Knowledge base
In short
Charge air cooler, charge cooler, intercooler and aftercooler all describe a cooler that takes heat out of the air a turbocharger has compressed, before that air enters the engine. In everyday use the names are mixed freely. Strictly, an intercooler sits between two compressor stages and an aftercooler after the last one, while charge air cooler is the general term most engine makers use for large engines. What matters for an enquiry is not the name but where the cooler sits and which circuit carries its heat away.
An enquiry asks for an "intercooler radiator", the engine data sheet talks about a "charge air cooler", and the site manager calls the same thing the "aftercooler circuit". All three may mean the same part, or they may not. The words grew up in different industries, cars, trucks, marine engines and power plants, and each kept its own habit. This guide sorts out what the names mean in plain words and where the difference starts to matter for the cooling plant.
One Job Behind All The Names
A turbocharger pushes more air into the engine than it could draw in by itself, and compressed air comes out hot. Before it reaches the cylinders it is cooled again, because cooler air carries more oxygen and keeps the combustion under control. The part that does this cooling is the subject of every name in the title.
Charge air cooler is the plain description: it cools the charge, the air that fills the cylinders. Charge cooler is a shorter form of the same word and is common in searches and on smaller engines. Our earlier guide on charge air cooling explains why the cooling matters; this one is only about the words.
Intercooler And Aftercooler, Strictly Speaking
The two older names come from engines and compressors with more than one compression stage. A cooler placed between two stages cools the air in the middle of the process, so it was called an intercooler. A cooler placed after the last stage, just before the air enters the engine, was called an aftercooler.
Over the years the strict meaning faded. The car and truck world says intercooler for almost any charge air cooler, while some engine makers, especially for heavy and off-road engines, say aftercooler for the same thing. On a large gas or diesel engine with a single turbocharger stage both words usually point to one and the same cooler. On an engine with two turbocharger stages they can point to two different coolers, and then the name tells you where in the air path the cooler sits.
Where The Heat Goes Matters More
For the cooling plant the important question is not what the part is called but how its heat leaves the engine. Some charge air coolers hand the heat directly to the air: the charge air is piped to a finned core that sits beside the engine radiator, and the same fan cools both. Others hand it to a water and glycol circuit, which carries the heat to a radiator that may stand far from the engine.
On large engines the second kind is the rule, and the charge air cooler is often split into two sections, one on the hot jacket water circuit and one on a separate cooler circuit. That cooler circuit is what the trade calls the LT circuit, and it is the circuit an LT/HT radiator is built for. So when an enquiry mentions an "intercooler radiator" or an "aftercooler radiator", it nearly always means the radiator section for this LT circuit, not the charge air cooler on the engine itself.
Writing An Enquiry That Leaves No Doubt
Most misunderstandings we see start with one word used for two things. The safest way is to describe the part by its place and its circuit: the cooler on the engine, or the radiator that cools its circuit; air cooled directly, or cooled through a liquid circuit; one section or two. The engine data sheet usually shows this in the cooling diagram, whatever name the engine maker uses, and it is the best thing to send.
TECS Engineering designs and builds LT/HT radiators and remote radiators that take the charge air heat of gas and diesel engines, alongside the jacket water circuit. Send the engine data sheet or the cooling diagram, tell us what you call the circuit on your site, and the proposal will name it the same way.
In Short
- Charge air cooler and charge cooler are the general names for the same part
- Strictly, an intercooler sits between compressor stages and an aftercooler after the last one
- In daily use the names are mixed; on many engines they mean one cooler
- Some coolers give the heat straight to the air, others to a liquid circuit
- On large engines the charge air heat usually goes to the LT circuit and an LT/HT radiator
- Describe the part by its place and its circuit, not only by its name
What To Send With An Enquiry
- Engine make and model, or the engine data sheet with the cooling diagram
- Whether the charge air is cooled directly by air or through a liquid circuit
- Whether the charge air cooler has one section or two, and which circuits they are on
- The heat duty, flow and temperatures of each circuit the radiator must serve
- Site ambient on the hottest day at full load and the altitude
- Where the radiator will stand and any sound limit
Questions We Are Often Asked
Is an intercooler the same as a charge air cooler?
In everyday use, yes. Both names describe the cooler that takes heat out of the compressed air before it enters the engine. Strictly, intercooler means a cooler between two compressor stages.
What is an aftercooler on an engine?
A cooler placed after the last compressor stage, just before the air enters the engine. Many engine makers use the word for the normal charge air cooler of a single stage engine.
What is a charge cooler?
A shorter name for a charge air cooler. It cools the air that fills the cylinders after the turbocharger has compressed it.
What does an intercooler radiator mean in an enquiry?
Usually the radiator, or the radiator section, that cools the liquid circuit of the charge air cooler. On large engines this is the LT circuit of an LT/HT radiator.
Does TECS make the charge air cooler on the engine?
The cooler on the engine normally comes with the engine. TECS designs and builds the radiators that take its heat away, and air-to-air charge air coolers where the installation calls for them.
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.
