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Development of energy saving measures and improving energy efficiency of the enterprise

Contents

Introduction

To date, paying electricity bills is one of the expenses of any enterprise. It is impossible to create a large-scale automated machine manufacture, complex automated control systems, to introduce electronic computer machines in heavy industry, transportation, civil engineering, scientific-research and design centers, planning organizations without high energy consumption [2]. In this connection, the issue of energy saving and increasing energy efficiency of the enterprise is urgent.

Currently, the ways of saving electricity are being constantly updated. The simplest way to save energy has always been the appointment of a person responsible for reducing the cost of lighting the premises, supplying computers during non-working hours, etc. However, in our age of innovation and progress there are simpler ways, some of which will be discussed in this abstract.

Types of energy saving measures

Energy saving measures can be divided into those that do not require significant interventions in the structural part of the building and those that require the change of the electrical or structural part of the building.

The first type includes such measures as the replacement of light bulbs with LEDs, drives withvariable frequency drives (VFD)..

The second type can comprise the introduction of capacitor units to the electric power circuit of the enterprise to compensate for reactive power, the installation of photovoltaic systems for independent generation of electric power, as well as the green roof technology to increase the service life of roofingmaterials, to improve sound insulation, heat saving and to increase the efficiency of the photovoltaic installations.

Light-emitting diodes as the most efficient light bulbs

Today, there are four main types of lightbulbs:

  1. 1. The traditional incandescent lamp is currently one of the most common lamps. Consisting of a base, a glass bulb and a tungsten filament. The filament is heated and emits light. It is on heating that 80% of the power of this lamp is spent, and only 20% - on lighting.
  2. 2. A halogen lamp is structurally similar to an incandescent lamp, the glow is also due to the incandescence of the tungsten filament, but the filament itself is placed in a bulb with halogen gas, which allows to significantly increase the light output and to make smaller lamps. Due to this feature, lamps of this type have found wide application in automobiles, as well as in small lamps.
  3. 3. A fluorescent lamp (energy-saving), is a gas-discharge light source in which an electric discharge in mercury vapor creates ultraviolet radiation, which is converted into visible light by means of phosphor. Lamps of this type have been actively used since 2010, mainly in offices, in the form of tubular lamps. The energy efficiency of these lamps is about 5 times higher than that of incandescent lamps.
  4. 4. An LED lamp is the most modern and energy-efficient type of lamps in terms of light sources evolution. The name shows that LEDs are used as the light source. Structurally, such lamps are more complicated, that is why their price is several times higher than of incandescent lamps. However, the cost recovery of these lamps is not more than two years, due to the fact that95-98% of the power is spent on light and only 2-5% on heating and less significant transit losses.

Comparison of the main characteristics hasbeen summarized in Table 1.

Table 1–. Comparison of lamps
Таблица сравнения энергоэффективности разных типов ламп

Conclusion: apparently, with the same light output, the energy consumption of LED lamps is several times lower, since heat output is minimal. Another advantage of LEDs in terms of energy efficiency is a long bulb life.

Variable frequency drive

At enterprises, most electric motors are asynchronous electric motors with a squirrel-cage rotorin view of their advantages. The rotor speed can be adjusted by traditional methods, such as throttling with the use of valves, the use of couplings for torque control, discrete On / Off control.

The disadvantage of such methods of capacity control is the lack of a direct energy saving effect. Power consumption is reduced, but not as efficiently as the use of a variable frequency drive.

Figure 1 – Comparison of power consumption between two ways of efficiencyregulation

Figure 1 – Comparison of power consumption between two ways of efficiencyregulation

As can be seen from the graph below, the main performance of the system is 70%. If the engine speed is reduced, this will lead to significant energy savings.

Обобщенный рабочий цикл систем нагрева, вентиляции, кондиционирования

Figure. 2 – Generalized operating cycle of heating, ventilation, air conditioning

In general, the use of a variable frequency asynchronous electric drive in pumping and fan units gives the following advantages:

  1. energy saving up to 60%;
  2. saving the transported product by reducing waste to 25%;
  3. reduction of a network failure rate and reduction of electrical equipment failure due to elimination of inrush currents;
  4. reduction of noise level produced by technological equipment;
  5. convenience of automation;
  6. convenience and ease of implementation.

Capacitor units (CU)

Many electrical installations, along with active power, also consume reactive power, which is spent on creating electromagnetic fields and being useless for the consumer. The reactive component reduces the quality of electricity, leads to additional losses and overheating of the wires, overload of the substation, voltagedrops in the network. Now, due to the introduction of modern devices (lighting and advertising, air conditioning, frequency converters of electric drives, etc.), the increase in reactive power exceeds the growth in the consumption of active power. To reduce the reactive power, capacitor installations are used.

Advantages of CUs are:

  1. small losses (up to 0.5 W per 1 kVar of power);
  2. simple installation and operation;;
  3. possibility to connect at any point of thenetwork;
  4. low operating costs;
  5. possibility of compensation of almost any reactive power;
  6. payback up to one year.

The use of CU will help to reduce the pay for the reactive powerconsumed.Active power will decrease because of the decrease in reactive power. CUscan help to avoid deep voltage drops at the remote consumer, and further, in the reconstruction, it will be possible to use a cable with a smaller cross-section.

