Keep your transformers cool, loaded and online
Grid Transformer Air Cooler
Elevating global standards with exceptional, unmatched Dutch craftsmanship in advanced industrial heat exchange.
What is a Grid Transformer Air Cooler?
A grid transformer air cooler removes the heat that a power transformer generates under load and releases it to the ambient air. Inside an oil-immersed transformer, copper and core losses heat up the oil. A pump circulates that hot oil through the cooler, where fans push air across a finned tube bundle and bring the oil temperature back down before it returns to the tank. This is the OFAF or ODAF cooling method used on most large substation transformers and on generator step-up transformers in power plants, wind farms and solar parks.
The cooler directly determines how much load a transformer can carry. Lower oil and winding temperatures slow down the aging of the paper insulation, which is the main factor that limits transformer life. A well designed air oil heat exchanger therefore protects one of the most expensive and hardest to replace assets on the grid.
Dutch excellence in heat exchange
At ICARUS Industrial, we blend Dutch craftsmanship with innovative technology, redefining the gold standard for industrial heat exchangers. Dive into the future of sustainable manufacturing, where our Dutch-engineered solutions elevate energy efficiency to unparalleled heights.
Lower total cost of ownership (TCO)
We go beyond performance with our heat exchangers, sculpting an unbeatable blend of.
Direct manufacturer benefits
Your unique needs are our command. We offer tailored heat exchanger solutions.
Customized solutions
With ICARUS Industrial, you're not just buying a product, you're engaging a partnership. Our direct sales model
Superior durability
Built from robust materials, our heat exchangers are a testament to resilience. They reduce maintenance
Transformer Cooling Built Around Your Unit
Lead times for new high-capacity power transformers have stretched to several years, while demand from data centers, renewables and electrification keeps growing. That makes every existing transformer more valuable. ICARUS designs transformer air coolers for new units, for uprating existing transformers and for replacing aging coolers, so your fleet can carry more load for longer.
OFAF and ODAF Oil-to-Air Coolers
For forced oil cooling, ICARUS builds compact oil-to-air coolers with finned tube bundles, fan sections and oil headers designed for the flow and pressure drop of your oil pumps. In OFAF operation the cooler handles the oil returning from the tank, in ODAF operation it works with directed oil flow through the windings for higher ratings. We size each cooler for the full load losses at the highest design ambient temperature of the site, so the transformer can run at rated load on the hottest day of the year. Read more about our oil heat exchangers.
Cooler Replacement and Retrofit
Older transformer coolers lose performance over time. Fins corrode, tubes foul, gaskets age and leaks let moisture into the oil. The result is higher operating temperatures, faster insulation aging and less load capacity. ICARUS builds replacement coolers that match the existing flanges, mounting points and fan arrangement, so they can be installed during a short outage. Where needed, we increase the surface or improve the materials so the new cooler performs better and lasts longer than the original.
Uprating Existing Transformers
Extra cooling capacity is one of the fastest ways to get more out of an existing transformer. By adding or upgrading coolers, the same unit can often carry a higher load within its temperature limits, which can postpone or avoid the purchase of a new transformer. ICARUS calculates the additional cooling capacity needed for your target rating and designs coolers that fit the available space around the tank.
Indoor and Enclosed Transformer Cooling
Transformers in buildings, containers, offshore substations and enclosed switchyards cannot rely on free air flow. For these installations ICARUS supplies water-to-air and glycol-to-air coolers that remove the heat from the transformer room or enclosure, including solutions for dry-type transformers. The heat is carried away through a closed liquid circuit to an outdoor air cooled heat exchanger, keeping dust, moisture and salt away from the transformer itself.
Materials, Noise and Harsh Environments
Grid transformers stand outdoors for 40 years or more, in coastal air, industrial pollution, desert heat or freezing winters. ICARUS selects tube, fin and frame materials to match the site, from galvanized steel and coated aluminum to fully stainless steel for corrosive locations. Low-speed fans and optimized fin spacing keep sound levels down for substations close to homes. For offshore and coastal sites we apply the same approach as our high corrosion environment heat exchangers.
