Energy saving in the company - main directions:
- Energy saving
- Reduction of heat and steam losses
- Reduction of losses in steam lines
Energy saving in the company - energy saving methods
- Selection of the optimal price category and revision of contractual supply conditions
- Electric motor optimization
- VFD installation
- Compressed air system optimization
Selection of the optimal price category for power supply
There are a total of 6 categories of power prices according to which companies can buy electricity from guaranteed suppliers.
All small companies with an installed capacity of less than 670 kW, at the time of concluding the contract for automatic power supply, fall into the first price category.
All companies with an installed capacity of more than 670 kW automatically fall into the third price category.
The first and third price categories are not always the most optimal and cheapest power supply categories.
In some cases, switching to another price category can reduce electricity costs by 5% -30%.
The topic of price categories is quite extensive, in our review of price categories we describe in detail how to correctly calculate and select the price category of power supply.
In addition to price categories, we recommend that you look carefully at other aspects of the power contract:
- voltage level,
- strength,
- electricity transmission tariff.
In our review, you can learn more about these and other methods to reduce energy costs.
Energy saving in the company - electric motors
It is necessary to take into account all the equipment that uses electric motors:
- pumps,
- compressors,
- fans,
- machine tools,
- production lines.
Electric motor control plan
The engine management plan should become an integral part of the plant's energy saving program.
Such a plan will help implement a long-term energy saving system for all electric motors in the company.
The engine management plan will ensure that failures and malfunctions do not occur, and if they do occur, they are resolved quickly and efficiently.
Steps to develop an engine management plan:
- Make a list of all engines in the building.
- Create a list of engines with their main parameters, technical condition, service life.
- Develop general instructions for performing repairs.
- Develop guidelines for preventive maintenance, lubrication and inspection.
- Create a safety stock of frequently used spare parts.
- Create a purchase specification for new engines.
Rewinding of electric motors
In general, rewinding an old electric motor is much cheaper than buying a new one.
The electric motor should be replaced if the rewinding costs are higher than 60% of the price of the new one.
Then it will all depend on how you rewind.
If the job is done at the highest level, then the engine will lose only 1% -2% percent of its efficiency.
If the rewind is performed poorly, then the losses in the electric motor will increase by 5% -10%.
Replacing an old electric motor with a new energy-efficient one makes sense in cases where the motor runs more than 2, 000 hours a year.
The payback period for a new energy efficient engine will not be longer than 1. 5 - 2 years.
Energy saving in the company by increasing the load factor
The load factor is the ratio of manpower to apparent power.
This is how energy is used efficiently.
The higher the load factor, the more efficiently the electricity is used.
The electric motor works optimally at a load of 75% and more.
Therefore, installing an engine above the required power (for safety reasons) will not only be more expensive, but also inefficient in terms of energy consumption.
The load factor can be increased as follows:
- switching off unloaded engines,
- replacement of engines loaded with less than 45% for less powerful models,
- load redistribution between existing electric motors.
Variable Frequency Drive (VFD)
Installing a variable frequency drive only makes sense for dynamic systems.
In static systems that are, for example, only included for lifting loads, the installation of a variable frequency drive will not help and can often be harmful.
The VFD balances the load and the speed of the motor, thus ensuring optimal use of electricity.
VFD can reduce engine power consumption by a minimum of 5% and a maximum of 60%.
The payback period for VFD is usually 1-3 years.
Compressed air system optimization
Compressed air is used in various industries.
In some companies, compressed air is the main consumer of electricity.
Compressed air is used in pneumatic devices and equipment, on conveyors, automatic lines.
The use of compressed air is popular because it is a convenient and safe source of energy.
But many people forget that compressed air is one of the most efficient sources of energy - only 5% of the electricity consumed in the production of compressed air is converted into useful work, and the remaining 95% goes into the pipe.
Energy savings in the company - compressed air:
- Do not use compressed air to clean the room.
- By reducing the air temperature at the compressor inlet by 3%, energy consumption is reduced by 1%.
- For those technical processes, where possible, reduce the compressed air pressure to a minimum. Lowering the pressure by 10% reduces energy consumption by 5%.
- Perform regular inspections, repairs of compressed air equipment and transmission lines. One, even the smallest leak of compressed air can sometimes reduce the efficiency of the equipment.
Energy savings in the company - we reduce heat and steam losses
Steam is often used in industry, especially in the textile, food and processing industries.
Improving the efficiency of steam boilers and reusing the heat produced can significantly reduce energy consumption in these plants.
