Pump Efficiency Research Articles

Numerical computations on thermal performance of large-scale Ti-Mn-based metal hydride storage reactor via open source CFD software

Certain metals and metal alloys can absorb hydrogen through an exothermic chemical reaction, resulting in the formation of metal hydrides. To maintain a rapid charging rate, the produced heat must be extracted as rapidly as it is generated. This study was attempted to evaluate the heat transfer enhancement in a cylindrical hydrogen storage reactor equipped with a central tube for large-scale applications using a 3D transient model. Finite-volume simulations are carried out using the open-source software package OpenFOAM to systematically investigate the impacts of material thermophysical properties, cooling media, and heat exchanger design on the heat transfer behaviors and hydrogen storage rate. The reactor’s performance was evaluated in terms of temperature and total hydrogen mass history profiles, in addition to pressure drop. The findings indicated that the charging time was improved by roughly 86%, compared to the case without thermal enhancement to attain 90% hydrogen storage capacity. A diminished pressure drop was observed between the water-based Al2O3 nanofluid with 5 vol% concentration and pure water at lowered coolant flow velocities, hence enhancing pumping power efficiency. Moreover, the results demonstrated that the storage rate is markedly improved by enhancing the effective thermal conductivity of the hydride bed, increasing the heat exchange area, accelerating the coolant flow rate, and lowering its temperature. The outcomes highlighted the possibility of advancing the current metal hydride reactor for practical application.

Determination of Experimental Characteristics of a Jet-vortex Pump

A methodology has been developed and the results of experimental studies of high-pressure jet-vortex pump models with a mixing chamber and working nozzle area ratio of 3.429 and 3.795 have been obtained. In the flow part of the pump, inclined guide elements for swirling the mixed flows are installed. An increase in the velocity of swirling screw jets increases the level of turbulence, intensifies the energy exchange of the mixed media, and improves the conditions for transferring kinetic energy from the working flow to the injected one. Improvement of the flow mixing mechanism allows increasing the energy efficiency of jet pumps. The velocity of swirling screw jets is determined by the angle of inclination of the guide elements and the flow rate of the mixed flows. The efficiency of simultaneous swirling of the mixed media may be less than the efficiency of swirling a separate flow if there is a difference in the directions of the velocity vectors of the swirling jets. There has been obtained the dependence of the injection coefficient on the Reynolds number of the working flow, pressure and energy characteristics for a straight-through jet pump for the case of swirling of the exclusively injected flow and simultaneous swirling of the working and injected flows. According to the results of the conducted studies, an increase in the injection coefficient, relative pressure and efficiency caused by swirling of the mixed flows was established by 26.34%, 19.43% and 23.75%, respectively.

Modeling of a solid-state laser module with pulse transverse diode pumping of Nd<sup>3+</SUP>:YAG active medium

In this work, a laser module (quantron) with transverse pulse diode pumping of a cylindrical Nd3+:YAG active element by the method of non-sequential ray tracing in the Zemax software environment is modeled. Numerically obtained distributions of the absorbed pump radiation power over the cross section of the active element and calculated the pumping efficiency of the quantron. A methodology for optimizing the quantron design is proposed, which results in an increase in the pumping efficiency of the active element.

Optimized impeller hydraulic performance of submersible drainage pumps: An experimental study

Optimizing the hydraulic efficiency of submersible drainage pumps (SDPs) is crucial for energy conservation and performance enhancement, especially in emergency applications. Therefore, this study aims to develop an energy-efficient SDP by designing an optimized impeller model using a numerical scheme and introducing a flow balance block (FBB) as an alternative to modifying the pump casing, thereby reducing internal space and improving performance. Experimental validation of the optimized impeller and FBB was conducted by comparing their performance with the original pump model. The results demonstrated that the optimized impeller increased efficiency by 3.35% at a flow rate of 0.195 m3/min, with an overall average efficiency improvement of 2.33%. Additionally, when the optimized impeller and FBB were combined, the pump's efficiency was further enhanced by 5%, and the flow rate increased by approximately 10%. The study also proposed that the tap bolt method is more effective for installing the FBB than the silicone attaching method. This research provides a comprehensive experimental approach to improving SDP efficiency and offers valuable insights for future pump optimization.

