An excursion into history. The origin of the problem of energy saving
The problem of saving the energy resources of the planet was identified in the second half of the 20th century. So in the 70s of the last century, an energy crisis broke out all over the world. Oil prices increased 14.5 times from 1972 to 1981. And although most of the difficult moments of that time were overcome, the problem of saving the global fuel and energy complex received the status of a global especially significant problem, and every year more and more attention is paid to this issue.
Energy saving today
Due to technological development, there is a rapid increase in energy consumption around the world. In order for the planet's resources to be enough for humanity in the future, people are looking for various ways and solutions: alternative natural energy sources (wind, water, solar panels) are used, environmentally friendly technologies for generating energy by processing garbage and various household wastes have been invented, technological equipment is being modernized from year to year in order to reduce the power consumption of this equipment.
The energy efficiency of equipment is a private concern for each of us. After all, the amount in the monthly electricity bill directly depends on it. In Europe, electricity is much more expensive than in Russia, so every European tries to select high-tech equipment that consumes as little energy as possible. In our country, a much smaller number of people think about this, but in our country, the use of energy-saving technologies can also have a beneficial effect on the “thickness of your wallet”. Paying monthly electricity bills, we do not think that the annual operating costs are an impressive amount that could be spent on other purposes.
Energy efficiency in ventilation
The main source of electricity consumption in ventilation installations, as you might guess, is the fan, and more specifically the electric motor (or motor), due to which the fan impeller rotates.
Energy efficiency class IE
The European DIN motor standards are based on the IEC (International Electrotechnical Commission) equipment energy efficiency classification standard.
According to international standards, four energy efficiency classes of motors IE1, IE2, IE3 and IE4 have been developed to date. IE means "International Energy Efficiency Class" - an international energy efficiency class
- IE1 standard energy efficiency class.
- IE2 high energy efficiency class.
- IE3 ultra-high energy efficiency class.
- IE4 is the highest energy efficiency class.
Below are the efficiency curves of the motor corresponding to the energy efficiency class versus the rated power.
Starting January 1, 2017, all European motor manufacturers, in accordance with the adopted directive, will produce electric motors with an energy efficiency class of at least IE3
Selecting the energy efficiency of motors when selecting installations in the QC Ventilazione program
TM QuattroClima offers ventilation units with asynchronous motors of IE2 and IE3 classes, as well as premium EC motors IE4.
The fan type is selected by pressing the left mouse button on the "Fan" tab.
Centrifugal direct drive fan – asynchronous motor(standard IE2).
Direct drive centrifugal fan with EC motor complies with IE4 class.
You can choose the desired energy efficiency class of an asynchronous motor here, just below.
From theory to practice
For clarity, let's look at an example. We calculate a standard air handling unit with a flow rate of 20,000 m3/h and a free pressure of 500 Pa in three options:
1) With asynchronous motor class IE2
2) With IE3 asynchronous motor
3) With EC motor class IE4
And then we compare the results.
Installation with IE2 asynchronous motor
Installation with IE3 asynchronous motor
Installation with EC motor class IE4
In this case, the program selected a section of two EC fans.
Now let's compare the results.
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Asynchronous motor Energy efficiency class IE2 |
Asynchronous motor Energy efficiency class IE3 |
EC motor |
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Fan efficiency, % |
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Rated power, kW |
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Power consumption, kW |
The power consumption of an IE3 motor is 0.18 kW less than that of an IE2 motor. And the power difference between two EC motors and an IE2 motor is already 1.16 kW.
In the case of similar calculations for supply and exhaust ventilation high-flow ventilation units, the difference in the power consumption of IE2 and IE3 motors can reach 25-30%. And if dozens of installations are used at the facility, then the energy consumption of ventilation can be reduced by an order of magnitude and, thanks to this, save hundreds of thousands, or even millions of rubles.
In the following articles, we will talk about other ways to reduce the power consumption of electric motors when selecting ventilation units in the QC Ventilazione program. Earlier, we talked about improving the energy efficiency of low-flow ventilation units with rotary heat exchangers. You can read the article.
To increase the power and significantly reduce the energy consumption of burned out and new asynchronous motors, a unique modernization technology using combined windings of the Slavyanka type allows. Today, it is successfully implemented in several large industrial enterprises. Such modernization allows to increase the starting and minimum torques by 10-20%, to reduce by 10-20% starting current or increase the power of the electric motor by 10-15%, stabilize the efficiency close to the nominal value in a wide range of loads, reduce the current idle move, reduce steel losses by 2.7-3 times, the level of electromagnetic noise and vibrations, increase reliability and increase the overhaul period by 1.5-2 times.
