Energy saving in the company - the main directions:
- Save electricity
- Reduction of heat and steam losses
- Reduction of losses in steam lines
Saving energy in the company - energy saving methods
- Selection of the optimal price category and revision of the contractual conditions for the power supply
- Optimization of electric motors
- VFD installation
- Optimization of compressed air systems
Selection of the optimal price category for the power supply
There are a total of 6 electricity price categories according to which companies can purchase electricity from guaranteed providers.
The first price category includes all small businesses with an installed capacity of less than 670 kW at the time of the conclusion of the contract for an automatic power supply.
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 a different price category can cut electricity costs by 5 to 30%.
The topic of price categories is quite extensive, in our test on price categories we explain in detail how to correctly calculate and select the price category of the power supply.
In addition to the price categories, we also recommend that you take a close look at other aspects of the electricity supply contract:
- Voltage level,
- Power,
- Electricity transmission tariff.
In our test report you can find out more about these and other methods for reducing energy costs.
Saving energy in the company - electric motors
It is necessary to consider all devices that use electric motors:
- Pumps,
- Compressors,
- Fans,
- Machine tools,
- Production lines.
Control plan for electric motors
The engine control 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 motor control plan ensures that failures and malfunctions do not occur and, if they do, are rectified quickly and efficiently.
Steps to Create a Motor Control Plan:
- Make an inventory of all motors in the facility.
- Make a list of engines with their most important parameters, technical condition and service life.
- Develop general instructions for carrying out repairs.
- Develop guidelines for preventive maintenance, lubrication, and inspection.
- Create a safety stock of commonly used replacement parts.
- Create a purchase specification for new engines.
Winding of electric motors
In general, winding up an old electric motor is much cheaper than buying a new one.
The electric motor should be replaced if the cost of winding it up is more than 60% of the cost of a new one.
Then it all depends on how the rewind is done.
When the work is done at the highest level, the engine will only lose 1% -2% of its efficiency.
If rewinding is done poorly, the losses in the electric motor increase by 5% -10%.
Replacing the old electric motor with a new, energy-efficient one makes sense if the motor runs for more than 2000 hours per year.
The payback period for a new energy-efficient motor is no more than 1. 5 - 2 years.
Energy savings in operation by increasing the degree of utilization
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 efficiently the electricity is used.
The electric motor works optimally from 75% load.
Therefore, installing motors above the required power (for safety reasons) is not only more expensive, but also inefficient in terms of energy consumption.
The load factor can be increased as follows:
- Switching off unloaded motors,
- Replacement of engines that are less than 45% loaded with less powerful models,
- Redistribution of the load between the existing electric motors.
Frequency converter (VFD)
The installation of frequency converters only makes sense in dynamic systems.
In the case of static systems that are only used to lift loads, for example, installing a frequency converter does not help and can often be harmful.
The VFD balances the load and speed of the motor and thus ensures that the electrical power is used optimally.
The VFD can reduce the energy consumption of the motor 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 equipments, on conveyor belts, automatic lines.
The use of compressed air is popular because it is a convenient and safe source of energy.
But many forget that compressed air is one of the most inefficient sources of energy - only 5% of the electricity used to generate compressed air becomes useful work, the remaining 95% goes into the pipeline.
Saving energy in operation - compressed air:
- Do not use compressed air to clean the premises.
- Reducing the air temperature at the compressor inlet by 3% reduces power consumption by 1%.
- In these technical processes, reduce the compressed air pressure to a minimum if possible. A 10% reduction in pressure reduces power consumption by 5%.
- Carry out regular inspections, repairs to compressor systems and compressed air lines. Even the smallest leak of compressed air can sometimes reduce the efficiency of the equipment.
Saving energy in operation - we reduce heat and steam losses
Steam is widely used in industry, especially in the textile, food and processing industries.
By improving the efficiency of steam boilers and reusing the heat generated, the energy consumption in these systems can be reduced significantly.
Steam production
The boiler works most efficiently at full power.
Due to the fact that the need for the amount of steam can change over time, it often happens that the boiler works under its optimal load.
The capacity of the installed boiler may be much higher than the company's needs due to a decline in product demand or unrealized plans to expand production.
In addition, the boiler capacity cannot be required due to improvements in the production process or the introduction of energy-saving measures.
In such cases, the boiler either does not work at full capacity or in the mode of short on-off cycles.
Both situations involve considerable energy losses.
There are no simple and cheap solutions to this problem.
The easiest way isInstall a "small" boiler that works at full capacitywith average or low occupancy in the company.
While this is not a cheap solution, the payback period for such an investment can be less than two years.
And in general, it is always more efficient to have several small interchangeable boilers, especially in companies with changing needs or strong seasonal fluctuations in heat and steam consumption.
Automatic regulation system
If the company has several boilers, then the installation makes senseautomatic system for regulating the boiler load. . .
The automation reacts to the company's steam demand, distributes the load between the boilers, switches the boilers on or off and thus significantly increases the efficiency of the entire system.
Gate valve
In companies in which the boiler is regularly switched off due to falling 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 switched off.
Prevention and maintenance
If left unattended, burners and condensate return systems can quickly deteriorate or fail.
This can reduce the efficiency of the boiler by 20 to 30%.
A simple maintenance program that ensures that all boiler components are working at the maximum level increases operational efficiency significantly.
In practice, regular maintenance reduces the boiler's energy consumption by 10%.
Insulation - heat loss from the surface of a properly insulated boiler should be less than 1%.
Removal of soot and scale
It is necessary to constantly monitor and eliminate the formation of soot on the boiler tubes and the scale.
