DX Ammonia Evaporators for Blast Freezer | Direct Expansion R717 Unit Coolers

DX Ammonia Evaporators (Direct Expansion Ammonia Unit Coolers) are optimized heat exchange equipment specially designed for industrial blast freezers. As a compact alternative to flooded ammonia evaporators, DX ammonia evaporators for blast freezer adopt direct expansion circulation, widely used for quick-freezing meat, seafood, poultry, fruits and prepared food. This R717 direct expansion solution delivers rapid pull-down temperature, stable low-temperature operation and significantly lower ammonia refrigerant charge, making it a cost-effective choice for new blast freezer construction and refrigeration system retrofits.

Blast freezers demand fast temperature reduction to -30°C ~ -40°C to rapidly freeze food products and lock freshness. Traditional flooded ammonia evaporators require large refrigerant inventory and complicated liquid level control systems. Our DX ammonia evaporators for blast freezer solve these pain points by utilizing direct expansion technology, matching the strict operating requirements of continuous quick-freezing production lines.

Working Principle of DX Ammonia Evaporators for Blast Freezer

The direct expansion ammonia evaporator works based on the vapor compression refrigeration cycle. High-pressure liquid ammonia passes through thermostatic expansion valves, which throttle and cool the refrigerant into two-phase liquid-vapor ammonia. The mixture enters the finned coil of the DX ammonia evaporator.

Cold two-phase ammonia flows inside heat transfer tubes. High-speed air inside the blast freezer blows across the coil surface. Heat transfers from the air to liquid ammonia, causing ammonia to evaporate and absorb massive heat. The air temperature drops sharply, forming ultra-low-temperature circulating air to rapidly freeze food inside the blast freezer.

After evaporation, low-pressure ammonia vapor exits the coil with controlled superheat. The vapor is drawn into the ammonia screw or reciprocating compressor to complete the refrigeration cycle. Accurate superheat control prevents liquid ammonia from entering the compressor and avoids liquid slugging faults.

Application Scenarios

• IQF blast freezers for shrimp, fish, shellfish and seafood products

• Blast freezing rooms for beef, pork, poultry and meat processing

• Quick-freezing tunnels for fruits, vegetables and processed ready meals

• Batch type industrial blast freezers for food factory production lines

• Medium-sized food cold chain quick-freezing facilities

As a professional manufacturer of industrial heat exchangers, we provide fully customized DX ammonia evaporators for blast freezer. We adjust cooling capacity, fin spacing, air volume, fan static pressure and defrost mode according to blast freezer size, freezing load and target temperature. Every unit undergoes strict hydraulic pressure testing and air tightness inspection before shipment.

Our product portfolio also includes flooded ammonia evaporators, ammonia evaporator for seafood cold storage, ammonia evaporator for dairy refrigeration, stainless steel glycol unit coolers, CO₂ gas coolers and industrial dry coolers to satisfy diversified refrigeration demands.

If you are sourcing reliable direct expansion R717 cooling equipment for quick-freezing projects, please contac our official email info@cstheatexchanger.com. Our refrigeration engineering team provides thermal calculation, drawing design and one-stop technical support for your blast freezer refrigeration system.