Energy savings in the company - the main directions:
- Saving electricity
- Reduction of heat and steam losses
- Reduction of losses in steam lines
Enterprise Energy Saving - Energy Saving Methods
- Selection of the ideal price category and review of contract terms for energy supply
- Optimization of electric motors
- VFD Installation
- Optimizing Compressed Air Systems
Choosing the right price category for power supply
In total, there are 6 power supply price categories under which companies can buy electricity from guaranteed suppliers.
All small enterprises with an installed capacity of less than 670 kW, at the time of signing the automatic energy supply contract, fall into the first price category.
All projects 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 ideal and cheapest power supply categories.
In some cases, switching to a different price category can reduce your electricity cost by 5%-30%.
The topic of price categories is quite extensive, in our review of price categories we tell you in detail how to correctly calculate and choose the power supply price category.
In addition to price categories, we also recommend taking a look at other aspects of the power supply contract:
- voltage level,
- electricity transmission tariff.
In our review, you can find out more about these and other methods for reducing energy costs.
Energy savings in the company - electric motors
It is necessary to take into account all equipment where electric motors are used:
- machine tools,
- production lines.
Electric Motor Control Plan
The engine control plan must become an integral part of the plant's energy conservation program.
This plan will help implement a long-term energy saving system for all of the company's electric motors.
The engine control plan will ensure that failures and malfunctions do not occur and, if they do, will be resolved quickly and efficiently.
Steps to Create a Motor Control Plan:
Rewinding electric motors
Generally, rewinding an old electric motor is much cheaper than buying a new one.
The electric motor must be replaced if the rewinding cost is more than 60% of the cost of a new one.
So it all depends on how the rollback is performed.
If the work is done at the highest level, the engine will lose only 1% -2% of its efficiency.
If rewinding is done poorly, electric motor losses will increase by 5% -10%.
Replacing the old electric motor with an energy-efficient new one makes sense in cases where the motor runs more than 2, 000 hours per year.
The payback period for a new energy efficient engine will not exceed 1, 5 - 2 years.
Energy savings in the company, increasing the load factor
The load factor is the relationship between operating power and apparent power.
This is how energy is used efficiently.
The higher the load factor, the more efficiently electricity is used.
The electric motor operates optimally at 75% load and above.
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 unloaded engines,
- replacement of engines, which are loaded at less than 45%, with less powerful models,
- load redistribution between existing electric motors.
Variable Frequency Unit (VFD)
Installing variable frequency drives only makes sense for dynamic systems.
In static systems, which are involved, for example, only to lift loads, installing a frequency converter will not help and can often cause damage.
The VFD balances the load and speed of the motor, thus ensuring optimal use of electrical energy.
VFD can reduce motor power 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, in 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 inefficient sources of energy - only 5% of the electricity spent in producing compressed air turns into useful work, the remaining 95% goes to piping.
Energy savings in the company - compressed air:
- Do not use compressed air to clean the premises.
- Reducing the compressor inlet air temperature by 3% reduces energy consumption by 1%.
- For these technical processes, whenever possible, reduce the compressed air pressure to a minimum. Lowering pressure by 10% reduces energy consumption by 5%.
- Perform regular inspections, repairs to compressor equipment and compressed air transmission lines. One, even the smallest leak of compressed air can sometimes reduce equipment efficiency.
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 generated can significantly reduce energy consumption in these plants.
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 works below its ideal load.
The capacity of the installed boiler can be much higher than the project's needs, due to a drop in demand for products or unrealized plans to expand production.
Furthermore, boiler capacity may not be needed due to improvements in the production process or the introduction of energy saving measures.
In these cases, the boiler does not work at full capacity or in short on-off cycles.
Both situations lead to significant energy losses.
There are no simple and inexpensive solutions to this problem.
The easiest option isinstall a "small" boiler that runs at full capacitywith a medium or low workload in the company.
Although not a cheap solution, the payback period for this 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 variable demand or significant seasonal fluctuations in heat and steam consumption.
automatic adjustment system
If the company has several boilers, it makes sense to installautomatic system to regulate boiler load. . .
Automation responds to the project's need for steam, redistributing the load between the boilers, turning the boilers on or off, significantly increasing the efficiency of the entire system.
In companies where boilers are regularly shut down due to a drop in steam demand, chimney heat losses can be quite high.
It is possible to block the loss of hot air through the chimneyinstalling a gate valvewhich closes the pipeline when the boiler is turned off.
Prevention and maintenance
If unsupervised, burners and condensate return systems can quickly deteriorate or fail.
This can reduce boiler efficiency by 20%-30%.
A simple maintenance program – ensuring that all boiler components are operating at their maximum level – will significantly increase operating efficiency.
In practice, regular maintenance reduces boiler energy consumption by 10%.
Insulation - the heat loss from the surface of a properly insulated boiler should be less than 1%.
