China is the world's largest elevator market, accounting for 43% of the global total.  From 2002 to 2022, the number of elevators in China has increased year by year, and  by the end of 2022, the number of elevators in use in China has reached 9.6446  million units, and the compound annual growth rate (CAGR) of the past five years has  reached 11%. With the improvement of social requirements for energy conservation  and environmental protection, elevator as an important part of building energy  consumption, its energy conservation has become an important part of green city  construction. Elevator energy saving not only helps to reduce building energy  consumption, but also reduces environmental pressure and promotes urban green  development to a new level.




At present, in the elevator industry, the more energy-saving permanent magnet  synchronous traction machine has become the mainstream model of elevator motor,  and the elevator energy regeneration system has become a new direction of elevator  energy saving.

The elevator is a potential load, which can be simply understood as a fixed pulley  group with the car and the counterweight respectively suspended at both ends, and  the balance coefficient between the car and the counterweight block is 0.45. Then  when the elevator light load up (less than 45% of the limit load) or heavy load down  (higher than 45% of the limit load) elevator power system under the action of potential  energy is a power generation state. This excess energy is temporarily stored in the  capacitor of the inverter DC circuit, as the working time of the elevator continues, the  power and voltage in the capacitor are higher and higher, if not released, it will lead to  overvoltage failure, so that the elevator stops working. In order to release the electric energy in the capacitor, the existing elevator power  system usually consumes it through the external heating resistance to ensure the  normal operation of the elevator. After the elevator power system increases the energy system, the electricity generated by the elevator under the power generation condition can be returned to the  building's power grid through the energy feedback system for other loads


The use of resistance braking mode can ensure the normal operation of the elevator,  but the electric energy generated by the elevator running time is wasted by the way of  resistance heating, and it also increases the burden of the elevator room control  cooling system and increases the power consumption of air conditioning.

The electric elevator system equipped with energy feedback system, through the  energy feedback system, the energy generated by the elevator operation is returned  to the power grid for the use of other loads in the building, so the purpose of node is  realized. In addition, due to the non-resistance combustion heat, reduce the ambient  temperature of the machine room, improve the operating temperature of the elevator  control system, so that the control system no longer crashes, extend the service life  of the elevator, but also reduce energy consumption for electric energy consumption.

Product characteristics
This system is mainly used in the old elevator retrofitting energy feedback function,  has the characteristics of strong versatility, beautiful appearance, short supply cycle,  convenient construction, simple declaration, can widely meet the energy feedback  retrofitting and transformation needs of the elevator in use.

Function overview
When the elevator goes up with light load and down with heavy load, it generates a lot  of kinetic energy or potential energy, which will be converted into renewable electric  energy at the side of the tractor. When the energy feedback function is not  configured, the elevator generally uses the brake resistor to convert the renewable  electric energy into heat energy. This not only wastes a lot of power, but also causes  the temperature of the room to rise, affects the life of the components, and increases  the consumption of the air conditioning in the room. When the energy feedback system is configured, this part of the regenerative energy  can be returned to the power grid to achieve the purpose of energy saving. It  improves the energy utilization rate of the elevator, alleviates the temperature rise  caused by heating in the machine room, protects the healthy use of components, and  reduces the use frequency of the air conditioner in the machine room.

Product application scope
The main application scenarios of this product are the in-use ladder that is not configured with the energy feedback function and the occasions where the energy feedback  function is installed. Most active ladders can handle it. It is recommended to choose the elevator with high  frequency of use, high floor and large tonnage, which has the best energy saving  effect.

Safety and stability
Energy feedback device and elevator compatibility High installation system does not  change the actual elevator control line, the elevator running stability is guaranteed;  When the device itself fails, the elevator will automatically return to the non-energy  feedback mode, using the brake resistance to consume electricity, does not affect the  elevator operation. The device includes power grid fault protection function - selfprotection for power grid overvoltage, undervoltage, overfrequency, underfrequency,  etc.

Commercial value
Directly save the electricity cost of public equipment
The energy feedback system sends the elevator's renewable electricity back into the  building system, where it is used for public lighting, water pumps, weak current systems or other elevators in the building, reducing the power consumption of the entire  building. As shown in the figure.

According to the calculation of previous projects, the average power saving rate of  the energy feedback system is 25%, according to the average power consumption of  a single elevator in China 40kWh, it can save 10 KWH of electricity per day, that is,  3650 KWH of electricity per year.

Indirectly save the electricity cost of air conditioning in the equipment room
The air conditioning in the machine room can save electricity. According to a 2-piece  air conditioning unit that operates for 3 months every summer and works 16 hours a  day, it consumes more than 2000 degrees of electricity a year. The energy feedback  device can greatly reduce the working time of the air conditioner in the equipment  room and reduce the electricity cost of the air conditioner. Note: The calculation formula is for valuation, subject to actual working conditions.

Save on elevator maintenance
The temperature of the equipment room is effectively reduced, the life of the elevator  parts can be effectively extended, and the number of parts replacement is reduced.  Taking the capacitor in the inverter as an example, when the ambient temperature  exceeds the allowable working temperature, the temperature is 10 degrees per liter,  and the service life of the capacitor is reduced by half.

Carbon index conversion
Conversion of carbon indicators (also known as carbon emissions) usually involves  the conversion of different forms of carbon or energy into a uniform unit of measure,  such as carbon dioxide equivalent (CO2e) or tons of carbon (tC). Different energy sources produce different amounts of carbon dioxide during combustion or use. For example, the burning of fossil fuels such as coal, oil and gas produces large amounts of carbon dioxide. In order to convert this energy consumption  into carbon emissions, we need to use their emission factors. Emission factors are  usually expressed in terms of the amount of carbon dioxide produced per unit of energy source (e.g., per ton of coal, per cubic meter of natural gas, per liter of gasoline,  etc.). Energy saving in elevators is equivalent to reducing carbon emissions.

Summary
The energy-saving unit of K-DRIVE has not only brought significant energy-saving  effects to the elevator system through technological innovation, but also promoted  the efficient utilization of power resources, making a positive contribution to the promotion of low-carbon lifestyle. Firstly, the implementation of a 20% -40% energy-saving rate for elevator energysaving units not only reduces the operating costs of elevators, but also brings considerable economic benefits to the company. Meanwhile, due to the reduction of energy consumption and dependence on fuel, it indirectly reduces carbon emissions  and has significant environmental benefits. Secondly, the energy-saving unit of the  elevator promotes the micro cycle formed by the integration of electricity consumption and power generation. In the application process, the regenerated energy  generated during the operation of traditional elevator systems can be recovered and  reused, forming a virtuous energy cycle. Finally, the application of energy-saving  units in elevators has made the elevator system an important component of lowcarbon life. By reducing the energy consumption of elevator systems and reducing  carbon emissions, it not only benefits personal health but also helps to protect the  Earth's environment and achieve sustainable development.