Blower Efficiency Research Articles

Study of Low-Temperature Energy Consumption Optimization of Battery Electric Vehicle Air Conditioning Systems Considering Blower Efficiency

Battery electric vehicle (BEV) air conditioning systems often use positive temperature coefficient (PTC) heaters to heat the passenger compartment. The heating process consumes a lot of energy in low-temperature environments, which seriously affects the driving range and user experience. This study aims to reduce the low-temperature energy consumption of the air conditioning system and improve energy efficiency through an innovative optimization method. In this study, the energy consumption composition of the air conditioning system was analyzed, and the goal of minimizing the sum of the total power consumption of the PTC heater and the blower was determined, while the efficiency characteristic of the blower was considered at the same time. The relationship between the average temperature of the passenger compartment measurement points and the PTC power and airflow rate was studied by combining experiments and numerical simulations, and the alternative operating conditions that met the temperature requirement were determined. On this basis, the total power consumption of the air conditioning system was analyzed and optimized. The results show that PTC power, airflow rate, and blower efficiency all have an important influence on the total power consumption of the air conditioning system. The optimized scheme could reduce the theoretical total power from 1315.32 W of the original scheme to 1246.83 W, and the actual total power from 1350.05 W of the original scheme to 1326.56 W, with reductions of 5.21% and 1.74%, respectively. The low-temperature energy consumption optimization method for the BEV air conditioning systems proposed in this study is instructive for the selection of blowers and the design of control strategies for air conditioning systems.

Analysis of flow characteristics of cylindrical and helical type multi-lobe roots blower

Roots blower is a positive displacement machine that has the advantage of a larger flow than conventional blowers. Roots blowers are widely used in industrial production such as chemicals, food, medical, etc. However, during actual operation, this type of machine often achieves low performance. One of the issues that greatly affect performance is the flow characteristics of the blower. Flow characteristics include factors related to flow rate, pressure, and flow phenomena in the blower chamber. Flow characteristic analysis is a complex problem in hydraulic machines. Flow analysis helps to investigate the motion of the flow to design high-performance machines. This study uses a mathematical model of gear theory to design the rotor profile with cylindrical and helical lobes of the multi-lobe Roots blower. The rotor profile is formed on the principle that the ellipse rolls without slipping on the base circle. On the basis of the mathematical model of the rotor profile, the paper compares the flow rate and pressure characteristics of the two blowers. The fluid dynamics analysis model was built on ANSYS software. The structural grid model is also built to increase the computational efficiency of the mathematical model. The lobes are embedded and rotated in the blower chamber. The results show that with the same radial and axial dimensions, the cylindrical lobe has a larger flow. However, the helical lobe has a more stable flow quality than the cylindrical lobe (15.2 % less flow fluctuation). In terms of pressure, the helical lobe type has a higher pressure than the cylindrical lobe type. In addition, the helical lobe type also reduces the influence of eddy currents acting on the blower chamber walls and rotors. That results in increased blower efficiency. The results of the paper will be a reliable basis for reducing time in the development of multi-lobe Roots blowers with high performance

Numerical modelling of electrohydrodynamic airflow induced in a wire-to-grid channel

Electrohydrodynamic (EHD) airflows provide a means of generating air motion by a gas discharge across two electrodes without the need for moving parts. A two-dimensional numerical model for a wire-to-grid EHD air blower is developed, validated against previous data, and used to investigate the influence of key design parameters on blower efficiency, including the emitter wire diameter, the blower height, the locations of the collecting surfaces and grid wires, and the collecting grid density. The optimal locations of both collectors from the corona wire are determined based on blower efficiency at a fixed operating power, resulting in improvements in the average outlet velocity between 9% and 15%, depending on blower thickness. The presence of the grid has a strong influence on the electric field distribution and increases the blower performance, with higher flow, lower operating voltage and reduced blower size. An investigation into the effect of grid density reveals that using coarse collecting grids is generally beneficial, leading to higher efficiency with lower pressure losses.

