Cooling fan assembly (the axial fan bank of a dry cooler that rejects process heat from water or glycol)
The fan bank of an air-cooled dry cooler for process water and glycol · fan count and diameter, AC or EC motors, on-off, cut-phase, inverter or EC speed control, noise at night, adiabatic pre-cooling, and reading a dry cooler datasheet
A dry cooler is a finned coil and a row of axial fans that reject process heat from water, glycol or oil to the outside air without contact between the two. The fan assembly sets how much air passes, how much power and noise that costs, and how the cooler follows a load that peaks only on the hottest days. Specify fan number, diameter and motor type, the speed control and its signal, the noise limits by time of day, and whether pre-cooling is added for peak ambient.
Axial fan banks of air-cooled dry coolers (closed-circuit fluid coolers) for process water, glycol and oil, with their motors, speed control, noise and adiabatic pre-cooling options. Air handling unit fan modules are covered on the Fan assembly for air handling units page; axial fans sold alone on the Axial fan page; electronics cooling fans on the Cooling fan (DC axial cooling fan for enclosures) page; CO2 gas coolers on the CO2 gas cooler for transcritical refrigeration and heat pump systems page; induction cap sealers on the Automated beverage container foil sealing machine page.
CNFX editorial research · Sources checked October 12, 2026 · 3 sources
A Kelvion Select RT datasheet for dry cooler LF-PD203T4H-080Y06D shows what a fan selection carries. Duty: 515.87 kW with 30% vol ethylene glycol from 55.0 °C to 42.0 °C at 32.0 °C ambient, 36.41 m³/h, 24 kPa. Fans: six, 400 V/3 ph/50 Hz, IP54, 800 mm, 870 rpm, power input 1,708 W each at the selected speed (nominal 1,850 W), air volume 130,014 m³/h, air outlet 44.8 °C, sound power 94 dB(A) and sound pressure 61 dB(A) at 10 m; operation mode AC. [2]
Editorial calculation from the datasheet: 515.87 kW over six fans is about 86 kW per fan; the six fans draw about 6 × 1,708 W ≈ 10.2 kW, so roughly 50 kW of heat is rejected per kW of fan power at that design point; the glycol leaves 10 K above ambient. [2]
The datasheet's notes warn that "The use of low speed fans in combination with phase control can cause humming noise" and to follow the fan-set maker's guidelines when frequency converters are used for speed control. [2]
Give the supplier the fluid and concentration, inlet and outlet temperatures, flow, design ambient and altitude, available pressure drop, and noise limits at the nearest boundary by day and night.
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Fan speed control and noise
Kaltra explains why speed control matters: dry coolers are designed for maximum ambient and load, a combination that "occurs for a very limited period of the year, making dry coolers oversized for a large part of the time." Controllers vary fan speed from the sensed fluid temperature to hold the outlet setpoint. EC motors take PWM, 0-10 V or 4-20 mA and "regulate the speed in a range of 10% to 100%"; Kaltra says EC fans at partial load enable "up to 70% power savings" against AC fans, though their use in low ambient conditions is limited and AC fans are recommended for very low ambient temperatures. [1]
For noise, Kaltra recommends EC fans to limit speed at night, larger impellers for less sound at the same airflow, and diffusers that it says save up to 25% energy and lower noise by up to 7 dB(A). It also notes that fans can be fitted with individual switch-offs so one can be serviced without shutting the unit down. [1]
Control
What Kaltra says
Source
EC motors
Maximum savings; drive costs more; limited at low ambient
Peak ambient: adiabatic pads that switch on above a threshold
Güntner offers its V-shape COMPACT dry cooler with hydroBLU, an adiabatic system based on humidification pads: "As long as the temperature in the cooling system doesn’t exceed a pre-set threshold, hydroBLU™ remains inactive and no cooling water is used"; above it, wetting is switched on and adjusted by its control modules. [3]
Kaltra adds the siting points that change fan performance: closely spaced units recirculating hot exhaust air, wind, altitude, and fans that must withstand the temperature of the air leaving the coil. [1]
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Dry cooler fan bank details
Paste it into your enquiry below or into an email to a maker, then replace every bracket.
Duty: [kW; fluid; concentration; in/out °C; flow]
Site: [design ambient; altitude; wind; spacing]
Fans: [number; diameter; AC or EC; IP]
Control: [EC signal; cut-phase; inverter; BMS protocol]
Noise: [day and night limits; distance]
Pre-cooling: [adiabatic pads; water quality]
Service: [individual fan isolation]
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
Why control fan speed on a dry cooler?
Kaltra notes the cooler is sized for peak ambient and load, which occur "for a very limited period of the year", leaving it oversized for a large part of the time; speed control saves energy and noise. [1]
EC or AC fans?
Kaltra says EC fans save up to 70% power at part load but are limited at low ambient, where AC fans are recommended. [1]
What does a fan selection look like?
Kelvion's example for 515.87 kW uses six 800 mm AC fans at 870 rpm and 1,708 W each. [2]
Does adiabatic pre-cooling use water all year?
Güntner says its hydroBLU pads stay inactive until a pre-set temperature threshold is exceeded. [3]
Sources and what still needs a direct check
Sources checked 2026-10-12. Kaltra publishes a dry cooler selection article; a Kelvion Select RT dry cooler datasheet is available from a reseller; Güntner publishes its V-shape COMPACT dry cooler page.