The performance analysis of a compressed air energy storage (CAES) for peak moving with cooling, Heating, and power production

This study focuses on modeling and optimizing a multifaceted geothermal-based energy production system within the context of Denmark. The primary objectives revolve around enhancing system efficiency and reducing operational costs. The system under investigation comprises geothermal components, an organic Rankine cycle, a compressed air energy storage facility, and an absorption chiller. The organic Rankine cycle operates using refrigerants R123 and ammonia, effectively converting thermal energy into electricity and thermal energy for various applications. Optimization was carried out employing the Response Surface Method in tandem with Design-Expert software, facilitating the fine-tuning of objective functions. Two key objectives were selected: Exergy Round Trip Efficiency and cost rate, aimed at improving technical performance and curbing economic expenditure. A range of design variables were considered for optimization, including turbine and pump inlet temperatures, geothermal mass flow rate, turbine and pump efficiencies, compressor and gas turbine efficiency, inlet pressure to the compressed air energy storage tank, and evaporator pinch point temperature. The system reached an impressive exergy efficiency peak of 77.98%, accompanied by a modest cost rate of 5.48 $/h. The costliest components in the system were the compressed air energy storage unit, followed closely by organic Rankine cycle 1 and organic Rankine cycle 2. In contemplating the practical implementation of this innovative energy system, ten cities in Denmark underwent rigorous analysis, accounting for technical and economic factors. Subsequent assessments identified Aarhus as the optimal location to initiate the system. The environmental results showed that by producing 13981.9 megawatts of electricity annually in Arhus City, it is possible to help reduce CO2 emissions by 2853.2 tons of CO2/year and avoid environmental costs of 68455.3 $/year. The environmental assessment also highlighted the potential for substantial green space expansion, estimating an additional 13 hectares of green areas in the city of Aarhus, Denmark.

Topological pumping in an inhomogeneous Aubry-André model

The Aubry-André model is a fundamental theoretical model that exhibits interesting topological features. In this paper, we examine topologically protected boundary states in the inhomogeneous off-diagonal Aubry-André model. In contrast to the homogeneous case, the inhomogeneity triggers boundary states at phase boundaries that separate two distinct non-trivial topological domains. Remarkably, the topological character of the boundary states is predicted through topological pumping, where a boundary state is transferred from one boundary across the bulk region to the other by adiabatically tuning the pump parameter. Moreover, the role of the off-diagonal modulation strength (λ) on the transfer efficiency of the topological pumping is addressed. To support our results, we investigate the time evolution of a continuous-time quantum walk and show that its spread rate and λ are inversely related. Our work provides a new avenue to harness topological features of the Aubry-André model, where topological pumping can be used for robust quantum transport.

Comparative experimental study on the thermal and hydraulic performances of capillary box heat exchanger and helical coil heat exchanger for surface water-source heat pump

The thermal and hydraulic performances of front-end heat exchangers significantly influence the energy efficiency of surface water-source heat pumps. To evaluate the performance of a capillary box heat exchanger (CBHE), a comparative study between the CBHE and a conventional helical coil heat exchanger (HCHE) was conducted under different tube velocities, heat transfer media, and temperatures. The comparison considered not only traditional metrics, such as the heat transfer coefficient, heat transfer efficiency, and pressure drop, but also the volume heat transfer coefficient and two thermal-hydraulic comprehensive performance parameters: the modified Colburn–Fanning factor ratio (JFK) with larger-the-better characteristics and the electricity consumption to extracted or rejected heat quantity ratio (EHR) with smaller-the-better characteristics. The results indicated that the heat transfer coefficient, heat transfer efficiency, and volume heat transfer coefficient of the CBHE were 10.1 W/(m2.°C)–25.58 W/(m2.°C), 34 %–45 %, and 1140 W/(m3.°C)–1416 W/(m3.°C) larger than those of the HCHE, whereas its total pressure drop was only 15 %–21 % of that of the HCHE. Additionally, the JFK and EHR of the CBHE were approximately three times and 11 %–16 %, respectively, those of the HCHE. This study serves as a reference for selecting and designing front-end heat exchangers.

Performance characteristics of rotary lobe pumps for high viscosity food medium

Abstract This paper analyses the effects of food media with high viscosity on the performance of rotary lobe pumps. Rotary lobe pumps have long been used in the food industry for pumping highly viscous media and are designed to operate for long periods of time without replacement of any parts. The study utilised publicly available data from factory tests of the PLP 3-4 pump for pumping food media of various viscosities μ (μ above 10,000 cP). The paper presents the results of processing these data, which allow us to draw some conclusions. It is established that the power input of the pump PLP 3-4, due to the viscosity of the food medium, is directly proportional to the rotor speed and increases with its increase. Thus the power spent on overcoming back pressure depends on rotor speed nonlinearly. At the same rotor speed the increase in pressure drop and dynamic viscosity coefficient do not affect the productivity, but lead to a significant increase in power consumption. The obtained results allow to draw a conclusion that it is not necessary to connect the increase of hydraulic efficiency of rotary lobe pump with improvement of energy efficiency of unit utilisation and to take into account the reason of increase of discharge pressure.

