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At CSTHEATEXCHANGER, we design and manufacture heavy-duty industrial blast freezer evaporators and quick-freezing air cooler units engineered specifically for commercial batch shock freezers, IQF tunnels, and continuous spiral freezing systems. Operating at evaporating temperatures from −35∘C down to −45∘C (delivering room air temperatures of −30∘C to −40∘C), CSTHEATEXCHANGER blast freezer evaporators feature progressive variable fin spacing (12 mm−20 mm at air intake down to 8 mm−10 mm at discharge), high-pressure aerodynamic aerofoil fans, food-grade stainless steel or copper coils, and rapid hot-gas or water defrost architectures. Our systems accelerate core product freezing past the critical ice crystal formation zone (−1∘C to −5∘C) in minutes, completely preventing cellular membrane rupture, eliminating post-thaw drip loss, and maximizing continuous production run times.
Blast freezing is fundamentally distinct from static low-temperature cold storage. While standard holding freezers maintain already-frozen products at steady state, a blast freezer must rapidly extract intense latent heat of fusion (Δhfus≈334 kJ/kgΔhfus≈334 kJ/kg) and sensible heat from warm food products (seafood, poultry cuts, red meat carcasses, bakery dough, ready meals, and berries).
RAPID SHOCK FREEZING THERMAL PATHWAY
+20°C (Product Intake)
│
▼ [Sensible Heat Removal: Liquid Water Cooling]
0°C
│
▼ [CRITICAL ZONE: Maximum Ice Crystallization (-1°C to -5°C)]
• FAST FREEZING (CSTHEATEXCHANGER Airflow): Micro-Crystals (Intact Cell Walls)
• SLOW FREEZING (Undersized Evaporators): Macro-Crystals (Cell Rupture & High Drip Loss)
-5°C
│
▼ [Deep Sub-Zero Sensible Heat Extraction]
-18°C / -25°C (Frozen Core Target Achieved in 30–120 Minutes)If product freezing occurs too slowly through the maximum ice crystal formation zone (−1.0∘C−1.0∘C to −5.0∘C−5.0∘C), water molecules agglomerate into large, sharp ice macro-crystals that puncture cellular walls. Upon defrosting, damaged cells bleed intracellular moisture, destroying product texture, reducing commercial sale weight (up to 5%–10% drip loss), and accelerating oxidative rancidity.
CSTHEATEXCHANGER Blast Freezer Evaporators deliver immense convective heat transfer rates by combining deep sub-zero evaporating temperatures with high-velocity, turbulent air distribution (4.0−8.0 m/s4.0−8.0 m/s over product surfaces), freezing the core rapidly and locking in peak product freshness.
At CSTHEATEXCHANGER, our blast freezer evaporator platforms are custom-built to overcome the severe physical challenges of deep sub-zero shock freezing:
When warm, moisture-laden product enters a blast freezer, air humidity instantly sublimates and forms dense frost on the entering face of the evaporator coil. In standard uniform-pitch coils, this causes rapid "frost bridging," choking airflow and forcing frequent production shutdowns for defrosting.
CSTHEATEXCHANGER incorporates progressive variable fin spacing:
Air Intake Rows: Wide fin spacing (14.0 mm−20.0 mm14.0 mm−20.0 mm) accommodates rapid front-face frost buildup without choking air passages.
Intermediate Rows: Medium fin spacing (10.0 mm−12.0 mm10.0 mm−12.0 mm) continues moisture extraction.
Air Discharge Rows: Dense fin spacing (7.0 mm−8.0 mm7.0 mm−8.0 mm) maximizes dry heat transfer surface area when air humidity has already dropped.
Result: Extends continuous blast freezing cycles by 200% to 300%, maintaining steady airflow throughout long production shifts.
Dense trolley racks, pallet boxes, and multi-tier spiral belts create massive aerodynamic air resistance. Our blast freezer units feature high-efficiency, aerodynamically profiled aluminum or composite sickle-blade fans equipped with deep intake venturis and air-straightening stream guides:
Delivers static pressure capabilities of 150 Pa to 350+ Pa.
Available in blow-through or draw-through configurations, ensuring deep, uniform air penetration across every product tray without dead zones.
Driven by heavy-duty low-temperature IP55/IP66 motors with internal winding thermistors and specialized synthetic low-temperature lubricants rated to −50∘C−50∘C.
Ammonia (R717 / NH3): Pumped overfeed or flooded recirculation coils utilizing seamless stainless steel (AISI 304L/316L) or hot-dip galvanized steel tubes with heavy-gauge aluminum or stainless steel fins.
Carbon Dioxide (R744 / CO2): Direct expansion or pumped liquid overfeed coils engineered for design pressures up to 60 bar to 90 bar, leveraging the superior heat transfer coefficients and low pumping viscosity of CO2CO2 at −40∘C.
HFC / HFO Refrigerants (R448A, R449A, R404A, R507): High-purity grooved copper tubes (5/8" or 1/2" OD) mechanically expanded into corrugated aluminum-magnesium or epoxy-coated fins.
Prolonged defrost cycles warm the blast freezing chamber, melting frost and causing ceiling condensation. CSTHEATEXCHANGER offers rapid defrost systems tailored to industrial throughput:
Hot-Gas Defrost: Direct injection of hot discharge vapor into evaporator coils and drain pan heating loops, melting frost from the inside out in 12 to 18 minutes.
Water Deluge Defrost: High-volume warm water spray headers distribute water evenly over the coil face, washing away heavy ice loads in 8 to 12 minutes.
Electric Defrost Elements: Incoloy-sheathed high-watt-density heating rods inserted into dedicated coil sleeve tubes and secured beneath the insulated drain pan.
Thermally Isolated Double Drain Pan: Double-wall polyurethane insulated drain pan with internal electric or hot-gas heating coils prevents condensate from re-freezing on pan surfaces and eliminates external pan sweating.
Seafood & Aquaculture Blast Freezing: IQF shrimp, whole salmon, tuna loins, squid, and surimi blocks rapidly frozen to −25∘C to preserve sashimi-grade cellular turgidity.
Meat & Poultry Processing Lines: High-velocity blast chilling and crust-freezing of poultry cuts, beef primal portions, pork bellies, and sausage links.
Bakery, Pastry & Par-Baked Dough: Immediate cryogenic-style freezing of raw laminated croissant dough, baguettes, and specialty pastries to stabilize yeast activity.
Prepared Meals & Frozen Vegetables: Rapid continuous spiral freezing of ready-to-eat meals, pizzas, diced fruits, and IQF berries.
Industrial & Biopharmaceutical Freezing: Deep-freeze environmental chambers and plasma blast freezers operating down to −45∘C.
Cooling Capacity Range: 10.0 kW to 250.0 kW per unit (Modular parallel banks scaling to multi-megawatt blast tunnels).
Evaporating Temperature Range: −30.0∘C down to −48.0∘C (Design air temperature −25.0∘C to −42.0∘C).
Airflow Volume: 5,000 m3/h to 95,000 m3/h with face air velocities up to 5.5−7.5 m/s.
External Static Pressure (ESP): 100 Pa to 350+ Pa.
Fin Spacing Geometry: Progressive variable pitch (14/12/10 mm or 18/14/10 mm) or uniform pitch (10 mm,12 mm,14 mm,16 mm).
Tube Materials: Seamless deoxidized copper, Stainless Steel AISI 304/316L, or Hot-Dip Galvanized Carbon Steel.
Fin Materials: Corrugated aluminum (AlMg2.5), hydrophilic coated aluminum, epoxy/Blygold coated, or full stainless steel 304.
Fan Diameters: ∅500 mm,∅630 mm,∅800 mm,∅910 mm high-pressure axial fans.
Casing Construction: Heavy-gauge stucco aluminum, marine-grade aluminum alloy, or food-grade AISI 304 stainless steel with hinged side inspection panels and swing-down drain pans.
During shock freezing of fresh, wet food products, the incoming air contains high moisture levels that quickly freeze onto the first few coil rows. Progressive fin spacing provides wide gaps (14 mm−20 mm) at the front to hold large frost volumes without blocking air channels, while tighter fins (8 mm−10 mm) at the back maximize heat transfer. This prevents frost choking and doubles or triples operating run times between defrosts.
Higher air velocity (4.0 m/s to 7.0 m/s) strips the stagnant boundary layer of warm air off product surfaces, dramatically increasing the surface heat transfer coefficient (hh). This pulls product core temperature through the critical ice crystal formation zone (−1∘C to −5∘C) in minutes, creating micro-crystals that preserve cell membranes and reduce post-thaw drip loss to under 0.5%–1.0%.
Yes. We manufacture fully certified stainless steel AISI 304/316L and high-pressure carbon steel coils engineered for direct-expansion, pumped liquid overfeed, and flooded ammonia (R717) systems, as well as ultra-high-pressure transcritical/subcritical CO2 (R744) blast freezers rated up to 90 bar.
Contact CSTHEATEXCHANGER today with your shock freezing project parameters:
Product Type, Incoming Temperature (∘C), and Target Final Core Temperature (e.g., −18∘C or −25∘C−)
Freezing Batch Throughput (kg/hour or tons/batch) & Target Freezing Cycle Time (Minutes/Hours)
Freezer Architecture (Batch Room with Trolleys, Continuous IQF Tunnel, or Spiral Freezer)
Refrigerant Selection (Ammonia R717, Carbon Dioxide R744, R448A/R449A, or Glycol/Brine)
Available Defrost Utilities (Hot Gas, Water Deluge, or Electric Elements)
Our industrial refrigeration engineering division will provide detailed thermodynamic load calculations, coil circuiting schematics, 3D CAD interface drawings, and factory-direct equipment quotations.
Website: https://www.cstheatexchanger.com/
Technical Inquiries: info@cstheatexchanger.com
