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Due to the constant rise in the cost of carbohydrate energy carriers, experts are paying more and more attention to the benefits of using electricity generated in a more economical way. One of the most economical and environmentally friendly...
Due to the constant rise in the cost of carbohydrate energy carriers, experts are paying more and more attention to the benefits of using electricity generated in a more economical way. One of the most economical and environmentally friendly ways to generate electricity is a hydroelectric power plant for the home, the costs of which are reduced to the primary construction and maintenance of equipment. But not every locality has natural opportunities for the construction of such structures, which require a powerful water flow and a large elevation difference created by the dam, in this case, mini hydroelectric power plants come to the aid of power engineers.
The principle of operation and mini hydroelectric power station
The principle of operation of this equipment is quite simple, which adds to its reliability. The water flow, falling on the blades of the turbine, rotates the hydraulic drive, coupled with the electric generator, which ensures the generation of electricity under the control of the control system.
Modern mini hydroelectric power plants are equipped with a control system that makes it possible to operate in automatic mode with an instant transition to manual control in the event of an emergency. A multi-level protection system allows you to avoid equipment overloads when external conditions change. The design of the stations allows minimizing construction work during the installation of the necessary equipment.
Varieties of mini hydroelectric power stations
A mini hydroelectric power plant is equipment with a capacity of 1 to 3000 kW, which includes a water intake device (turbine), a generating power unit and an equipment control system.
Depending on the water resources used, mini hydroelectric power plants are divided into several categories:
- run-of-river stations using the energy of small rivers with organized reservoirs. They are mainly used on flat terrain;
- stationary stations using the energy of a fast current in the operation of mountain rivers;
- stations using water flow differences at industrial enterprises;
- mobile stations using reinforced hoses to organize the flow.
According to the expected pressure of the water flow, the hydroelectric unit and its turbine are designed to match the power of the power generating unit to provide the required generator speed and facilitate the creation of the required current frequency.
For various operating conditions of mini hydroelectric power plants, appropriate turbine designs have been developed:
- with a large water flow pressure of more than 60 m, radial-axial and bucket turbines are used;
- with an average flow intensity of 25 - 60 m, turbines of a rotary-blade and radial-axial design have proven themselves well;
- on low-pressure flows, it is more profitable to use rotary-vane and propeller structures placed in reinforced concrete chambers.
Video homemade hydroelectric power plant
Features of connecting a mini hydroelectric power station
The device of this equipment allows you to connect stations directly to the power supply network, in this case a synchronous generator is used. To create a local network, an asynchronous unit is used, which is equipped with a ballast load unit necessary to dissipate excess power in order to avoid failure of power supply systems and abrupt changes in the main network parameters.
Advantages and disadvantages of mini hydroelectric power plants
The advantages of such systems include:
- environmental safety of equipment and no need to flood large areas;
- low cost of generated electricity, which is several times cheaper than that generated at thermal power plants;
- simplicity and reliability of the equipment used and the possibility of its offline operation;
- inexhaustibility of the natural resource used
The disadvantages include:
- interruptions in the power supply of certain regions in the event of equipment failure, in the case of using a mini hydroelectric power station as a local source. This is compensated by the presence of an emergency power supply, connected automatically;
- weak production and repair base of this branch of energy supply in our country.
Since electricity tariffs have recently begun to rise, renewable sources of electricity are becoming increasingly important among the population, allowing them to receive electricity almost free of charge. Among such sources known to mankind, it is worth highlighting solar panels, wind turbines, as well as home hydroelectric power plants. But the latter are quite complex, because they have to work in very aggressive conditions. Although this does not mean at all that it is impossible to build a mini-hydroelectric power station with your own hands.
To do everything correctly and efficiently, the main thing is to choose the right materials. They should ensure maximum durability of the station. Homemade hydro generators, which are comparable in power to those of solar panels and windmills, can produce much more energy. But although a lot depends on the materials, everything does not end there.
Varieties of mini hydroelectric power plants
There are a large number of different variations of mini-hydroelectric power plants, each of which has its own advantages, features and disadvantages. There are the following types of these devices:
- garland;
- propeller;
- rotor Daria;
- water wheel with blades.
The garland hydroelectric power station consists of a cable on which the rotors are fixed. Such a cable is pulled across the river and immersed in water. The flow of water in the river begins to rotate the rotors, which in turn turn the cable, at one end of which there is a bearing, and at the other - a generator.
The next type is a water wheel with blades. It is installed perpendicular to the water surface, immersing less than half. Since the flow of water acts on the wheel, it rotates, and makes the generator for the mini-hydroelectric power station spin, on which this wheel is fixed.