Study on the Energy Efficiency Optimization of Solar Power System

In this paper, we design solar power controller based on the model in which the HVAC(Heating, Ventilation, Air Conditioning) fan driving type and hybrid charging type are combined to optimize the energy efficiency of eco-friendly solar cell-based vehicle HVAC system. Because the system characteristics of the traditional MPPT method have many limitations to be applied in vehicle with relation to driving the HVAC blower motor, the limitations and efficiency of such pre-existing system was improved through designing the MPPT load variation method that is able to be used with the MCU(Micro Controller Unit) and is altered from the MPPT P&O(Perturbation and Observation). The DC step down converter(Buck) was used, which allowed for the efficiency to be increased by at least 10% when applied in the HVAC blower motor. And the system was designed to allow the battery to be charged by using the DC-DC step up converter(Boost). In order to confirm the efficiency of the proposed controller system, the results from conducting the operating experiment and vehicle performance evaluation verified the system efficiency.

Potential energy consumption reduction of automotive climate control systems

In recent years fuel consumption of passenger vehicles has received increased attention by customers, the automotive industry, regulatory agencies and academia. One area which affect the fuel consumption is climate control systems.Twenty-one energy saving measures were evaluated regarding the total energy use for vehicle interior climate using simulation. Evaluated properties were heat flow into the passenger compartment, electrical and mechanical work. The simulation model included sub models of the passenger compartment, air-handling unit, Air Conditioning (AC) system, engine and engine cooling system. A real-world representative test cycle, which included tests in cold, intermediate and warm conditions, was used for evaluation.In general, few single energy saving measures could reduce the energy use significantly. The measures with most potential were increased blower efficiency with a reduction of 46% of the electrical work and increased AC-system disengage temperature with a reduction of 27% of the mechanical work. These results show that the operation of the climate control system had a large effect on the energy use, especially compared to the required heating and cooling of the passenger compartment. As a result energy saving measures need to address how heating and cooling is generated before reducing the heat flow into the passenger compartment.

Emergency blower ventilation to disperse hydrogen leaking from a hydrogen-fueled vehicle

The effect of blower ventilation to disperse hydrogen leaking from a hydrogen fueled vehicle in an emergency was studied numerically with comparison with experimental data to investigate the practicability of rapid hydrogen dispersion to mitigate dangerously high hydrogen concentrations. The hydrogen gas was assumed to leak at 2000 NL/min at the center of the vehicle chassis while the blower was placed on the left side of the vehicle. Steady-state calculations showed that the blower significantly reduced the hydrogen concentrations around the vehicle with the hydrogen concentrations in most of the area below the lower flammability limit. Transient calculations showed that the hydrogen concentration just downstream of the vehicle had a high concentration peak shortly after the ventilation began with the hydrogen then being rapidly dispersed with additional ventilation. More cases with various air capacities and blower shapes were analyzed to find a better blower geometry with a higher blower efficiency. The results show that both a larger air capacity and a smaller blower with a higher air velocity improved the hydrogen dispersion, with the smaller blower shape being the more efficient method because the greater air entrainment into the jet for higher jet velocities improved the hydrogen dispersion, especially when the leak position was known.

Performance Enhancement of 20kW Regenerative Blower Using Design Parameters

This paper describes performance enhancement of a regenerative blower used for a 20 kW fuel cell system. Two design variables, bending angle of an impeller and blade thickness of an impeller tip, which are used to define an impeller shape, are introduced to enhance the blower performance. Internal flow of the regenerative blower has been analyzed with three-dimensional Navier-Stokes equations to obtain the blower performance. General analysis code, CFX, is introduced in the present work. SST turbulence model is employed to estimate the eddy viscosity. Throughout the numerical analysis, it is found that the thickness of impeller tip is effective to increase the blower efficiency in the present blower. Pressure is successfully increased up to 2.8% compared to the reference blower at the design flow condition. And efficiency is also enhanced up to 2.98 % compared to the reference one. It is noted that low velocity region disturbs to make strong recirculation flow inside the blade passages, thus increases local pressure loss. Detailed flow field inside the regenerative blower is also analyzed and compared.

