300 m² Multi-Temperature Fresh Food Logistics Cold Storage, Suzhou

Layout Design & System Scheme for 300 ㎡ Warehouse

XNAIR adopts a layout strategy of dry-wet separation and gradual temperature gradient transition for this 300-square-meter warehouse. The space is divided into three functional zones arranged from high to low temperature as below:

Receiving & Delivery Buffer Corridor: 5–10°C, acting as a transition buffer between outdoor ambient and cold storage to absorb heat and moisture load from frequent door openings.

Fresh Produce Refrigerated Zone: 2–8°C for vegetables and fruits, with combined rack storage and floor stacking layout.

Frozen Storage Zone: Independent enclosed area maintained at -18°C for frozen meat products.

A 150 mm thick double-sided color steel polyurethane partition wall separates the refrigerated and frozen zones, pre-embedded with anti-condensation heating circuits to eliminate structural icing induced by huge temperature difference. Flexible separation between buffer corridor and refrigerated zone is achieved via high-speed roller shutters paired with double air curtains. During peak sorting hours, roller doors stay open, and high-velocity air curtains stabilize temperature boundaries between zones.

Design Capacity Parameters

Core Refrigeration System Configuration

Based on thermal load calculation, the cooling load is 28 kW for the refrigerated zone, 22 kW for the frozen zone and 8 kW for the buffer corridor. Given dramatic load fluctuations of logistics cold storage and prominent demand for centralized night cooling, the system is configured as follows:

The refrigerated zone and buffer corridor share one set of 10 HP low-temperature parallel scroll compressor units with evaporation temperature of -8°C. Equipped with electronic expansion valves and ceiling-mounted air coolers featuring 4.5 mm fin spacing, the system adapts to high-humidity conditions for fruits and vegetables.

The frozen zone is equipped with an independent set of 15 HP low-temperature parallel scroll compressor units with evaporation temperature of -28°C. Its air coolers are fitted with stainless steel electric heating defrosting modules; defrost cycles are automatically adjusted via frost thickness sensors to cut unnecessary power waste from fixed-timed defrosting.

R449A refrigerant is adopted throughout the project. Its GWP value is around 65% lower than R404A, complying with global trends of eco-friendly refrigerant replacement.

An intelligent controller supports remote cloud monitoring, enabling real-time viewing of zone temperatures, compressor EER, defrost status and push notifications for equipment alarms.

Anti-Frost Heave Floor Construction

An 80 mm thick XPS extruded polystyrene board (compressive strength ≥ 300 kPa) is laid as thermal insulation on the original bare concrete factory floor, topped with a 100 mm thick reinforced concrete slab embedded with anti-freeze ventilation ducts. The frozen zone floor is additionally fitted with electric heat tracing to keep subsoil temperature above 0°C all year round, fundamentally preventing floor frost heave and cracking.

Energy-Saving Lighting & Open Sorting Optimization

To meet high illumination requirements for community group-buying sorting and withstand harsh low-temperature environments, special IP65-rated linear LED cold storage lights are installed across the whole facility, with operating temperature ranging from -40°C to +40°C. Lights are arranged along rack aisles to deliver an average illuminance of 220 lx on sorting platforms with uniformity above 0.7. Shadow-free working surfaces reduce misjudgment of vegetable freshness and barcode scanning failures.

Lighting control integrates microwave induction and door magnetic interlock:

Lights in the buffer corridor switch to 100% brightness when personnel or forklifts enter, and dim to 20% standby brightness 3 minutes after evacuation.

Lights in refrigerated and frozen zones interlock with door status and automatically power off during off-peak idle hours.

Actual testing shows the lighting system saves approximately 42% electricity compared with conventional all-day lighting schemes.

Open Sorting Circulation Route

Solid partition doors between the refrigerated zone and buffer corridor are removed. High-volume air curtains form stable temperature barriers during daytime continuous sorting. Movable sorting trolleys are placed inside the buffer corridor. Fruits and vegetables are weighed, labeled and packed into bins under 2–8°C refrigeration. Forklifts then retrieve frozen goods directly from the frozen zone for consolidated loading. The unidirectional circulation layout avoids heat load buildup caused by repeated cross-traffic and reverse personnel movement.

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