Industrial freezing of berries and vegetables calls for more than just a powerful freezing tunnel — it also requires a reliable low-temperature refrigeration system capable of running year-round without interruption. One of the most effective solutions for this task is an IQF (Individual Quick Freezing) blast freezer tunnel paired with an industrial refrigeration system running on the natural refrigerant CO₂ (R744).
In this case study, we walk through a completed turnkey project: an IQF blast freezer tunnel, Unidex TZF-4A, sized for strawberries (4,500 kg/h) and green peas (5,500 kg/h), supplied by a CO₂ (R744) booster transcritical station built on 16 Bitzer 4NSL-30K compressors. The facility is located in Zhovkva, Lviv region, Ukraine.
What Is the Unidex TZF-4A IQF Blast Freezer Tunnel — and What Is It For
The Unidex TZF-4A is an IQF tunnel freezer — a type of industrial blast freezer in which each piece of product is frozen individually, exposed to a powerful stream of cold air at a refrigerant boiling temperature of -40°C. Under this regime, every berry or pea freezes on its own without clumping to its neighbors — critical for downstream packing and for keeping the product’s visual quality intact.
This class of tunnel freezer equipment is used for the rapid freezing of:
- berries (strawberries, raspberries, blueberries, currants);
- peas and other legumes;
- diced vegetables;
- fruit;
- mushrooms.
IQF technology minimizes the formation of large ice crystals inside the product’s cells, preserving structure, color, flavor, and nutritional value — whether the product is a berry or a pea. It’s worth noting the distinction from conventional blast freezing: while both rely on rapid cold-air exposure, IQF specifically keeps individual pieces separated on a moving belt or fluidized bed rather than freezing product in a fixed block, which is what makes it the preferred choice for loose, free-flowing produce like berries and peas.
Technical Parameters of the Zhovkva Project
The facility in Zhovkva has an installed Unidex TZF-4A IQF blast freezer tunnel with the following operating parameters:
- tunnel model — Unidex TZF-4A;
- refrigerant boiling temperature in the tunnel — -40°C;
- strawberry freezing capacity — 4,500 kg/h;
- green pea freezing capacity — 5,500 kg/h.
The difference in throughput between strawberries and peas comes down to product shape, size, and moisture content — a standard consideration when configuring IQF freezing systems for a specific production range.
CO₂ Booster Transcritical Station Supplying the Tunnel
Refrigeration for the tunnel is supplied by a booster transcritical station running on the natural refrigerant CO₂ (R744) — an energy-efficient, environmentally friendly solution for deep-freeze applications that is increasingly replacing traditional HFC refrigeration systems on industrial sites.
Key components and features of the station:
- 16 Bitzer 4NSL-30K compressors combined into a CO₂ booster transcritical station — this configuration provides the necessary refrigeration capacity headroom and reliability through redundancy;
- Guntner air coolers — a compact design with a large heat-exchange surface, well suited to the tunnel’s heavy low-temperature load;
- Carel monitoring and control system, which manages the compressor station, maintains the set process parameters, and ensures safe, energy-efficient operation in automatic mode.
This kind of refrigeration automation keeps the system running reliably even at a deep boiling temperature of -40°C — one of the key engineering challenges when designing industrial blast freezing systems.
Why This Matters for Food Processing
The combined solution — an IQF blast freezer tunnel plus a CO₂ booster station on Bitzer compressors — gives a food processor:
- consistent freezing throughput for both berries and peas at a single facility;
- energy efficiency from a transcritical CO₂ cycle on a natural refrigerant with low climate impact;
- reliability and redundancy from a 16-compressor Bitzer 4NSL-30K configuration;
- automated control of every refrigeration circuit parameter via the Carel system;
- high-quality frozen berries and vegetables thanks to Individual Quick Freezing (IQF) technology.
Conclusion
The Zhovkva project is an example of a complete, turnkey engineering approach to industrial berry and vegetable freezing — from the Unidex TZF-4A IQF blast freezer tunnel to a high-capacity CO₂ booster transcritical station on 16 Bitzer 4NSL-30K compressors with Carel automation. The result lets a food processor turn out consistently high-quality frozen product — both strawberries and peas — with minimal environmental impact and strong energy efficiency.
If you’re planning a similar project — a blast freezer tunnel and a CO₂ (R744) refrigeration station — get in touch with Koriel Group. We provide turnkey delivery: from equipment selection and system design for your specific product range and process, through installation and ongoing service.