A 0. 8 millimeter thick layer of soot reduces heat transfer by 9. 5%, while a 4. 5 millimeter thick layer reduces heat transfer by 69%!
Scale forms when calcium, magnesium, and silicon build up on the boiler's heat exchanger.
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 exhaust gases or by visual inspection when the boiler is not in operation.
The soot and scale formation must be monitored particularly carefully if the boiler is operated with solid fuels (coal, peat, firewood).
Gas boilers are less prone to soot problems.
Boiler blowdown optimization
Boiler blowdown is the draining of boiler water in order to clean the water in the boiler of impurities and salts.
The purpose of the boiler blowdown is to avoid or reduce the formation of scale.
Insufficient boiler drainage can result in water getting into the steam or deposits forming in the boiler.
Excessive blowdown means loss of heat, water and chemicals.
The optimal blowdown level depends on the boiler type, the operating pressure in the boiler, the treatment and quality of the water used.
The first thing to look out for is water treatment. With well-treated water (low salt content), the blowdown rate can be 4%.
In the case of foreign bodies and salts in the water, the blowdown rate is 8% -10%.
The automatic desalination 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 caused by air entering the boiler and chimney through leaks and openings.
This reduces heat transfer and increases the load on the compressor system.
Leaks and holes can easily be repaired, all that is required is a periodic visual inspection of the boiler and chimney.
Air regulation
The more air that is used to burn fuel, the more heat that is thrown into the wind.
An amount of air that is 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% additional air, which leads to excessive exhaust emissions.
An efficient gas burner requires 2 to 3% additional oxygen or 10 to 15% additional air to burn the fuel without producing carbon monoxide.
As a rule of thumb, the boiler efficiency increases by 1% for every 15% less additional air.
It is therefore necessary to constantly check the air-fuel ratio.
This event does not cost anything, but it has a very good effect.
Monitoring of smoke development
The amount of oxygen in the flue gas is the sum of additional air (to increase safety and reduce emissions) and air that enters the boiler through holes and leaks.
The presence of leaks and holes can easily be identified by setting up a monitoring system for the incoming air and the oxygen content in the flue gases.
Using the 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 monitoring and analysis system for exhaust emissions usually pays for itself in less than a year.
Saving energy in the company - installation of an economizer
The heat from the flue gases can be used to heat the water entering the boiler.
The heated water enters the boiler and requires less heat to be converted into steam, which saves fuel.
The efficiency of the boiler increases by 1% for every 22 ° C decrease in the flue gas temperature.
The economizer can reduce fuel consumption by 5% - 10% and will pay for itself in less than 2 years.
Heat exchanger for the recovery of heat from water and steam from the boiler blow-down
The heat exchanger helps recycle around 80% of the water and steam heat from the boiler blowdown.
This heat can be used to heat buildings or to heat the water that feeds the boiler.
Any boiler with a constant blowdown rate of 5% or more is an excellent candidate for a heat exchanger.
If the desalination system is not working in a constant mode, it makes sense to think about putting it in a constant mode and 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 condensation economizer
Hot condensate can be returned to the boiler, saving energy and reducing the need for treated water.
The condensing economizer can increase the efficiency of the system by a further 10%.
The installation of such an economizer should be carried out under the strict supervision of specialists, taking into account all the nuances of such a system, its impact on the boiler and the chemical composition of the water.
Using a system that returns 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 a stream of air.
And in terms of energy efficiency, a cooling tower is a device that gives off heat to the wind.
Energy saving potential in cooling towers:
- In some companies it makes sense to do without cooling towers entirely. There are many cases where a heater is used to heat a room and a cooling tower is used to dissipate heat at the same time. Installing a heat pump solves the heating problem and at least partially reduces 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 fans (glass fiber and plastic casting) can reduce energy consumption by up to 30%.
Reduction of losses in steam lines
Separate steam lines that are not in use
Steam demand and consumption are constantly changing.
This can mean that not the entire steam distribution system is fully utilized, 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 requirements is very expensive and may not be feasible.
However, detecting and shutting down steam lines that are rarely used can be a very effective energy saving measure.
Saving energy in the company - 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 insulation on pipelines carrying steam or hot water is around 1 year.
Condensate lines for 1, 5-2 years.
Monitoring of steam traps
A simple monitoring program for the technical condition of steam traps can significantly reduce heat loss.
For example, if no maintenance has been performed for 3 to 5 years, typically about a third of the steam traps are defective, allowing steam to enter the steam trap system.
In practice, in companies that have a monitoring program for steam traps, not more than 5% of the steam traps are in a faulty condition.
The average payback time for replacing or servicing a steam trap is less than six months.
A steam trap monitoring program typically reduces steam losses by 10%.
Thermostatic condensate drain
The use of modern thermostatic steam traps can reduce energy consumption and at the same time increase the reliability of the overall system.
The main advantage of thermostatic steam traps is that they
- opened when the temperature approaches the saturated steam level (+/- 2 C °),
- release non-condensable gases after each opening and
- are in the open state at the beginning of system operation, which ensures rapid heating.
In addition, these steam traps are very reliable and can be used over a wide pressure range.
Disconnect the condensate drain
You can reduce energy consumption by switching off condensate drains on the superheated steam lines when not in use.
Elimination of steam leaks
A steam leak repair program for small holes can pay off in as little as 3 to 4 months.
We must remember that small leaks go unnoticed for years and can permanently damage the system.
Reuse of condensate and steam
When a steam trap removes condensate from a steam system, the pressure drop creates steam from that condensate.
This steam can be used together with condensate in a heat exchanger to heat feed water or air.
Most importantly, it is possible to use this steam and condensate near the point of exit, as it can be very costly to create a separate piping system to transport it to the point of use.