Dual-Zone Catering Cold Storage Project of Shanghai Langxin Hotel

1. Cold Storage Envelope Design

150 mm double-sided color steel polyurethane insulation panels (PIR system, oxygen index ≥ 30) are adopted. All panels feature double-side sealed tongue-and-groove joints, and six sides of the warehouse are equipped with independent cold-bridge prevention structures. A 100 mm partition wall separates the freezer and chiller rooms, each fitted with an independent swing door with embedded anti-condensation electric heating wires inside door frames. An SBS moisture & vapor barrier and load-bearing insulated base floor are laid at the bottom of the warehouse to completely eliminate condensation.

2. Refrigeration System Configuration

The freezer and chiller are each equipped with a separate air-cooled condensing unit matched with ceiling-mounted evaporators. This avoids efficiency loss caused by compromised evaporation temperatures when sharing a single system.

Freezer Zone (-18°C)

Emerson Copeland ZB series low-temperature enhanced hermetic scroll compressors with eco-friendly R449A refrigerant, designed evaporation temperature: -25°C. The air-cooled condensing unit is fitted with infinitely variable EC fans that automatically adjust airflow based on condensing pressure for prominent energy savings in winter. Inside the warehouse, Jinxue D series low-temperature ceiling evaporators come standard with electric defrost, 6 mm fin spacing, and IP54 external rotor fan motors.

Chiller Zone (2~8°C)

Emerson Copeland ZB series medium-temperature hermetic scroll compressors charged with R449A, designed evaporation temperature: -5°C. The condensing unit also features EC variable-speed fans. Jinxue H series high-temperature ceiling evaporators are installed indoors with 4.2 mm fin spacing, requiring no regular defrost. Dual-side air outlet airflow layout reduces weight loss of food ingredients.

3. Intelligent Control System

XNAIR XC-8000 dedicated cold storage controller with PLC + touchscreen architecture is deployed to realize the following functions:

Independent dual-zone temperature control with accuracy of ±0.5°C; Pt100 platinum resistance temperature probes (two redundant sensors per room).

Logical interlock and sequential start/stop for compressors, condenser fans and evaporator fans; graded EC fan speed control based on condensing pressure.

Electric defrost management for freezer: dual modes of timed defrost & demand-based intelligent defrost. Defrost trigger points are determined by running hours and evaporator fin temperature, with dual protection of defrost temperature cut-off and maximum duration limit.

Remote monitoring & alarm: 4G DTU uploads temperature, humidity and equipment operating status to cloud platform; WeChat & SMS alarms push abnormal signals within 15 seconds, complying with automatic recording requirements of HACCP.

Energy efficiency management: Records cumulative compressor runtime, defrost frequency and daily average power consumption, and generates weekly reports sent to the hotel engineering department to support energy consumption optimization.

4. Key Installation & Commissioning Points

The warehouse envelope is fully assembled on site; all panel joints are sealed with butyl sealing tape and neutral silicone sealant. Ventilated anti-freeze structures are added to the freezer base floor to prevent frost heave caused by underground moisture condensation. All condensing units are mounted on equipment platforms above the warehouse. Exhaust ducts are connected to existing ventilation shafts fitted with silencing plenum chambers, resulting in operating noise of 59 dB(A) that meets the exhibition center standard.

After pressure holding, vacuum pumping and quantitative R449A refrigerant charging, an empty-room pull-down test is performed for the -18°C freezer. The temperature drops from ambient to -18°C within 1 hour and 45 minutes, achieving temperature control precision of ±0.3°C against setpoint.

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