Characteristics of Air-Cooled and Water-Cooled Diesel Generators

Air-Cooled Generators:
Use small diesel engines (often 1-2 cylinders) cooled by fans blowing air directly onto the engine. Common for small units. Requiring open installation due to noise, they feature simple design, low failure rates, easy starting, and low fuel/fan power consumption. They avoid freezing or overheating risks, need minimal air, and are easier to maintain. Ideal for high-altitude, dry, or cold areas as they require no water, eliminating boiling/freezing concerns. However, limited by heat and stress, their power output is generally small.

Water-Cooled Generators:
Use larger diesel engines (e.g., 4, 6, 12 cylinders). Coolant circulates internally and externally, with a radiator and fan removing heat. Common for large units. Their structure is more complex and harder to build, with greater environmental demands. At high altitudes, power must be reduced and coolant additives used to adjust boiling/freezing points. Water cooling is more efficient, enabling smaller size and lighter weight for equivalent power versus air-cooled units, with superior heat transfer. Most large generators are water-cooled.