The Shanghai Rongqing Logistics 20,000 m³ Low-Temperature Cold Storage Project is a large-scale frozen logistics warehouse constructed by HAOCOOL for Shanghai Rongqing International Storage and Transportation Co., Ltd.

The project was designed for -20°C low-temperature storage and has a total refrigerated volume of approximately 20,000 m³ with a cold room height of 5 meters. Construction began in March 2011 and the project was completed and accepted in June 2011, with a total construction period of approximately 60 days.

To meet different frozen product storage requirements, the facility was divided into four independent cold rooms. Two rooms use forced-air evaporators, while the other two use aluminum tube evaporator systems. This combination allows the warehouse to support both high-turnover frozen logistics and medium- to long-term low-temperature storage.

Project Information

Dual Evaporator Cold Storage Design

One of the main features of this logistics cold storage project is the use of two different evaporator solutions.

Forced-Air Evaporator Cold Rooms

Two cold rooms are equipped with industrial air coolers. Forced-air refrigeration provides relatively fast temperature pull-down and strong air circulation, making it suitable for products with frequent loading and unloading, higher heat loads, and fast warehouse turnover.

These rooms are ideal for logistics operations requiring rapid product movement and efficient temperature recovery after door openings.

Aluminum Tube Evaporator Cold Rooms

The other two cold rooms use aluminum tube evaporator systems.

Although initial pull-down may be slower than forced-air systems, aluminum tubing provides excellent thermal conductivity and is well suited to medium- and long-term frozen storage. Reduced air movement can also help minimize product dehydration, making this solution suitable for products requiring extended low-temperature preservation.

Parallel Screw Compressor Refrigeration System

The project uses a parallel screw compressor rack system controlled by PLC.

Multiple compressors are connected to common suction, discharge, liquid receiver, and oil management systems. A centralized controller automatically adjusts compressor operation according to actual refrigeration demand.

This configuration provides several important advantages:

• Refrigeration capacity according to actual load
• Improved partial-load efficiency
• Higher system redundancy
• Centralized equipment management
• Compact machine room layout
• Automatic fault alarms and protection
• Stable continuous operation

Compared with multiple completely independent refrigeration units, the parallel compressor system was designed to improve overall energy efficiency and reduce equipment footprint.

Hot Gas Defrost System

The forced-air evaporators use hot gas defrost technology.

During defrosting, high-temperature refrigerant gas discharged from the compressor is directed through the evaporator coil to melt accumulated frost and ice.

This method makes use of heat already available within the refrigeration system and reduces dependence on electric resistance heaters. For large industrial freezer applications, hot gas defrost can improve defrosting speed and support more energy-efficient operation when properly designed.

Enclosed Low-Temperature Loading Dock

The project also features an enclosed refrigerated loading dock.

Maintaining a low-temperature environment from the warehouse to the loading platform helps reduce cold chain interruption during product transfer. This is particularly important for frozen food logistics, where temperature fluctuations during loading and unloading can affect product quality.

The refrigerated dock creates a more continuous cold chain between storage, handling, and refrigerated transportation.

Siemens PLC Intelligent Control

The complete refrigeration system is controlled by Siemens PLC programmable controllers and touchscreen interfaces.

The system supports automatic operation, centralized equipment control, alarm management, and PC-based monitoring. Operators can supervise multiple refrigeration components from a centralized platform, improving system management and maintenance efficiency.

Project Results

The Shanghai Rongqing Logistics 20,000 m³ Low-Temperature Cold Storage Project combines frozen warehousing, high-turnover logistics, long-term storage, intelligent control, and energy-efficient refrigeration technologies.

Through the integration of parallel screw compressor racks, forced-air evaporators, aluminum tube evaporators, hot gas defrost, liquid pump refrigerant circulation, refrigerated loading docks, and Siemens PLC control, HAOCOOL delivered a comprehensive frozen logistics cold storage solution.

The project provides a practical reference for large logistics cold warehouses, frozen food distribution centers, meat and seafood storage facilities, refrigerated logistics hubs, and industrial low-temperature cold storage projects.