface defects in electronic water pump shells,the manual detection efficiency is low,prone to misdetection and leak detection,and encounters problems,such as uncertainty.To improve the speed and accuracy of surf...For surface defects in electronic water pump shells,the manual detection efficiency is low,prone to misdetection and leak detection,and encounters problems,such as uncertainty.To improve the speed and accuracy of surface defect detection,a lightweight detection method based on an improved YOLOv5s method is proposed to replace the traditional manual detection methods.In this method,the MobileNetV3 module replaces the backbone network of YOLOv5s,depth-separable convolution is introduced,the parameters and calculations are reduced,and CIoU_Loss is used as the loss function of the boundary box regression to improve its detection accuracy.A dataset of electronic pump shell defects is established,and the performance of the improved method is evaluated by comparing it with that of the original method.The results show that the parameters and FLOPs are reduced by 49.83%and 61.59%,respectively,compared with the original YOLOv5s model,and the detection accuracy is improved by 1.74%,which is an indication of the superiority of the improved method.To further verify the universality of the improved method,it is compared with the results using the original method on the PASCALVOC2007 dataset,which verifies that it yields better performance.In summary,the improved lightweight method can be used for the real-time detection of electronic water pump shell defects.展开更多
To evaluate the performance of heat pumps using refrigerant HFC125,an experimental rig of a DC-inverter heat pump water heater is designed and set up,and the research on the transcritical heat pump water heater is car...To evaluate the performance of heat pumps using refrigerant HFC125,an experimental rig of a DC-inverter heat pump water heater is designed and set up,and the research on the transcritical heat pump water heater is carried out experimentally.It is found that there is a top value of the coefficient of performance(COP)when the system runs at 95 Hz of frequency.The relationships between the COP and compressor frequency,condensation pressure,evaporation pressure,condensation water temperature rise,and discharge temperature are discussed and analyzed at 95 Hz.And the COP of the HFC125 transcritical cycle is also compared with that of a R410 subcritical heat pump under the same conditions.The results indicate that there exists an optimum frequency for a better COP,and the system COP shows an increasing tendency with the decrease in condensation pressure and compressor ratio while the evaporation pressure remains invariant,and the COP decreases rapidly when cooling water temperature rises over 47.5 ℃.Compared with the R410A sub-critical cycle,the COP of HFC125 transcritical cycle significantly increases by 12% on average.展开更多
Jordan has,</span><span style="font-family:""> </span><span style="font-family:"">to a satisfactory degree,</span><span style="font-family:"&quo...Jordan has,</span><span style="font-family:""> </span><span style="font-family:"">to a satisfactory degree,</span><span style="font-family:""> </span><span style="font-family:"">managed its scarce water resources, especially during the last few decades due to the regional conflicts and refugee waves hosted in the country since 1948.</span><span style="font-family:""> </span><span style="font-family:"">The waves of refugees in 1967, and after), returnees from the Gulf States 1991/92, during the first Gulf war), Lebanon (1970s and 1980s), Iraq (2003 and after, and lastly Syria (2011-2017 have</span><span style="font-family:""> </span><span style="font-family:"">as well</span><span style="font-family:""> </span><span style="font-family:"">severely impacted the management of water resources which has negatively impacted the water sector especially in terms of allocating new water resources to satisfy the needs of the country. In addition, shortsightedness of some water policy-makers has led to the deteriorations in the water resources quantitatively and qualitatively, which has resulted in social and economic discomfort of the population. In this article, the shortcomings in the water sector are addressed, such as setting an end to groundwater overexploitation, providing water to the population in a continuous way, improving water use efficiency in agricultural uses and the way forward is</span><span style="font-family:""> </span><span style="font-family:"">delineated</span><span style="font-family:""> </span><span style="font-family:"">based on a critical judgment of the actual situation of the water sector in order to reach at a more robust water sector with all its</span><span style="font-family:""> </span><span style="font-family:"">positive impacts on the social, economic and political life in the country.展开更多
