Energy saving in the company - the main directions:
- Save electricity
- Reduction of heat and steam losses
- Reduction of losses in steam lines
Energy saving in the enterprise - Energy saving methods
- Selection of the optimal price category and revision of the contractual conditions of supply
- Optimization of electric motors
- VFD installation
- Optimization of compressed air systems
Choice of the optimal price category for feeding
In total, there are 6 power price categories, under which enterprises can purchase electricity from guaranteed suppliers.
All small businesses with installed power below 670 kW, at the time of signing a contract for automatic power supply, fall into the first price range.
All companies with an installed power 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 economical power categories.
In some cases, switching to a different price category can reduce the cost of electricity by 5% -30%.
The topic of price categories is quite broad, in our price categories review, we tell in detail how to correctly calculate and choose the price category of the power supply.
In addition to the price categories, we recommend that you also investigate other aspects of the power supply contract:
- voltage level,
- power,
- electricity transmission tariff.
In our review, you can find out about these and other methods of reducing energy costs.
Energy Saving in the Company - Electric Motors
It is necessary to take into account all equipment in which electric motors are used:
- pumps,
- compressors,
- fan,
- machine tools,
- production lines.
Electric motor control plan
The motor control plan should become an integral part of the plant's energy saving program.
This plan will help implement a long-term energy saving system for all of the company's electric motors.
The engine check plan will ensure that no faults and malfunctions occur, and if they do occur, they are resolved quickly and efficiently.
Steps to create an engine control plan:
- Conduct an inventory of all engines in the facility.
- Make a list of engines with their main parameters, technical conditions, duration.
- 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 the new engines.
Rewinding of electric motors
Typically, rewinding an old electric motor is much cheaper than buying a new one.
The electric motor should be replaced if the cost of rewinding is over 60% of the cost of a new one.
So everything will depend on how the rewinding is done.
If the work is done at the highest level, the engine will lose only 1% -2% of its efficiency.
If the rewinding is performed poorly, the losses in the electric motor will increase by 5% -10%.
Replacing the old electric motor with a new, energy-efficient one makes sense in cases where the motor runs more than 2000 hours per year.
The payback period for a new energy efficient motor will not exceed 1. 5 - 2 years.
Energy saving in the company by increasing the load factor
The load factor is the ratio of operating power to apparent power.
This is how energy is used efficiently.
The higher the load factor, the more efficient the use of electricity.
The electric motor works optimally with a load of 75% and more.
Therefore, installing motors 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:
- shutdown of exhausted engines,
- replacement of motors, with a load of less than 45%, for less powerful models,
- load redistribution between existing electric motors.
Frequency converter (VFD)
The installation of frequency converters only makes sense for dynamic systems.
In static systems, which are only involved in lifting loads, for example, installing a frequency converter does not help and can often cause damage.
The VFD balances the load and the speed of the motor, thus ensuring that the electrical energy is used optimally.
The VFD can reduce motor energy consumption by a minimum of 5% and a maximum of 60%.
The payback period for VFD is usually 1-3 years.
Optimization of compressed air systems
Compressed air is used in a wide variety of industries.
In some companies, compressed air is the main consumer of electricity.
Compressed air is used in pneumatic devices and equipment, on conveyor belts, 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 inefficient sources of energy: only 5% of the electricity spent on producing compressed air turns into useful work, the remaining 95% goes into the pipe.
Energy saving in the company - compressed air:
- Do not use compressed air to clean the premises.
- Reducing the air temperature at the compressor inlet by 3% reduces energy consumption by 1%.
- For those technical processes, where possible, minimize the compressed air pressure. Lowering the pressure by 10% reduces energy consumption by 5%.
- Carry out regular inspections, repairs of compressor equipment and compressed air transmission lines. One, even the smallest loss of compressed air, can sometimes reduce the efficiency of the equipment.
Energy saving in the company: we reduce heat and steam losses
Steam is often used in industry, particularly in the textile, food and processing industries.
Improving the efficiency of steam boilers and reusing the heat generated can significantly reduce energy consumption in these systems.
Steam production
The boiler works most efficiently at full power.
