Public equipment energy-saving technology/equipment application

Sustainable Column 2020-11-02

Taiwan’s own energy shortage is 98% dependent on imports, and its dependence on fossil energy is high. It faces the adoption of the “Greenhouse Gas Reduction and Management Law” in 2015 and the “Paris Agreement” (Paris Agreement) adopted by the United Nations Framework Convention on Climate Change (COP21). Regarding greenhouse gas reduction regulations, my country must adapt to this wave of energy transition and grasp the opportunity for green growth. Following my country’s energy development strategy, the energy development policy goal of 2025, the promotion of energy transformation, and the transformation path of greening, increasing gas, reducing coal, and non-nuclear can ensure a stable power supply.

On the other hand, on the energy consumption side, an energy management law and an energy verification system have been formulated to encourage energy users to attach importance to energy management and energy conservation, and carbon reduction.
Most factories start from the lack of planning and design for energy-saving energy-consuming equipment, which leads to problems of energy consumption or inefficiency after equipment operation and use, and subsequent improvements will cost more. If it is not the original plan for factory relocation/building, re-planning and designing is a major project for the factory. In addition to the high investment cost, the downtime loss must be considered. So this article briefly introduces the energy-saving improvement potential of public equipment and the application of energy-saving technology common to existing factories.


【Power Systems】
1. Application of time price
Taipower provides a variety of electricity price options. Users can choose the most suitable electricity tariff pricing method according to their electricity usage patterns. For example, a 24-hour production factory can evaluate and choose a three-stage electricity price. Generally speaking, there is about 5% of savings.


2. Optimal contract capacity
A contract that is too high will increase the basic electricity cost, while a contract that is too low will increase the over-contract surcharge. The user should evaluate and adjust the contract capacity according to the normal electricity usage situation. The principle is to exceed 3-4 times within a year. Generally speaking, This setting method is more economical in terms of the annual electricity bill.


3. Power factor adjustment


(1) Reducing electricity bills: According to the Taiwan Power Company’s electricity billing basis, the power factor clause stipulates that when the power factor is lower than 80%, for every 1% lower, the electricity bill will increase by 0.1% in the current month. When the power factor exceeds 80%, the electricity bill will be reduced by 0.1% in the current month for every 1%.


(2) Reduce the loss of lines and substation equipment: adding suitable capacitors can reduce the internal power loss caused by excessive currents.


(3) Improve voltage: increase the voltage at the end of the line and stabilize the voltage fluctuation rate.


(4) Increasing equipment margin: When the equipment capacity of the power system remains unchanged, increasing the power factor can be said to increase the load.
4. Power demand controller


The installation of a power demand controller can use the dispatchable loads in the factory (such as air conditioners) to avoid over-booking fines and can evaluate reasonable power contract capacity to save basic electricity bills. It can also cooperate with Taipower’s power curtailment to integrate power monitoring and power Demand, scheduling, and setpoint control.

 

【Lighting system】
1. Switch to high-efficiency lighting
Depending on the requirements of the operating environment, under the same illumination, use more energy-efficient lamps. For example, the mercury lamp is changed to an induction lamp/ceramic compound metal lamp, and the traditional T8 fluorescent lamp is changed to an LED.


2. Lower the lighting setting height/set the key auxiliary lighting
According to the requirements of the working environment, the lighting setting height should be lowered to improve the illuminance. For example, the high-altitude lighting is changed to side lighting, which can reduce the wattage of the lamps and even replace them with fluorescent lamps; auxiliary lighting is provided in key work areas, and high illuminance is not required for the entire plant.


3. Automatic ignition device
If the lighting equipment of walkways, stairwells, parking lots, and other areas that do not need to be turned on normally, if the lighting equipment is turned on and off by a switch, it will be turned on at work and turned off after getting off work. The lights will still be lit when there is no use for a long time, which wastes excess lighting electricity. It is improved by installing an automatic lighting device to automatically start the lighting equipment when there are people to reduce energy consumption.


4. Utilize natural light
Areas with better daylight can be evaluated to reduce lighting settings, and reduce daylight lighting when there is sufficient sunlight.


5. Zone switch
The multi-segment lighting switch configuration provides more flexibility to turn on the lights. The lighting switches should be set according to different working areas.

 

【Air Compression System】
1. Gas production efficiency detection / adopt high-efficiency models
Regularly conduct performance tests on existing and old air compressors to understand the decline in gas production to evaluate the reference for replacement. If there is a need for replacement, priority should be given to high-efficiency models.


2. Import frequency conversion control
The air compressor still consumes about 30% of its energy consumption when it is running empty, that is, it only consumes electricity but does not produce gas. For air compressor systems under variable loads, each system should evaluate and import 1 variable frequency air compressor for load regulation.


3. Leakage improvement/use of energy-saving consumables
Introduce energy-saving double-ring quick connectors, double-layer wear-resistant high-pressure air pipes, energy-saving air spray guns, and other consumables to reduce high-pressure air consumption and high-pressure air leakage caused by aging consumables.


4. Adopt no gas-consumption type drain
Common manual drains, point drains, and timing drains are prone to high-pressure air leakage, while floating-ball drains are prone to abnormal operation, resulting in high-pressure air leakage or inability to drain, which affects the quality of high-pressure air.


