Energy saving in the company - the main directions:
- Saving electricity
- Reduction of heat and steam loss
- Reduction of steam line losses
Energy saving in the company - energy saving methods
- Selecting the optimal price category and reviewing the contract terms of the power supply
- Optimization of electric motors
- VFD installation
- Optimization of compressed air systems
Selecting the optimal price category for the power supply
There are a total of 6 power supply price categories that allow businesses to purchase electricity from guaranteed suppliers.
When concluding a contract for automatic power supply, all small businesses with an installed capacity of less than 670 kW 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 category.
In some cases, switching to another price category can reduce the cost of electricity by 5-30%.
The topic of price categories is quite broad, in our overview of price categories we explain in detail how to correctly calculate and select the price category of power supply.
In addition to price categories, we also recommend that you carefully consider other aspects of your power contract:
- voltage level,
- force,
- electricity transmission tariff.
In our review, you can learn about these and other ways to reduce energy costs.
Energy saving in the company - electric motors
All equipment where electric motors are used must be considered:
- pumps,
- compressors,
- fans,
- machine tools,
- production lines.
Electric motor control plan
The engine control plan should become an integral part of the plant's energy conservation program.
Such a plan will help introduce a long-term energy-saving system for all of the company’s electric motors.
The engine control plan ensures that faults and malfunctions do not occur and if they do occur, they are resolved quickly and efficiently.
Steps to create an engine control plan:
- Make an inventory of all the engines in the facility.
- Make a list of motors, their main parameters, technical condition, service life.
- Make general instructions for making repairs.
- Develop guidelines for preventive maintenance, lubrication and inspection.
- Make a safety kit for frequently used spare parts.
- Create a procurement specification for new engines.
Rewind of electric motors
In general, rewinding an old electric motor is much cheaper than buying a new one.
The electric motor must be replaced if the cost of rewinding exceeds 60% of the cost of the new one.
Then it all depends on how the rewind is performed.
If the work is done at the highest level, the engine loses only 1% -2% of its efficiency.
If the rewind is performed incorrectly, the losses of the electric motor will increase by 5% -10%.
Replacing an old electric motor with a new, energy-saving motor makes sense if the motor runs for more than 2, 000 hours a year.
The payback period of a new, energy-saving engine can be up to 1. 5 to 2 years.
Energy savings 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 operates optimally at a load of 75% and higher.
Therefore, mounting the motors above the specified 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:
- stopping unladen engines,
- replacement of engines with less than 45% load on less powerful models,
- load redistribution between existing electric motors.
Variable frequency converter (VFD)
Installing variable frequency drives only makes sense for dynamic systems.
In static systems, for example, which are only related to load lifting, installing a variable frequency drive does not help and can often be harmful.
The VFD balances the load and speed of the motor, thus ensuring the optimal use of electrical energy.
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.
Optimization of compressed air systems
Compressed air is used in many areas of industry.
In some businesses, compressed air is the main consumer of electricity.
Compressed air is used in pneumatic tools and equipment, conveyors, 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 efficient sources of energy - only 5% of the electricity used to produce compressed air becomes useful work and the remaining 95% goes into the pipe.
Energy saving 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%.
- In these technical processes, the compressed air pressure must be kept to a minimum where possible. A 10% reduction in pressure reduces power consumption by 5%.
- Perform regular inspections and repairs on compressor equipment and compressed air transmission lines. One, even the slightest leakage of compressed air, can sometimes reduce the efficiency of the equipment.
Save energy for your business - 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.
Steam production
The boiler operates most efficiently at full power.
As the demand for the amount of steam can change over time, it is often the case that the boiler operates under optimal load.
Built-in boiler capacity can be much higher than the needs of the business, due to reduced demand for products or unrealized plans to expand production.
Boiler capacity is not necessarily required due to the improvement of the production process or the introduction of energy saving measures.
In such cases, the boiler operates either at full capacity or in short on-cycle cycles.
Both situations involve significant energy losses.
There are no simple and inexpensive solutions to this problem.
The easiest option isinstall a "small" boiler that will operate at full capacityat medium or low load.
Although this is not a cheap solution, the payback period for such an investment can be less than two years.
And it is usually always more efficient to have several small replaceable boilers, especially in businesses with variable demand or significant seasonal fluctuations in heat and steam consumption.
Automatic control system
If your business has multiple boilers, it makes sense to install itautomatic system for boiler load control. . .
Automation responds to the steam demand of the business, redistributes the load between the boilers, switches the boilers on or off, thus significantly increasing the efficiency of the entire system.
Gate valve
In businesses where boilers are regularly shut down due to reduced steam demand, heat loss through the chimney can be quite high.
The loss of hot air through the chimney can be preventedby installing a gate valvewhich closes the pipe when the boiler is switched off.
Prevention and maintenance
Unattended burners and condensate return systems can quickly fail or malfunction.
This can reduce the efficiency of the boiler by 20-30%.
A simple maintenance program - which ensures that all parts of the boiler operate at maximum level - significantly increases 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 limescale
The formation of soot on the boiler tube, inside the boiler, must be constantly monitored and eliminated.
The 0, 8 millimeter thick carbon black layer reduces heat transfer by 9. 5%, while the 4. 5 millimeter thick layer reduces heat transfer by 69%!
The scale is formed when calcium, magnesium and silicon are deposited on the boiler heat exchanger.
The 1 millimeter thick scale increases energy consumption by 2%.
