Different Generator Cooling Methods

Generators range from the small portable kinds that people use as backup power for their homes to large industrial units used as the prime power source at remote oil drilling sites. Whatever the size or function, generators have one thing in common – they all generate heat.


Why Do Generators Need Cooling?

Most generators have numerous conductors, all of which produce heat as current flows through them. That heat can build up quickly within the system and it must be properly removed to reduce the risk of damage.

If heat is not properly removed from the system, damage to the windings occurs rather quickly. A number of issues can occur including clearance and balance problems. But, it is possible to reduce this heat significantly through various cooling systems. By consistently cooling the generator, it is possible to minimize the risk of any damage to the generator itself. Ultimately, this reduces frustration and prevents the need for repairs.


Air-Cooled Systems

Knowing the value of cooling generators, it is then important to understand how the best air-cooled systems work. For air-cooled systems, there are two main methods of cooling available.

The first is open-ventilated systems. Here, the air in the atmosphere is used with a type of exhaust system. This allows for the air to be released right back into the atmosphere. It pulls in the air and pushes it back out into the surrounding area.

The second type is an enclosed system. An enclosed system, as the name implies, keeps the air in place. It works to then recirculate the air. As it does, the air is cooled which, in turn, keeps the generator cool.

Air cooled systems have some limits including the risk of overheating. However, air cooled systems are mostly restricted to small standby and portable generators that produce up to 22 kilowatts of power per unit.


Liquid-Cooled Systems

Liquid-cooled systems, sometimes referred to as water-cooled systems, are another option. There are numerous types of liquid-cooled systems. Some operate using oil while others use coolants. Hydrogen is another cooling element.

A liquid-cooled system features a water pump that moves the coolant around the engine using a number of hoses. The heat from the generator transfers naturally to the coolant, cooling the unit. This type of system is best for larger generators in particular. They require more heavy duty components to keep the generator cool. This does increase the cost, but these are the most common option for commercial and industrial use.

One key option is the hydrogen-cooled system. These are also used for large generators. The hydrogen used in them has a high thermal conductivity. This allows these systems to pull out heat at a faster rate. As a result, they work well for larger systems that cannot be efficiently cooled using other coolants.



When choosing the right cooling solution for a generator, the size and use of the generator plays a significant role in the decision process. For systems that are larger, usually all of those over 22 kilowatts of power, air-cooled systems are simply not effective. They cannot pull enough of the heat from the system, allowing them to overheat quickly. Liquid-cooled systems are the most common option for commercial and industrial spaces.

Air-cooled systems are best for portable generators and those used in residential settings. Here, there is less power and less demand, creating less heat. Air-cooled systems work well here and cost less.


Cost Comparison

When it comes to costs, the price comes down to size and power. Liquid-cooled systems are more complex and designed with more components. They feature a sophisticated design using a radiator (and other elements) to operate effectively. Because they are more powerful, durable, and robust overall, these systems are more expensive. Within the range of liquid-cooled systems, hydrogen-cooled units tend to be the most reliable and effective, but also some of the most expensive.

Air-cooled systems are less efficient for larger generators. But, they tend to be an affordable option overall for those looking for a simple system for a smaller generator.



When choosing cooling systems, maintenance should be a key consideration. The simpler the machine is, the more simplistic the maintenance program will be. Air-cooled systems are easier to maintain because they have a rather simple design. They do not create as much of a mess during the cleaning process and can be done by anyone that is handy enough.

Maintenance for liquid-cooled systems is more complex. Most require a specialized kit available to clean the system. And, maintenance is required more frequently with these systems.


Noise Levels

Another key consideration is the noise level. Depending on the circumstances of use, one style may be better than the other. Air-cooled systems are louder than liquid-cooled systems. The sound comes from the air the system blows over the engine to cool it. On the other hand, most liquid-cooling systems operate with low noise levels. Though all cooling systems and all generators do produce a good amount of noise overall. Some liquid-cooled systems are very quiet because they can be enclosed with some level of sound reduction.