The energy-saving principle of elevators is to release the high-voltage DC waste electricity from the frequency converter to the braking resistor during the operation of the elevator. After being recovered, rectified, inverted, and filtered by the energy feedback equipment, it forms a new regenerated electric energy feedback and is returned to the three-phase public power grid in the building for use. Then, the waste electricity is reused reasonably to achieve energy-saving and reduce the temperature of the elevator machine room.
The economic and environmental benefits of installing elevator energy feedback equipment:
The energy feedback device has a conversion rate exceeding 97.5% and will not pollute the power grid. According to actual testing, the energy-saving rate of synchronous elevators can reach 30-48%, while asynchronous elevators can achieve 20-30%. And the higher the speed, the greater the power, the greater the load, and the better the energy-saving effect. And the original braking resistor no longer heats up, causing the temperature in the machine room to drop, saving the purchase cost and power consumption of cooling equipment in the machine room.
The power consumption of air conditioning equipment in the computer room for general users is about 4KW. It operates for 300 days a year according to demand, with 12 hours of operation per day, resulting in a total electricity consumption of 14400 kWh per year. In many places, the cost of purchasing, consuming electricity, and maintaining air conditioning in computer rooms alone is a significant expense. And the elevators in the community are not all generating electricity at the same time. Some elevators are generating electricity while others are using it up. The total electricity meter of the property measures the electricity consumption of the external power grid, which will reduce the total meter measurement and correspondingly decrease the payment to the power company.
2. Elevators have become the second largest consumer of electricity in today's society, second only to air conditioning, accounting for about 20% -30% of the community's public electricity consumption. At the end of 2016, the number of elevators in China exceeded 4.5 million, making it an international elevator powerhouse with a market share of 60% worldwide. Elevator energy conservation has become an important category of social energy conservation in China. A typical elevator consumes about 30-80 kWh of electricity per day. Based on an average daily power consumption of 50 kWh per elevator and an annual operation of 300 days, with 4 million units in use nationwide, the daily electricity consumption of elevators is 200 million kWh, which is 60 billion kWh per year! The consumption of electricity exceeds two-thirds of the annual power generation of the Three Gorges, indicating the huge power consumption of elevators! Therefore, it is very necessary to save energy in elevators in practice.
The impact of energy feedback equipment on elevators:
1. It will not affect the normal operation of the elevator at all.
The energy feedback device will not alter any circuits or wiring of the elevator's original control system. Simply connect the input end in parallel to the high-voltage DC bus of the elevator's frequency converter discharge, and connect the output end in parallel to a 380V power switch.
The energy feedback device intercepts and recovers the high-voltage DC waste electricity released by the frequency converter to the high-power braking resistor during the operation of the elevator. After rectification, inversion, and filtering, it forms a new regenerated electric energy feedback and is used to repair the three-phase public power grid in the building. This achieves the energy-saving effect of the elevator and will not affect its normal operation.
The energy feedback equipment has undergone maximum optimization planning in terms of software and hardware for elevator maintenance. Full bridge rectification input is selected at the input port to ensure normal operation even when the DC power supply is reversed. The three-phase power supply fed back to the grid does not need to know the phase sequence, and the software will automatically detect the phase sequence in real time and intelligently adjust it. Therefore, in terms of wiring, it completely eliminates the possibility of abnormal equipment operation or elevator operation caused by misconnected wires. And fast fuse safety is separately connected in series on the cables connecting the DC discharge and feedback three-phase power grid of the elevator. If there is an abnormal occurrence, the fast fuse safety will immediately disconnect the feedback equipment from the elevator, ensuring the safety of the elevator and feedback equipment.
2. Will the generator have an impact on the energy feedback equipment after a power outage
No impact. After a power outage in the elevator, the energy feedback device will intelligently identify the power grid outage and immediately suspend output. When the generator generates electricity, it can distinguish the frequency and phase of the power supply of the power generation equipment, reducing the load and heat generation of the generator, which not only achieves energy-saving effect but also extends the service life of the generator.
3. Will there be any impact on rescuing trapped people and manually sliding the slide
No impact. When rescuing a trapped person in an elevator, it is necessary to cut off the power. At this time, both the equipment and the elevator have no power supply and are in a suspended state. Even if the DC bus voltage rises, the equipment will not operate.
4. Does it affect the operating environment of the elevator
Has an impact, higher quality!
The energy feedback device intelligently recovers and converts the waste electricity discharged during the operation of the elevator into new electrical energy to build the power grid for reuse. The braking resistor reduces heating, and the temperature of the entire control cabinet tends to room temperature, greatly reducing the operating temperature of the frequency converter, greatly improving the operating environment of the elevator control system, and extending the service life of the control system and elevator. The computer room no longer uses air conditioning and other cooling equipment, which can save the power consumption of air conditioning and cooling equipment in the computer room, save energy and environmental protection, and make the entire system more energy-efficient.