Refrigerated container shipping is the primary method enabling Vietnamese agricultural products to reach distant markets such as Europe, the United States, the Middle East, and northern Chinese ports. With voyages lasting from 15 to 35 days, fresh agricultural products (such as...) dragon fruit, seedless lemon, South American ripe banana, sand mango, green pomeloThese fruits are highly susceptible to premature ripening, stem rot, peel wilting, or chilling injury if the cold chain is broken.
Tan Long Refrigeration and Electrical Engineering's cold storage project for preserving dragon fruit and other agricultural products for export meets international standards.
A common mistake many businesses make is relying entirely on the refrigeration system inside the container. In reality, refrigerated containers are designed only to... maintain temperature, insufficient capacity to rapid cooling A large quantity of fresh, hot agricultural products are brought directly from the fields. Therefore, investing in a system is necessary. industrial produce cold storage and process Pre-cooling The packing station at the port is a crucial link that determines the success or failure of an export shipment.
1. Why are agricultural products exported by sea prone to loss and deterioration in quality?
Unlike frozen seafood or meat (which are biologically inactive products), fresh agricultural products remain a viable option after harvesting. The living organism continues the process of respiration.:
- Respiratory heat dissipation phenomenon: The process of sugar consumption and the release of CO2, along with heat, increases the temperature inside the sealed pallet.
- Ethylene gas (C2H4): Ethylene is a natural plant hormone that stimulates rapid ripening of fruits. When many pallets of produce are packed in a confined space, ethylene gas accumulates exponentially, causing the entire shipment to turn yellow at the stems and become mushy before the ship reaches port.
- Surface water loss: The difference in water vapor pressure between the fruit and the cold chamber air causes the fruit to lose weight (usually 3–71 TP3T), resulting in wrinkled skin and stem detachment.
2. Tan Long Forced Pre-cooling Process
To completely prevent intense post-harvest respiration, the best method is to pass agricultural products through a chamber. Pre-cooling using forced-air:
- Cold air under high pressure is drawn in or pushed through the ventilation slots of the packaging carton and the gaps between the fruits.
- Field heat is released rapidly, lowering the fruit temperature from +30°C to a safe level (+4°C to +12°C depending on the fruit type) in just a short time. 2 to 4 hours, six times faster than storing in a conventional static cold storage.
- As soon as the required storage temperature is reached, the goods are transferred. cold storage for logistics transit and packed in specialized containers.
Dragon fruit for export is packed in specialized cardboard boxes and pre-chilled before shipment.
3. Standard Temperature and Humidity Charts for Major Export Fruit Varieties
| Agricultural Product Type | Cold Storage Temperature (°C) | Relative Humidity (RH %) | Sea Storage Time | Important Technical Notes |
|---|---|---|---|---|
| Dragon fruit (Red and white flesh) | +3°C to +5°C | 90% – 95% | 25-35 days | Below +2°C, cold exposure can easily cause ear discoloration and ear atrophy. |
| Seedless lemons | +6°C to +8°C | 85% – 90% | 30-45 days | Regular ventilation is necessary to prevent yellowing of the peel due to ethylene. |
| Cavendish bananas (South American Cavendish bananas) | +13°C to +14°C | 90% – 95% | 20 – 30 days | Absolutely do not store below +12°C to avoid the skin turning black and not cooking properly. |
| Green-skinned pomelo | +10°C to +12°C | 85% – 90% | 40-60 days | Disinfect and wrap with perforated shrink wrap before packaging. |
| Chu/Hoa Loc mangoes | +10°C to +12°C | 85% – 90% | 20-25 days | Highly sensitive to ethylene gas and anthracnose pathogens. |
4. Tan Long's Agricultural Refrigeration System Design Solution
Cold storage for agricultural products requires very different technical criteria compared to cold storage for meat and fish:
- Dedicated evaporator (small Delta T): Tan Long utilizes a large heat exchange area evaporator coil with a small temperature difference between the coil surface and the room temperature (ΔT only 3–5°C). This prevents condensation from freezing on the coil fins, maintaining high natural humidity in the storage room (90–95°C), minimizing fruit drying out.
- Ventilation fan system & Ethylene air filter: Automatic periodic fresh air exchange and removal of generated ethylene gas keep the fruit in a deep dormancy state throughout the journey.
- Condenser unit & optimized equipment: Incorporating world-leading energy-efficient compressor lines. Bitzer, Mayekawa Mycom, combine Tan Long evaporative condenser It helps stabilize condensation pressure in hot, humid tropical climates.
High-efficiency Tan Long evaporative condenser units installed at a large cold storage project in Long Hau.
Tan Long B2B Technical Consulting
Get your Cold Chain Capacity Calculation & Estimate within 24 Hours
Tan Long's engineering team conducts on-site surveys, calculates cooling load, and advises on equipment configurations to optimize operating electricity costs and meet stringent export standards (HACCP, FDA, GACC China).
✓ 10,000m² factory in Duc Hoa 1
✓ Partners: Bitzer, Mayekawa
5. Why Do Export Businesses Choose Tan Long as Their General Contractor?
With a modern, large-scale mechanical and refrigeration equipment manufacturing plant. 10,000m² in Duc Hoa 1 Industrial Park, Long An With a team of engineers boasting over 16 years of experience, Tan Long provides turnkey solutions:
- We conduct site surveys and provide advice on the most suitable capacity for pre-cooling chambers and cold storage facilities, based on the export capacity of each season.
- We provide a complete system of high-grade fire-resistant PIR panels, airtight insulated cold storage sliding doors, and an automated central temperature and humidity control system with data logging (Data Logger), fully meeting the inspection standards of our international partners.
- We are committed to providing on-site maintenance and technical support services 24/7.
Customers who need cold storage design for agricultural export or expansion of their cold chain infrastructure, please contact Tan Long immediately via Hotline. 0933 357 058 For personalized advice.
Is your business in need of a survey, upgrade, or new design for your industrial refrigeration system?
With over 18 years of practical experience leading more than 29 major national projects, Tan Long's team of HVAC engineers is committed to providing accurate thermal load calculations, optimizing the COP efficiency coefficient, switching between natural refrigerants NH3/CO2, and saving 20–30% in operating electricity costs.
Engineer Nguyen Toan Thinh (Technical Director)
With over 18 years of practical experience in directing, consulting, designing, and constructing heavy industrial refrigeration systems, ASRS automated warehouses, and IQF freezing systems across more than 29 major national projects.