Classic water wheel - well forgotten old As for the propeller hydroelectric power station, it is a windmill located under water with a vertical rotor. The width does not exceed 2 centimeters. This width is enough for water, because it is this value that allows you to produce the maximum amount of electricity with minimal resistance. True, this width is optimal only for flow rates up to 2 meters per second.
As for other conditions, the parameters of the rotor blades are calculated separately. And the Darrieus rotor is a vertically positioned rotor, which operates on the principle of differential pressure. Everything happens similarly with the wing of the aircraft, which is affected by the lifting force.
Advantages and disadvantages
If we consider the garland hydroelectric power station, then it has a number of obvious shortcomings. Firstly, the long cable used in the construction is a danger to others. Rotors hidden under water also pose a great danger. Well, in addition, it is worth noting the low efficiency and high material consumption.
As for the disadvantages of the Darier rotor, in order for the device to start generating electricity, it must first be untwisted. True, in this case, power is taken directly above the water, so no matter how the flow of water changes, the generator will generate electricity.
All of the above are factors that make the hydro turbine for mini-hydro power plants and water wheels more popular. If we consider the manual construction of such devices, then they are not so complicated. And in addition, at minimal cost, such mini-hydroelectric power plants are able to produce maximum efficiency indicators. So the criteria for popularity are obvious.
Where to start building
The construction of a mini-hydroelectric power station with your own hands should begin with measuring the speed indicators of the flow of rivers. This is done very simply: just mark a distance of 10 meters upstream, pick up a stopwatch, throw a chip into the water, and note the time it takes for it to cover the measured distance.
Ultimately, if 10 meters is divided by the number of seconds elapsed, you get the speed of the river in meters per second. It should be borne in mind that there is no point in building mini-hydroelectric power stations in places where the flow velocity does not exceed 1 m / s.
If the reservoir is far away, you can build a bypass channel If you need to figure out how mini-hydroelectric power stations are made in an area where the river speed is low, then you can try to increase the flow by organizing a height difference. This can be done by installing a drain pipe into the reservoir. In this case, the diameter of the pipe will directly affect the rate of water flow. The smaller the diameter, the faster the flow.
This approach allows you to organize a mini-hydroelectric power station even if a small stream passes near the house. That is, a collapsible dam is organized on it, below which a mini-hydroelectric power station is directly installed to power the house and household appliances.
I have always been attracted to getting free energy from natural resources. And somehow I had the idea to make a simple mini power plant that would generate electricity from a passing water stream.
It all started with the idea of using the drum of an old washing machine as a water wheel, a miniature homemade hydroelectric power plant.
Straight blades made of moisture-resistant plywood were attached to the drum using metal corners.
Torque from the water wheel is transmitted by a belt to a bicycle dynamo (DC generator). The generated electricity is fed to the LED. It is enough to turn the wheel slightly with your hand, and the LED will start flashing.
The basis of the whole structure is a bicycle frame.
Two bearings allow the water wheel to spin freely.
The first tests on a small river showed that the water wheel on the frame is set too high, which prevents the flow of water from spinning it normally.
After small changes in the frame design, the wheel began to be located lower and the rotation speed increased dramatically. As a result, the dynamo began to rotate and the 4.5 V LED lit up.
This is how a home-made hydroelectric power station turned out from the old trash.
Further, the mini hydroelectric power station assembly was installed on a small stream.
It produces only a few volts, but they are enough to light the LED.
It was a good experiment to start with.
Further improvement in the project
Further improvement of the water wheel should affect:- Build a mini-dam to increase water pressure. At the same time, it is not planned to completely block the river so that the fish can leave in the second stream.
- Under the dam, install a pipe through which water will flow to a makeshift turbine. Arrange a casing from a rubber conveyor belt in the pipe. By blocking the flow of water through the pipe, you can service the mechanisms.
- According to calculations, the turbine will produce about twice as much power as the water wheel. In addition, replacing the water wheel with a turbine should eliminate the problem of freezing in winter.
- The flow of water will spin the turbine, transferring torque to the generator. The turbine will be held on two bearings made of solid wood. With regular lubrication, they will last a long time. The thrust washer will keep the mechanism from lateral displacement.
- Make metal blades, calculating the angle at which they need to be bent (the power of the hydroelectric power plant depends on this parameter). The blades will need to be screwed using rubber gaskets to avoid their separation.
- To transmit torque, use a shaft assembled from pipes.
- Install generator. Install a pulley smaller than the one mounted on the shaft on the generator. This will increase the speed, which is necessary for the efficient operation of the generator.