A novel nanoscale watermill for the unidirectional transport of water molecules through a curved single-walled carbon nanotube(SWNT) is proposed and explored by molecular dynamics simulations. In this nanoscale syst...A novel nanoscale watermill for the unidirectional transport of water molecules through a curved single-walled carbon nanotube(SWNT) is proposed and explored by molecular dynamics simulations. In this nanoscale system, a revolving charge is introduced to drive a water chain confined inside the SWNT, the charge and the tube together serving as a nano waterwheel and nano engine. A resonance-like phenomenon is found, and the revolving frequency of the charge plays a key role in pumping the water chain. The water flux across the SWNT increases with respect to the revolving frequency of the external charge and it reaches its maximum when the frequency is 4 THz. Correspondingly, the number of hydrogen bonds in the water chain inside the SWNT decreases dramatically as the frequency increases from 4 THz to 25 THz. The mechanism behind the resonance phenomenon has been investigated systematically. Our findings are helpful for the design of nanoscale fluidic devices and energy converters.展开更多
Intenal combustion pump (ICP) is a new type power device turning the thermal energy from fuel combustion into fluid pressure energy. Three cylinders prototype has just been developed. The study on the influence of v...Intenal combustion pump (ICP) is a new type power device turning the thermal energy from fuel combustion into fluid pressure energy. Three cylinders prototype has just been developed. The study on the influence of valve's characteristic on ICP's total performance will found the base for its optimum design. Based on the theoretical and testing fruits of single cylinder prototype, the performance of the valves and complete appliance of the latest is simulated. When the natural frequency of valves is approximately to the round number times of the working frequency, volumetric efficiency is seriously low. The nominal rotational speed of the prototype is nearly to the speed where the volumetric efficiency is lowest, which is harmful to the normal work of ICP, so further structure optimization of valves should be carried out. The change of volumetric efficiency has great influence on the fuel consumption rate, output flow, effective thermal efficiency, effective power, and so on, but little on output pressure.展开更多
In order to investigate the effect of sampling frequency and time on pressure fluctuations, the three-dimensional unsteady numerical simulations were conducted in a circulating water pump. Through comparison of turbul...In order to investigate the effect of sampling frequency and time on pressure fluctuations, the three-dimensional unsteady numerical simulations were conducted in a circulating water pump. Through comparison of turbulence models with hydraulic performance experiment, SST k-co model was confirmed to study the rational determination of sampling frequency and time better. The Fast Fourier Transform (FFT) technology was then adopted to process those fluctuating pressure signals obtained. On these bases, the characteristics of pressure fluctuations acting on the tongue were discussed. It is found that aliasing errors decrease at higher sampling frequency of 17 640 Hz, but not at a lower sampling frequency of 1 764 Hz. Correspondingly, an output frequency range ten-times wider is obtained at 17 640 Hz. Compared with 8R, when the sampling time is shorter, the amplitudes may be overvalued, and the frequencies and amplitudes of low-frequency fluctuations can not be well predicted. The frequencies at the tongue are in good agreement with the values calculated by formula and the frequency compositions less than the blade passing frequency are accurately predicted.展开更多
During Jan.1995 to Dec.1996, monthly investigations on the zoobenthic communities of West Lake, samples were collected from six sampling stations. A total of 26 species of macrozoobenthos were identified. The seasonal...During Jan.1995 to Dec.1996, monthly investigations on the zoobenthic communities of West Lake, samples were collected from six sampling stations. A total of 26 species of macrozoobenthos were identified. The seasonal changes in density and biomass of zoobenthos in this lake were analyzed. The annual mean densities were 980~2751 ind/m\+2 and mean biomass was 19.69-122.80 g/m\+2. The densities in winter and early spring were higher than those in summer and autumn. Comparative study of theprevious data (1982 to 1983) collected by the authors, showed that the succession of zoobenthic communities, dominated by \%Procludius choreus\% in density and \%Bellamya purificata\% in biomass, had been occurred in Xiaonan sub\|lake after Qiantang River water was drawn into it; and that the species and biomass of zoobenthos were then increased and the density was decreased. In other sub\|lakes, the dominant species were \%Limnodrilus hoffmeisteri\% and \%Tokunagayusurika akamusi \%in density and \%Branchiura sowerbyi\% and \%Tokunagayusurika akamusi \%in biomass. The water quality was bad in these sub\|lakes because these dominant species are indicators of eutrophication. According to the Margalef index and Goodnight index, West Lake is still an eutrophic lake. Only the water quality of Xiaonan sub\|lake was improved after water drawn from the Qiantang River was introduced into it.展开更多
The dynamics differential equations are constructed, and the initial conditions are also given. Simulation shows the following conclusions: The water pressure in cylinder has great instantaneous pulsation and phase s...The dynamics differential equations are constructed, and the initial conditions are also given. Simulation shows the following conclusions: The water pressure in cylinder has great instantaneous pulsation and phase step when outlet valve or inlet valve opens, but is more gently in other time; The volume efficiency is influenced by the output pressure slightly, and decreases as the working rotational speed increases; When the inherent frequency of the valves is integer multiple of the working frequency, the volume efficiency of system will decrease evidently.展开更多
