Where Are Heat Exchanger Radiators Used?
A heat exchanger is a piece of equipment that transfers heat between two fluids without mixing them. A radiator is also a heat exchanger, working between air and a liquid. This article summarizes the basic types, the typical applications of each, and where the air-oil cooler fits in this picture, using general principles.
Basic heat exchanger types
| Type | Heat transfer | Typical use |
|---|---|---|
| Air-to-liquid | From hot liquid to ambient air | Vehicle radiators, hydraulic oil coolers |
| Air-to-air | From hot air to cooler air | Intercoolers on turbocharged engines |
| Liquid-to-liquid | From one liquid to another | Water-cooled oil coolers, process lines |
| Plate | Liquid to liquid between thin plates | Places that need a large surface in a small volume |
| Shell and tube | Between a tube bundle and the shell | Higher pressure and large systems |
This table is a general classification; detailed suitability is assessed against the manufacturer's technical data.
Where the air-oil cooler fits
An air-oil cooler is an air-to-liquid heat exchanger in which hot oil passes through a finned coil and air is blown or drawn across it. The air and the oil never touch. It is a practical solution where there is no cooling water line or where using water is not desired, because ambient air is available everywhere.
Safkan's fan-cooled radiators and compressor radiators belong to this group and are based on an aluminum bar-plate construction. For how it works, see the article what is oil cooling.
Which type is preferred in which situation?
- No water line, or water is costly or restricted: An air-to-liquid type is generally more suitable. Mobile machines belong to this group.
- Cooling water is easy to get, and space is tight: Liquid-to-liquid or plate types can stay more compact.
- Very hot environment: In an air-cooled system the oil cannot drop below the ambient temperature; if a water source is available, a liquid-to-liquid type can be considered.
- Dusty and dirty environment: For finned air coolers, ease of cleaning and fin spacing are important.
- High pressure: The radiator's maximum working and test pressure should be compared with the system pressure.
What do construction differences change?
In heat exchangers, performance is determined by the surface area between the two fluids and the temperature difference. A finned construction enlarges the surface on the air side, while a plate construction creates many thin channels in a small volume. Turbulence in the internal channels can increase heat transfer by disturbing the boundary layer of the fluid. The separator design in Safkan's bar-plate construction is based on this principle.
On the other hand, a denser surface and narrower channels also increase the risk of clogging and pressure loss with dirty or thick fluids. In other words, each construction can be an advantage in one application and a disadvantage in another.
Common points to consider when selecting
Whichever type is chosen, the key data are the same: the heat load to be rejected, fluid flow rate, inlet and target temperatures, ambient conditions, pressure and space constraints. How to collect this data is explained step by step in the radiator selection checklist.
The type of heat exchanger matters as much in operation as the equipment itself. A clogged fin surface or insufficient airflow will reduce the performance of even a correctly selected product.
Ease of maintenance is another criterion. A fin design whose air side is easy to clean helps keep operation stable for a long time in dusty environments; in designs with narrow liquid-side channels, the cleanliness of the fluid becomes more decisive. When deciding, consider not only the initial setup but also the operating period.
Next step
To see the general place of radiators in industry and in vehicles, take a look at the article what is a radiator and where is it used. To discuss whether an air-oil cooler suits your application and to get technical information on product selection, contact us.