共查询到20条相似文献,搜索用时 15 毫秒
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介绍了一个简洁实用化的宾馆卫生热水供应系统,并通过实例对两种卫生热水供应用系统作了可操作性和投资运行性两方面的比较,结论是减少了初投资的10%和运行电费的60%。 相似文献
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Natthaphon Roonprasang Pichai Namprakai Naris Pratinthong 《Applied Thermal Engineering》2009,29(8-9):1598-1605
This research purpose was to perform a parametric study of a novel thermal water pump well fitted in a simulated solar water heating system (SWHS). The SWHS was composed of a heating tank (HT), a hot water storage tank (ST) and an overhead tank (OT). The HT together with a specially designed valve act as a novel thermal water pump that gets power from hot water vapor and air pressure produced by a built-in electric heater in order to transfer heat from the HT to ST. The general operation of this pump has four stages for each cycle: heating, water circulating, vapor circulating and water supplying. The discharge water heads were varied with an increment of 0.25 m from 0.75 to 3 m. According to the experiment, it was found that the pump could operate at an average HT temperature of about 80–95 °C leading to 70–80 °C ST temperatures and 20–35 pumping cycles and consumed 17 MJ energy input during 9-h period. The overall thermal efficiency of the SWHS was 33–42% and the mean pump efficiency was about 0.005–0.011% depending upon the discharge heads. 相似文献
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变频调速技术在电厂循环水系统优化运行中的研究与节能分析 总被引:8,自引:0,他引:8
介绍了变频调速技术的原理和变频调速水泵运行工作点的求解方法。以某电厂 30 0MW机组循环水系统为例建立了优化运行的数学模型并对其进行了求解 ,得到了系统的最佳运行方式。将变频调速方式的优化结果与循环水系统其它调节方式的优化结果进行比较发现 ,变频调速技术应用在循环水系统中是切实可行的 ,节能潜力较大。 相似文献
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将矿井中水通过深度处理后回用于采暖循环水系统,对缓减煤矿企业生活用水矛盾,节约水资源具有较强的现实意义.通过在晋城古矿矿区采暖循环水系统进行应用研究试验,提出了BF-30a防腐阻垢荆的应用方法和工艺特点. 相似文献
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Casada D.A. Kueck J.D. Staunton H. Webb M.C. 《Energy Conversion, IEEE Transaction on》2000,15(3):240-244
This is a report of efficiency testing of an induction motor powered from three different pulse width modulated adjustable speed drives. The motor was operated at a range of speeds and torques, and each drive was operated at the highest, lowest, and an in-between carrier frequency. The motor was a typical NEMA design B motor, and the drives were typical, industrial scalar drives using the default volts/Hz setting. The testing showed that the drive efficiencies remained above 90% until torque was lowered to below 20% of rated torque. Combined motor and drive efficiencies remained above 80% until speeds or horsepower loads were lowered to below 20% of rated torque. The test was performed using a unique data acquisition scheme that permitted acquisition of a large number of torque settings for each speed selection 相似文献
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Induction motor driven by vector control method makes high performance control of torque and speed possible. The decoupling of flux and electromagnetic torque obtained by field orientation depends on the precision and the accuracy of the estimated states. Rotor asymmetries lead to perturbations of air gap flux patterns in induction machines. These perturbations in flux components affect the electromagnetic torque, as well as stator currents and voltages. This paper first investigates the control of the induction motor using an extended Kalman filter (EKF) for a direct field-oriented control. It then studies the broken rotor bars (BRBs) fault by the monitoring the rotor resistance. The hypothesis on which the detection is based is that the apparent rotor resistance of the motor will increase when a rotor bar breaks. The rotor resistance is estimated and compared with its nominal value to detect BRBs fault. The EKF estimates the rotor flux, speed and rotor resistance on line by using only measurements of the stator voltages and currents. Simulation results show the effectiveness of the proposed method in the cases of load torque perturbation and speed reversion. 相似文献
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Speed and power factor controller for AC adjustable speed drives 总被引:1,自引:0,他引:1
The speed and power factor of an adjustable speed slip power recovery drive are controlled in order to optimize the operation. This is accomplished by means of a variable-voltage-variable-frequencies power converter. The function of the digital controller of the power converter is to provide the online speed and power factor regulation. The hardware and software are described. This scheme has an accurate voltage output with very low harmonic content, a good resolution for the phase angle regulation and the frequency control with the possibility of range extension 相似文献
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Attaianese C. Tomasso G. Damiano A. Marongiu I. Perfetto A. 《Energy Conversion, IEEE Transaction on》1999,14(4):939-945
With reference to speed controlled induction motor drives, an algorithm which allows the on-line estimation either of the speed and one motor parameter or, alternatively, of two motor parameters, is presented in the paper. The results obtained by simulation fully confirm the validity of the proposed algorithm. Finally, the problems arising from the implementation of the proposed algorithm on a DSP-based control hardware are analysed 相似文献
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《Energy Conversion and Management》2005,46(9-10):1365-1378