As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introd...As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introduces a new design of for steam feeding the water pump of an air-cooled unit using the back-pressure steam turbine as the prime motor. Using variable condition analysis on a 600 MW direct air-cooled unit, and with consideration of the effect on the ambient conditions, the feasibility, economy, and adaptability of the design are verified.展开更多
Large water pump motor,whose operation decides the reliability of the whole production line,plays a very important role.Therefore,its online condition monitoring can help companies better know its operation,process fa...Large water pump motor,whose operation decides the reliability of the whole production line,plays a very important role.Therefore,its online condition monitoring can help companies better know its operation,process fault analysis and protection.The essay mainly studies and designs large water pump motor′s real time vibration monitoring and fault diagnosis system.The essay completes the systems project design,the establishment of the system and performance test.Eddy-currentsensor,XM-120 vibration module,XM-320 axial translation module,XM-362 temperature module,XM-360 process amount module and XM-500 gateway module are used to measure the axial vibration and displacement of main motors.Laboratory tests prove that the system can meet the requirements of motor vibration monitoring.展开更多
Dajingshan, Fenghuangshan and Meixi reservoirs are located in Zhuhai, a coastal city in southern China, and they function to supply drinking water to Zhulaai and Macao. For effectively supplying waster, they are hydro...Dajingshan, Fenghuangshan and Meixi reservoirs are located in Zhuhai, a coastal city in southern China, and they function to supply drinking water to Zhulaai and Macao. For effectively supplying waster, they are hydrologically connected and Dajingshan Reservoir first receives the water pumped from the fiver at Guangchang Pumping Station, and then feeds Fenghuangshan Reservoir, and the two well-connected reservoirs are mesotrophic. Meixi Reservoir is a small and oligotrophic water body and feeds Dajingshan Reservoir only in wet seasons when overflow occurs. Particulate organic matter (POM) was collected from three hydrologically connected water supply reservoirs, and seasonal variations of POM were ascertained from stable carbon and nitrogen isotopes in wet and dry seasons, and the effects of pumping water and reservoir connectivity on POM variations and composition were demonstrated by the relationships of the stable isotope ratios of POM. Seasonality and similarity of stable carbon and nitrogen isotopes of POM varied with hydrodynamics, connectivity and trophic states of the four studied water bodies. The two well- connected reservoirs displayed more similar seasonality for δ13CPOM than those between the fiver station and the two reservoirs. However, the opposite seasonality appeared for δSNPOM between the above waters and indicates different processes affecting the stable carbon and nitrogen isotopes ofPOM. δ13CPOM and δ15NPOM changed little between wet and dry seasons in Meixi Reservoir-a low productive and rain-driven system, suggesting little POM response to environmental changes in that water system. As expected, connectivity enhanced the similarity of the stable isotope ratios of POM between the water bodies.展开更多
A series of experiments on the dynamic performance of the HPWH (heat pump water heater) unit with EXV (electronic expansion valve) under different environmental conditions were conducted. The dynamic heating capac...A series of experiments on the dynamic performance of the HPWH (heat pump water heater) unit with EXV (electronic expansion valve) under different environmental conditions were conducted. The dynamic heating capacity and COP (coefficient of performance) of the HPWH unit under different EXV openings were measured. The effects of the EXV opening on the performance of the HPWH unit were analyzed. Meanwhile, the dynamic performance of the HPWH with EXV was simulated and the results were compared with the experimental one. The experimental results indicate that during heating process, the COP increases firstly and then decreases for a fixed EXV opening, which is in good agreement with the numerical result. For different EXV openings, the COP and heating capacity of the system using larger EXV opening are superior to those using the smaller one in the initial heating stage. While in the late stage, the performance of system using smaller EXV opening is better. It is found that the system performance is improved significantly by changing the EXV opening in the different heating period and the average COP of the HPWH system is increased by 7.6%.展开更多
