Study regarding the use of wind energy in the area of water supply

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1 Study regarding the use of wind energy in the area of water supply BADEA LEPADATESCU 1, IOAN GHIMBASEANU 2 1 Department of Engineering Technology 1 and Materials Science 2 Transylvania University of Brasov B-dul Eroilor, nr.29 ROMANIA lepadatescu@unitbv.ro, ghimbasani@unitbv.ro Abstract: - In the paper is presented a solution to solve the problem of water supply for an isolated small community where the area posses an outstanding wind potential. It is a place with a few buildings which are located near a river and is needed water for daily requirements. The water must be taken from the river and send it to a tank from where it is sending anytime where is needed. It was taken into consideration two types of wind turbine, one with horizontal axis and other with vertical axis. After studying the advantages of each one it was taken a decision to produce and install a wind turbine with horizontal axis. Key-Words: - wind turbine, domestic water, renewable energy. 1 Introduction All around the world is a number of small isolated communities, like island and rural villages without access to a large electricity grid. The absence of an electrical network in their major area or the prohibitively high connection cost, force this remote consumers to cover their urgent electrification needs to use small diesel electric generators with all the problems of pollution of environment and noise. The development of renewable energy sources is a central aim of European Union energy policy reflecting the clear benefits that clean, sustainable and secure energy generations of Europeans, as well as other peoples worldwide. Clean-because they reduce the pollution that scars our cities and countryside. Sustainable because they are renewable and do not contribute to the build up of greenhouse gases that cause climate change. Secure-because they are sourced within Europe, not imported, and thus they reduce our dependency on events elsewhere in the world that we cannot control Because we want to build a wind turbine was to pump water is necessary to know first the percentage of renewable energy sources in total consumption and the energetic potential of renewable energy sources. These are shown in Table 1[1]. supplies will bring to current and future Table 1. Energetic potential of renewable energy sources in Romania. Renewable energy source Energetic potential on year Equivalent safety energy Solar Energy: -Thermal -PV 60x106 GJ GWh 103,2 Wind energy GWh 1978 Hydro Energy 0000 GWh 16 Biomass 318x106 GJ 797 Geothermal Energy 7x106 GJ 167 ISBN:

2 Wind turbines are classified as vertical or horizontal axis machines depending on the axis of rotation of the rotor. The energy available in the wind is proportional to the cube of the wind speed: if the wind speed is doubled, there is eight times the available power. Wind turbine has many applications as: Stock water sheep, cattle, horses; Domestic applications household water for drinking, sanitation, and washing; Irrigation for house and vegetable gardes; Filling dams, reservoirs, fish ponds, lakes; Dewatering wet lands; Water for small industry; Waste water removal; Sewage; Remote locations; The selecting of a wind turbine should be based on the next criteria: wind conditions, source a water supply, water requirements, total pumping head, and governing. Regarding of wind conditions, the right combination of wind turbine and pump is one which will work easily in light winds (about 10 km/h). This will also depend on the total pumping head [2]. Wind turbine will be useful for pumping water for stock and domestic supplies in isolated rural areas. It can be an economical alternative where: Wind conditions are reliable; Unattended pumping is required for long periods; There is no other viable power source; The user requires environmentally clean power; The principal advantages of using a wind turbine are outlined below: run unattended for long periods; low maintenance; suits isolated locations; no energy costs; Some of their disadvantages are: high capital costs; intermittent pumping in very light winds; requires auxiliary storage; We will study the two solutions of wind turbines with their advantages and disadvantages to can take a decision to solve the problem for domestic water supply. 2 Wind turbine with vertical axis The idea is to use a wind turbine with vertical axis to produce electricity that will be used to pump water from a river. For the remote locations, and when is desired to be independent regarding the electric energy source, it was designed a wind turbine with vertical axis helical type (Fig.1). Fig.1 Rotor of a wind turbine with vertical axis helical type. This type of wind turbine is easy to mount on the roof of a house, having the main advantage of don t need to be pointed into the wind direction with a system as other types of wind turbines. In the same time it works without any noise and the shape of the rotor make these turbines to be with any damage for the birds [2]. The rotor of this wind turbine was made by the FINEX Company, patented in Romania, and is with three blades with fiber glass material. The main advantages of this type of wind turbine with helical type rotor whose main rotor shaft runs to the flow ISBN:

3 streamlines, from other type of wind turbines with horizontal axis are: - simplicity in construction and good strength; - high reliability; - smaller cost with 20 % as similar turbines; - specific power bigger on the active surface; - big torque moment at starting; - at the wind speed bigger than 20 m/sec is self breaking without mechanical components, due to its original shape of rotor [3]; - doesn t need orientation after the wind direction; - it can works to high wind speed, as 0 m/s; - it is only one wind turbine that is accepted by environmental agencies, because it doesn t kill birds; - doesn t make noise during its function; The rotor was mathematically designed and tested in experimental conditions on the car adapted as a mobile laboratory, where were measured the next parameters: - wind speed [m/s]; - rotational movement of rotor shaft [rpm]; - generator power [W]; - air temperature [ 0 C]; One rotor can generate a power of 600 W, at the wind speed of 12 m/s, and by mounting on a common axle of two rotors, it is obtained a total power of 1200 W. Because the rotational movement of the rotor shaft is of maximum 120 rpm, it was needed to use a device that increase the rotation movement and ensure an optimum conditions of working for the PGM (permanent generator magnet). The electric current is threephase and is needed to use a device to modify it in order to be measured as good accuracy as possible the current generated at different number of rotor shaft rotation. To select a wind turbine we must taken into consideration some points as a water source, which in our case is a river, the volume of water to be pumped (livestock requirements) and the lift (from water level to top of the tank). In Table 2 is showing technical characteristics of wind turbine with vertical axis for a power of 1000 W. Table 2 Technical characteristics of wind turbine with vertical axis. Power 1000 W Wind speed Cut-in wind speed: 1.8 m/s; Nominal wind speed: 12 m/s; Cut-out wind speed: 20 m/s Blade numbers 3 Rotor diameter 1.20 m Current GL-PMG 1000 generator Turbine weight 13 kg This type of wind turbine is very efficient at wind speeds of m/s, when the probability of using it is between %. For many reasons, this type of wind turbine is more efficient than other wind turbine with horizontal axis and with three blades. Table 3 shows the values of power that were obtained for different wind speeds at a various probability of wind. Table 3. The values of wind speeds and power generated according with the wind probability. Wind Speed (m/s) Power (W) 0 0 0% Wind Probability (f) % % % % % % % % % ISBN:

4 3 Wind turbine with horizontal axis to pump water for domestic supply To select a wind turbine we must taken into consideration some points as a water source, which in our case is a river, the volume of water to be pumped (livestock requirements) and the lift (from water level to top of the tank). Some estimations available wind must be made, preferably from site readings using an anemometer. The wind turbine outlets are normally discharged into an open tank i.e. into the top of the tank. The wind is a natural resource that is available everywhere. As a general rule the wind blows for between 8 to 10 hours per day, at a speed that is useful for the wind turbine. Table called Beaufort scale-is used to assess local wind conditions [3]. Table. Assessment of local wind conditions. Force Name Definition Speed range m/s (kph) 0 Calm Smoke rises vertically 0 (0) 1 Light air Direction shown by smoke, but not vane 1 (7) 2 Light breeze Wind felt on face, leaves rustle 2-3 (1-21) 3 Gentle breeze Leaves, small twigs & flags in motion - (28-3) Moderate Raises dust and paper, small branches move 6-8 (2-6) Fresh breeze Small trees in leaf sway 9-11 (63-7) 6 Strong breeze Large branches move, wires whistle 11-1 (77-98) 7 Near gale Whole trees move, walking slightly impeded 1-17 (98-119) 8 Gale Breaks twigs off trees, walking difficult (119-10) 9 Sever gale Slight structural damage 21-2 (17-168) 10 Storm Trees uprooted, considerable damage > 2 (>17) Table will be used to determine the volume of water that is needed for the wind turbine to pump. After is doing the total requirements is needed to add a safety margin. Table. Determination of the water volume needed. Estimated Water use daily use (Litres) Domestic drinking (per person) 2 Domestic hygiene, bathing (per 10 person) Domestic toilet (per person) 10 Domestic-laundry (per person) 1 Domestic-household cleaning 10 Swimming pool 70 regime will need more (to allow for the days when the wind does not blow) []. The idea was to build a wind turbine which is used to pump water for domestic supply necessities in a holiday location where are a number of 10 houses. The holiday place is near to a river and they intend to use the water from the river for their daily needs. In Fig.1 is shown the principle of the idea of taking water from a river and to send it to the tank from where it can be used anytime. The main elements of the wind turbine used to extract water from the river shown in Fig.2 are: 1-the water tank; 2-wind turbine body; 3-diaphragm pump; - pipe system; - the river. Usually this margin is between 10 to 0 % and depends on the reliability of the wind resource a good wind resource will only require a 10 % margin, while a light wind ISBN:

5 Fig.2 The principle of wind turbine to pump water. To achieve the needs regarding the domestic supply water was designed and realized a wind turbine with horizontal axis which is presented in Fig.3. The main parts of the wind turbine are: 1- the multiblades rotor; 2- the tower or mast made by tubular steel with two sections of pipe coupled together; 3-the guy wires attached to the tower in three points and with an underground concrete anchor for each set; - the diaphragm pump; - the concrete base; The rotor is mage by 12 blades and has a diameter of 1, m. The height of entire turbine is 6 m. The wind turbine is located at m distance from the river whose water we intend to use for domestic needs. To pump the water was chosen a diaphragm pump shown in Fig.. The pump is acted by a cable () that has a reciprocating motion which is received from the rotor mechanism. The rotor mechanism transforms the revolution motion into reciprocating motion through a cam. In a cam operated wind turbine, the lift of the water occurs during more than one-half the cycle. Using a cam that allows for threequarters of the cycle lifting and one-quarter return, starting torque is reduced by 60 percent. The wind turbine will start in light winds, and if combined with counterbalancing, starting torque is reduced by 72 percent Fig.3 A wind turbine with horizontal axis to pump water. A diaphragm pump () is a pump that uses a combination of the reciprocating action of a membrane made by rubber and non return check valves to pump water. When the volume of a chamber is increased the diaphragm moving up- the pressure decreases, and fluid is drawn into the chamber. When the chamber pressure increases from decreased volume the diaphragm moving down- the fluid previously drawn in is forced out. After that, the diaphragm is moving up again draws fluid into the chamber, completing the cycle. The entire perimeter of the diaphragm is tightly held and sealed in place between the side of the displacement chamber and a flange, which is tightly bolted to the chamber. 3 ISBN:

6 Fig. Mechanism added to increase the volum of water pumped. Fig. Diaphragm pump used to pump water. Each displacement chamber has two valves, usually spring-loaded ball valves made from the same material as the diaphragm. One of the valves admits the water being pumped to the diaphragm chamber, and the other allows the material to exit the diaphragm chamber. It is a driving mechanism that flexes the diaphragm in and out of the chamber to suction in and force out the water. The water is taken from the river through the device 7 and is sending to the water tank by the flexible pipe 3. The body of the pump 7 is connected to the tower 1 by the plate 2 by a bolt and bush-bearing which helps when the mast is erected in position. The initial design was for a wind turbine which is able to pump l/h. During the tests on the site location, the quantity of water wasn t enough because the length of reciprocation motion was shorter. To increase the length of reciprocation motion that acts the pump was designed a mechanism shown in Fig.. This mechanism is able to double the stroke of the reciprocating motion and in this way to increase the water pumped. It was bolted on the plate 2 (Fig.), by the plate, the wire coming from the rotor is fixed with the screws 6 on the cylinder surface 7 and from the cylinder face 2 through the screws 1 the stroke is transmit to the diaphragm pump. The energy available in the wind is proportional to the cube of the wind speed: if the wind speed is doubled, there is eight times available power. The power output of a wind turbine is dependent on the rotor diameter and the wind speed. The energy captured by the rotor is proportional to the square of the rotor diameter and the cube of the wind speed. The potential output of a multiblades wind turbine is given by this equation []: P = 0,002 D 2 V 3 (1) where: P = power in watts; D = rotor diameter in meters; V = wind speed in kilometres per hour If we expect to have an average wind speed between 3-7 m/s then the wind turbine will give a power between 0,12-1, W which will be enough to start the water pump working. But in the site where the wind ISBN:

7 turbine is located the wind speeds can have sometimes more than 7 m/s which ensure a good supply of energy for water pump. For the time when the wind doesn t blow in the site is a tank where the water is stored and can supply enough water for domestic needs. Conclusions The renewable energy sources have clear benefits that distinguish them from fossil fuels. They are diverse: renewable energy sources can be exploited in more ways and in more places than fossil fuels. They are environment friendly origin, being known as green electricity : either they do not lead to greenhouse gas emissions, as in wind and solar energy production. That is way we use the wind energy to pump water in a location that is remote from electricity grid and that is unattended for long periods. For our purpose we take the decision to install in the site the wind turbine with horizontal axis which meets all the conditions required for the water supply of buildings in the small community. In this case wasn t necessary to have a turbine to produce electricity for a water pump. It is possible to use only the turbine itself to supply water for domestic use. References: [1] Mugea, N., Smuda, E. - Wind multiblade turbine to pump water. In Conference INMATECH 2001, Bucharest, Romania. [2] Manwell, J.F. - Wind energy, New York: Wiley, [3] Paul, G. - Wind power: renewable energy for home, farm and business. Chelsea Green Publishing Co., 200. [] Colangelo, V. J., - Engineering aspects of product liability. American Society for Metals, [] Dermot, M.G. Wind for home energy. Ney York: McGraw Hill, ISBN: