小型风力提水机的低实度风轮设计及其数值模拟

针对传统风力提水机实度大、风能利用率低的缺点,采用NACA4412航空翼型及叶素动量理论对小型风力提水机叶片的气动外形进行设计,采用6叶片风轮形式,引入修正因子,并根据工程实际优化了叶片的弦长及安装角,并采用CFD方法对风轮进行数值模拟。结果表明,设计的风力提水机在2.8 m/s的微风下可起动,在额定工况下风能利用系数达0.43,叶片具有很好的三维流动特性,风能利用系数高,降低了传统风力提水机风轮的实度,扩大了风能的利用范围。研究结果对风力提水机的改进设计有指导意义。     

Wind resource assessment of the Jordanian southern region

Wind data in terms of annual, seasonal and diurnal variations at Queira, which is located in the southern part of Jordan was studied and analyzed. For this purpose, long-term wind speed data for a period of 12 years (1990–2001) was used. The analysis showed that the seasonal and diurnal pattern of wind speed matches the electricity load pattern of the location. Higher winds of the order of 6 m/s and more were observed during both the summer months of the year (May–August) and peak hours (1100–1500) of the day. The wind duration availability is discussed as the number of hours during which the wind remained in certain wind speed intervals. The possibility of electricity generation from wind power at Queira was carried out using three different wind energy systems of sizes 100, 22 kW rated power, and a wind farm consisting of 25 small wind turbines; each of 4 kW rated power with hub heights of 20, 30, and 40 m. The energy production analysis showed higher production from the wind farm with a 20 m hub height than the production from the other two wind turbines. Similarly, the cost analysis showed that the lowest generation costs of 1 kWh were obtained for the wind farm compared to the other two wind turbines. The possibility of water pumping using the wind farm was also investigated. The results showed that water pumping using wind turbines is an appropriate alternative for the photovoltaic water pumping in the region.     

Sliding Mode Control for Efficiency Optimization of Wind Electrical Pumping Systems

Wind energy conversion systems have been receiving increasing attention in recent years, particularly in remote areas, where power from the utility is not available or is costly to install. Among many applications, wind electrical systems are successfully used for pumping water. Owing to the non‐linear characteristics of these systems, their control is essential to attain high efficiency. In this work, concepts of sliding mode control are employed to guarantee global stability and to optimize the efficiency of a wind electrical water‐pumping system. The measurement of wind speed is avoided. A thorough analysis of stability and dynamic behaviour is realized. Simulation results are presented. Copyright © 2003 John Wiley & Sons, Ltd.     

Wind Turbines in Latin America

An overview of the development of wind turbines, water pumping and electric generation, in Latin America is given. There are a number of regions with average windspeeds above 5 m/s, however the greatest wind energy potential is in Southern Argentina. The market potential is large, but substantial barriers impede the use of wind energy for generating electricity.     

Energy conversion efficiency of the pumping kite wind generator

This paper is devoted to analytical modelling and numerical simulation of the so-called pumping kite wind generator whose operating principle is to mechanically drive a groundbased electric generator using tethered kites. On the basis of the refined crosswind motion law, the mathematical model of steady crosswind motion of the tethered kite is constructed. Necessary conditions for optimality of the mean mechanical power functional are derived. Optimal control of the tether length rate is studied for the cases of open-loop and closed-loop figure-of-eight trajectories. The performance coefficient of the pumping kite wind generator is introduced. Simple formulas for the mechanical power output are obtained.     

小型风电泵水系统控制方法的研究

概述风力提水系统的发展历程，分析了小型风电泵水系统的主要构成及原理。论述了SPWM的产生原理，设计了单片机控制系统的软硬件。以1kW的风电泵水系统为对象进行了试验，其输出的机械特性表明采用该控制方法具有较好的动态性能。     

Modelling the integrated output of wind-driven roto-dynamic pumps

Roto-dynamic pumps offer better match with wind rotors for low lift-high discharge water pumping applications. Tremendous potential for such systems does exist in many developing countries like India. In the present study, a mathematical model is proposed for estimating the performance of wind-driven roto-dynamic pumps at various operating conditions. In contrast with the earlier attempts in this direction, an integrated approach incorporating the characteristics of the rotor, pump and the wind regime is envisaged for formulating the model. The model is validated using the field performance data from a 5 m, five-bladed experimental rotor coupled with a low speed centrifugal pump. Performance of the system at fluctuating conditions of wind regimes is estimated and compared with that of a system with reciprocating pump. Wind driven roto-dynamic pumps are found to offer distinctly better performance than the conventional system with reciprocating pumps. Effects of the specific speed and specific diameter of the pump on the gear ratio and optimum pump size are also discussed. A low specific speed roto-dynamic pump with reasonable specific diameter is found to be suitable for coupling with wind rotors for water pumping application.     

