Views: 0 Author: Site Editor Publish Time: 2026-09-30 Origin: Site
A dry cooler is an air-cooled heat exchanger for liquids. Warm process fluid - water, water-glycol or oil - is pumped through a fin-and-tube coil; axial fans draw outdoor air across the fins; heat passes from the fluid, through the tube wall and fins, into the air; the cooled fluid returns to the process in a closed loop. Nothing evaporates and the fluid never touches the air, which is why it is called "dry". The fluid can be cooled to a few degrees above the outdoor dry-bulb temperature - never below it. CSTHEATEXCHANGER manufactures dry coolers, free coolers, hybrid and adiabatic coolers from a few kilowatts to about 2,000 kW, built to the customer's drawing or duty.
Component | Function | CSTHEATEXCHANGER construction |
|---|---|---|
Finned coil | The heat transfer surface: fluid inside the tubes, air across the fins | Staggered seamless copper tubes (15.9 or 12.7 mm) with aluminium rippled/corrugated fins (0.14 or 0.17 mm); 2.5 mm fin spacing for optimal air turbulence |
Headers | Distribute fluid into the tube circuits and collect it again | Thick seamless copper headers; threaded steel connections (flanged on request) |
Fans | Move the air; the only energy consumer on the unit | Direct-drive axial fans with integrated motor and guard, balanced as a unit to grade G6.3; maintenance-free; sealed bearings and encapsulated motor; AC or EC |
Casing and frame | Hold the coil and fans, direct the air, carry the weight | Heavy-gauge hot-dip galvanized steel with zinc-aluminium coating |
Controls | Hold the fluid outlet temperature by varying fan speed or staging fans | EC fans automatically control speed and save energy |
Every unit is pressure tested at 15 bar before shipment.
Warm fluid enters the top header at the process return temperature (for example 45 °C).
Fluid flows through the tube circuits, usually counter-flow to the air so the coldest air meets the coldest fluid at the outlet.
Fans pull outdoor air through the coil face at a few metres per second.
Heat conducts from fluid to tube wall (copper, high conductivity), from tube to fin (mechanical expansion gives full contact), and from fin surface to air by convection — the corrugated fin increases turbulence and surface area.
Air leaves warmer, fluid leaves cooler (for example 35 °C), and returns to the process.
The controller measures fluid outlet temperature and trims fan speed so the setpoint is held as the outdoor temperature changes through the day and year.
Aspect | Dry cooler | Evaporative cooling tower |
|---|---|---|
How heat leaves | Sensible heat to air | Latent heat — water evaporates |
Water consumption | None | Continuous make-up and blow-down |
Water treatment | None (closed loop) | Biocide, scale and corrosion control |
Legionella risk | None | Must be managed |
Lowest fluid temperature | A few °C above outdoor dry-bulb | A few °C above outdoor wet-bulb (lower) |
Fluid contamination | None — sealed | Open to atmosphere |
Winter freezing | Protected by glycol | Open water, freeze risk |
Maintenance | Fans and fin cleaning | Basin, nozzles, fill, chemistry |
Our Free Cooler page states the benefits directly: very low water consumption, no contamination of the process water, no contamination from external factors, and easy installation in existing cooling circuits.
The trade-off is temperature: because a dry cooler is limited by dry-bulb rather than wet-bulb, it cannot reach as low a fluid temperature on a hot afternoon. That is why CSTHEATEXCHANGER also builds adiabatic and hybrid versions, which wet the inlet air or coil only in peak hours — our Free Cooler spray option lowers the water temperature by 5–8 °C compared with a conventional free cooler.
From our product pages: data center liquid cooling and immersion cooling, chiller free cooling, injection molding and plastics, diesel and gas generator jacket-water and intercooler cooling, power plant radiators, solar, factory process cooling, transformer and lube oil cooling, battery energy storage.
No. It cools a liquid directly with air; there is no compressor or refrigerant. It is often paired with a chiller so the chiller runs only when the dry cooler alone cannot reach setpoint.
To within a few degrees of the outdoor dry-bulb temperature. On a 35 °C day, roughly 38–40 °C fluid is realistic; see our article on dry cooler approach temperature.
To protect the fluid from freezing in winter. See our article on glycol in dry coolers.
Functionally yes — a genset remote radiator is a dry cooler for engine coolant. We build both.
Periodic fin cleaning and a visual check of fans; the fans themselves are maintenance-free.
Send CSTHEATEXCHANGER your fluid, flow, inlet and required outlet temperature, site design ambient and footprint. We will size the dry cooler, advise whether an adiabatic stage is needed, and return a drawing for approval.
Email: info@cstheatexchanger.com
International business: +86 0519 8878 2189
Website: https://www.cstheatexchanger.com/
CSTHEATEXCHANGER — dry coolers built the way the principle demands: good coil, good fans, sealed loop.