In Russia, according to various estimates, asynchronous motors account for 47 to 53% of the consumption of all generated electricity, in industry - an average of 60%, in cold water supply systems - up to 80%. They carry out almost all technological processes associated with movement and cover all spheres of human life. In each apartment you can find more asynchronous motors than residents. Previously, since there was no task of saving energy resources, when designing equipment, they tried to “keep it safe” and used engines with a power exceeding the calculated one. Energy savings in design faded into the background, and such a concept as energy efficiency was not so relevant. The Russian industry did not design and produce energy-efficient motors. The transition to a market economy has dramatically changed the situation. Today, saving a unit of energy resources, for example, 1 ton of fuel in conventional terms, is half the price of extracting it.
Energy-efficient motors (EMs) are asynchronous EMs with a squirrel-cage rotor, in which, due to an increase in the mass of active materials, their quality, as well as due to special design techniques, it was possible to increase by 1-2% (powerful motors) or by 4-5% ( small engines) nominal efficiency with some increase in the price of the engine.
With the advent of engines with combined windings "Slavyanka" according to a patented scheme, it became possible to significantly improve the parameters of engines without increasing the price. Due to the improved mechanical characteristics and higher energy performance, it became possible to save up to 15% of energy consumption for the same useful work and create a variable speed drive with unique characteristics that has no analogues in the world.
Unlike standard ones, motors with combined windings have a high multiplicity of moments, have an efficiency and power factor close to the nominal value in a wide range of loads. This allows you to increase the average load on the engine up to 0.8 and improve the performance of the equipment serviced by the drive.
Compared to the known methods of improving the energy efficiency of an asynchronous drive, the novelty of the technology used by the Petersburgers lies in changing the fundamental principle of the design of classic motor windings. The scientific novelty lies in the fact that completely new principles for designing motor windings, choosing the optimal ratios of the numbers of grooves of the rotors and the starter have been formulated. Based on them, industrial designs and schemes of single-layer and double-layer combined windings have been developed, both for manual and automatic laying of windings on standard equipment. A number of RF patents have been obtained for technical solutions.
The essence of the development is that, depending on the scheme for connecting a three-phase load to a three-phase network (star or triangle), two systems of currents can be obtained, forming an angle of 30 electrical degrees between the vectors. Accordingly, it is possible to connect an electric motor to a three-phase network that does not have a three-phase winding, but a six-phase one. In this case, part of the winding must be included in the star, and part in the triangle and the resulting vectors of the poles of the same phases of the star and the triangle must form an angle of 30 electrical degrees with each other. The combination of two circuits in one winding makes it possible to improve the shape of the field in the working gap of the engine and, as a result, significantly improve the main characteristics of the engine.
Compared to the known ones, a frequency-controlled drive can be made on the basis of new motors with combined windings with an increased frequency of the supply voltage. This is achieved due to lower losses in the steel of the motor magnetic circuit. As a result, the cost of such a drive is significantly lower than when using standard motors, in particular, noise and vibration are significantly reduced.
The use of this technology in the repair of asynchronous motors allows, due to energy savings, to recoup the costs within 6-8 months. Per Last year Only the Research and Production Association "Saint Petersburg Electrotechnical Company" has modernized several dozens of burned out and new asynchronous motors by rewinding stator windings at a number of large enterprises in St. Petersburg in the bakery, tobacco industries, building materials plants and many others. And this direction is developing successfully. Today, the Scientific and Production Association "Saint Petersburg Electrotechnical Company" is looking for potential partners in the regions who are able to organize a modernization business together with Petersburgers asynchronous electric motors in your area.
Prepared by Maria Alisova.
Reference
Nikolay Yalovega- the founder of technology - professor, doctor of technical sciences. Received a US patent in 1996. As of today, it has expired.
Dmitry Duyunov— developer of methods for calculating layouts for laying combined motor windings. A number of patents have been issued.
Electric motors are among the main consumers of energy resources. One of the ways to increase the efficiency of electric motors is to replace the old fleet of electric machines with new modifications with improved energy saving characteristics. These are so-called high performance or energy efficient motors.
An energy-efficient engine is one in which efficiency, power factor and reliability are increased using a systematic approach in design, manufacture and operation.
Energy efficient IE2 motors are motors that are more efficient than standard IE1 motors, which means less energy consumption at the same load power level.
Along with energy savings, switching to IE2 motors allows:
- increase the life of the engine and related equipment;
- increase engine efficiency by 2-5%;
- improve power factor;
- improve the overload capacity;
- reduce maintenance costs and reduce downtime;
- increase the resistance of the engine to thermal loads and to violations of operating conditions;
- to reduce the workload for maintenance personnel due to the almost silent operation.
