Blast Freezer & IQF Tunnel Guide
Reference guide to specifying blast freezers and IQF tunnels for meat, seafood, fruits, and prepared foods.
Blast vs slow freezing
Slow freezing (in a -18°C cold store) forms large ice crystals that rupture cell walls — meat loses 8–12% drip on thaw. Blast freezing (-30 to -40°C, high air velocity 3–5 m/s) forms micro-crystals — drip loss drops to 1–3%. FSSAI mandates blast freezing for export-grade meat & seafood.
Batch blast freezer
Capacity per batch: 0.5–10 MT. Cycle time: 8–12 hours to take product from +5°C to -18°C core. Trolley-loaded with stainless racks; product spread in pans for surface area. Refrigeration: ~1.8–2.2 TR per MT of throughput per cycle (significantly higher than steady-state cold rooms). Refrigerant: R-404A / R-507 for Freon systems, R-717 (ammonia) for plants above 50 MT/day.
IQF tunnel
Continuous belt freezer for individually quick-frozen products (peas, shrimp, French fries, paneer). Belt speed adjustable, mesh stainless steel, total residence time 10–30 minutes. Product enters at +10°C, exits at -18°C surface. Capacity: 250 kg/hr to 5 MT/hr. Energy: 0.8–1.2 kWh per kg frozen.
Plate freezer
For block-frozen fish, meat patties: product compressed between refrigerated SS plates (-40°C), freezing time 90–120 min for 50 mm block. Capacity 0.5–3 MT per cycle. Highest energy efficiency among freezing methods (no air movement).
BOQ (5 MT batch blast freezer, Freon)
PUF panels 150 mm (~140 m²): ₹6–7 lakh. Insulated door 1.8 × 2.1 m: ₹1.2–1.5 lakh. Refrigeration package (2 × 10 HP Bitzer + air-cooled condenser + low-temp evaporator): ₹11–14 lakh. SS trolleys + pans: ₹1.5–2 lakh. Controls + alarms + data logger: ₹1.8–2.5 lakh. Hot-gas defrost piping & valves: ₹1.5–2 lakh. Civil insulated floor: ₹1.5–2 lakh. Installation: ₹2–2.5 lakh. Total: ₹26.5–33.5 lakh + GST.
Ammonia (R-717) systems
For plants above 50 MT/day, ammonia is the economic choice — 15–20% lower energy, zero GWP, refrigerant cost negligible vs Freon. But CAPEX is 1.4–1.7× higher (welded steel piping, safety, ammonia detection, scrubber, trained operators required). PESO licensing mandatory for refrigerant charge >100 kg.
Frequently Asked Questions
Can a regular cold room be used as a blast freezer?
No — air velocity, evaporator design, and TR/m³ ratio are fundamentally different. Using a cold room as blast freezer will give 36+ hour freeze times and severe quality loss.
How cold is 'blast' really?
Air at -30 to -40°C, with product surface reaching -18°C within 2–4 hours and core within 8–12 hours, is the FSSAI / EU benchmark for blast freezing.
Need an engineered cold room quote?
Get a line-item BOQ from HyperCold's engineering team — heat load, PUF, refrigeration, controls, civil, all priced separately.
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