If a river or even a small stream flows near your home, then with the help of a home-made mini hydroelectric power station you can get free electricity. It may not be a very big budget replenishment, but the realization that you have your own electricity costs much more. Well, if, for example, in a country house, there is no central power supply, then even small power capacities will be simply necessary. And so, to create a home-made hydroelectric power station, at least two conditions are necessary - the presence of a water resource and desire.
If both are present, then the first thing to do is to measure the flow rate of the river. It is very simple to do this - throw a twig into the river and measure the time during which it swims 10 meters. By dividing meters by seconds, you get the speed of the current in m/s. If the speed is less than 1 m / s, then a productive mini hydroelectric power station will not work. In this case, you can try to increase the flow rate by artificially narrowing the channel or by making a small dam if you are dealing with a small stream.
As a guide, you can use the ratio between the flow velocity in m/s and the power of the electricity removed from the propeller shaft in kW (propeller diameter 1 meter). These are experimental data, in reality the received power depends on many factors, but it is suitable for evaluation. So:
0.5 m/s - 0.03 kW,
0.7 m/s - 0.07 kW,
1 m/s - 0.14 kW,
1.5 m/s - 0.31 kW,
2 m/s - 0.55 kW,
2.5 m/s - 0.86 kW,
3 m/s -1.24 kW,
4 m/s - 2.2 kW, etc.
Power homemade mini hydroelectric power station proportional to the cube of the flow rate. As already mentioned, if the flow rate is insufficient, try to artificially increase it, if this is of course possible.
Types of mini hydroelectric power plants
There are several basic options for homemade mini hydroelectric power plants.
Water wheel
This is a wheel with blades mounted perpendicular to the surface of the water. The wheel is less than half immersed in the stream. Water presses on the blades and rotates the wheel. There are also turbine wheels with special blades optimized for the liquid jet. But these are rather complex designs, rather factory-made than home-made.
Rotor Daria
It is a vertical axis rotor used to generate electrical energy. A vertical rotor that rotates due to the pressure difference on its blades. The pressure difference is created due to the fluid flow around complex surfaces. The effect is similar to the lift of a hydrofoil or the lift of an airplane wing. This design was patented by Georges Jean-Marie Darier, a French aeronautical engineer, in 1931. It is also often used in the construction of wind turbines.
Garland hydroelectric power station
The hydroelectric power plant consists of light turbines - hydro vingrotors, strung and rigidly fixed in the form of a garland on a cable thrown across the river. One end of the cable is fixed in the support bearing, the other end rotates the generator rotor. The cable in this case plays the role of a kind of shaft, the rotational movement of which is transmitted to the generator. The flow of water rotates the rotors, the rotors rotate the cable.
Propeller
Also borrowed from the designs of wind farms, such a "underwater windmill" with a vertical rotor. Unlike an air propeller, an underwater propeller has blades of a minimum width. For water, a blade width of only 2 cm is sufficient. With this width, there will be a minimum resistance and a maximum rotation speed. This width of the blades was chosen for a flow velocity of 0.8-2 meters per second. At high speeds, other sizes may be optimal. The propeller does not move due to water pressure, but due to the occurrence of lift. Just like an airplane wing. The propeller blades move across the flow rather than being carried along by the flow in the direction of the flow.
Advantages and disadvantages of various homemade mini hydroelectric systems
Flaws garland hydroelectric power station obvious: high material consumption, danger to others (long underwater cable, rotors hidden in the water, blocking the river), low efficiency. Garland HPP is a kind of small dam. It is advisable to use in deserted, remote places with appropriate warning signs. You may need permission from the authorities and environmentalists. The second option is a small stream in your garden.
Rotor Daria- difficult to calculate and manufacture. At the beginning of work, it needs to be untwisted. But it is attractive in that the rotor axis is located vertically and the power take-off can be made above the water, without additional gears. Such a rotor will rotate with any change in the direction of flow - this is a plus.
Most widespread at construction of self-made hydroelectric power plants got propeller and water wheel diagrams. Since these options are relatively simple to manufacture, require minimal calculations and are implemented at minimal cost, have high efficiency, are easy to set up and operate.
If you do not have a water energy resource, you can independently make a home wind farm.
P An example of the simplest mini hydroelectric power station
The simplest hydroelectric power station can be quickly built from an ordinary bicycle with a dynamometer for a bicycle headlight. Several blades (2-3) must be prepared from galvanized iron or not thick sheet aluminum. The blades should be 2-4 cm long from the wheel rim to the hub, and 2-4 cm wide. These blades are installed between the spokes in any improvised way or pre-prepared mounts.