Asynchronous squirrel-cage motors are currently a significant part of all electrical machines, more than 50% of the electricity consumed is accounted for by them. It is almost impossible to find a sphere where they are not used: electric drives industrial equipment, pumps, ventilation equipment and much more. Moreover, both the volume of the technological park and the engine power are constantly growing.
Energy-efficient ENERAL motors of the AIR…E series are designed as three-phase asynchronous single-speed motors with a squirrel-cage rotor and comply with GOST R51689-2000.
The energy-efficient motor of the AIR…E series has increased efficiency due to the following system improvements:
1. The mass of active materials has been increased (copper stator winding and cold-rolled steel in stator and rotor packages);
2. Electrical steels with improved magnetic properties and reduced magnetic losses are used;
3. The tooth-groove zone of the magnetic circuit and the design of the windings are optimized;
4. Used insulation with high thermal conductivity and electrical strength;
5. Reduced air gap between rotor and stator with high-tech equipment;
6. A special fan design is used to reduce ventilation losses;
7. Higher quality bearings and lubricants are used.
New consumer properties of the energy-efficient motor of the AIR…E series are based on design improvements, where a special place is given to protection from adverse conditions and increased sealing.
So, design features AIR…E series allow minimizing losses in stator windings. Due to the low temperature of the motor winding, the service life of the insulation is also extended.
An additional effect is the reduction of friction and vibration, and hence overheating, through the use of high-quality lubricants and bearings, including a denser bearing lock.
Another aspect associated with a lower running engine temperature is the ability to operate at a higher ambient temperature or the ability to reduce costs associated with external cooling of a running engine. This also leads to lower energy costs.
One of important benefits new energy-efficient motor – reduced noise level. IE2 class motors use less powerful and quieter fans, which also plays a role in improving aerodynamic properties and reducing ventilation losses.
Minimization of capital and operating costs are key requirements for industrial energy efficient motors. As practice shows, the compensation period due to the price difference when purchasing more advanced asynchronous electric motors of the IE2 class is up to 6 months only by reducing operating costs and consuming less electricity.
AIR 132M6E (IE2) P2=7.5kW; Efficiency=88.5%; In \u003d 16.3A; cosφ=0.78AIR132M6 (IE1) P2=7.5kW; Efficiency=86.1%; In=17.0A; cosφ=0.77
Power consumption: P1=P2/efficiency
Load characteristic: 16 hours a day = 5840 hours per year
Annual energy cost savings: 1400 kWh
When switching to new energy-efficient motors, the following are taken into account:
- increased demands on environmental aspects
- energy efficiency requirements and performance characteristics products
- energy efficiency class IE2 acts as a unified “quality mark” for the consumer along with the saving possibilities
- financial incentive: opportunity to reduce energy consumption and operating costs integrated solutions: energy efficient motor + efficient control system (variable drive) + efficient protection system = best result.
Therefore, energy efficient motorsare engines of increased reliability for enterprises focused on energy-saving technologies.
The energy efficiency indicators of AIR…E electric motors manufactured by ENERAL comply with GOST R51677-2000 and the international standard IEC 60034-30 in terms of energy efficiency class IE2.
Modern three-phase energy-saving motors can significantly reduce energy costs due to a higher coefficient useful action. In other words, such engines are able to generate more mechanical energy from each kilowatt expended. electrical energy. More efficient energy consumption is achieved through individual reactive power compensation. At the same time, the design of energy-saving electric motors is characterized by high reliability and long service life.
Universal three-phase energy-saving electric motor Vesel 2SIE 80-2B version IMB14
Application of three-phase energy-saving motors
Three-phase energy-saving motors can be used in almost all industries. They differ from conventional three-phase motors only in their low energy consumption. With energy prices constantly rising, energy-saving electric motors can become a truly profitable option for both small producers of goods and services and large industrial enterprises.
The money spent on the purchase of a three-phase energy-saving motor will quickly return to you in the form of savings on the purchase of electricity. Our store offers you to get additional benefit by purchasing a quality three-phase energy-saving motor at a really low price. Replacing morally and physically obsolete electric motors with the latest high-tech energy-saving models is your next step to a new level of business profitability.
In accordance with the Federal Law of the Russian Federation "About energy saving" at an industrial enterprise, measures should be developed to save energy in relation to each electrical installation. First of all, this applies to electromechanical devices with an electric drive, the main element of which is an electric motor. It is known that more than half of all electricity produced in the world is consumed by electric motors in electric drives of working machines, mechanisms, and vehicles. Therefore, measures to save energy in electric drives are most relevant.
The tasks of energy saving require an optimal solution not only during the operation of electrical machines, but also during their design. During the operation of the engine, significant energy losses are observed in transient modes and, first of all, during its start-up.