On wind speed pattern and energy potential in Nigeria

The aim of this paper is to review wind speed distribution and wind energy availability in Nigeria and discuss the potential of using this resource for generation of wind power in the country. The power output from a wind turbine is strongly dependent on the wind speed and accurate information about the wind data in a targeted location is essential. The annual mean wind speeds in Nigeria range from about 2 to 9.5 m/s and the annual power density range between 3.40 and 520 kW/m² based on recent reported data. The trend shows that wind speeds are low in the south and gradually increases to relatively high speeds in the north. The areas that are suitable for exploitation of wind energy for electricity generation as well as for water pumping were identified. Also some of the challenges facing the development of wind energy and suggested solutions were presented.     

The economics of wind energy in South Africa

Battery charging and water pumping has been the only applications for wind energy in South Africa till now. A conservative estimate of the wind resource indicates that approximately 5% to 6% of the South African energy demands can be supplied from wind. However the low cost of electricity due to the abundance of cheap coal has made it difficult to justify the use of grid connected wind turbines. As with other countries where wind energy is now a part of the total energy package, South Africa will also have to go through a process of wind energy having to prove itself as a viable option while at the same time have a cost disadvantage.     

Wind power utilization for water pumping using small wind turbines in Saudi Arabia: A techno-economical review

An attempt has been made, may be first time in Saudi Arabia, to utilize power of the wind for pumping the water for remotely located inhabitants not connected with national power grid. Small turbines of 1–10 kW have been chosen in conjunction with Goulds 45 J model water pumps to produce energy from wind and pump water using the produced energy at Arar, Rawdat Ben Habbas and Juaymah localities in Saudi Arabia. Wind speed measurements made at different heights using 40 m tall towers have been utilized in the present work. Higher wind speeds were noticed during summer time compared to winter time at all the locations. Both energy yield and cost of energy point of view, 2.5 kW wind turbine from Proven was found to be most suitable for wind power generation at all sites. It is shown that annual total water pumping capacity of 30,000 m³ is possible from a depth of total dynamic head of 50 m when using 2.5 kW Proven wind turbine with hub heights 15–40 m at all three sites with cost of water pumping as low as 1.28 US¢/m³.     

Optimised design and dimensioning of low-technology wind pumps

This article describes the currently operational version of the low-technology wind pump of high efficiency, as presented in [Valdès L-C, Raniriharinosy K. Low technical wind pumping of high efficiency. Renewable Energy 24 (2001) 275–301]. The pump, made entirely of wood and using roller bearings for the rotating links and a rubber membrane for water tightness, is of a more modular conception. Its manufacture is slightly more complicated, but its dimensioning has been greatly simplified, its reliability significantly improved and the use of wind energy optimised.     

The design of the Banki wind turbine and its testing in real wind conditions

This paper discusses a proposed design of the Banki wind turbine based on the classical hydraulic machines theory. To evaluate that design, a 1 × 1 m prototype is experimentally investigated in real wind with and without a guiding vanes system. The turbine has a maximum power coefficient of 0.3 and a cut-in wind speed of 1.2 m/s. Furthermore, the turbine has a high starting torque and a rigid structure. These among many other interesting characteristics indicate that the turbine is suitable for water pumping and electricity generation.     

Estimation of the mechanical energy output of the kite wind generator

This paper is devoted to analytical modelling of so-called pumping kite generator whose operating principle is to mechanically drive a groundbased electric generator using tethered kites. The refined crosswind motion law is derived in the case of equilibrium motion of the kite. The paper also presents the theory of a gently sloping kiteline. The main purpose of the study was to estimate the mechanical energy output of the pumping kite wind generator. A simple approximate formula for the mean mechanical power generated by the deploying kite is obtained.     

Safety systems for the ESES 2002 wind pump

The ESES 2002 wind pump, a 4.6 m rotor diameter high-performance water pumping windmill, was tested at four different sites (Cairo, Giza, Wadi El Natroun and El-Tor city on the Red Sea coast) from September 1997 to July 1999. These machines utilize a 3:1 gearbox and a hydrodynamic sealing piston pump. These four ESES 2002 wind pumps were tested by pumping from a motionless water depth of 3 m up to an 84 m deep well. A variety of pump diameter sizes varying from 64 to 1400 mm were used. The water pumped was returned to the well after flowing through a settling storage tank having a capacity of 3 m³. The instrumentation provided a 16 channel data acquisition system to accurately measure the machine performance, including rotor rpm, number of stroke, starting wind speed, flow rate, tail furl angle and other variables. The results verify that the ESES 2002 wind pump is a robust machine as two machines have been running for 2 years continuously without requiring any replacement parts or major or minor maintenance.     

