Counterflow Closed Circuit Cooling Tower
The XLN Series operates on a simple principle: air and spray water flow in opposite directions. Ambient air enters through the bottom or lower side grille and rises vertically through the coil, while spray water is distributed from the top and falls downward, meeting in counterflow on the coil surface. This opposing flow maintains a high log mean temperature difference (LMTD) and delivers strong heat transfer performance. The coil carries a closed-loop process fluid—softened water, antifreeze, or specialty fluids—isolated from external contaminants to eliminate scaling and fouling. With vertical air discharge and a compact footprint, the tower suits space‑constrained installations like factory floors or rooftops. The casing is corrosion‑resistant steel, and the coil is available in stainless steel or copper to balance thermal conductivity with corrosion resistance based on operating conditions. Specifications Heat capacity: 30 – 2,000 kW Flow rate: 26 – 1,761 gpm / 6 – 400 m³/h Configuration: Counterflow / Axial fan / Induced draft
How it works?
The counterflow closed-circuit cooling tower works through three combined mechanisms: closed internal circulation, external spray, and counterflow heat exchange. Process fluid (softened water, antifreeze, or specialty fluids) circulates inside the coil, isolated to prevent scaling. Spray water from the top forms a film on the coil, absorbing heat. Ambient air drawn upward from the bottom meets the falling spray in counterflow, maintaining a high log mean temperature difference (LMTD) for strong heat transfer. Evaporation removes latent heat and air removes sensible heat. The moist air passes a drift eliminator before discharge; cooled spray returns to the basin and process fluid completes its closed loop.
Structure & Characteristics
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1 、Heat Exchange Coil:
Process fluid circulates inside the coil in a closed loop, with heat transferring through the tube wall to the external spray water—this is the core of a closed-circuit tower. Standard coils are 304 stainless steel, with options for 316L, copper, or duplex steel. All coils are pressure-tested for leak-proof performance. Multi-layer serpentine layout with optimized tube spacing allows smooth air passage and efficient heat transfer.
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2 、Fan:
The fan drives airflow across the coil and fill media to carry away heat; airflow volume directly affects cooling performance. All units feature special axial fans with nylon or aluminum blades, galvanized steel supports and guards. Motors are IP55-rated, Class F insulation, with optional VFD for energy-saving speed control.
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3 、Spray Pump:
The spray pump draws water from the basin and delivers it to the top distribution system, powering the external circulation loop. Xuelun uses high-performance branded pumps with high flow, low power draw, and quiet operation. Pump bodies and impellers are available in cast iron or stainless steel to suit different water quality conditions.
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4 、Water Distribution System:
The distribution system sprays water evenly over the coil surface to form a continuous film—uniform coverage directly impacts heat transfer efficiency. On counterflow towers, the system sits at the top, using high-capacity ABS basket-type nozzles that resist clogging and are easy to remove for cleaning.
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5 、Air Inlet Louver:
The inlet louver guides air evenly into the tower while blocking debris like leaves, insects, and dust to prevent coil and nozzle fouling. It features PVC fill with a metal frame and is fully removable—simply lift upward and pull outward from the bottom for convenient cleaning.
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6 、Drift Eliminator:
The drift eliminator sits below the fan or at the air outlet, using inertial impingement to capture fine water droplets from the moist air and return them to the basin, reducing water loss. Made of corrosion-resistant PVC, it limits drift loss to under 0.1%.
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7 、Casing:
The casing provides structural support and weather protection for internal components, shielding them from rain, sun, and spray corrosion, while also reducing noise and improving appearance. Constructed from ZAM-coated steel or 304 stainless steel, laser-cut for precision—offering superior corrosion resistance over standard galvanized or FRP shells.
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8 、Collection Basin:
Located at the base, the basin collects spray water and provides a stable suction source for the spray pump. The basin is typically made of the same material as the casing—ZAM-coated steel, with 304 or 316 stainless steel available as upgrades for enhanced durability in demanding environments.
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9 、Base Frame:
The base frame supports the entire tower, transferring weight to the ground and ensuring stable, level operation. Constructed from galvanized channel steel; stainless steel is available as an option for applications requiring additional corrosion protection in humid or chemically aggressive environments.
Basic norm
