120 m³ Constant Temperature Warehouse for Semiconductor Silicone Raw Materials in Xuhui, Shanghai

1. Modular Insulated Enclosure Design

100 mm-thick double-sided color steel polyurethane sandwich panels are adopted, with a density of 42 kg/m³ and thermal conductivity ≤0.022 W/(m·K). Panels are connected via tongue-and-groove joints filled with sealant. Pre-fabricated modular panels weigh only 14 kg/m² and require no wet construction during installation, fully complying with floor load limits.

The enclosure dimensions are 7.2 m × 5.4 m × 2.4 m (L×W×H) with an effective volume of approximately 93 m³. One 800×1900 mm semi-recessed sliding door is equipped, with built-in 36 V electric heating wires in the door frame for anti-condensation purposes.

2. Core Configuration of Refrigeration System

Compressor Unit

Fully hermetic scroll compressors manufactured by Brazil-based Embraco, Model VEGY6H, rated power 3.5 HP, charged with R449A refrigerant. The continuous compression process of scroll compressors inherently suppresses suction pulsation. Driven by frequency converters, the capacity can be steplessly regulated within 20%–100% to match part-load operating conditions.

Condensing Side

Remote air-cooled condensers fitted with EC variable-speed fans that automatically adjust rotation speed based on condensing pressure, enabling stable operation under ambient temperatures ranging from -15℃ to +45℃.

Evaporating Side

Custom low-profile ceiling-mounted air coolers with an overall height of merely 350 mm and dual air outlets, equipped with external rotor axial fans and an air volume of 2,500 m³/h. The 4.5 mm fin spacing provides dustproof performance, with an electric defrost power of 2.1 kW. Defrost logic is optimized by the controller to minimize temperature rise inside the warehouse.

3. Precision Control System

The master controller adopts Carel PJ series digital thermostats paired with NTC temperature sensors offering ±0.2℃ accuracy, installed in the return air zone at the geometric center of the warehouse.

Control Strategies

PID plus feedforward algorithm is applied to pre-compensate cooling capacity according to door opening frequency;

Dual defrost modes of demand-based defrost plus time backup are adopted. Defrost terminates when coil temperature reaches ≥8℃ or after a maximum duration of 10 minutes, limiting warehouse temperature rise to ≤2℃ during defrost cycles;

Remote alarming: dry contacts connect to the client’s BMS system to push alerts for over/under temperature, power failure and sensor faults to the facility management team.

4. Air Distribution Layout Matched with Racking Systems

To eliminate airflow dead zones caused by stacked raw material barrels, an air circulation scheme of top supply and bottom return is designed. The ceiling-mounted air cooler is installed at the central position, with arc deflectors mounted at air outlets to attach cold airflow to the ceiling and deliver it to the far end. Cold air sinks naturally and returns through the bottom of racks. CFD simulation verifies that the maximum temperature difference across 9 measuring points inside the warehouse is 0.9℃, meeting process requirements.

5. Electrical & Safety Configuration

Separate WDZ-YJY-5×4 mm² cables are laid, matched with input filters for compressor inverters to suppress harmonic distortion. Emergency call buttons and IP65 LED explosion-proof lamps are installed inside the warehouse, while a Carel display screen outside the door shows real-time warehouse temperature, setpoint and unit operating status.

List of Core Equipment & Technical Parameters

Commissioning & Qualification Test Process

Cooling-down Test: The empty warehouse cools down from ambient 28℃ to setpoint 7℃ within 38 minutes.

Steady-state Performance: Continuous 48-hour operation at set temperature 5℃. Temperature records fluctuate between 4.8℃ and 5.6℃ with a standard deviation of 0.18℃; no alarms triggered except during defrost cycles.

Defrost Interference Test: Manual defrost initiated at warehouse temperature 5℃ and 50%RH. The peak warehouse temperature reaches 5.9℃ upon defrost completion and recovers to 5.3℃ within 10 minutes.

Power Failure Recovery Test: After 30-minute power cut, compressors start with delay without abnormal alarms. Warehouse temperature recovers from 6.8℃ to 5.5℃ in 22 minutes.

All test data are archived and delivered to the client as part of as-built documentation.

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