The demand for water pumping in urban water supply and irrigation in Bangladesh is significantly influenced by electricity deficits and high diesel costs. To address these challenges, the adoption of solar power for w...The demand for water pumping in urban water supply and irrigation in Bangladesh is significantly influenced by electricity deficits and high diesel costs. To address these challenges, the adoption of solar power for water pumping emerges as a viable alternative to traditional systems reliant on grid power and diesel. In recent years, there has been a growing emphasis on clean and renewable energies, aligning with the environmental and economic priorities of Bangladesh. The agricultural sector, serving as the backbone of the country’s economy, witnesses an escalating demand for water as the population increases. The extraction and transfer of water for agricultural and drinking purposes translate to high-energy consumption. Leveraging the abundant and essentially free solar energy, particularly during the crop growth periods when irrigation is crucial, presents an optimal solution. This study underscores the underutilization of this vital resource in Bangladesh and advocates for the widespread implementation of solar energy conversion programs, specifically in photovoltaic pumping systems. By comparing these systems with conventional diesel pumps, this paper aims to inspire policymakers, statesmen, and industry professionals to integrate green energy into the water sector. The envisioned outcome is a strategic shift towards sustainable development, with a focus on harnessing solar power to pump water for villages and agriculture, thus contributing to economic and environmental sustainability.展开更多
文摘The energy efficient product can be operated with longer duration.They offer wonderful solutions compared to other conventional water pumping system as it needs less maintenance,simple in installation,zero fuel cost,longer operating life,highly reliable and free from production of greenhouse gases.In this paper we analyzed the different topologies of DC–DC converter in terms of their operating region of MPPT,quality of input and output currents.We discussed the MPPT algorithms to address partial shading effects in SPV array,present state of the technology,factors affecting the performance of the system,efficiency improvements and identified the research gaps.Also,the economic feasibility analysis has been done for the real time scenario using the Homer Pro software.The estimation of total dynamic head and horse power calculation has been done to decide the total load capacity.The economic analysis results such as cumulative cash flow over project lifetime of 25 years are presented.It is observed that the capital investment requirement is$7,425 for installing Fronius PV system that has a nominal capacity of 2.47 kW and annualized savings will be$134.93.In the long-term perspective,the return on investment is−2.18%as per the present tariff plan.
文摘This paper is about the optimized design and analysis of two solar water pumping systems in which one of the systems is designed with a battery bank and other with a cylindrical water tank for a selected site in Pakistan. The design, sizing, cost analysis and steady state analysis of the proposed systems were done in HOMER and dynamic analysis of the designed system with battery bank was performed in MATLAB/Simulink. The simulations performed in HOMER involved proper mapping of the loads which helped to evaluate the PV panel requirement, inverter rating, batteries (in case of battery based solution), modeling of water tank as a deferrable load (in case of solution based of water tank) and detailed cost analysis for a life time of 25 years. To verify the design of the solar water pumping system with battery bank, a simulation in MATLAB/Simulink for study of dynamic behavior of the overall system was performed which involved mathematical modeling of a PV panel, buckboost converter, inverter, battery bank and motor/pump, a perturb and observe maximum power point tracking algorithm based control system. Analysis was conducted based on the economic results that indicate designed solar water pumping system with water tank would be a cheaper solution as compared to solar water pumping system with a battery bank. This work can be taken as a case study for the understanding and optimized designs of solar water pumping system with battery bank and with cylindrical tank in Pakistani conditions.
文摘Many papers exploiting the various MPPT (maximum power point tracking) techniques in PV (photovoltaic) applications, from the simple to the most complicated, can be found in literature. However, these techniques may not always be easy to implement in industrial applications. The main challenge of this paper is to model and implement the P & O (perturb and observe) algorithm in a low-cost PV-powered pumping system. To that end, a comparative investigation of the performance characteristics of the most popular MPPT methods, such as FOCV (fractional open circuit voltage), FSCC (fractional short circuit current), FLC (fuzzy logic control), ANN (artificial neural network) and INC (incremental conductance) is presented. This analysis is helpful to highlight the relevance of the P & O technique taking better account of complexity, difficulty of implementation and cost considerations in water pumping applications. The targeted PV-powered pumping system is based on a single-phase induction motor supplied by a three-phase inverter controlled by the DTC (direct torque control) technique. This stand-alone PV system is dedicated to water pumping, especially in rural areas that have no access to national grids but have sufficient amount of solar radiation. Simulation modeling (Matlab/Simulink) and experimental results are presented to demonstrate the relevance of the system.