5. Adopt loop pipeline/add air tank/adjust the set pressure appropriately
The end of the high-pressure air pipeline often has insufficient pressure due to pipe damage, so that the pressure supply end must increase the set pressure. The annular pipeline configuration can be used to reduce the pressure drop. An additional air tank can be used for instantaneous air consumption. After the buffering, and with the improvement of pipeline leakage, the set pressure can be reduced by evaluation. Every 1kgf/cm2 reduction can reduce energy consumption by about 6~8%.


6. Set up waste heat ducts to improve the ambient temperature of the computer room
Poor ventilation in the air compressor room leads to the circulation of hot air, resulting in an increase in the ambient temperature, which affects the operating efficiency of the air compressor and refrigerated dryer.


7. Air compressor waste heat recovery
The power consumption of air pressure, of which 15% of the energy is converted into air potential energy, 85% of the energy is converted into heat energy, which is discharged into the air through air-cooling or water-cooling, resulting in a waste of energy. This part of the heat can be passed Heat recovery device for recycling. Such as boiler feed water preheating or process hot water heating.

 

【Air Conditioning System】
1. Ice machine performance test and replacement
Regularly conduct performance tests on existing ice water machines to evaluate the reference for replacement. If there is a need for replacement, high-efficiency models should be given priority.


2. Water pump frequency conversion
In the case of sufficient head and water pressure, for the over-designed area pumps in the factory, implement variable flow control of ice water area pumps to reduce operating energy consumption.


3. Cooling water quality management
Introduce conductivity control, control the cooling water concentration factor to be about 6-10 times for drainage, and strengthen cleaning and maintenance to prevent the heat sink from affecting the heat dissipation efficiency due to scaling.


4. Cooling tower fan temperature control
By using the wet-bulb temperature of the outside air and the inverter to control the windmill speed of the cooling water tower, this will not waste the power consumption of the water tower fan, and will not affect the operating efficiency of the main engine. Generally, in areas where there is a large change in the temperature of the external air wet bulb, this method can save the power consumption of the water tower fan by 20%~65% compared with a fixed frequency fan and a fixed water temperature control system.


5. Use a high-efficiency cooling tower fan
High-efficiency fans such as aluminum extrusion fans, airfoil fans or carbon fiber materials are used in industrial cooling towers and heat exchange equipment to avoid corrosion and oxidation, and can also effectively reduce weight, thereby reducing the burden on operators and reducing maintenance The special spiral design and streamlined arc can not only improve efficiency but also reduce the consumption of power source, so the equipment can maintain the best operating condition.

 

【Boiler System】
1. Exhaust gas oxygen content monitoring
According to the “Energy Check and Energy Conservation Case Manual” of the Energy Administration, every 1% reduction in exhaust oxygen content can save about 0.75% of fuel. At present, domestic boilers generally have an oxygen content of more than 5.5%. If the exhaust oxygen content can be reduced, fuel consumption will be effectively saved. When the fuel is heavy oil, the oxygen content can be controlled below 2.5%; when the fuel is natural gas, the oxygen content can be controlled below 1.5%, effectively saving fuel use and reducing fuel costs.


2. Flue waste heat recovery
The high-temperature exhaust gas discharged from the boiler contains a lot of heat energy. If the exhaust temperature is higher than 250℃, it is recommended to install waste heat recovery equipment. By using a heat exchanger, the waste heat of the flue gas can be recovered and used as the preheating energy for the intake air. Or feed water preheating can effectively reduce the use of fuel, usually by about 3% to 10%.

 

【Wastewater Treatment System】
1. Introduce dissolved oxygen control
The aerobic treatment tank needs to provide enough oxygen to maintain the activity of microorganisms. Excessive aeration will increase operating costs. Excessive oxygen will not increase the activity of microorganisms proportionally, but will easily break up the sludge plume and make activated sludge. Puffing and floating. It is advisable to evaluate the monitoring of dissolved oxygen collection and the automatic control of air volume to improve processing efficiency and save operating costs.


2. Introduce variable frequency air-floating blower
The air-bearing high-speed turbo blower with frequency conversion control can save power by 20%-40% compared with traditional Lu-type blowers. The initial investment cost can be recovered in a short time, and vibration and noise problems can be improved (about 70-85 decibels, Depends on operating speed and wind pressure).

 

Energy users such as enterprises/factories can use energy-saving counseling consultants to enter the factory for energy-saving diagnosis, explore energy-saving potential, and assist in evaluating the applicability of the energy-saving technology and improving benefits. Energy-saving and carbon-reduction measures can be implemented through energy technology service providers The actual measurement and construction are carried out in the factory. Improvement measures with higher investment costs can also be considered to operate in the ESCO project mode to repay the energy-saving improvement investment costs with the saved energy costs.

 

[Information on Energy Saving Subsidy]
Demonstration and promotion of energy-saving performance assurance project
https://www.moeaboe.gov.tw/ECW/populace/Law/Content.aspx?menu_id=1053
Power and public equipment subsidy operations
https://www.moeaboe.gov.tw/ECW/populace/content/Content.aspx?menu_id=8784
Subsidy operation of waste heat and waste cold recovery technology demonstration application project
https://www.moeaboe.gov.tw/ECW/populace/content/Content.aspx?menu_id=8786