Industrial freezing of berries, cut vegetables and fruit is one of the most critical steps in modern food processing. Final product quality, shelf life and shape retention all depend directly on the freezing technology and equipment used. One of the most efficient solutions available today is the IQF fluidized bed tunnel freezer (Individual Quick Freezing). In the project described below, this role is filled by a tunnel freezer of the Unidex TZF 1500M model.
This article covers a completed installation: a Unidex TZF 1500M IQF tunnel freezer for quick freezing raspberries at a capacity of 1,500 kg/h, together with the screw compressor rack that supplies its refrigeration. The facility is located in Vinnytsia, Ukraine.
What Is the Unidex TZF 1500M IQF Tunnel Freezer and What Is It Used For
The Unidex TZF 1500M is an IQF fluidized bed tunnel freezer: a strong, cold airstream suspends the product in a fluidized state on the conveyor belt, so each piece is frozen individually instead of clumping together. This is essential for downstream sorting, grading and packing lines.
This type of industrial freezing equipment is used for quick freezing of:
- berries (raspberries, strawberries, blueberries, currants);
- diced and sliced vegetables;
- fruit;
- mushrooms;
- meat and minced meat;
- selected seafood products.
Individual Quick Freezing (IQF) preserves the product’s structure, colour, taste and nutritional value by minimising the formation of large ice crystals inside the cells — a key requirement for premium frozen fruit and frozen vegetable exports.
Technical Parameters of the Project: Unidex TZF 1500M Raspberry Freezing Line at 1,500 kg/h
The IQF fluidized bed tunnel freezer installed in Vinnytsia is configured for raspberry freezing with the following parameters:
- freezing line capacity — 1,500 kg/h;
- product inlet temperature — +15°C;
- product outlet (core) temperature — -18°C, in line with standard frozen food storage requirements;
- air temperature supplied to the conveyor belt — -30°C.
Running the tunnel at this duty requires a powerful, stable refrigeration supply capable of operating at very low evaporating temperatures.
Screw Compressor Rack for the IQF Tunnel’s Refrigeration Supply
Refrigeration for the tunnel freezer is supplied by a screw compressor rack engineered specifically for low-temperature freezing duty.
Key components and features of the compressor rack:
- 3 screw compressors with stepless capacity control on each unit, allowing the system to precisely match refrigeration output to the tunnel’s actual load;
- economizer system, which increases the coefficient of performance (COP) and energy efficiency at deep sub-zero conditions;
- water-cooled condenser for stable heat rejection even under high thermal loads;
- refrigerant evaporating temperature — -40°C;
- saturated suction temperature required for tunnel operation — -30°C, a necessary condition for maintaining the correct freezing regime;
- automation based on three CAREL pRack 300 compressor rack controllers, which manage the compressors, maintain set parameters and ensure safe, energy-efficient automatic operation.
This configuration delivers high efficiency even at very low evaporating temperatures — one of the main engineering challenges when designing industrial refrigeration plants for quick freezing applications.
Why This Matters for Food Processors
A combined IQF tunnel freezer and screw compressor rack solution gives a processing plant:
- stable freezing throughput even at peak loads;
- lower energy consumption thanks to the economizer cycle and stepless compressor capacity control;
- fully automated control of every parameter in the refrigeration circuit;
- consistently high-quality frozen berries, vegetables, fruit, mushrooms, meat and seafood thanks to Individual Quick Freezing technology.
Conclusion
The Vinnytsia project is an example of a complete engineering approach to industrial freezing: from the Unidex TZF 1500M IQF fluidized bed tunnel freezer to a low-temperature screw compressor rack automated with CAREL pRack 300 controllers. This combination allows food processors to produce high-quality frozen product while keeping energy costs to a minimum.