The Differences between Air-Cooled and Liquid-Cooled Generators


Are you curious to know the fundamental differences between air-cooled and water-cooled generators? How do they work? Which one of them is more efficient? How to choose the best generators?

You’ll get the answer to all these questions in this blog. Let’s assume, you need a backup power supply and stumble across these two possibilities. 

First, let’s talk about how they cool down.

Air-cooled generators operate efficiently by circulating air around the engine via fans or blowers. Consider it a steady stream that aids in heat dissipation. It’s comparable to how a small fan helps your laptop stay cool. Only here, the fan is much larger.

The air-cooled generator pulls in air from its surroundings, directs it over the engine’s components and then releases the heated air. This constant airflow enables the diesel engine to maintain an ideal temperature and work non-stop.

Water-cooled generators, on the other hand, use a different cooling process. To keep the system cool, they employ a liquid coolant which is a blend of water and additives. 

The coolant circulates the diesel engine, absorbing heat from various components in the same way that a car’s radiator does to keep the engine temperature stable. 

The heated coolant is then sent through a radiator to cool before being recirculated back into the engine.

Which is more efficient? Air-cooled diesel generators or water-cooled diesel generators?

Air-cooled generators are efficient, but they have limitations. Because they rely on the surrounding air, their cooling capacity is determined by the ambient temperature and the airflow created by the fans or blowers. As a result, in hotter climes or under severe loads, these generators may operate a little hotter.

Water-cooled generators can dissipate heat more effectively with their liquid coolant. Consider having an automobile with a robust cooling system that keeps the diesel engine running smoothly even on hot summer days. 

That is the advantage of using fluid cooling in generators. It enables them to handle continuous high-power output and maintain operations without tiring.

How do I choose the best diesel generator?

Choosing the best diesel generator between air-cooled and water-cooled depends on your specific needs and circumstances: 

1. Power Requirements:

Identify the wattage and energy required to power the appliances or equipment you want to use.  

If you have high power requirements or need to handle heavy loads regularly, a water-cooled generator may be a better option.

2. Operating Environment: 

It’s essential to consider the environment where the generator will be used. Air-cooled generators are often smaller and more suitable for use in smaller rooms or outdoors. 

Whereas, if you operate in a hot region or have limited airflow, water-cooled generators provide much better cooling.

3. Run Time and Sustained Operation:

A water-cooled generator is often better prepared to manage extended run hours without overheating if you anticipate protracted power interruptions or continuous running. 

When compared to air-cooled generators, it can maintain performance for longer periods.

4. Noise Level:

Consider the noise level, especially if you need a quieter power solution. Because of the fans or blowers used for cooling, air-cooled generators tend to make more noise. 

Water-cooled generators, on the contrary, due to their enclosed design, frequently maintain lower noise levels.

5. Portability and Size:

In case you need to move, transport, or store a generator easily, air-cooled generators are typically more compact and lightweight. 

Typically, water-cooled generators are larger and less portable than air-cooled generators.

6. Maintenance and Service: 

Air-cooled diesel generators are generally simpler in design and require less maintenance. 

In comparison, water-cooled diesel generators may require extra maintenance due to their cooling systems, such as coolant checks and radiator maintenance.


By taking these elements into account, you can make an informed decision depending on your power needs, operating conditions, noise preferences, portability requirements, and maintenance capabilities. 
Nevertheless, we at Mitsubishi Heavy Industries-VST diesel engines recommend that you consult with a diesel generator specialist or supplier who can provide advice specific to your requirements and operations.


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