Soot and limescale can be removed mechanically or with acids.
The formation of soot and limescale can be determined by increasing the temperature of the flue gases or by visual inspection when the boiler is not operating.
Particular care must be taken to check the formation of soot and limescale if the boiler is running on solid fuel (coal, peat, firewood).
Gas boilers are less prone to soot problems.
Optimization of boiler blowing
Blowing down the boiler allows the boiler water to clean the water inside the boiler from dirt and salts.
The purpose of blowing the boiler is to avoid or reduce the formation of limescale.
Insufficient blowing of the boiler can lead to water vapor or the formation of deposits in the boiler.
Excessive blowing means loss of heat, water and chemicals.
The optimal purge level depends on the type of boiler, the operating pressure of the boiler, the preparation and quality of the water used.
The first thing to look out for is water preparation. If the water is treated well (low salinity), the blow-off rate can be 4%.
If there are foreign substances and salts in the water, the blow-off rate will be 8% -10%.
An automatic purge system can also significantly reduce energy consumption.
The payback period of such a system is usually 1-3 years.
Reducing 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 compressor system.
Leaks and holes can be easily eliminated, only visual inspection of the boiler and chimney is required periodically.
Air regulation
The more air is used to burn fuel, the more heat is thrown into the wind.
For safety reasons, a slightly higher air volume above the ideal stoichiometric fuel / air ratio is required 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 flue gas emissions.
An efficient gas burner requires 2-3% additional oxygen or 10-15% additional air to burn the fuel without carbon monoxide formation.
The general rule of thumb is that the boiler efficiency increases by 1% after each additional 15% decrease.
Therefore, the fuel / air ratio must be constantly monitored.
This event costs nothing, but it 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 for monitoring the amount of oxygen in the incoming air and flue gas is installed.
The fuel / air ratio of the boiler can be optimized using data on the amount of carbon monoxide and oxygen.
Installing a flue gas monitoring and analysis system usually pays off in less than a year.
Energy saving in the business - Installing 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 convert to steam, thus saving fuel.
The efficiency of the boiler increases by 1% with each reduction of the flue gas temperature by 22 ° C.
Energy savings can reduce fuel consumption by 5-10% and pay for themselves in less than 2 years.
Heat exchanger for extracting water from water and steam when blowing the boiler
The heat exchanger helps to recycle 80% of the water and steam heat from the boiler blowdown.
This heat can be used to heat buildings or heat the water that feeds the boiler.
Any boiler with a constant blow-off speed of at least 5% is excellent for a heat exchanger.
If the purge system is not in constant mode, you may want to consider switching to constant mode while installing the heat exchanger at the same time.
The average payback time of the heat exchanger does not exceed 1, 5 - 2 years.
Condensing economist equipment
The hot condensate can be returned to the boiler, thus saving energy and reducing the need for treated water.
The condensing economy can increase the efficiency of the system by an additional 10%.
The equipment of such an economist must be carried out under the close supervision of professionals who take into account all the nuances of such a system, its effect on the boiler and the chemical composition of the water.
The use of a system for returning condensate to the boiler usually pays for itself in 1-1, 5 years.
The system that directs the condensate to the 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 throws heat into the wind.
Energy savings in cooling towers:
- For some businesses, it makes sense to leave the cooling towers altogether. In many cases, heating is used to heat the room, while a cooling tower is used to dissipate the heat. Installing a heat pump solves the heating problem and at least partially reduces the need to use a 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 plastic molded) can reduce energy consumption by up to 30%.
Reduction of steam line losses
Disconnection of unwanted steam lines
Steam demand and consumption are constantly changing.
This can lead to the entire steam distribution system not being used at full capacity, but only by 20-50%, which inevitably leads to heat loss.
Obviously, optimizing or reconfiguring the entire steam distribution system to meet new needs will be very costly and perhaps not feasible.
However, identifying and shutting down little-used steam lines can be a very effective energy saving measure.
Energy saving in the business - Thermal insulation of pipes
Thermal insulation steam pipes can reduce energy loss by up to 90%.
This is one of the fastest returns on energy savings in the steam distribution system.
The average payback time for pipe insulation through which steam or hot water is supplied is about 1 year.
Condensate lines for 1, 5-2 years.
Checking the steam traps
A simple program to check the technical condition of steam traps can significantly reduce heat loss.
For example, if maintenance has not been performed for 3-5 years, usually about one-third of the steam traps will not operate, causing steam to seep into the condensate drain system.
In practice, for businesses with a steam trap monitoring program, up to 5% of steam traps are in defective condition.
The average payback time for replacing or maintaining a steam trap is less than six months.
A steam trap monitoring program typically reduces steam loss 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 are
- is open when the temperature approaches the saturated steam level (+/- 2 C °),
- emits non - condensable gases after each opening and
- they are open at the start of system operation, ensuring rapid warm-up.
In addition, these steam traps are very reliable and can be used over a wide pressure range.
Separation of steam traps
You can reduce energy consumption by turning off steam traps on overheated steam lines when not in use.
Elimination of steam leaks
A small hole steam leak repair program can pay off in less than 3-4 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 discharges condensate from a steam system, the pressure drop generates steam from the condensate.
This steam, together with the condensate, can be used in a heat exchanger to heat the supplied water or air.
Most importantly, this steam and condensate can be used near the discharge point, as it can be very expensive to create a separate piping system for transport to use.