Due to the fact that the demand for the amount of steam can vary over time, it often happens that the boiler is operating below its optimum load.
The capacity of the installed boiler can be much greater than the needs of the enterprise, due to a decline in demand for products or unrealized plans to expand production.
In addition, the capacity of the boiler 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-off cycles.
Both of these situations involve significant energy losses.
There are no simple and inexpensive solutions to this problem.
The simplest option isinstall a "small" boiler that will operate at full capacityto a medium or low workload in the enterprise.
While this is not an economical solution, the payback period for such an investment can be less than two years.
And, in general, it is increasingly efficient to have several small interchangeable boilers, especially in enterprises with changing demand or significant seasonal fluctuations in heat and steam consumption.
Automatic adjustment system
If the enterprise has several boilers, then it makes sense to install itautomatic system for regulating the boiler load. . .
The automation responds to the need for steam in the company, redistributing the load between the boilers, switching the boilers on or off, thus significantly increasing the efficiency of the entire system.
Gate valve
In enterprises where the boilers are regularly turned off due to a drop in steam demand, the heat losses through the chimney can be quite high.
It is possible to block the loss of hot air through the chimneyby installing a gate valvewhich closes the pipe when the boiler is off.
Prevention and maintenance
If left unattended, burners and condensate return systems can quickly deteriorate or fail.
This can reduce the boiler efficiency by 20% -30%.
A simple maintenance program - ensuring that all boiler components are operating at the highest level - will significantly increase operational efficiency.
In practice, regular maintenance reduces the energy consumption of the boiler by 10%.
Insulation: the heat loss from the surface of a properly insulated boiler must be less than 1%.
Removal of soot and encrustations
It is necessary to constantly monitor and eliminate the formation of soot on the boiler pipes, scale inside the boiler.
A 0. 8mm thick soot layer reduces heat transfer by 9. 5%, while a 4. 5mm thick layer reduces heat transfer by 69%!
Fouling is formed when calcium, magnesia and silicon settle on the boiler heat exchanger.
The 1mm thick scale increases power consumption by 2%.
Soot and encrustations can be removed mechanically or with acids.
The formation of soot and scale can be determined by an increase in the temperature of the fumes or by visual inspection when the boiler is not in operation.
The formation of soot and encrustations must be monitored with particular attention if the boiler works with solid fuels (coal, peat, firewood).
Gas boilers are less prone to soot problems.
Optimization of boiler purging
Boiler purging is the boiler water drain to clean the water inside the boiler of impurities and salts.
The purpose of the boiler purging is to avoid or reduce the formation of scale.
Insufficient bleeding of the boiler can lead to water entering the steam or the formation of deposits in the boiler.
Excessive purging means loss of heat, water and chemicals.
The optimal bleeding level depends on the type of boiler, the operating pressure in the boiler, the preparation and the quality of the water used.
The first thing to pay attention to is the preparation of the water. If the water is well treated (low salt content), the purge rate can be 4%.
If there are foreign substances and salts in the water, the purge rate will be 8% -10%.
The automatic purge system can also significantly reduce energy consumption.
The payback period for such a system is usually 1-3 years.
Reduction of smoke emissions
Excessive smoke is often the result of air entering the boiler and chimney through leaks and openings.
This reduces heat transfer and increases the load on the compression system.
Leaks and holes can be easily eliminated, it is only necessary to periodically carry out a visual inspection of the boiler and chimney.
Air regulation
The more air is used to burn fuel, the more heat is thrown into the wind.
A quantity of air slightly higher than the ideal stoichiometric fuel / air ratio is necessary for safety reasons, to reduce NOx emissions, and depends on the type of fuel.
Boilers in poor technical condition can use up to 140% more air, resulting in excessive smoke emissions.
An efficient gas burner requires 2% to 3% supplemental oxygen, or 10% to 15% supplemental air, to burn the fuel without generating carbon monoxide.
The general rule is that the boiler efficiency increases by 1% for every 15% of additional air reduction.
Therefore, it is necessary to constantly check the fuel / air ratio.
This event costs nothing, but it has a great effect.
