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At CSTHEATEXCHANGER, we design and manufacture high-efficiency, hygienic Hot Gas Defrost IQF Evaporator Coils and Unit Coolers engineered specifically for continuous shrimp, prawn, fish fillet, scallop, and cephalopod freezing lines (Spiral Freezers, Fluidized Bed IQF Tunnels, and Multi-Belt Crust Freezers) (refrigeration capacities engineered from 40 kW to over 1,200 kW per coil block, operating at evaporating temperatures of −35∘C to −45∘C with ammonia NH3, CO2, or Freon refrigerants). Engineered with interlaced multi-circuit hot gas defrost headers, dual-circuit insulated drain pan heating loops, and progressive variable fin spacing (16 mm / 20 mm inlet down to 8 mm / 6 mm discharge), our seafood IQF evaporators complete full, clean defrost cycles in under 15–20 minutes, completely eliminating ice damming, steam misting, and refreezing drips. Built with heavy-wall seamless AISI 304/316L stainless steel tubes, marine-grade AlMg3 aluminum fins (or 100% all-stainless construction), and TIG-welded hygienic drain pans with continuous 3∘ sloped drainage, CSTHEATEXCHANGER ensures maximum food safety, zero salt-corrosion pitting, and minimal glaze cracking on delicate seafood products.
Continuous shrimp and seafood freezing (cooked peeling shrimp, raw head-on shell-on prawns, glazed fish fillets) introduces unique operational and thermodynamic challenges:
SEAFOOD IQF FREEZING & HOT GAS DEFROST THERMODYNAMIC CYCLE
======================= WARM GLAZED SEAFOOD / STEAMING SHRIMP =======================
[ High Moisture + Trace Marine Salt Carried into -38°C Spiral / Tunnel Enclosure ]
│
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┌────────────────────────────────────────────────────────────────────────────┐
│ [PHASE 1: CONTINUOUS 16 - 24H SEAFOOD FREEZING RUN] │
│ • Progressive fin pitch (20 mm -> 12 mm -> 6 mm) captures heavy brine frost │
│ • Marine-grade AlMg3 / AISI 316L tubes resist salt aerosol pitting │
└───────────────────────────┬────────────────────────────────────────────────┘
│ (Defrost cycle initiated after production shift)
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┌────────────────────────────────────────────────────────────────────────────┐
│ [PHASE 2: RAPID 15-MINUTE DUAL-CIRCUIT HOT GAS DEFROST CYCLE] │
│ • High-pressure hot discharge gas (+35°C to +40°C) enters bottom pan first │
│ • Heated pan prevents falling ice slabs from refreezing or damming drain │
│ • Interlaced coil circuit melts frost from inside-out; ice sheds in sheets │
└───────────────────────────┬────────────────────────────────────────────────┘
│
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======================= COMPLETE GRAVITY DRAINAGE VIA 3° SLOPED PAN =======================
[ 100% Dry, Sanitized Evaporator Surface Ready for Instant Restart in < 20 min ]================================================================================
CST HOT GAS DEFROST SEAFOOD COIL VS. CONVENTIONAL ELECTRIC & WATER DEFROST
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Defrosting Parameter CST Rapid Hot Gas Defrost Coil Conventional Electric Defrost Water Spray Defrost
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Average Defrost Duration 15 to 20 Minutes (Rapid) 45 to 75 Minutes (Sluggish) 30 to 45 Minutes
Enclosure Room Temp. Rise Minimal (+2°C to +5°C max) High (+12°C to +18°C heat load) High humidity spike (Fogging)
Energy Cost per Defrost Near Zero (Reuses reject heat) Very High (Immense kW power) High (Water heating & pumping)
Ice Slab Drainage Efficiency 100% (Heated pan melts lumps) Ice refreezes on cold pan edges Ice dams block floor drains
Risk of Heating Element FailureZero (No electrical elements) Frequent element burnouts/leaks Zero electrical risk
CIP Washdown & Salt Durability AISI 316L / Marine AlMg3 Base Electrical wiring water ingress Plastic spray nozzles clog
Enclosure Steam Mist / Fogging None (Sealed thermal circuit) Moderate Severe moisture misting
Seafood Glaze Quality Impact Zero Glaze Melting / Clumping Thermal shock melts glaze Water droplets splash product
================================================================================Electric defrost requires heating elements that add massive electrical operating costs and warm the entire insulated freezer enclosure, taking over an hour to recover. CSTHEATEXCHANGER's interlaced hot gas defrost circuits utilize high-pressure compressor discharge gas (+35∘C to +40∘C) to melt frost from the inside out, shedding ice sheets in under 15 to 20 minutes with minimal enclosure temperature rise.
A frequent failure in seafood freezing is ice slabs falling into a cold drain pan, creating ice dams that overflow onto the freezer floor. Our systems route hot gas through the insulated bottom drain pan before entering the coil block, ensuring the pan surface is fully preheated (+25∘C) to instantly melt falling ice chunks and ensure 100%100% liquid drainage.
Seafood processing environments carry high humidity combined with trace chlorides and cleaning sanitizers:
CST SEAFOOD IQF EVAPORATOR STRUCTURAL ELEVATION
======================= FULL AISI 304/316L STAINLESS CASING =======================
[ Heavy Sloped Hygienic Framework with Hot Gas Headers & IP66 Axial Fans ]
│
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┌────────────────────────────────────────────────────────────────────────────┐
│ CORE SUBASSEMBLY INTEGRATION │
│ ┌────────────────────────┐ ┌────────────────────────┐ ┌──────────────────┐ │
│ │ AISI 316L TUBE CORE │ │ HEATED DRAIN PAN │ │ AXIAL FAN ARRAY │ │
│ │ AlMg3 or SS316L Fins │ │ Dual hot-gas coils │ │ IP66 Washdown │ │
│ │ Variable Fin Pitch │ │ 3° continuous slope │ │ Cast Al Impeller │ │
│ └────────────────────────┘ └────────────────────────┘ └──────────────────┘ │
└────────────────────────────────────────────────────────────────────────────┘ CST FULL HYGIENIC CIP SLOPED DRAIN PAN & HOT GAS MANIFOLD
FROM REFRIGERATION COMPRESSOR DISCHARGE (+35°C HOT GAS)
┌─────────────────────────────────────────────────────────────────────────┐
│ [ STAGE 1: DUAL-CIRCUIT STAINLESS STEEL DRAIN PAN HEATING COILS ] │
│ Preheats pan to +25°C -> Instantly melts falling ice chunks & glaze │
├─────────────────────────────────────────────────────────────────────────┤
│ [ STAGE 2: INTERLACED TUBE COIL HOT GAS EXPANSION HEADERS ] │
│ Inside-out thermal conduction breaks tube-to-frost bond in < 8 minutes │
└─────────────────────────────────────────────────────────────────────────┘
ALL DRAIN WATER EXPELLED VIA OVERSIZED SLOPED DRAIN FITTINGS IN < 15 MINSeafood processing brine and glaze water contain active sodium chloride ions. We fabricate our tube bundles from seamless AISI 316L stainless steel (with molybdenum addition) and utilize marine-grade AlMg3 magnesium-aluminum alloy fins (or optional 100% AISI 316L stainless steel fins) to resist pitting corrosion from marine salts and daily chlorinated/acidic CIP foam washdowns.
The evaporator casing is continuous TIG-welded from 2.5 mm to 3.0 mm AISI 304/316L stainless steel. With an engineered continuous 3∘ sloped bottom, oversized drain ports, and aerodynamic fan cowls, our units eliminate standing water pools and prevent defrost moisture droplets from blowing back onto frozen shrimp.
CSTHEATEXCHANGER SEAFOOD IQF EVAPORATOR ARCHITECTURES
[1. CONTINUOUS SHRIMP SPIRAL FREEZER EVAPORATORS]
• High-static horizontal airflow design mounted along the spiral drum enclosure wall.
• Features 20 mm -> 12 mm -> 6 mm progressive fin pitch for 24-hour continuous glazing runs.
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[2. FLUIDIZED BED IQF TUNNEL FREEZER COILS]
• Vertical upward high-velocity aeration design for individual quick freezing of shrimp & scallops.
• Heavy-gauge AlMg3 fins withstand high-frequency fluidization pulsations without fatigue.
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[3. MULTI-PASS CRUST FREEZING & GLAZING PRE-COOLERS]
• High-velocity blast coils designed for rapid crust freezing before secondary water glazing lines.(Note: The following engineering parameters represent standard manufacturing design envelopes. Tube circuits, progressive fin pitch stages, hot gas headers, and casing dimensions are customized to specific seafood processing line drawings.)
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CSTHEATEXCHANGER HOT GAS DEFROST SEAFOOD IQF EVAPORATOR (CST-IQF-SEA SERIES)
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Engineering Parameter Standard Manufacturing & Design Range
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Refrigeration Capacity Range 40 kW to 1,200+ kW per evaporator unit (Scalable)
Air Circulation Flow Rates 15,000 m³/h to 250,000+ m³/h (8,800 to 147,000+ CFM)
Operating Evaporating Temp. -35°C to -45°C (-31°F to -49°F) Deep Freezing
Compatible Refrigerants NH3 (R717 Overfeed Pump Circulation), CO2 (R744), R404A, R507
Defrosting Technology Rapid Dual-Circuit Hot Gas (Pan-First Heating Loop)
Average Defrost Duration 15 to 20 Minutes Complete Cycle (Rapid Thermal Shedding)
Progressive Fin Pitch Stages Inlet: 16–25 mm -> Middle: 10–14 mm -> Discharge: 6–8 mm
Tube Metallurgy Options Seamless AISI 304, AISI 316L Stainless Steel, Heavy Copper
Tube Outside Diameter & Wall 5/8" (15.88 mm) or 3/4" (19.05 mm) OD; Wall: 0.8 mm to 1.5 mm
Fin Material Options Marine-Grade AlMg3 Aluminum Alloy, Pure Al, AISI 316L Stainless
Fin Thickness Range 0.35 mm to 0.50 mm (Heavy gauge for high-pressure CIP washdown)
Casing & Frame Construction Continuous TIG-Welded AISI 304 or AISI 316L Stainless Steel
Drain Pan Configuration Double-Wall Insulated, 3° Sloped Bottom, Dual Hot-Gas Heating Coils
Axial Fan Array Specifications IP66 Washdown Direct-Drive Axial Fans, Cast Aluminum Impellers
Operating Pressure Rating NH3 / Freon: 25 bar (362 psi) | CO2: Up to 90 bar (1,305 psi)
Pressure Vessel Compliance ASME Section VIII Div. 1, CE / PED 2014/68/EU, 3-A Sanitary / USDA
Quality Assurance & Leak Gate 100% Helium Mass Spectrometer Vacuum Testing (Zero Leak Standard)
================================================================================Hot gas defrost melts frost from the inside of the tubes outward using waste heat from the refrigeration compressors (+35∘C to +40∘C). It clears the entire coil in under 15–20 minutes with almost zero electrical power consumption and avoids heating the entire freezer enclosure or creating steam fog that melts protective ice glazes on shrimp.
When ice melts from the upper coil, heavy chunks fall into the bottom pan. If the pan is cold, these chunks refreeze and block the drain line. CSTHEATEXCHANGER's pan-first circuit routes hot discharge gas through stainless steel coils welded inside the insulated drain pan before reaching the coil, preheating the pan surface to +25∘C+25∘C so falling ice immediately melts and drains away.
Glazed or cooked shrimp carry high surface moisture that rapidly condenses onto the first few tube rows. With wide 16–20 mm fin spacing at the inlet, frost deposits evenly along the fin depth without bridging the face. The fin spacing then tightens to 6–8 mm6–8 mm at the discharge, extending continuous defrost-free freezing runs to 16–24+ hours.
Maximize seafood freezing throughput, eliminate defrost downtime, and ensure complete food hygiene compliance with CSTHEATEXCHANGER:
Custom Hot Gas Defrost Seafood IQF Evaporator Coils (40 kW to 1,200 kW+)
Seamless AISI 316L Stainless Tubes with Marine AlMg3 or All-Stainless Steel Fins
Rapid 15–20 Minute Dual-Circuit Pan-First Hot Gas Defrost Systems
Progressive Variable Fin Pitch (20 mm→12 mm→6 mm) for 24h Uptime
Sanitary TIG-Welded Stainless Steel Casings with Double-Wall Insulated Sloped Drain Pans
Full ASME / CE PED Compliance, IP66 Washdown Axial Fans & Factory-Direct Global OEM Supply
Contact our specialized seafood refrigeration engineering department today with your product type (shrimp/fish/scallop), hourly freezing capacity (kg/h), enclosure dimensions, refrigerant type, and evaporating temperature for custom CAD proposals and factory-direct quotations.
Website: https://www.cstheatexchanger.com/
Technical Inquiries: info@cstheatexchanger.com