If you are using two blades, then set them opposite each other. If you want to add more blades, then divide the circumference of the wheel by the number of blades and install them at regular intervals. You can experiment with the depth of immersion of a wheel with blades in water. Usually it is immersed from one third to half.
The option of a camping wind farm was considered earlier.
Such a micro hydroelectric power station does not take up much space and will serve cyclists well - the main thing is the presence of a stream or river - which is usually the case at the campsite. A mini hydropower plant from a bicycle will be able to light a tent and charge cell phones or other gadgets.
The history of hydropower originates from a simple water wheel, which our ancestors had the idea to install on the rapids of the river. At first it was used for a mill, thereby facilitating the work of millstones. Later, people learned to use the power of water for a variety of purposes - papermaking, sawing logs, blacksmithing, and even brewing. The crown of creation was an electric generator, which was connected to a turbine. This is how hydroelectric power stations appeared, the principle of which is used today for home inventions, including today's homemade products.
Its author managed to assemble it literally from an old washer, slightly modernizing and competently using the resources of the nearest river in his suburban area. He claims that he has been living for several years without being connected to the electrical grid, and does not pay a penny for electricity. The power from the hydro generator is enough to supply electricity not only to all electrical appliances in the house, but also to pull the work of the workshop with power tools. How is this possible? Let's take a look together.
The principle of operation of a hydroelectric generator
In this home development, the native body of the washing machine is used. The engine is remounted to generator mode, and placed back in its seat. The Pelton wheel is used as a driving turbine that accumulates water flows and transfers kinetic energy to a generator. Alternating 3-phase current obtained at the output of the generator is passed through a rectifier of three diode bridges. Direct current is supplied to charge the batteries through the controller, and from them to the 12V / 220V inverter, again receiving a variable frequency.Materials, tools
Materials:- Old washing machine with inverter motor;
- Pelton wheel;
- A small piece of awning;
- Plywood;
- Plexiglas or plexiglass;
- Silicone;
- Waterproofing for plastic - paint or mastic;
- Self-tapping screws, nuts, washers, bolts and sandpaper.
- Drill with a crown cutter, drills and a nozzle for self-tapping screws;
- Reciprocating saw or electric jigsaw;
- Hand tools: wrenches, pliers, paint knife and silicone gun.
We assemble a hydroelectric generator
Preparatory dismantling workFirst you need to disassemble the washing machine, leaving only the parts we need.
The machine is of a vertical type, so we remove the end cover from the front side and dismantle the electronic control panel for washing modes.
We take out the outer drum and dismantle the pump and excess water supply hoses.
We do not need a flywheel for washing, as well as an internal steel container for laundry.
All that should be left is the outer plastic drum and the motor on the shaft.
As we can see, the rewired inverter motor already produces electricity when the shaft rotates.
Now you need to disassemble the engine, leaving only the shaft with bearings on the housing.
Hydro turbine manufacturing
A rubber gasket cut from an old chamber will help seal our shaft. We make a hole in it in the middle, and fit it tightly on the shaft shaft.
A small Pelton wheel will take the water. This invention is almost one and a half hundred years old, but it still does not lose its relevance and is used even at some hydroelectric power plants. It must be fixed on the shaft so that it can move freely and does not touch the housing.
We mark a hole under it in the body for water supply, and drill it with a crown cutter.
With a jigsaw or reciprocating saw, we make a drain hole in the shape of a rectangle, and close it with self-tapping screws with a segment of a waterproof awning. It should look like this (photo).
Next, you need to make a plug for the tank of our hydraulic turbine. We make it from a piece of moisture-resistant plywood, cutting a circle with a jigsaw equal to the inner diameter of the drum. We make an inspection hole in the plug itself to control the operation of the unit. Which will then be covered with plexiglass.
We coat the end of the plywood with silicone, and put it inside. We fix it with self-tapping screws through the turbine housing.
We cut out a gasket for plexiglass from a rubberized material, and glue it on silicone to plywood.
We drill four holes on the sides of the window rectangle, and from the inside we place clamping bolts in them. We will fix plexiglass on them so that it is removable in case of unforeseen breakdowns.
We seal the joint of our plug with the body with silicone.
To protect the electrical part of the unit, the author installed an additional plastic casing on the edge of the turbine using self-tapping screws. The plastic case itself was painted over with paint to protect the plastic from cracking.
It was the turn to assemble the engine, install it on the unit. We fasten the stator to the landing bolts.
To obtain direct current for charging batteries, we fix a bar of three diode bridges, each per phase.
We cover the engine with a rotor cover, and plug the extra drain holes for the hoses remaining in the housing.