Steam production
The boiler works most efficiently at full power.
Due to the fact that the demand for the amount of steam can change over time, it often happens that the boiler operates below its optimal load.
The capacity of the installed boiler can be much higher than the needs of the company due to falling demand for products or unrealized plans to expand production.
Also, boiler capacity may not be required due to improvements in the production process or the introduction of energy saving measures.
In such cases, the boiler operates either not at full capacity, or in the mode of short on and off cycles.
Both of these situations result in significant energy losses.
There are no easy and cheap solutions to this problem.
The easiest option isinstall a "small" boiler that will operate at full capacitywith an average or low workload in the enterprise.
Despite the fact that this is not a cheap solution, the payback period of such an investment can be shorter than two years.
And in general, it is always more efficient to have several small interchangeable boilers, especially in companies with variable demand or significant seasonal oscillations in heat and steam consumption.
Automatic control system
If the company has several boilers, then it makes sense to install itautomatic boiler load control system. . .
Automation responds to the need for steam in the company, redistribution of load between boilers, switching on and off boilers, which significantly increases the efficiency of the entire system.
Shut-off valve
In companies where boilers are regularly shut down due to falling steam demand, heat losses through the chimney can be quite high.
It is possible to block the loss of hot air through the chimneyby installing a shut-off valvewhich closes the pipe when the boiler is switched off.
Prevention and maintenance
If burners and condensate return systems are left unattended, they can quickly break down or fail.
This can reduce boiler efficiency by 20% -30%.
A simple maintenance program - which ensures that all boiler components are operating at their maximum level - will significantly increase operational efficiency.
In practice, regular maintenance reduces the energy consumption of the boiler by 10%.
Insulation - heat losses from the surface of a properly insulated boiler should be below 1%.
Soot and scale removal
It is necessary to constantly monitor and eliminate the formation of soot on the pipes of the boiler, limescale inside the boiler.
A layer of carbon black with a thickness of 0. 8 millimeters reduces heat transfer by 9. 5%, while a layer with a thickness of 4. 5 millimeters reduces heat transfer by 69%!
Calculus is formed when calcium, magnesium and silicon are deposited on the boiler heat exchanger.
A 1 millimeter thick scale increases energy consumption by 2%.
Soot and scale can be removed mechanically or with acids.
The formation of soot and scale can be determined by increasing the temperature of the flue gases or by visual inspection when the boiler is not working.
The formation of soot and scale must be especially carefully monitored if the boiler is running on solid fuels (coal, peat, firewood).
Gas boilers are less prone to soot problems.
Boiler exhaust optimization
Boiler blowing is the discharge of water from the boiler in order to clean the water in the boiler from impurities and salt.
The purpose of boiler exhaust is to avoid or reduce scale formation.
Insufficient exhaust of the boiler can lead to the entry of water into the steam or the formation of deposits in the boiler.
Excessive blowing means loss of heat, water and chemicals.
The optimal level of exhaust depends on the type of boiler, the working pressure in the boiler, the preparation and the quality of the water used.
The first thing to pay attention to is water preparation. If the water is treated well (low salt content), the blowing rate can be 4%.
If there are foreign substances and salts in the water, then the blowing rate will be 8% -10%.
An automatic exhaust system can also significantly reduce energy consumption.
The payback period for such a system is usually 1-3 years.
Smoke emission reduction
Excessive smoke is often the result of air penetrating the boiler and chimney through leaks and vents.
This reduces heat transfer and increases the load on the compressor system.
Leaks and holes can be easily removed, it is only necessary to periodically perform a visual inspection of the boiler and chimney.
Air regulation
The more air used to burn fuel, the more heat is thrown into the wind.
The amount of air slightly above the ideal stoichiometric fuel / air ratio is required for safety reasons to reduce NOx emissions and depends on the type of fuel.
Boilers in poor technical condition can use up to 140% of additional air, which results in excessive emissions of flue ducts.
An efficient gas burner requires 2% to 3% of additional oxygen or 10% to 15% of additional air to burn fuel without producing carbon monoxide.
As a general rule, the efficiency of the boiler is increased by 1% for every 15% reduction of additional air.
Therefore, it is necessary to constantly check the ratio of fuel and air.
This event costs nothing, but has a very good effect.
Smoke emission control
The amount of oxygen in the flue gases is the sum of the additional air (added to increase safety and reduce emissions) and the air that enters the boiler through holes and leaks.
The presence of leaks and holes can be easily detected if a system is in place to monitor the incoming air and the amount of oxygen in the flue gases.