文摘This paper investigates the operation and analysis of the photovoltaic water pumping system in detail. Power electronic controllers were designed and developed for the water pumping system using a boost converter along with an inverter followed by an induction motor pump set. The proposed system could be employed in agricultural irrigation under any operating condition of varying natures of solar irradiances and temperatures. The configuration and implementation of the system were described in detail. Further, the detailed method of analysis and simulation characteristics of such PV water pumping system was also presented. With the concern of shortage of fossil fuel, global warming and energy security, the proposed PV based water pumping significant demand of electricity agricultural sector. system can meet the and serve for the
基金This work was supported by the National Natural Science Foundation of China (Grant No. 51106110).
文摘Based on energy conservation equation and Darcy's law, a model of beach well infiltration intake system applied in a seawater source heat pump system was established. The model consists of the seawater seepage and the heat transfer process. A porous medium model in a software named FLUENT was applied to simulate the seepage and the heat transfer process. This model was also validated by field experiment conducted on the seashore in Tianjin, China. The maximum relative error between simulation results and experimental results was 2.1% (less than 5%), which was acceptable in engineering applica- tion. The porosity and coefficient of thermal conductivity of the aquifer soil were determined to be 0.49 W/(m. K) and 1.46W/(m.K), respectively in the simulation. In addition, the influencing factors of pumping water of beach well were also analyzed. The pumping water was found to increase when the distance between the beach well and the impervious boundary becomes longer, when the distance between the beach well and the supplying water source shortens, when the diameter of the beach well enlarges, and the drawdown enlarges.
文摘In the present work,an assessment of the rural water supply potential by mechanical wind pumping around the floodplains of Lake Chad has been considered.Inside the floodplains around Lake Chad,available surface water is largely contaminated and represents health hazards to populations.Access to underground and clean water has increasingly become rare.Moreover,clean water scarcity has led to conflict and territorial pressures,which are contributing factors to poverty in the considered area.Four localities,Baga,Baga-Sola,Makari and Nguigmi,respectively,in Nigeria,Chad,Cameroon and Niger have been selected inside the floodplains around Lake Chad,to evaluate the potential of wind power and prospects of windmills development to provide safe drinking-water supply,livestock watering and small-scale irrigation.Long-term satellite-derived data,obtained through the Prediction of Worldwide renewable Energy Resources have been considered suitable and viable alternative to missing site-specific data from ground stations.Windmill of Multi-blade driven piston pump is the preferred water pumping option for this study because of its higher overall system efficiency.The results of this study indicate that mean wind speeds,at 10 m height above ground level,are 4.64 m/s for Baga,4.76 m/s for Baga-Sola,4.32 m/s for Makari and 4.44 m/s for Nguigmi.In addition,wind speeds for Baga,for instance,are in the range of 2.5–10 m(working range of a wind pump),at 10,15,20 and 25 m height agl,for 79.64,82.80,84.79,and 86.19 per cent of the time.Corresponding values for Baga-Sola,Makari and Nguigmi are in the range of 80.50–87.76 per cent,76.86–85,58 per cent,77.92–86.21 per cent,respectively.For a Windmill with a 2 m-blade,a 25 m-height tower and considering a total dynamic head of 30 m,average monthly discharges for the dry season are 1,330,1,374,1,200 and 1,199 m3,respectively for Baga,Baga-Sola,Makari and Nguigmi.Furthermore,corresponding costs of water are 9.53,9.23,10.56 and 10.57 XAF/m3,for Baga,Baga-Sola,Makari and Nguigmi,in that order.
基金This work is supported by the Qing Lan Project of the Higher Education Institutions of Jiangsu Province,the 2022 Jiangsu Science and Technology Plan Special Fund(International Science and Technology Cooperation)(BZ2022029).