Use of solar assisted geothermal heat pump and small wind turbine systems for heating agricultural and residential buildings

The main objective of the present study is twofold: (i) to analyze thermal loads of the geothermally and passively heated solar greenhouses; and (ii) to investigate wind energy utilization in greenhouse heating which is modeled as a hybrid solar assisted geothermal heat pump and a small wind turbine system which is separately installed in the Solar Energy Institute of Ege University, Izmir, Turkey. The study shows 3.13% of the total yearly electricity energy consumption of the modeled system (3568 kWh) or 12.53% of the total yearly electricity energy consumptions of secondary water pumping, brine pumping, and fan coil (892 kWh) can be met by using small wind turbine system (SWTS) theoretically. According to this result, modeled passive solar pre heating technique and combined with geothermal heat pump system (GHPS) and SWTS can be economically preferable to the conventional space heating/cooling systems used in agricultural and residential building heating applications if these buildings are installed in a region, which has a good wind resource.     

Assessment and applications of wind energy in Jordan

A technical and economic assessment has been made of the generation of electricity using windmills located at three most promising potential wind sites in Jordan: Ras Muneef (RA), Mafraq (MF), and Aqaba (AQ). The assessment was made for two different systems, one using a relatively large single windmill and the other using 25 small windmills arranged in a wind farm. The power output of each system at each site was determined, and the electricity-generating costs in each case were also determined and compared with the generating costs of generating electricity using steam or gas turbines, furnished by the Jordanian Electricity Authority (JEA).Finally, the possibility of water pumping from 30-m and 100-m deep wells using a windmill is investigated and the quantities of water pumping from these depths at each of the three sites are given.     

Prospects for creating in karakalpakstan wind electric stations of large capacity utilizing the wind energy resources of the Ustyurt Plateau

The prospects for creating a wind electric station (WES) of capacity 120 MW on the Ustyurt Plateau are examined; its fundamental parameters and operating characteristics are determined on the basis of the wind conditions recorded by the Zhaslyk weather station. The primary energy deficient consumers in the rural region of Karakalpakstan (the ungasified rural population centers, the electrical water purification facilities, and the pumping stations) are analyzed and the possibility for covering this shortage by the power that is generated by the WES is determined.     

Renewable energy in the outback of Australia

Many stations and small communities, particularly Aboriginal Communities, have switched from diesel generators to sensible Remote Area Power Supply (RAPS) systems consisting of wind and/or solar input, battery bank, inverter and generator back-up.The introduction of Synergy Power Corporation's low-wind regime turbines that can hover/reef rather than furl has allowed wind powered RAPS to penetrate markets in the desert communities that were previously considered unsuitable for wind systems. The unique reefing system is described and some interesting case studies given.Solar water pumping and solar powered microwave telecommunications have been common for the past ten years and have proved extremely reliable and have been well accepted.     

中小型风力发电提水智能控制系统的设计

叙述了1种风光互补抽水智能控制系统设计方案,指出通过智能芯片对太阳能光电板和风力发电机发出来的能量进行合理的管理和分配,可有效地最大化地利用风能和太阳能,提出了1种新型抽水控制方法,试验表明,该方案取得了很好的效果。     

Assessment of wind-generation potentiality in Jordan using the site effectiveness approach

Wind data gathered over 3–10 years is used for a feasibility analysis of optimum future utilization of wind-generator potentiality in 22 sites covering all landscape types and regions in Jordan. The yearly mean wind speed and the yearly average available wind energy flux were computed for each site. Yearly mean wind speeds at a height of 24 m could reach as high as 7.6 m/s and available wind energy flux close to 3 MWh/m²/year could be attained. Detailed technical assessment for the nine most promising potential wind sites was made using the site effectiveness approach. The maximum site effectiveness and its corresponding cut-in speed were indicated, both of which depended on the site. The investigation was performed assuming three models of small and medium size wind machines representing different ranges of characteristic speeds and rated power suitable for water pumping and electric supply. The results show that small and medium wind turbines could be installed in the highlands and desert regions and utilized for water supply and electrical power generation, provided the correct wind machine-site is selected.