Smoke emission monitoring
The amount of oxygen in the fumes is the sum of additional air (added to increase safety and reduce emissions) and air that filters into the boiler through holes and leaks.
The presence of leaks and holes can be easily detected if a system is set up to monitor the incoming air and the quantity of oxygen in the fumes.
Using data on the amount of carbon monoxide and oxygen, it is possible to optimize the fuel / air ratio in the boiler.
The installation of a smoke emission monitoring and analysis system usually pays for itself in less than a year.
Energy saving in the enterprise - Installation of an economizer
The heat from the fumes can be used to heat the water that enters the boiler.
The heated water enters the boiler and requires less heat to be converted into steam, thus saving fuel.
The boiler efficiency increases by 1% for every 22 ° C decrease in the flue gas temperature.
The economizer can reduce fuel consumption by 5% - 10% and pays for itself in less than 2 years.
Heat exchanger to extract heat from the water and steam from the boiler purge
The heat exchanger will help recycle approximately 80% of the water and steam heat from the boiler purge.
This heat can be used to heat buildings or to heat the water that feeds the boiler.
Any boiler with a constant bleed rate of 5% or more is a great candidate for a heat exchanger.
If the purge system is not operating in constant mode, it makes sense to consider transferring it to constant mode while installing a heat exchanger at the same time.
The average payback period for a heat exchanger will not exceed 1. 5 - 2 years.
Installation of a condensing economizer
Hot condensate can be returned to the boiler, thus saving energy and reducing the need for treated water.
The condensing economizer can increase system efficiency by an additional 10%.
The installation of such an economizer should be carried out under the strict supervision of specialists 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 the condensate to the boiler usually pays for itself in 1-1. 5 years.
A system that directs condensate to a hot water supply pays for itself 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 discharges heat to the wind.
Energy saving potential in cooling towers:
- In some companies, it makes sense to abandon cooling towers altogether. There are many cases where heating is used to heat a room and at the same time a cooling tower is used to dissipate the heat. Installing a heat pump will solve the heating problem and at least partially reduce the need to use the cooling tower.
- Installing circuit breakers for cooling tower fans can reduce energy consumption by 40%.
- Replacing aluminum or iron fans with new ones (molded in fiberglass and plastic) can reduce energy consumption by up to 30%.
Reduction of losses in steam lines
Disconnection of unclaimed steam lines
Steam needs and consumption are constantly evolving.
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 losses.
It is clear that optimizing or reconfiguring the entire steam distribution system to meet new needs will be very costly and perhaps not feasible.
However, identifying and closing underused steam lines can be a very effective energy saving measure.
Energy saving in the company - Thermal insulation of pipes
Steam pipe insulation can reduce energy losses by up to 90%.
This is one of the fastest energy savings returns in a steam distribution system.
The average payback period for the insulation of the pipes through which steam or hot water is transmitted is approximately 1 year.
Condensate pipes for 1, 5-2 years.
Monitoring of condensate drains
A simple program to monitor the technical condition of the steam traps can significantly reduce heat loss.
For example, if maintenance is not done for 3 to 5 years, typically around one third of steam traps are out of order, allowing steam to enter the condensate drain system.
In practice, in enterprises that have a steam trap monitoring program, no more than 5% of the steam traps are in faulty condition.
The average payback period for replacing or servicing a steam trap is less than six months.
A steam trap monitoring program will generally 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 they
- open when the temperature approaches the saturated steam level (+/- 2 C °),
- emit non-condensable gases after each opening e
- they are in the open state at the beginning of the system operation, which ensures its rapid heating.
In addition, these steam traps are very reliable and can be used over a wide range of pressures.
Disconnection of condensate drains
Energy consumption can be reduced by turning off steam traps on superheated steam lines when not in use.
Elimination of steam leaks
A small hole vapor leak repair program 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 a steam trap drains condensate from a steam system, the pressure drop creates steam from that condensate.
This vapor, along with condensate, can be used in a heat exchanger to heat the feed water or air.
More importantly, it is possible to use this vapor and condensate near the point of release, as it can be very expensive to create a separate piping system to transport it to the point of use.