文摘For surface defects in electronic water pump shells,the manual detection efficiency is low,prone to misdetection and leak detection,and encounters problems,such as uncertainty.To improve the speed and accuracy of surface defect detection,a lightweight detection method based on an improved YOLOv5s method is proposed to replace the traditional manual detection methods.In this method,the MobileNetV3 module replaces the backbone network of YOLOv5s,depth-separable convolution is introduced,the parameters and calculations are reduced,and CIoU_Loss is used as the loss function of the boundary box regression to improve its detection accuracy.A dataset of electronic pump shell defects is established,and the performance of the improved method is evaluated by comparing it with that of the original method.The results show that the parameters and FLOPs are reduced by 49.83%and 61.59%,respectively,compared with the original YOLOv5s model,and the detection accuracy is improved by 1.74%,which is an indication of the superiority of the improved method.To further verify the universality of the improved method,it is compared with the results using the original method on the PASCALVOC2007 dataset,which verifies that it yields better performance.In summary,the improved lightweight method can be used for the real-time detection of electronic water pump shell defects.
基金The National Natural Science Foundation of China(No.50676059)
文摘To evaluate the performance of heat pumps using refrigerant HFC125,an experimental rig of a DC-inverter heat pump water heater is designed and set up,and the research on the transcritical heat pump water heater is carried out experimentally.It is found that there is a top value of the coefficient of performance(COP)when the system runs at 95 Hz of frequency.The relationships between the COP and compressor frequency,condensation pressure,evaporation pressure,condensation water temperature rise,and discharge temperature are discussed and analyzed at 95 Hz.And the COP of the HFC125 transcritical cycle is also compared with that of a R410 subcritical heat pump under the same conditions.The results indicate that there exists an optimum frequency for a better COP,and the system COP shows an increasing tendency with the decrease in condensation pressure and compressor ratio while the evaporation pressure remains invariant,and the COP decreases rapidly when cooling water temperature rises over 47.5 ℃.Compared with the R410A sub-critical cycle,the COP of HFC125 transcritical cycle significantly increases by 12% on average.
文摘Jordan has,</span><span style="font-family:""> </span><span style="font-family:"">to a satisfactory degree,</span><span style="font-family:""> </span><span style="font-family:"">managed its scarce water resources, especially during the last few decades due to the regional conflicts and refugee waves hosted in the country since 1948.</span><span style="font-family:""> </span><span style="font-family:"">The waves of refugees in 1967, and after), returnees from the Gulf States 1991/92, during the first Gulf war), Lebanon (1970s and 1980s), Iraq (2003 and after, and lastly Syria (2011-2017 have</span><span style="font-family:""> </span><span style="font-family:"">as well</span><span style="font-family:""> </span><span style="font-family:"">severely impacted the management of water resources which has negatively impacted the water sector especially in terms of allocating new water resources to satisfy the needs of the country. In addition, shortsightedness of some water policy-makers has led to the deteriorations in the water resources quantitatively and qualitatively, which has resulted in social and economic discomfort of the population. In this article, the shortcomings in the water sector are addressed, such as setting an end to groundwater overexploitation, providing water to the population in a continuous way, improving water use efficiency in agricultural uses and the way forward is</span><span style="font-family:""> </span><span style="font-family:"">delineated</span><span style="font-family:""> </span><span style="font-family:"">based on a critical judgment of the actual situation of the water sector in order to reach at a more robust water sector with all its</span><span style="font-family:""> </span><span style="font-family:"">positive impacts on the social, economic and political life in the country.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11005093 and 61274099)the Research Fund of Education Department of Zhejiang Province,China(Grant No.Y201223336)+2 种基金the Zhejiang Provincial Science and Technology Key Innovation Team,China(Grant No.2011R50012)the Key Laboratory of Zhejiang Province,China(Grant No.2013E10022)the Hong Kong Polytechnic University,China(Grant No.G-YL41)
文摘A novel nanoscale watermill for the unidirectional transport of water molecules through a curved single-walled carbon nanotube(SWNT) is proposed and explored by molecular dynamics simulations. In this nanoscale system, a revolving charge is introduced to drive a water chain confined inside the SWNT, the charge and the tube together serving as a nano waterwheel and nano engine. A resonance-like phenomenon is found, and the revolving frequency of the charge plays a key role in pumping the water chain. The water flux across the SWNT increases with respect to the revolving frequency of the external charge and it reaches its maximum when the frequency is 4 THz. Correspondingly, the number of hydrogen bonds in the water chain inside the SWNT decreases dramatically as the frequency increases from 4 THz to 25 THz. The mechanism behind the resonance phenomenon has been investigated systematically. Our findings are helpful for the design of nanoscale fluidic devices and energy converters.