A hybrid fuzzy controller for speed control of switched reluctance motor (SRM) drives is presented in this paper. The developed hybrid fuzzy control law consists of a proportional integral (PI) controller at steady state, a PI type fuzzy logic controller (FLC) at transient state and a simple logic controller between the steady and transient states to achieve the desired performance at various operating conditions under soft chopping operation. The importance of the hybrid fuzzy controller is highlighted by comparing the performance of various control approaches, including PI control, PI type fuzzy logic control and PD type fuzzy control for speed control of SRM motor drives. The complete control algorithm is demonstrated by intensive experimental results. It is shown that the presented hybrid controller for SRM drive has fast tracking capability, less steady state error and is robust to load disturbance. The complete speed control scheme of the SRM drive incorporating the hybrid control is experimentally implemented and validated using a high speed digital signal processor board TMS320F2812 for a prototype 1.2 kW SRM. 相似文献
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《International Journal of Hydrogen Energy》2022,47(50):21435-21449
The hydrogen circulating pump is an essential component of hydrogen fuel cell systems. It plays a vital role in improving hydrogen utilization efficiency and optimizing hydrothermal control capabilities. Due to its compact design, high efficiency, and outstanding low-temperature adaption performance, the lobe hydrogen circulating pump has excellent potential for hydrogen recirculation in fuel cell vehicles (FCVs). This paper investigated the internal flow characteristics of a lobe hydrogen pump for FCV under different rotational speeds by experiments and computational fluid dynamics (CFD). Moreover, the lobe rotor domain was calculated using the dynamic mesh method. The effects of different rotating speeds on transient pressure pulsation, exhaust flow rate, external noise, and vibration were studied. The result reveals that the volumetric efficiency improves with the increased lobe rotor speed when the pressure ratio remains constant. The vibration acceleration level (VAL) and the external noise also increase. The vibration is most significant at the pump casing outlet and tends to decrease as the frequency increases. The sound pressure level spectrum has a discrete character in the low-frequency band, with peaks mainly concentrated at the rotating fundamental frequency and harmonics. The middle and high frequency bands have prominent broadband characteristics, and the energy is relatively concentrated. 相似文献
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Pongsakorn Kerdchang Maung MaungWin Sombat Teekasap Jongjit Hirunlabh Joseph Khedari Belkacem Zeghmati 《Solar Energy》2005,78(4):518-527
This paper presents a numerical study about the performance of a Beta Stirling solar thermal engine system. This system is composed of a solar collector box connected to a regenerator hydraulic system and a transmitting power system. The objective of the system is to offer a new alternative to help solving stagnant water pollution in hot countries like Thailand by circulating water in canals, lakes, ponds etc. for aeration using solar energy.The purpose of this study is to determine the power output and actual heat transfer on the performance of the solar thermal engine. The solar thermal engine is analyzed using a mathematical model based on the first law of thermodynamics for processes with finite speed, with particular attention to the energy balance at the receiver. The result of calculations showed that the regenerator volume and phase angle must be chosen carefully to fulfill the requirement that total fluid mass in the system is constant and to obtain maximum power output throughout the day. 相似文献
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冷端系统是火电厂发电机组重要的辅助系统,它的工作状态和运行特性对整个电站机组的稳定性、安全性和经济性都有较大的影响。对某660 MW超超临界机组两台循环水泵电机进行改造,增加了循环水泵运行方式(单机运行时一小、一大、一大一小;双机运行时二小、一大一小、二大、二大一小);建立了机组冷端性能分析计算模型,结合实际运行状况,给出了不同负荷、不同温升等工况下循环水泵组合优化运行方式;针对机组频繁启停状况,通过合理利用运行机组循环水,达到降低开停机过程循环水泵耗电量的目的。研究为同类机组冷端系统运行方式提供借鉴。 相似文献
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本文针对 35t/h循环流化床锅炉给水系统存在“抢水”现象 ,使汽包水位自动调节的性能降低的问题。对锅炉给水调节系统作了改进 ,取得成效。 相似文献
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A stator resistance estimation scheme for speed sensorless rotor flux oriented induction motor drives 总被引:2,自引:0,他引:2
Accurate knowledge of stator resistance is of utmost importance for correct operation of a number of speed sensorless induction motor control schemes in the low speed region. Since stator resistance inevitably varies with operating conditions, stable and accurate operation at near-zero speed requires an appropriate online identification algorithm for the stator resistance. The paper proposes such an identification algorithm, which is developed for the rotor flux-based model reference adaptive system (MRAS) type of the speed estimator in conjunction with a rotor flux oriented control scheme. In this speed estimation method, only one degree of freedom (out of the two available) is utilized for speed estimation. It is proposed to utilize the second available degree of freedom as a means for adapting the stator resistance online. The parallel stator resistance and rotor speed identification algorithm is developed in a systematic manner, using Popov's hyperstability theory. It increases the complexity of the overall control system insignificantly and enables correct speed estimation and stable drive operation at near-zero speeds. The proposed speed estimator with parallel stator resistance identification is at first verified by simulation. Extensive experimentation is conducted next at low speeds of rotation and successful stator resistance identification is achieved down to 0.5-Hz frequency of rotation. 相似文献