By using data on the amount of carbon monoxide and oxygen, it is possible to optimize the ratio of fuel and air in the boiler.
The installation of a flue gas monitoring and analysis system usually pays off in less than a year.
Energy saving in the company - installing economizers
The heat of the flue gases can be used to heat the water entering the boiler.
Heated water enters the boiler and needs less heat to be converted into steam, which saves fuel.
Boiler efficiency increases by 1% for every 22 ° C decrease in flue gas temperature.
The economizer can reduce fuel consumption by 5% - 10% and will pay off in less than 2 years.
Heat exchanger for extracting heat from water and steam from the boiler exhaust
The heat exchanger will help recycle about 80% of the water and steam from the boiler heat.
This heat can be used to heat buildings or to heat water that supplies boiler.
Any boiler with a constant exhaust rate of 5% or more is an excellent candidate for a heat exchanger.
If the exhaust system does not work in a constant mode, then it makes sense to consider switching it to a constant mode, while installing a heat exchanger.
The average return period of the heat exchanger will not be longer than 1, 5 - 2 years.
Installing a condensing economizer
The hot condensate can be returned to the boiler, which saves energy and reduces the need for purified water.
Condensation economizer can increase system efficiency by an additional 10%.
The installation of such an economizer should be performed under the close supervision of an expert who will take into account all the nuances of such a system, its effect on the boiler and the chemical composition of the water.
Using a system that returns condensate back to the boiler usually pays off in 1-1, 5 years.
A system that directs condensate to the hot water supply pays for in less than a year.
Cooling towers (cooling towers)
A cooling tower is a heat exchanger in which water is cooled by an air stream.
And in terms of energy efficiency, a cooling tower is a device that dissipates heat to the wind.
Energy saving potential in cooling towers:
- In some companies, it makes sense to completely abandon cooling towers. There are many cases when heating is used to heat a room and at the same time a cooling tower is used to dissipate heat. Installing a heat pump will solve the heating problem and at least partially reduce the need to use a cooling tower.
- Installing a switch for cooling tower fans can reduce energy consumption by 40%.
- Replacing aluminum or iron fans with new fans (fiberglass and plastic) can reduce energy consumption by up to 30%.
Reduction of losses in steam lines
Disconnection of steam lines without requirements
Steam needs and consumption are constantly changing.
This can lead to the fact that the entire steam distribution system is not used at full capacity, but only 20% -50%, which inevitably leads to heat loss.
It is clear that optimizing or reconfiguring the entire steam distribution system according to new needs will be very expensive and, perhaps, unfeasible.
However, identifying and closing steam lines that are rarely used can be a very effective energy saving measure.
Energy saving in the enterprise - Thermal insulation of pipes
Insulating steam pipes can reduce energy losses by up to 90%.
This is one of the fastest energy savings in a steam distribution system.
The average payback period for the insulation of pipelines through which steam or hot water is transferred is about 1 year.
Condensing pipes 1, 5-2 years.
Steam trap control
A simple program to monitor the technical condition of steam traps can significantly reduce heat loss.
For example, if maintenance has not been carried out for 3 to 5 years, then, as a rule, approximately one third of the steam siphons are faulty, which allows steam to pass into the condensate drainage system.
In practice, in companies that have a steam trap monitoring program, a maximum of 5% of steam traps are in poor condition.
The average payback period for the replacement or maintenance of one steam trap is less than six months.
A steam trap monitoring program will usually reduce steam losses by 10%.
Thermostatic steam traps
The use of modern thermostatic steam traps can reduce energy consumption and at the same time increase the reliability of the entire system.
The main advantage of thermostatic steam traps is that
- open when the temperature approaches the level of saturated steam (+/- 2 C °),
- emit non-condensing gases after each opening and
- they are in the open state at the beginning of the system operation, which ensures its rapid heating.
Also, these steam traps are very reliable and can be used in a wide range of pressures.
Turn off steam traps
You can reduce energy consumption by turning off steam traps on overheated steam lines when not in use.
Steam leak removal
A program to repair steam leaks in small holes can pay off in less than 3 to 4 months.
We must not forget that small leaks can go unnoticed for years, constantly damaging the system.
Reuse of condensate and steam
When the steam trap releases condensate from the steam system, a pressure drop creates steam from that condensate.
This steam, together with condensate, can be used in a heat exchanger to heat feed water or air.
Most importantly, this steam and condensate can be used near the point of discharge, as it can be very expensive to create a separate piping system to transport it to the point of use.