基金supported by National Natural Science Foundation of China (Grant No. 50575107)
文摘Intenal combustion pump (ICP) is a new type power device turning the thermal energy from fuel combustion into fluid pressure energy. Three cylinders prototype has just been developed. The study on the influence of valve's characteristic on ICP's total performance will found the base for its optimum design. Based on the theoretical and testing fruits of single cylinder prototype, the performance of the valves and complete appliance of the latest is simulated. When the natural frequency of valves is approximately to the round number times of the working frequency, volumetric efficiency is seriously low. The nominal rotational speed of the prototype is nearly to the speed where the volumetric efficiency is lowest, which is harmful to the normal work of ICP, so further structure optimization of valves should be carried out. The change of volumetric efficiency has great influence on the fuel consumption rate, output flow, effective thermal efficiency, effective power, and so on, but little on output pressure.
基金Project supported by the Priority Academic Development Program of Jiangsu Higher Education Institutions, ChinaProject(CXZZ12_0680) supported by Postgraduate Innovation Foundation of Jiangsu Province, ChinaProject(12JDG082) supported by the Advanced Talent Foundation of Jiangsu University, China
文摘In order to investigate the effect of sampling frequency and time on pressure fluctuations, the three-dimensional unsteady numerical simulations were conducted in a circulating water pump. Through comparison of turbulence models with hydraulic performance experiment, SST k-co model was confirmed to study the rational determination of sampling frequency and time better. The Fast Fourier Transform (FFT) technology was then adopted to process those fluctuating pressure signals obtained. On these bases, the characteristics of pressure fluctuations acting on the tongue were discussed. It is found that aliasing errors decrease at higher sampling frequency of 17 640 Hz, but not at a lower sampling frequency of 1 764 Hz. Correspondingly, an output frequency range ten-times wider is obtained at 17 640 Hz. Compared with 8R, when the sampling time is shorter, the amplitudes may be overvalued, and the frequencies and amplitudes of low-frequency fluctuations can not be well predicted. The frequencies at the tongue are in good agreement with the values calculated by formula and the frequency compositions less than the blade passing frequency are accurately predicted.
文摘During Jan.1995 to Dec.1996, monthly investigations on the zoobenthic communities of West Lake, samples were collected from six sampling stations. A total of 26 species of macrozoobenthos were identified. The seasonal changes in density and biomass of zoobenthos in this lake were analyzed. The annual mean densities were 980~2751 ind/m\+2 and mean biomass was 19.69-122.80 g/m\+2. The densities in winter and early spring were higher than those in summer and autumn. Comparative study of theprevious data (1982 to 1983) collected by the authors, showed that the succession of zoobenthic communities, dominated by \%Procludius choreus\% in density and \%Bellamya purificata\% in biomass, had been occurred in Xiaonan sub\|lake after Qiantang River water was drawn into it; and that the species and biomass of zoobenthos were then increased and the density was decreased. In other sub\|lakes, the dominant species were \%Limnodrilus hoffmeisteri\% and \%Tokunagayusurika akamusi \%in density and \%Branchiura sowerbyi\% and \%Tokunagayusurika akamusi \%in biomass. The water quality was bad in these sub\|lakes because these dominant species are indicators of eutrophication. According to the Margalef index and Goodnight index, West Lake is still an eutrophic lake. Only the water quality of Xiaonan sub\|lake was improved after water drawn from the Qiantang River was introduced into it.
基金This project is supported by National Natural Science Foundation of China(No.10342003).
文摘The dynamics differential equations are constructed, and the initial conditions are also given. Simulation shows the following conclusions: The water pressure in cylinder has great instantaneous pulsation and phase step when outlet valve or inlet valve opens, but is more gently in other time; The volume efficiency is influenced by the output pressure slightly, and decreases as the working rotational speed increases; When the inherent frequency of the valves is integer multiple of the working frequency, the volume efficiency of system will decrease evidently.
文摘As the performance of an air-cooled condenser is apt to be affected by the fluctuating ambient condition, some difficulties are brought to the use of a steam feeding water pump in an air-cooled unit. This paper introduces a new design of for steam feeding the water pump of an air-cooled unit using the back-pressure steam turbine as the prime motor. Using variable condition analysis on a 600 MW direct air-cooled unit, and with consideration of the effect on the ambient conditions, the feasibility, economy, and adaptability of the design are verified.
