Wolong EC Fan Energy Efficiency Retrofit Case | Yichang Ziquan Beverage Industry Co., Ltd. | Permanent Magnet Direct-Drive EC Fan Retrofit for Workshop Air Handling Units

[Project Background] A total of 2 workshop air handling units (AHUs) with retrofit potential were identified across Line 1 and Line 2 at Ziquan Beverage Industry Co., Ltd. The Line 1 AHU features a motor power of 18.5kW, an airflow rate of 35000m m³/h, and a total pressure of 1150Pa. The Line 2 AHU has a motor power of 30 kW, an airflow rate of 40000m m³/h, and both lines operate approximately 7920 hours annually. Originally, the AHU drive systems utilized standard impellers, belt drives, and three-phase asynchronous motors. [Pre-Retrofit Issues] Belt drives suffer from slip losses, lag losses, air resistance, and bearing friction, resulting in a transmission efficiency of only about 90%. They also generate high vibration and noise, causing frequent wear and damage to belts and fan bearings, leading to high failure rates and requiring dedicated staff for regular inspections. Three-phase asynchronous motors typically operate at efficiencies between 77% and 91%, with significant efficiency drops under low loads. As service life increases, excessive heating further reduces efficiency, keeping the entire fan system operating in a low-efficiency zone for extended periods. [Retrofit Solution] The project replaces the original supply air combination with a Wolong permanent magnet rotor synchronous motor direct drive, an intelligent variable frequency drive (VFD) system, and a high-efficiency EC fan system. The configuration includes 6 high-static-pressure EC fans, 1 batches of fan frames and accessories, and 2 control cabinets (Equipment Nameplate: ATB EC Fan Control Cabinet, Model ATB-A-EC-A-S-M-1-B, Rated Voltage 380VAC 50Hz, Protection Rating IP42, manufactured by Wolong (Shanghai) Energy Saving Technology Co., Ltd. in 2025 12). The EC motor features integrated drive and control design, utilizing permanent magnet circuit simulation and high-thermal-conductivity plastic encapsulation to prevent bearing electrical erosion. The energy-saving drive controller employs DFC software control algorithms and film capacitor technology, supporting interconnection, group control, and remote monitoring. The control system integrates with existing infrastructure, maintaining current control methods. The HMI main interface displays power, speed, current, load rate, and the operational status of each fan, while tracking cumulative operating hours and energy consumption. [Retrofit Results] Input power for the Line 1 AHU decreased from a measured 17.4kW to a designed 14.7kW, while Line 2 dropped from 21.9kW to 11.7kW. Based on an annual operation of 7920 hours and an electricity cost of 0.8 CNY/kWh, annual energy consumption was reduced from 311,256kWh to 209,088kWh, saving 102,168kWh annually with an energy savings rate of 32.8%. Total annual costs (including maintenance) decreased from 250,004 CNY to 167,270 CNY, saving approximately 82,734 CNY per year. On-site HMI measurements showed an operating power of 6.7 kW, speed of 1624r/min, current of 12.9 A, and load rate of 57.0%, with stable operation of the 5 fan group under centralized control. [Audit & Service] Energy audit is conducted by comparing hourly consumption over 72 hours under similar operating conditions before and after retrofitting. Acceptance is granted if saved energy W3=W1-W2 and energy savings rate =W3/W1 are achieved, and airflow/pressure meet pre-retrofit performance requirements. After-sales services include free maintenance and repair during the contract period, 7x24 rapid response, scheduled inspections, spare parts guarantee, and safety training.