Combined Rotor Rack Generation for Twin Screw Vacuum Pump Rotor Profile Design

Abstract Rotor profile design is a critical factor influencing the efficiency and functionality of twin screw vacuum pumps. This paper delves into a specific aspect of rotor profile design using the rack generation method. The paper utilises an algorithm of rack generation tailored specifically to twin screw vacuum pump applications. The utilization of straight lines to form the rack ensures the generation of involute profiles on the rotors. Additionally, rack-generated rotors are typically easier to manufacture. Geometrical parameters, such as displacement and meshing line length across three rack generated rotor profiles are explored. Furthermore, chamber modelling is employed for the development of rotor profiles, augmenting the efficacy and reliability of the rack generation process. By focusing on rack generation, this paper offers valuable insights into rotor profile design, contributing to a deeper understanding of the methodologies driving innovation in twin screw vacuum pump technology.

Investigations to reduce rarefied gap flows within positive displacement vacuum pumps by utilising surface structures

Abstract The ultimate pressure and efficiency of positive displacement vacuum pumps is limited by the backflow through the gaps within the machines. These gap flows are typically reduced by decreasing the gap height, which is limited for reasons of operational safety. Therefore, this study concentrates on the reduction of rarefied gap flows by means of suitable surface structures whose dimensions are small compared to the gap height without simultaneously reducing the minimum gap height. For this purpose, a method is presented to efficiently calculate the impact of the surface structure on these gap flows. Based on this method, design parameters for the choice of a suitable surface structure are discussed. Furthermore, a possible transfer for the application on the rotors is shown including a proposal for the machining process.

Enhancing Seasonal Performance of Heat Pumps integrated into Building Ventilation Systems using a Multi-Stage Volume Enlarger: a Comparative Study across European Regions

The buildings sector is one of the largest energy consumers in the EU, accounting for approximately 40% of final energy consumption and around 36% of greenhouse gas emissions. European governments are implementing various measures to reduce these figures. One effective approach to lowering energy consumption is to enhance the energy efficiency of HVAC systems in buildings. Extending the control range of heat pumps can significantly improve their seasonal energy efficiency, thereby reducing carbon dioxide emissions and enhancing building sustainability. Modern heat pump capacity control commonly involves a variable-speed compressor and an electronic expansion valve. In this study, the authors introduce an additional control component—variable volume in the active loop of the heat pump.The paper evaluates the performance of a variable-volume heat pump integrated into a ventilation system across different European regions (Vilnius, Helsinki, and Milan). A comparison is made between the conventional control approach, which uses a compressor and expansion valve, and an enhanced control method that incorporates an additional device to regulate the heat pump circuit volume. Based on data from prior experiments—specifically, the dependencies of the heat pump heat output and efficiency on compressor speed, expansion valve position, and circuit volume—a control algorithm was developed with Matlab to simulate heat pump performance in a ventilation system over a typical meteorological year for each city.Key findings highlight that the use of additional volume control in the heat pump loop significantly extends the unit’s operational time compared to conventional control methods. Specifically, operational time increased from several percent to as much as 69.97% across the regions analysed, positively impacting seasonal performance. These results underscore the critical importance of optimizing heat pump control strategies, as they not only enhance energy efficiency but also contribute to reducing reliance on auxiliary heating and lowering overall carbon emissions. Furthermore, despite these advantages, the study notes a significant limitation: the current lack of commercially available tools for implementing dynamic volume adjustment in heat pumps, which presents challenges for practical application in the field.

Heat sink temperature modeling for reservoir source heat pumps with experimental validation

Heat-pump systems utilizing renewable resources can significantly enhance the energy efficiency of building air conditioning. This study focuses on a system that uses reservoir water as a renewable resource and develops a macroscopic numerical model to simulate heat sink temperatures, which critically influence the energy efficiency of heat pumps. Experiments were conducted to gather essential data for constructing this model. Heat was released, simulating the exhaust heat from a heat pump, from the bottom of an experimental tank filled with water. Initially, the water was thermally stratified, with the lower half at 15 °C and the upper half at 25 °C, mimicking summer conditions. The experimental results indicated that the heat release caused temperature increases exclusively in the lower layer, elevating the boundary between the layers by 0.2–0.4 m over 5 h. Consequently, we developed a heat sink temperature model by simulating the plume and entrainment of ambient water to replicate this phenomenon. The model accurately represented the increase in the boundary height across different scenarios, demonstrating a high level of agreement between the simulated heat sink temperature and the experimental values, with a deviation of <0.8 K.

