Sichuan Barkam 2000m³ CA Cold Storage: High-Altitude Fruit Preservation EPC Case

Author: Western Sichuan Plateau Agricultural Cold Chain Senior Engineer

11 years EPC experience for high-altitude fruit bases in Aba Prefecture. Familiar with GB 50072 Cold Storage Standard, GB/T34399 Controlled Atmosphere Specification & NY/T4696 Postharvest Preservation Norm, specialize in low-pressure, large temperature difference plateau CA warehouse customized design.

Project Overview

This 2,000 m³ dual-purpose CA & freezer cold storage locates in Barkam, Sichuan (altitude ~2600m), dedicated for local apples, plums, wild berries long-term off-season storage.
Plateau core environmental challenges: Thin air leads 10~12% refrigeration loss per 1000m altitude; day-night temperature gap over 25℃, strong UV & sand wind, freezing winter soil. Ordinary plain cold room design will cause unstable temperature and rapid fruit rot.

Core Standard Engineering Data

1 Zoning volume: 1020 m³ CA chamber (-5~0℃) + 1056 m³ -18℃ freezer, total 2076 m³

• GB50072 calculation (500~10000m³ η=0.55, plateau fruit ρ=0.23t/m³)
• Total usable mixed storage ton = 2076 × 0.55 × 0.23 ≈ 263 tons

2 Full delivery cycle: 45 working days (including CA air tightness pressure test & 72h full load calibration)
3 Compliance: GB/T34399 CA national standard, NY/T4696 fruit fresh-keeping specification, plateau low-pressure refrigeration adaptation design

Pre-Construction Client Pain Points

1 Local fruit stored in simple earth cellar, spoilage rate up to 34% within 30 days, forced low-price harvest sales;
2 Outsourced cold storage in Chengdu requires long-distance transport, high logistics cost & fruit mechanical damage;
3 Ordinary refrigeration units fail to reach target temperature under plateau thin air;
4 No sealed CA structure, fruit ripen quickly and cannot supply off-season market.

1 Plateau Exclusive Anti-Freezing & UV Resistant Envelope System

Comply with high altitude large temperature difference construction requirement:

Zone Type	PU Panel Spec	Plateau Optimization Upgrade
-5~0℃ CA Chamber	100mm B1 low-smoke PUR	Double HDPE full warm-side vapor barrier; three-layer glue + two non-woven airtight joint construction (meet GB/T34399 500Pa 30min pressure standard); exterior anti-UV coating to resist sand wind aging
-18℃ Freezer	150mm B1 high-density PUR	Double X anti-freeze floor insulation to prevent permafrost floor heave; low-temperature elastic airtight door rubber strip

Core construction rule: All wall-ceiling-floor joints filled mildew-proof low-temp sealant; nylon cold-bridge gaskets for all suspension brackets to eliminate wall condensation under 25℃ temperature swing.

2 Low-Pressure Adapted N+1 Redundant Refrigeration System

All compressors configured with 28% power redundancy to compensate plateau cooling attenuation:
1 CA Zone: 4×10HP Emerson Copeland scroll units, 1-main-1-standby auto switch per room; enlarged condenser heat exchange area to offset thin air heat dissipation loss;
2 Freezer Zone: 2×28HP Frascold piston units with plateau pressure parameter pre-calibration;
3 Universal matching DL/DD low-speed evaporator (air flow ≤0.6m/s) to avoid fruit water loss;
4 Unified dual-circuit hot gas defrost without local temperature spike damaging berries.

3 GB/T34399 Standard CA Gas Regulation System

Full Runops integrated gas control with Siemens PLC core:
1 O₂/N₂ Generator + CO₂ Scrubber + Ethylene Remover integrated unit;
Classified gas parameters for local plateau fruits:

• Apple/plum: O₂ 2~4%, CO₂ 1~3%
• Wild berry: O₂ 3~5%, CO₂ ≤2%

2 Mandatory air tightness test: 500Pa initial pressure, pressure drop ≤100Pa after 30min as qualified;
3 Independent pressure balance bag inside each CA room to avoid wall deformation from internal-external pressure difference; explosion-proof observation window for daily inspection.

4 HACCP Zoning & 2-Year Tamper-Proof Monitoring Platform

Solid Wall Three-Zone Layout (Curtain Separation Forbidden)

1 Yellow Pending Pre-Cool Buffer (6h mandatory field heat removal after picking)
2 Green Qualified CA/Freezer Storage Area
3 Red Moldy/Damaged Fruit Isolation Room

Intelligent Trace System

Multi-point temp/O₂/CO₂ sensors deployed per 120㎡; auto record every 30min, minimum 2-year non-editable cloud storage complying NY/T4696; multi-level SMS + onsite sound-light alarm for over-limit & equipment fault.

5 Measurable 12-Month Operation Benefits

1 Standard CA air tight design extend fruit shelf life from 30 days to 150 days for off-season high-price sales;
2 Plateau optimized unit cut annual power consumption by 24%;
3 Fruit spoilage rate reduced from 34% down to 2.8%;
4 Abandon long-distance outsourced cold storage logistics cost, full investment payback period: 18 months.

7 Common Plateau CA Cold Storage Construction Pitfalls

1 Use plain low-power compressor without 20~30% redundancy → Cannot reach target temp at high altitude
2 Skip three-layer airtight joint construction → CA gas leakage, preservation cycle halved
3 No anti-freeze XPS floor → Winter ground frost heave crack panel
4 Omit exterior UV coating → Outer panel aging within 2 years
5 Mix different fruits without isolation → Ethylene cross-ripening mass loss
6 Editable short-term data record → Fail agricultural product export audit
7 No standby compressor → Long maintenance downtime cause whole batch fruit scrapping

Simple Plateau CA Warehouse ROI Calculation Formula

Annual Net Income = Off-Season Fruit Price Premium − Long-Distance Logistics Saving − Annual Power & Maintenance − Spoilage Loss Reduction
Full Payback Months = Total EPC Investment ÷ Average Monthly Net Profit

FAQ For Western Sichuan Fruit Cooperative Managers

Q1 Why add extra compressor power for Barkam high altitude?

Thin air reduces heat dissipation, every 1000m altitude causes ~10% cooling capacity loss.

Q2 What’s the national standard for CA warehouse air tightness?

500Pa initial pressure, pressure drop no more than 100Pa after 30 minutes test.

Q3 How long can local apples be stored in this plateau CA cold room?

Up to 150 days under standard O₂/CO₂ gas control.

Q4 Special ground design for plateau winter?

Double XPS anti-freeze floor insulation to prevent permafrost frost heave.

Custom High-Altitude CA Cold Storage Inquiry

Provide main fruit varieties & local altitude to get air tight construction drawing & itemized quotation.

Construction & Completion Photos