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Here’s a professional and structured "Standard Specifications for the Construction and Operation of Flower Cold Storage" in English, aligned with international postharvest technology and industry best practices:
| Grade | Application | Temp. Accuracy | Humidity Control | Atmosphere Control | Pre-cooling Facility |
|---|---|---|---|---|---|
| A | Export/Premium flowers, bulb storage | ±0.3°C | ±3% RH | Full CA (Controlled Atmosphere) | Vacuum + Forced-air pre-cooling |
| B | Domestic wholesale, transit storage | ±0.5°C | ±5% RH | Basic MA (Modified Atmosphere) | Forced-air pre-cooling |
| C** | Short-term storage (<72h) | ±1°C | ±10% RH | None | Direct cooling in cold room |
Total cooling load (Q_total) must include:
Q_{total} = Q_{envelope} + Q_{respiration} + Q_{ventilation} + Q_{equipment} + Q_{operations}Respiration heat values (e.g., roses: 120–180 W/ton; lilies: 80–120 W/ton).
Floor frost protection: Ventilated subfloor + heating cables (≥25 W/m² in cold climates).
CA storage airtightness: Pressure decay test (100 Pa → 50 Pa in ≥10 min, per ISO 28460).
| Component | Technical Requirements |
|---|---|
| Compressor | Scroll or semi-hermetic piston, COP ≥3.2 (at −5°C evaporation) |
| Evaporator | Copper tube-aluminum fin, face velocity ≤2 m/s, ΔT ≤5 K |
| Refrigerant | R449A/R452A (GWP <1500) or CO₂ cascade systems |
| Defrost control | Time + ΔT + max interval triple logic |
| Method | Applicable Flowers | Cooling Curve | Final Temp. |
|---|---|---|---|
| Vacuum cooling | Leafy cut flowers | 20°C → 4°C in ≤15 min | Target ±0.5°C |
| Forced-air cooling | Roses/Carnations | 20°C → 5°C in ≤2h (airflow ≥1 m/s) | Core temp. ≤7°C |
| Hydro-cooling | Tropical flowers | Water at 5±1°C, 15–30 min soak | Stem temp. ≤10°C |
Threshold: ≤0.1 ppm (sensitive orchids: ≤0.05 ppm).
Solutions:
Active: Catalytic oxidizers (efficiency ≥95%).
Passive: KMnO₄-Al₂O₅ filters.
Dew-point method:
When T_{storage} = 2°C, T_{dew} ≥1°C (RH ≈95%).Anti-condensation: Ultrasonic humidifiers + temp. fluctuation ≤0.5°C/h.
| Cold Storage Type | Allowable Power (kW/ton) | Annual Energy Use (kWh/m³) |
|---|---|---|
| A (CA storage) | ≤0.8 | ≤120 |
| B (Conventional) | ≤1.2 | ≤180 |
Insulation: Polyurethane panels (λ ≤0.022 W/m·K), thickness ≥150 mm.
Heat recovery: Reject heat reuse for water heating (efficiency ≥65%).
Personnel safety:
Cold gear (EN 342 compliant) for temperatures <5°C.
O₂ monitors (CA storage: alarm at <18%).
Refrigerant safety: NH₃ systems require leak detectors (threshold 25 ppm).
Required records:
Temperature/humidity logs (automated, 5-min intervals).
Ethylene/CO₂ levels (CA storage).
Pre-cooling time-temperature profiles.
Certifications:
ISO 9001 (Quality Management).
BRCGS Cold Storage (for export facilities).