생활폐기물 자동집하시설용 다단직렬연결 원심블로어 운전특성

), Efficiency(효율), Pressure(압력), Auxiliary Blower(보조블로어) ABSTRACT This paper describes blower performance characteristics of a automated vacuum waste collection system. Blowers serially connected to six or seven centrifugal blowers are evaluated by experimental measurements to understand blower performances according to blower numbers operated. Two different blowers and duct diameters connected to the main blowers are considered. Data acquisition system is introduced to measure pressure and pressure difference at the main duct simultaneously, which is connected to several blowers serially. A auxiliary blower, which is installed between a filter room and an air deodorizing apparatus, is also added to simulate its performance effect on the main blower. Throughout the experimental measurements of the blower system, it is found that pressure and inlet velocity at the upstream of a blower increase 3.7 and 2.4 times separately by increasing the operating blower numbers from one to seven. It is noted that blower efficiency and pressure measured at the system vary according to the distance between a air intake and a blower system. Auxiliary blower is effective to increase blower inlet suction pressure, while total energy consumption is increased relatively.

임펠러 입출구각에 따른 양흡입 원심송풍기 성능특성

Effects of design variables on the performance of a double-inlet centrifugal blower have been analyzed based on the three-dimensional flow analysis. Two design variables, blade inlet and outlet angles, are introduced to enhance a blower performance. General analysis code, ANSYS-CFX13, is employed to analyze internal flow and a blower performance. SST turbulence model is employed to estimate the eddy viscosity. Throughout the shape optimization of an impeller at the design flow condition, the blower efficiency and pressure are successfully increased by 4.7 and 1.02 percent compared to reference one. It is noted that separated flow observed near cut-off region can be reduced by optimal design of blade angles, which results in stable flow pattern in the blade passage and increase of a blower performance. The stable flow at the impeller also makes good effects at the outlet of a volute casing.

임펠러 형상에 따른 양흡입 원심송풍기 성능특성

This paper presents the performance enhancement of a double-inlet centrifugal blower by the shape optimization of an impeller. Two design variables, a number of blade and a length of chord, are introduced, and analyzed by a response surface method. Three-dimensional compressible Navier-Stokes equations are used to analyze the blower performance and the internal flow of the blower. Throughout the numerical simulation of the blower, blower efficiency can be increased by reducing separation flow generating from the blade leading edge of a blade pressure surface. It is noted that recirculation flow observed inside the blade passage induces low velocity region, thus increases pressure loss. Efficiency and pressure of the optimum blower are successfully increased up to 3% and 3.9% compared to those of reference blower at the design flow condition, respectively. Detailed flow field inside the blower is also analyzed and compared.

Effect of radial curvature on the internal flow and performance of the vaned diffuser for a compact centrifugal blower

Compact centrifugal blowers with vaned diffusers are often used in home electric vacuum cleaners. To achieve high efficiency and low noise, it is important to improve the performance of impellers and diffusers. In this study, the authors used a large solidity diffuser whose flow duct is low in height. The authors studied the influence of internal flow on the diffuser performance by using PIV and pressure measurement and visualizing the flow field in detail. From the authors' measurement results, low velocity was observed in the middle span section and the pressure side in the middle of the overlapped region. Pressure recovery increased gradually at the downstream of the low velocity region. From the authors' simulation results, the authors found that in the low velocity area, limiting streamlines from hub and shroud sides concentrate toward the mid-span, which lead to low velocity in the middle of the overlapped region. Compared with diffusers with small radial curvatures, diffusers with large radial curvatures are more likely to suppress secondary flow generated from the hub and shroud sides of the pressure side of the overlapped regions. Also, by suppressing separation at the hub-side and suction-side surface of the overlapped region, it is possible to improve the flow stagnation at the mid-span of the overlapped region. The authors can therefore achieve high blower efficiency by gaining larger pressure recovery at the rear part of the overlapped region.