When electric motors, compressors, pumps are used, the load has an inductive character, which leads to a current lagging behind the voltage. In this case, the power factor is reduced, which must be compensated for by the capacitive load. Capacitor units serve this purpose, compensating the reactive power in automatic mode, and thereby reducing the overall loss of the consumer. In particular, with a rise in the cosine of fi from 0.5 to 0.9, the reduction in the total power consumption is 44%.

Photovoltaic systems

Uninterrupted supply of production processes is extremely importantfor industrial enterprises, since most processes are built on the basis of complex controllers and automation systems. De-energizing a generator at the starting time is extremely undesirable and often destructive for them.

Of course, it is possible to solve the issue of uninterrupted operation by means of a generator, but the cost of fuel, fire-retardant premises and slow start-up makes industrial enterprises install photovoltaic modules. Another advantage is the "green" tariff, which allows you to sell surplus electricity to the grid, which will significantly reduce the payback period of the solar battery. Unfortunately, there are a number of drawbacks, such as a decrease in efficiency at work of the photocell in the heat, but this disadvantagecan be solved at the expense of another energy-saving measure, namely, the green roof technology.

Diagram of the energy distribution, when using a <q>green,</q> rate

Figure 3 – Diagram of the energy distribution, when using a green, rate
(animation: 7 frames, 5 cycles of repeating, 376 kilobytes)

Green roof technology

There are two types of green roofs. Theseare extensive roofs, which requiremaintenance 1-2 times a year and are lightweight and are established on a very thin layer of soil, and intense roofs, which require regular maintenance, in the form of grass mowing, fertilizing, watering, weeding, and so on. Any type will have a beneficial effect on energy saving, because green roofs improve the microclimate, increase water absorption, reduce energy costs, reduce the cost of the roof reconstruction, and create additional space.[1]

Consider the following:

  1. . Green roofs cool and humidify the air, which significantly reduces the load on the air-conditioning system of the room.
  2. They absorb from 50 to 90% of precipitation and reduce the peak load of the drainage system. Drains, pipes and drainage holes can be manufactured with less capacity, thereby reducing construction costs.
  3. Green roofs are a kind of temperature buffer, which improves the energy consumption in the building.
  4. The green roof protects waterproofing from the effects of temperature fluctuations, ultraviolet radiation and mechanical damage. This greatly increases the waterproofingservice life, which allows you to reduce its maintenanceand repair cost.

Another important factor is the dependence of the solar panel efficiency on the ambient temperature. The temperature of the Standard Test Mode, by which the PV modules were measured, is 25 °С. But in practice, the temperature of the modules rises significantly due to the solar radiation. This is intensified by the hot roof surface, for example, by dark waterproofing or a roof with a layer of gravel, which can easily raise the temperature to 90 °С.

ZinCo has conducted studies of solar panel efficiency, depending on the ambient temperature and the surface where these panels are installed. The tests included two modules mounted on "bare" bituminous surfaces, which were compared with one module mounted on a green cover. In each case, attention was focused on the temperature in the lower panel.[1].

Аn example of the temperature chart, measured in the afternoon in July

Figure 4 – Аn example of the temperature chart, measured in the afternoon in July. The temperature of the modules on the bituminous surfaces (black and gray lines) rises to almost 40°C, while the module on the green surface (green line) does not exceed the maximum value of 27°C, which is close to the ambient temperature (red line )

The change in the efficiency of the module is related to the temperature and demonstrated using a temperature coefficient. It depends on the product and reaches 0.5% per degree Kelvin in the standard solar panel. Due to the fact that the temperature coefficient of the idle voltage is much larger than the temperature coefficient of the short-circuit current, with increasing temperature the voltage drop is greater than the increase in the current strength. Therefore, the power of the solar battery, as a product of the current to voltage, decreases with increasing temperature, and the battery operates at a lower efficiency. [4]

Сonclusion

With the increase in electricity consumption due to the electrification of production processes, the cost of electricity increases, but new energy-saving systems will help reduce costs with a minimum payback period.

Bibliography

  1. ZinCo. Руководство по планированию. Солнечная энергия и зеленые кровли.
  2. Веселовский О.Н., Шнейберг А.Я. Очерки по истории электротехники. [Электронный ресурс]. – режим доступа:http://www.electrolibrary.info/history/progress.htm.
  3. Демин В. П., Коваленко В.И., Сахби Зантур. Энергосберегающие технологии в промыщленности
  4. Йе Вин. Виссарионов В.И. Исследование влияния температуры характеристики фотоэлектрических преобразователей.//Научно-техническое творчество молодежи — путь к обществу, основанному на знаниях: Москва, ВВЦ, 2012. — 486—488 с.
  5. DIBT, Май -2012.
  6. Официальный сайт ООО Чистая Энергия [Электронный ресурс] – Режим доступа:http://sunalt.ru/.
  7. Издательство СибАК [Электронный ресурс] — Режим доступа: http://sibac.info .
  8. Сравнение видов освещения [Электронный ресурс] — Режим доступа: http://svetlix.ru/.
  9. Портал магистров ДонНТУ [Электронный ресурс] — Режим доступа: http://masters.donntu.ru/.