Energy losses in transient conditions can be significantly reduced through the use of motors with lower values of the rotor inertia, which is achieved reduction of the rotor diameter while increasing its length, since the engine power must remain unchanged. For example, this is done in engines of crane and metallurgical series, designed to operate in intermittent mode, with a large number of starts per hour.
An effective remedy to reduce losses when starting motors is starting with a gradual increase in the voltage supplied to the stator winding. The energy consumed during engine braking is equal to the kinetic energy stored in the moving parts of the electric drive when it is started. The energy-saving effect of braking depends on the braking method. The greatest energy-saving effect occurs with regenerative regenerative braking with energy transfer to the network. During dynamic braking, the motor is disconnected from the network, the stored energy is dissipated in the motor and no energy is consumed from the network.
The greatest energy losses are observed during counter-current braking, when the power consumption is equal to three times the energy dissipated in the motor during dynamic braking. In the steady state operation of the engine with a rated load, the energy losses are determined by the nominal value of the efficiency. But if the electric drive operates with a variable load, then during periods of load decline, the efficiency of the motor decreases, which leads to an increase in losses. An effective means of energy saving in this case is to reduce the voltage supplied to the motor during periods of its operation with underload. This energy saving method can be implemented when the engine is running in a system with adjustable transducer if it contains feedback by load current. The current feedback signal corrects the drive control signal, causing a decrease in the voltage supplied to the motor during periods of load reduction.
If the drive is an asynchronous motor operating when the stator windings are connected "triangle", then the reduction of the voltage supplied to the phase windings can be easily implemented by switching these windings to the connection "star", since in this case the phase voltage decreases by 1.73 times. This method is also expedient because this switching increases the power factor of the motor, which also contributes to energy savings.
When designing an electric drive, it is important to correctly engine power selection. Thus, the choice of an engine with an overrated rated power leads to a decrease in its technical and economic indicators (efficiency and power factor) caused by underloading the engine. Such a decision when choosing an engine leads both to an increase in capital investments (with an increase in power, the cost of the engine increases) and operating costs, since losses increase with a decrease in efficiency and power factor, and, consequently, unproductive power consumption increases. The use of motors of underestimated rated power causes their overload during operation. As a result, the overheating temperature of the windings increases, which contributes to an increase in losses and causes a reduction in the life of the motor. Ultimately, accidents and unforeseen stops of the electric drive occur and, consequently, operating costs increase. This is especially true for engines. direct current due to the presence of a brush-collector assembly sensitive to overload.
Of great importance rational choice of ballasts. On the one hand, it is desirable that the processes of starting, braking, reversing and speed control are not accompanied by significant losses of electricity, since this leads to an increase in the cost of operating the electric drive. But, on the other hand, it is desirable that the cost of ballasts would not be extremely high, which would lead to an increase in capital investments. Usually these requirements are in conflict. For example, the use of thyristor ballasts provides the most economical start-up and motor control processes, but the cost of these devices is still quite high. Therefore, when deciding whether to use thyristor devices, one should refer to the work schedule of the designed electric drive. If the electric drive is not subject to significant speed adjustments, frequent starts, reverses, etc., then the increased costs for thyristor or other expensive equipment may not be justified, and the costs associated with energy losses may be insignificant. And vice versa, with intensive operation of the electric drive in transient conditions, the use of electronic ballasts becomes appropriate. In addition, it should be borne in mind that these devices are practically maintenance-free and their technical and economic indicators, including reliability, are quite high. It is necessary that the decision on the use of expensive electric drive devices is confirmed by technical and economic calculations.
The solution to the problem of energy saving is facilitated by the use of synchronous motors, which create reactive currents in the supply network that lead the voltage in phase. As a result, the network is unloaded from the reactive (inductive) component of the current, the power factor in this section of the network increases, which leads to a decrease in the current in this network and, as a result, to energy saving. The same goals are pursued by the inclusion in the network synchronous compensators. An example of the expedient use of synchronous motors is an electric drive compressor units supplying the company with compressed air. This electric drive is characterized by starting at a small load on the shaft, continuous operation at a stable load, lack of braking and reversing. This mode of operation is consistent with the properties of synchronous motors.
By using the overexcitation mode in a synchronous motor, significant plant-wide energy savings can be achieved. For a similar purpose, power capacitor units are used ( "cosine" capacitors). By creating a current in the network that leads the voltage in phase, these installations partially compensate for inductive (lagging in phase) currents, which leads to an increase in the power factor of the network, and therefore to energy savings. The most effective is the use capacitor units type UKM 58 with automatic maintenance of the set value of the power factor and with a step change in reactive power in the range from 20 to 603 kvar at a voltage of 400 V.
It must be remembered that energy saving is aimed at solving not only economic, but also environmental problems associated with the production of electricity.