Development of Anode Off-Gas Recycle Blowers for High Efficiency SOFC Systems

Prototype of efficient anode-off gas recycle blowers was developed with a 3D turbo impeller and a DC brush-less built-in motor for high efficiency SOFCs. Performance test of the blowers clarified 26% and 52% total blower efficiency for the type SSR-70 for 10 kW-class SOFC and SSR-140 for 250 kW, respectively. System performance simulation of an SOFC system with the SSR-70 blower elucidated that 59% net AC electrical efficiency can be expected. When the blower efficiency is improved to 50% as of SSR-140, electrical efficiency will become 60%. We will continue developing more efficient recycle blowers.

Optimal design of splitters attached to turbo blower impeller by RSM

This paper describes the optimization of the impeller having splitters for a turbo blower. Two design variables, chord of splitter and pitch of splitter, are introduced to enhance the blower performance. Blower pressure and efficiency are selected as an object function, and the optimization of the blower impeller is performed by a response surface method (RSM). Three-dimensional Navier-Stokes equations are introduced to analyze the internal flow of the blower and to find the value of the object function for each case. Throughout the shape optimization of the splitters attached to the impeller in the turbo blower, pressure and efficiency at the design flow condition are successively increased by 5.9 percent and 17.9 percent respectively based on the reference blower. The higher blower efficiency obtained by optimization of impeller having splitters is mainly caused by reducing the number of impeller blades and optimal design of splitters in the blade passage while pressure increase keeps almost the same with the reference blower. For the object function of pressure, pressure increase is obtained at the design and off-design conditions while efficiency keeps higher compared to the reference blower. The enhancement of blower performance is due to the reduction of reverse and circulation flows in the blade passage.

Shape Optimization of a Regenerative Blower Used for Building Fuel Cell System

This paper describes the optimal design of a Cathode blower used for a building fuel cell system. The Cathode air blower has a regenerative blower type. Two design variables, extension angle and number of impeller blade are introduced to enhance the blower performance. Pressure and efficiency of the blower are selected as an object function, and the optimal design is performed by a response surface method. Three-dimensional Navier-Stokes equations are introduced to analyze the performance and internal flow of the blower and to find the value of object function for the training data. Throughout the design optimization, it is found that an extension angle is effective to increase blower efficiency in the blower. The pressure rise for the optimal blower is successfully increased up to 3.17% compared with that of reference one at the design flow rate. It is noted that low velocity region disturbs to make strong recirculation flow in the each blade passage, thus increases local pressure loss. Detailed flow field inside a regenerative blower is also analyzed and compared.

Shape Optimization of a Regenerative Blower Used for Building Fuel Cell System

This paper describes the optimal design of a Cathode blower used for a building fuel cell system. The Cathode air blower has a regenerative blower type. Two design variables, extension angle and number of impeller blade are introduced to enhance the blower performance. Pressure and efficiency of the blower are selected as an object function, and the optimal design is performed by a response surface method. Three-dimensional Navier-Stokes equations are introduced to analyze the performance and internal flow of the blower and to find the value of object function for the training data. Throughout the design optimization, it is found that an extension angle is effective to increase blower efficiency in the blower. The pressure rise for the optimal blower is successfully increased up to 3.17% compared with that of reference one at the design flow rate. It is noted that low velocity region disturbs to make strong recirculation flow in the each blade passage, thus increases local pressure loss. Detailed flow field inside a regenerative blower is also analyzed and compared.