A study on the combination of crystallization-controllable phase change materials and solar-assisted heat pump for electricity demand shifting in space heating

Supercooled phase change materials offer a promising solution for space heating due to their ability to release latent heat upon crystallization initiation, even when stored at ambient temperatures. This unique property makes them ideal for solar-assisted space heating, where external activation enables on-demand heat release, addressing the critical need for energy-efficient heating solutions. In this study, a system promoting demand shifting is proposed, aiming to transfer energy consumption from morning and evening peak periods to daytime and high solar irradiance days, thereby enhancing the efficiency of solar heat pumps and reducing grid stress through the use of supercooled crystallization-controllable phase change materials. A model was developed, consisting of evacuated tube collectors, a buffer tank, heat storage tanks with crystallization-controllable phase change material, and a building heating demand model. The study introduces a novel system control methodology, focusing on an effective operation of tank shifting based on the heating requirement and solar energy availability. Real weather data were used to calculate system performance. With 50 m2 of collectors, a 1000-liter buffer tank, and a heat pump with a maximum output of 7 kW, the heat storage tanks are charged and discharged following the developed operational methodology. The system achieved a weekly coefficient of performance of 3.56 and successfully shifted electricity demand to solar hours, with only 28.5% of the total consumption occurring during domestic morning and evening peak times.

Studying the Impact of Diffuser Return Guide Vanes on the Energy Performance of a Multistage Centrifugal Pump

The head, efficiency, and cavitation characteristics of centrifugal pumps are highly dependent on the velocity field in front of the impeller inlet. In multistage pumps, the velocity field in front of the second and each subsequent stage is determined by the shape (design) of the diffuser return guide vanes. This current work presents the results obtained by performing a numerical study using ANSYS CFX 14.0 to determine the impact of the shape (design) of diffuser return guide vanes on the head and coefficient of efficiency of one stage of a multistage centrifugal pump. Three RGVs with different Outlet angles are studied: α6 —original RGV with α6=90 deg, RGV1 with α6=110 deg and RGV2 with α6=128 deg. The results obtained after performing CFD modeling indicate that with one of the studied RGVs, the pump stage head increases by nearly 20%, while the hydraulic coefficient of efficiency remains almost constant. Applying entropy production theory is used to determine the impact of the various components of entropy production on the total head loss in the studied pump stage. The impact of the Outlet angle of the RGV on the velocity field of the flow in front of the next impeller (stage) as well as the RGV head is also analyzed. The numerical results of the original RGV are compared with the experimental data obtained from large-scale studies of pumps performed at the Laboratory of Hydraulic Machines of the University “Angel Kanchev” of Ruse, Bulgaria. When using the modified RGVs, the head curve of the original pump can be obtained by operating at a lower speed or with a smaller impeller diameter. This may lead to an overall increase in the energy efficiency of the machine, which could be explored as a future task.

ANALISIS EFISIENSI POMPA SENTRIFUGAL PADA DESALINASI DENGAN PROSES REVERSE OSMOSIS

This study provides information for the desalination industry in an effort to improve the performance and efficiency of desalination systems using the reverse osmosis method. By paying attention to the factors that influence the efficiency of centrifugal pumps, the provision of clean water in areas experiencing a water crisis will be better. Reverse Osmosis (RO) is a system in desalination technology that is often used to replenish fresh water supplies. RO performance depends on the quality of sea water as the raw water source. RO works by utilizing osmotic pressure. Hydrostatic pressure which is greater than osmotic pressure is used to reverse the flow, thereby producing fresh water. RO utilizes a high-pressure pump process to flow seawater through a membrane polymer structure. In RO there is a main membrane module configuration which has two functions, namely supporting the performance of the RO membrane and providing efficient fluid management. The desalination system used at PT Perusahaan Air Indonesia America (PAIA) still uses centrifugal pumps and can produce a production capacity of 600-700 m3/day, and is still in the system upgrade stage. From the calculations that have been carried out, the pump efficiency value is 59.16%.

Volumetric efficiency in motor-driven two-dimensional piston pumps with leakage and reverse flow under high pressure

This paper presents a volumetric efficiency model for high-pressure motor-driven 2D piston pumps, incorporating key factors such as axial internal and external leakage, circumferential leakage, and reverse flow. The model integrates hydraulic fluid compressibility and variations in flow coefficients to improve simulation accuracy. Co-simulation using AMESim and Simulink, along with experimental validation, demonstrates the model’s reliability across various operating conditions. The results show that rotational speed enhances volumetric efficiency due to its minimal effect on leakage and reverse flow, while pressure significantly reduces efficiency, particularly through reverse flow and circumferential leakage. Reducing trapped volume proves to be an effective strategy for minimizing reverse flow and improving overall pump performance. Additionally, refining flow coefficients to improve the accuracy of the simulation model remains an important area for further development.

