Air blast freezers and air blast freezing tunnels both freeze product with forced cold air, so many investors assume they are the same thing. In fact, the two differ in chamber construction, loading method and the scale they suit. Understanding the difference helps a plant choose correctly from the start, avoiding equipment that cannot keep up with output or investment beyond what is needed.
Construction and loading method
Air Blast Freezer is a factory-built cabinet whose freezing chamber is divided into several compartments, each with its own door. Product is laid on stainless steel trays placed on racks in each compartment. Workers load and unload one compartment at a time, so the other compartments stay cold.
Air Blast Tunnel Freezers is a large freezing room with an insulated panel envelope, containing evaporators and high-capacity fans. Product is laid on trays stacked on multi-tier trolleys, and the whole trolley is pushed into the tunnel. The tunnel is designed to each plant's own dimensions and output.
Comparison of the main criteria
| Criteria | Air Blast Freezer | Air Blast Tunnel Freezers |
|---|---|---|
| Form | Factory-built cabinet, divided into compartments | Freezing room designed for the project |
| Loading method | Trays placed on racks in each compartment | Trays stacked on trolleys, whole trolley pushed into the tunnel |
| Output | 300 / 450 / 600 kg per batch (Tan Long TABF series) | By design, usually larger and expandable |
| Room temperature | About -33°C to -37°C | Usually -35°C or lower depending on design |
| Product flexibility | Good, each compartment runs independently | Very good, handles many product types and tray sizes |
| Floor space | Cabinet about 7.7–15.1 m long depending on capacity | Needs room area and trolley aisles |
| Installation time | Fast, as the equipment is factory-built | Longer, as the panel envelope and refrigeration system are built on site |
When to choose an air blast freezer
- Output per batch is below about 600 kg and steady through the year.
- Loading and unloading in small lots, alternating between several products.
- You want fast installation and an early start to production.
- The building has a long footprint but limited width.
When to choose an air blast freezing tunnel
- Output is large or highly seasonal, and spare capacity is needed for the peak season.
- Many product types with different tray sizes, including cartons.
- The plant is used to working with tray trolleys and wants to use its existing trolleys.
- Output expansion is planned, and the freezing room needs to be upgradable.
Factors that affect the performance of both
- Tray loading: trays stacked too densely or blocking the airflow lengthen freezing time and give uneven temperatures between positions.
- Air velocity and distribution: fans and air guide plates must be designed so air passes evenly through every tray level.
- Evaporator defrost: a frosted coil reduces airflow, so defrost on the correct cycle.
- Product temperature on entry: product pre-cooled before freezing shortens the batch time.
For high-volume block product, also consider a contact freezer. For loose product needing continuous throughput, an IQF conveyor is the better option.
Frequently Asked Questions
Which uses less electricity, an air blast freezer or a blast freezing tunnel?
It depends on the load. An air blast freezer has the advantage at part load because each compartment works separately. An air blast freezing tunnel is efficient when run continuously at full load with large volumes.
Can an air blast freezing tunnel be converted into a frozen store?
Technically it can run at frozen storage temperature, but the tunnel is designed for a large freezing heat load, so running it as a store is not optimal for power use.
Which refrigerant does an air blast freezer use?
Tan Long air blast freezers run on both NH3 and Freon, depending on the plant's existing refrigeration system.
Get advice from Tan Long engineers
Tan Long's engineering team surveys the site and proposes a solution to fit each plant's output, floor space and budget. Call the hotline 0933 357 058 (Mr. Thinh) for advice.
