Knowledge base
In short
A dry cooler is an air-cooled heat exchanger that sends data center heat to the outside air without using water. When the outside air is cold enough, it can do most of the cooling alone, which is called free cooling and saves a great deal of electricity. The site climate, the cooling loop and the way the plant is run decide the design.
A data center turns almost all the electricity it uses into heat, and that heat has to leave the building all day and all night. Dry coolers have become a common answer, because they use outside air instead of water and they allow free cooling in cooler weather. This guide explains in plain words why data centers choose them and what a buyer should have ready before asking for a proposal.
Why Data Centers Need A Constant Heat Sink
Servers produce heat without a pause, and they stop working properly when they get too hot. The cooling plant therefore has to run all year, in every season and at any hour, and it has to keep running when something fails. Whatever heat is taken out of the building finally has to be given to something, and the outside air is the cheapest and most available heat sink there is.
A dry cooler is the part that hands this heat to the air. The warm liquid from the building runs through a finned coil, fans move outside air across it, and the heat leaves without any water being evaporated or used up.
What Free Cooling Means
A chiller uses a lot of electricity to make cold water. In cool or cold weather that work is not needed, because the outside air is already cold enough to take the heat directly. When the dry cooler does the cooling alone and the chiller is switched off or turned down, the plant is in free cooling mode.
In many climates this covers a large part of the year, which is why free cooling is often the main reason a dry cooler is chosen. The warmer the liquid loop is allowed to run, the more hours of the year can be covered, and modern liquid cooling of servers runs warmer loops than older air-cooled rooms did.
Water Use And Where The Heat Goes
Evaporative cooling towers use water all the time, and in dry regions or places with water limits that is a real cost and sometimes a permit problem. A dry cooler uses no process water, which is why it is often preferred where water is scarce, expensive or politically sensitive. It also avoids the water treatment and the hygiene care that wet systems need.
The trade-off is that a dry cooler depends on the air temperature, so on the hottest days it may need help from a chiller or from a water spray stage. How the plant balances these is part of the early design.
Planning A Dry Cooler For A Data Center
Data center owners ask for reliability first. That means spare capacity, several fans so that one failure does not stop the unit, coils split into sections that can be isolated, and fan control that follows the load and the weather. Noise at the site boundary and the space available on the roof or the ground also play a part in the choice.
The cooling loop often uses a water-glycol mixture so the outdoor part is protected from frost, and sometimes a plate heat exchanger separates the outdoor circuit from the building circuit. TECS Engineering designs and builds dry coolers and radiators for cooling plants, including data center and critical power sites. Send the heat load, the loop temperatures, the site climate and the space available, and the engineering team will propose a unit that fits.
In Short
- A data center needs a heat sink all year, at every hour
- A dry cooler gives the heat to outside air and uses no process water
- Free cooling lets the dry cooler do the work alone in cool weather
- Warmer cooling loops mean more free cooling hours
- On the hottest days a chiller or a water spray stage may help
- Heat load, loop temperatures, climate and space come first in every enquiry
What To Send With An Enquiry
- The heat load to be rejected and any planned growth
- The liquid, the loop temperatures and the flow
- Site location, hottest and coldest air and altitude
- Roof or ground installation and the space available
- Any sound limit at the site boundary
- The level of redundancy and the fan power supply
Questions We Are Often Asked
Why do data centers use dry coolers?
They send the heat to the outside air without using water, they run with little upkeep, and they allow free cooling when the weather is cool, which saves electricity.
What is free cooling?
It means the outside air does the cooling and the chiller is off or working very little. The dry cooler carries the heat from the building to the air on its own.
Does a dry cooler use water?
No process water is used. The heat goes from the liquid to the air through a finned coil. Some designs add an optional water spray for the hottest days.
Can a dry cooler cool a data center on its own in hot weather?
Not always. On the hottest days the air may be too warm, so a chiller or a spray stage can be added. The site climate and the loop temperature decide how often this is needed.
What should I send to get a dry cooler proposal for a data center?
The heat load, the loop liquid and temperatures, the site climate, the space for the unit, any sound limit and the redundancy you need.
Contact Us
Send us the heat duty, the fluid temperatures and flow rates, the ambient conditions and the installation limits. We answer with a design proposal - or write to us on WhatsApp.