Efficiency Analysis (Debit &amp; Head Losses) of Centrifugal Pumps at PDAM Tirta Terubuk Bengkalis

A pump is a device used to raise liquid from a lower position to a higher position. This study analyzes the efficiency of the centrifugal pump used in the air supply system at the Tirta Terukalis Bengkalis Water Supply Company (PDAM). The main focus of the analysis is on the parameters of water discharge, head losses, and centrifugal pump efficiency. This analysis was carried out at PDAM Tirta Terubuk Bengkalis. The data used in this study include the results of an airflow rate of 0.0073 m3/s, a pressure loss of 11 m, and a pump efficiency of 73%. The results of the study revealed that the water discharge was 0.0073 m3/s and the loss stress was 11 m, the pump efficiency reached 73%. This study provides insight into the performance of centrifugal pumps in certain situations in PDAM Bengkalis.

Quantitative MODS-Wayne assay for rapid detection of pyrazinamide resistance in Mycobacterium tuberculosis from sputum samples.

PZA susceptibility testing continues to be a challenge, particularly in countries with high TB incidence. In response to this pressing need, we have developed a quantitative MODS-Wayne (MODS-WQ) assay. This approach offers a direct and cost-effective solution representing a significant advancement in TB diagnostics, particularly benefiting resource-limited laboratories, primarily in developing regions. The MODS-WQ assay stands out for its ability to quantify pyrazinoic acid (POA) production, as a reliable indicator of PZA resistance. Unlike traditional qualitative assays, MODS-WQ eliminates the inherent subjectivity in interpretation, providing more accurate and actionable results. Moreover, the MODS-WQ approach accounts for critical factors influencing PZA resistance, including enzymatic efficiency and efflux pump activity. By integrating these factors into the detection process, our methodology offers a comprehensive understanding of PZA resistance levels, enabling tailored treatment strategies for patients.

Optimization of submersible LNG centrifugal pump blades design based on support vector regression and the non-dominated sorting genetic algorithm Ⅱ

Optimizing the impeller blade design of submersible LNG centrifugal pump significantly enhances mechanical efficiency, reducing energy consumption and carbon emissions during LNG storage and transportation. This study focuses on optimizing blades of the centrifugal pump, combining Bezier blade design, CFD simulations, optimal Latin Hypercube sampling, Support Vector Regression (SVR), and Non-Dominated Sorting Genetic Algorithm II(NSGA-II) multi-objective optimization into a systematic method. During the development of this optimization method, it was found that directly applying sampled CFD simulation data for machine learning led to poor overall predictive performance of the models. To address this, a data augmentation method based on Gaussian noise was proposed. Through Bayesian optimization of the machine learning model's hyperparameters, the R2 of the predictive model was successfully increased from below 0.8 to above 0.99. The optimized design improved the prototype pump's efficiency from 70 % to 77.8 % under rated flow and head conditions. This efficiency gain is due to the significant reduction in flow separation vortices between blades and decreased turbulent kinetic energy between the impeller and diffuser vanes. Additionally, sensitivity and linear relationship analyses using the Sobol method and Pearson correlation provided valuable insights for blade optimization design.

A comparative study on the performance of ice-source heat pumps versus other heat source heat pumps: A case study in the UK

Eliminating natural gas as a fuel for heating residential and industrial units is crucial for reducing environmental pollutants. The challenge lies in finding alternative heating systems and repurposing existing infrastructures, like gas pipes. This article presents a new approach to supplying energy to heat pumps in a post-natural gas era using repurposed gas pipes to transport water for ice-source heat pumps. It highlights the advantages of ice-source heat pumps and compares their thermal performance with other types. The proposed system integrates ice-source and geothermal heat pumps, offering space efficiency, compact design, cost-effective centralization, optimized subsidies, seasonal cooling, weather resilience, and eliminates the need for new piping.This study evaluates heat pump efficiency using various low-grade heat sources: ambient air, ground, domestic wastewater, river and lake water, piped water, and latent heat. It focuses on optimizing heat pump performance under the UK's climatic conditions, addressing efficiency challenges during peak cold periods. The research demonstrates the system's robust performance in cold, densely populated areas, potentially reducing water mass for energy supply by up to 95 % with a 70 % ice slurry concentration. Additionally, the ice-source heat pump requires about 36.7 times less water volume than traditional systems for residential heating.