터보블로어 설계인자의 성능특성 연구

This paper describes the shape optimization of a blower impeller used for a refuse collection system. Two design variables, which are used to define the blade angles of an impeller, are introduced to increase the blower performance. A blower efficiency is selected as an object function, and the shape optimization of the blade angles is performed by a response surface method (RSM). Three-dimensional Navier-Stokes equations are introduced to analyze the internal flow of the blower and to find the value of object function for the training data. Relatively good agreement between experimental measurements and numerical simulation is obtained in the present study. Throughout the shape optimization, blower efficiency for the optimal blade angles is successfully increased up to 3.6% compared with that of reference at the design flow rate. Detailed flow field inside the turbo blower is also analyzed and discussed.

An aeration energy model for an immersed membrane bioreactor

A simple model for evaluating energy demand arising from aeration of an MBR is presented based on a combination of empirical data for the membrane aeration and biokinetic modelling for the biological aeration. The model assumes that aeration of the membrane provides a proportion of the dissolved oxygen demanded for the biotreatment. The model also assumes, based on literature information sources, a linear relationship between membrane permeability and membrane aeration up to a threshold value, beyond which permeability is unchanged with membrane aeration. The model was benchmarked against two full-scale plant to obtain the most appropriate and conservative value of the slope of the flux:aeration curve and the blower efficiency. Benchmarking in this way produced a match to within 20% of all key process plant operational parameters. The model demonstrated that significant reductions in aeration energy could be obtained through operation at lower flux and reducing the membrane aeration requirement accordingly, so-called “proportional aeration” at lower flows. Similarly, increasing oxygen transfer from membrane aeration would also be expected to decrease energy demand. A sensitivity analysis of some of the key parameters revealed that, of the key operating parameters, loading, SOTE and MLSS concentration remain the most critical in determining energy demand. It is suggested that a key parameter representing membrane aeration in MBRs is the mean in-module air upflow velocity U, since this gives a reasonable representation of the shear applied through membrane aeration. U was found to vary between 0.04 and 0.1 m/s across a number of modern large pilot and full-scale plant. An analysis reveals that significant reductions in energy demand are attained through operating at lower MLSS levels and membrane fluxes. Evidence provided from recent controlled pilot trials implies that halving the flux can reduce the aeration is suggested whereby the number of membrane tanks on line and/or the membrane aeration intensity is adjusted according to the flow, and thus flux, so as to reduce the overall aeration energy demand.

ダクテッド・プロペラ性能の迅速自動計算法

A quick automatic method for computing aerodynamic performance of ducted propellers is presented. The thrust- and power-coefficients and propulsive efficiency are calculated and plotted against the advance ratio. The representative blade section is investigated. It is found that the most suitable section is one at 75% radius as the same as nonducted cases. Thrust coefficient is predicted satisfactorily. But propulsive efficiency is overestimated; the difference seems to be “blower efficiency” defined in a previous paper.

Contact-slit face seal for impellers in centrifugal-flow machines

The serv ice life of the components and the efficiency of centrifugal-flow compres so r s depends to a great extent on the design of the ro to r impel ler seal. Conventional floating-type contac t f ree seals loaded with elast ic steel springs cannot be used in the blowers on mainline gas ducts at compres so r stations. End whip of the ro tor is experienced in these blowers because of the high rotation speed (n ~8000 rpm), which sets the seal r ing vibrating. A s l i t type face seal backing up the radia l labyr in th seal great ly improves the blower efficiency and reduces the axial force acting on the thrust bearing [1]. However this type of seal also has its shor tcomings. Gas f rom the delivery cavity leaks through the slit into the intake cavity imnorma l operation. Under surge conditions, the ro to r is set vibrating at a high frequency in the axial direction, and its cover disk s t r ikes its end face against the seal ring and wreaks havoc with the latter. After a surge lasting no more than 3-5 sec, the sys tem will still function as a whole, but it will have to be taken off s t r eam in o rder to replace the ring in the mechanical shaft seal. If the ro tor is shifted axially toward the intake site in an accident because of wear on the thrust bearing, the braking torque on the shaft brought about by the frict ion force of the ro to r on the fixed seal r ing will be so formidable that the reduction gear train in the blower power drive will be hopelessly ruined.