Removal of soot and encrustations
It is necessary to constantly monitor and eliminate the formation of soot in the boiler tubes, incrustation inside the boiler.
A 0. 8mm thick layer of soot reduces heat transfer by 9. 5%, while a 4. 5mm thick layer reduces heat transfer by 69%!
Scale forms when calcium, magnesia and silicon are deposited in the boiler heat exchanger.
The 1mm thick scale increases power consumption by 2%.
Soot and scale can be removed mechanically or with acids.
The formation of soot and scale can be determined by an increase in flue gas temperature or by visual inspection when the boiler is not in operation.
The formation of soot and scale must be monitored with special attention if the boiler works with solid fuels (coal, peat, firewood).
Gas boilers are less prone to soot problems.
Optimization of boiler discharge
Boiler purge is the discharge of boiler water to clean the water inside the boiler of impurities and salts.
The purpose of boiler purging is to prevent or reduce scale formation.
Insufficient boiler drain can lead to water entering the steam or boiler deposits.
Excessive purging means loss of heat, water and chemicals.
The ideal purge 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 water preparation. 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 usually the result of 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 be easily eliminated by making a periodic visual inspection of the boiler and chimney.
The more air that is used to burn fuel, the more heat is released into the wind.
An amount of air slightly above the ideal fuel/stoichiometric 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, resulting in excessive combustion emissions.
An efficient gas burner requires 2% to 3% supplemental oxygen, or 10% to 15% supplemental air, to burn fuel without generating carbon monoxide.
The general rule of thumb is that boiler efficiency increases by 1% for every 15% reduction in additional air.
Therefore, it is necessary to constantly check the fuel/air ratio.
This event costs nothing but has a very good effect.
Smoke emission monitoring
The amount of oxygen in the flue gas 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 to monitor the intake air and the amount of oxygen in the flue gases is established.
Using the amount of carbon monoxide and oxygen data, it is possible to optimize the fuel/air ratio in the boiler.
Installing a combustion emissions monitoring and analysis system usually pays for itself in less than a year.
Energy savings across the enterprise - installing an energy saver
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 to steam, saving 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 payback in less than 2 years.
Heat exchanger for extracting heat from boiler purge water and steam
The heat exchanger will help recycle about 80% of the water and steam heat from the boiler purge.
This heat can be used to heat buildings or 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 purge system does not operate in a constant mode, then it makes sense to consider transferring it to a constant mode while simultaneously installing a heat exchanger.
The average payback period for a heat exchanger will not exceed 1, 5 - 2 years.
Installing a Condensation Economizer
Hot condensate can be returned to the boiler, conserving energy and reducing the need for treated water.
The condensation economizer can increase system efficiency by another 10%.
The installation of such an economizer must be carried out under the 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 condensate to the boiler usually pays for 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 dumps heat into 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 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 fans (fiberglass and molded plastic) can reduce energy consumption by up to 30%.
Reduction of losses in steam lines
Disconnection of unclaimed steam lines
Steam requirements 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 losses.
It is clear that optimizing or reconfiguring the entire steam distribution system to meet new needs will be very expensive and perhaps unfeasible.
However, identifying and disconnecting steam lines that are rarely used can be a very effective energy-saving measure.
Energy savings in the company - Thermal insulation of pipes
Insulating steam pipes can reduce energy losses by up to 90%.
This is one of the quickest returns to energy savings in a steam distribution system.
The average payback period for insulating ducts through which steam or hot water is transmitted is about 1 year.
Condensate tubes for 1, 5-2 years.
A simple program to monitor the technical condition of traps can significantly reduce heat loss.
For example, if maintenance has not been carried out for 3 to 5 years, then as a rule about one third of the steam traps are broken, allowing steam to drain into the condensate drain system.
In practice, in projects that have a trap monitoring program, a maximum of 5% of the traps are defective.
The average payback period for the replacement or maintenance of a trap is less than six months.
A trap monitoring program will typically reduce steam losses by 10%.
Thermostatic steam purifiers
The use of modern thermostatic traps can reduce energy consumption and at the same time increase the reliability of the entire system.
The main advantage of thermostatic traps is that they
- open when the temperature approaches the saturated steam level (+/- 2 C °),
- emit non-condensable gases after each opening and
- they are in the open state at the start of system operation, which guarantees their rapid warm-up.
Furthermore, these steam traps are very reliable and can be used over a wide range of pressures.
Disconnecting steam traps
You can reduce energy consumption by turning off steam traps on superheated steam lines when not in use.
Elimination of steam leaks
A small hole steam 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, causing constant damage to the system.
Reuse of condensate and steam
When a steam trap discharges condensate from a steam system, the pressure drop creates steam from that condensate.
This steam, along with the condensate, can be used in a heat exchanger to heat water or air.
Most importantly, it is possible to use this steam and condensate close to the point of release as it can be very expensive to create a separate piping system to transport it to the point of use.