文摘Large water pump motor,whose operation decides the reliability of the whole production line,plays a very important role.Therefore,its online condition monitoring can help companies better know its operation,process fault analysis and protection.The essay mainly studies and designs large water pump motor′s real time vibration monitoring and fault diagnosis system.The essay completes the systems project design,the establishment of the system and performance test.Eddy-currentsensor,XM-120 vibration module,XM-320 axial translation module,XM-362 temperature module,XM-360 process amount module and XM-500 gateway module are used to measure the axial vibration and displacement of main motors.Laboratory tests prove that the system can meet the requirements of motor vibration monitoring.
基金Supported by the National Natural Science Foundation of China(No.31170436)the Science and Technology Project of Guangdong Province(No.2013B080500022)
文摘Dajingshan, Fenghuangshan and Meixi reservoirs are located in Zhuhai, a coastal city in southern China, and they function to supply drinking water to Zhulaai and Macao. For effectively supplying waster, they are hydrologically connected and Dajingshan Reservoir first receives the water pumped from the fiver at Guangchang Pumping Station, and then feeds Fenghuangshan Reservoir, and the two well-connected reservoirs are mesotrophic. Meixi Reservoir is a small and oligotrophic water body and feeds Dajingshan Reservoir only in wet seasons when overflow occurs. Particulate organic matter (POM) was collected from three hydrologically connected water supply reservoirs, and seasonal variations of POM were ascertained from stable carbon and nitrogen isotopes in wet and dry seasons, and the effects of pumping water and reservoir connectivity on POM variations and composition were demonstrated by the relationships of the stable isotope ratios of POM. Seasonality and similarity of stable carbon and nitrogen isotopes of POM varied with hydrodynamics, connectivity and trophic states of the four studied water bodies. The two well- connected reservoirs displayed more similar seasonality for δ13CPOM than those between the fiver station and the two reservoirs. However, the opposite seasonality appeared for δSNPOM between the above waters and indicates different processes affecting the stable carbon and nitrogen isotopes ofPOM. δ13CPOM and δ15NPOM changed little between wet and dry seasons in Meixi Reservoir-a low productive and rain-driven system, suggesting little POM response to environmental changes in that water system. As expected, connectivity enhanced the similarity of the stable isotope ratios of POM between the water bodies.
文摘A series of experiments on the dynamic performance of the HPWH (heat pump water heater) unit with EXV (electronic expansion valve) under different environmental conditions were conducted. The dynamic heating capacity and COP (coefficient of performance) of the HPWH unit under different EXV openings were measured. The effects of the EXV opening on the performance of the HPWH unit were analyzed. Meanwhile, the dynamic performance of the HPWH with EXV was simulated and the results were compared with the experimental one. The experimental results indicate that during heating process, the COP increases firstly and then decreases for a fixed EXV opening, which is in good agreement with the numerical result. For different EXV openings, the COP and heating capacity of the system using larger EXV opening are superior to those using the smaller one in the initial heating stage. While in the late stage, the performance of system using smaller EXV opening is better. It is found that the system performance is improved significantly by changing the EXV opening in the different heating period and the average COP of the HPWH system is increased by 7.6%.
文摘The demand for water pumping in urban water supply and irrigation in Bangladesh is significantly influenced by electricity deficits and high diesel costs. To address these challenges, the adoption of solar power for water pumping emerges as a viable alternative to traditional systems reliant on grid power and diesel. In recent years, there has been a growing emphasis on clean and renewable energies, aligning with the environmental and economic priorities of Bangladesh. The agricultural sector, serving as the backbone of the country’s economy, witnesses an escalating demand for water as the population increases. The extraction and transfer of water for agricultural and drinking purposes translate to high-energy consumption. Leveraging the abundant and essentially free solar energy, particularly during the crop growth periods when irrigation is crucial, presents an optimal solution. This study underscores the underutilization of this vital resource in Bangladesh and advocates for the widespread implementation of solar energy conversion programs, specifically in photovoltaic pumping systems. By comparing these systems with conventional diesel pumps, this paper aims to inspire policymakers, statesmen, and industry professionals to integrate green energy into the water sector. The envisioned outcome is a strategic shift towards sustainable development, with a focus on harnessing solar power to pump water for villages and agriculture, thus contributing to economic and environmental sustainability.