Download a sample DWG
Discover precision engineering: Download a sample DWG of our top-notch heat exchangers.
Request a Transformer Air Cooler from ICARUS
ICARUS supplies transformer coolers to transformer manufacturers, utilities, EPC contractors and service companies. As a direct manufacturer, we design and build every cooler in our own production facility, from a single replacement unit for one transformer to series production for a new transformer type. See our project references for examples of our work.
To prepare a quotation, send us:
- Transformer rating and cooling class (ONAF, OFAF, ODAF)
- Losses to be removed per cooler in kW
- Oil flow, inlet temperature and allowable pressure drop
- Maximum ambient temperature and site conditions
- Drawings or photos of the existing cooler for replacement projects
- Sound level requirements and the number of units
Our engineers review your request and come back with a technical proposal. Do you only know the transformer rating? Send it anyway and we will help you define the cooling requirements.
Request a quotation
Elevate your efficiency with Dutch-engineered solutions tailored for your needs. Fill out the details below, and our team will provide a personalized quote to help you harness the power of optimized energy in manufacturing. Step into the future, one quote at a time.
ICARUS Heat Exchangers
Quotation Form
Why choose ICARUS for transformer cooling?
- Engineered per transformer: every cooler is calculated for your losses, oil flow and site conditions instead of picked from a catalog.
- Drop-in replacements: we match existing flanges, mounting points and fan arrangements to keep outages short.
- Built for decades outdoors: material and coating choices matched to coastal, industrial and extreme climates.
- Direct manufacturer: thermal design, production and testing under one roof in the Netherlands, for single units and series.
Our specialized team at ICARUS
Transforming challenges into opportunities
A transformer that runs too hot loses capacity and ages faster, and replacing it can take years. ICARUS turns that risk into an opportunity: with the right cooler, your existing transformers carry more load, run cooler and stay in service longer. Our engineers look at the full picture, from losses and oil flow to site climate and installation space, and design a cooler that keeps your grid assets performing.
Facts about ICARUS
> 27
With over 27 years in business, we’ve carved out a reputation for excellence and innovation.
> 120+
Our global presence is marked by a diverse clientele of over 120 customers worldwide.
> 850+
Moreover, our portfolio boasts more than 850 completed projects.
FAQ about Grid Transformer Air Coolers
What is the difference between ONAF, OFAF and ODAF transformer cooling?
In ONAF cooling the oil circulates naturally and fans blow air over radiators. In OFAF cooling pumps force the oil through an external oil-to-air cooler with fans, which gives more capacity in a smaller footprint. ODAF works like OFAF, but the pumped oil is directed through the windings for even better heat transfer, which is used on the highest ratings. ICARUS builds air coolers for OFAF and ODAF transformers.
Can a new cooler increase the capacity of an existing transformer?
Often, yes. Transformer loading is limited by oil and winding temperatures. When the cooling capacity is increased, the same transformer can carry more load within those limits. The possible gain depends on the transformer design, so ICARUS calculates the required cooling capacity together with you or the transformer manufacturer.
When should a transformer cooler be replaced?
Typical signs are rising oil temperatures at the same load, oil leaks at the cooler, corroded or damaged fins, fouling that cannot be cleaned and noisy or failing fans. Leaking coolers are especially risky because moisture can enter the oil and damage the insulation. A replacement cooler restores the original capacity and often improves it.
Can ICARUS build a cooler that fits our existing transformer?
Yes. For replacement projects we work from drawings, photos and measurements of the existing cooler, and design a new unit that matches the oil connections, mounting points and fan arrangement. This keeps the installation simple and the outage short.
What information do you need to quote a transformer air cooler?
The most important inputs are the transformer rating and cooling class, the losses to be removed, the oil flow and temperatures, the maximum ambient temperature and the installation space. For replacements, drawings or photos of the current cooler help a lot. If some data is missing, send what you have and our engineers will help you complete the specification.
