Energy Solutions Provider Serving the Northeast
Customer Portal

Residential & Industrial Generator Blog

Jul 27

A Comparison Of Generator Cooling Systems

By: Patti Dinneen


Generators produce an extraordinary amount of heat, and so the interior components must be constantly cooled to ensure that the generator is not damaged. The majority of generators are air-cooled or liquid-cooled. The cooling method is an essential design element of a generator, and is often determined by the size and type of generator. Air cooling systems are usually implemented for smaller generators, whereas larger generators call for liquid-cooled systems.

In this post, we will discuss the advantages and disadvantages of air-cooled and liquid-cooled generator systems.

Air-Cooled Systems

These systems make use of air circulation to cool the unit. With air-cooled systems, the engine takes in cooler air from the atmosphere, blowing this air internally across the generator set, keeping the generator from overheating. Typically, air-cooled engines are used for portable generators and standby generators up to 22 kilowatts. With air-cooled systems, you have two options: open ventilated systems and complete enclosed. Open ventilation systems use atmospheric air and the exhaust is then released back into the atmosphere. On the other hand, enclosed ventilation systems keep re-circulating the air to cool the internal generator parts.

Air-cooled engines have some limitations; they have the potential to over-heat if used for a long duration in excessive heat, so we recommend being aware of the ambient temperature and duration of use. When air-cooled engines fail, there is the potential for needing significant repairs. The preventative maintenance and repair tasks require a more attentive approach compared with liquid-cooled systems. Air-cooled engines are slightly less robust as oil break downs at a relatively quick pace in hotter conditions. This could lead to damage occurring without many previous symptoms.

Liquid-Cooled Systems

Liquid-cooled systems use several types of oil/coolant to cool the internal generator parts. Compared to air-cooling systems, liquid cooled systems offer much better cooling, which is why liquid-cooled Kohler generators are priced higher than air-cooled units. Essentially, liquid-cooled engines are comparable to small car engines.

Liquid-cooling systems include a radiator and water pump, with the pump distributing the liquid coolant to the engine block through hoses. The heat is transferred to the coolant, which is directed through the radiator where the air cools it. Generally, modern generators above 22 kW utilize liquid-cooling, with air-cooled engines dominating portable generators. Liquid-cooling systems are more expensive to produce than air-cooled engines; they require additional design consideration and parts, including a radiator. They are more durable and powerful than their air-cooled counterparts. Since these types of generator sets are more expensive, they are widely used for commercial and industrial purposes where the cooling demand is larger than small residential and portable units.

Which System Do You Need?

Each system comes with pros and cons. Air-cooled systems are simpler and less expensive than liquid-cooled systems. Liquid-cooled systems are more robust and effective. At the end of the day, the cooling system you choose will most likely be designed to be sufficient for your needs. Air-cooled systems are very capable for the range they are utilized in. Unless the ambient temperature is exceedingly hot, most residential generators will have no problem being cooled via air.

Add your comment (for display after moderator approval)
(email address will not be displayed)