A compressor cooled by forced or induced air using fan over a heat exchanger cooling the lubricant (oil) and air OR the casing / cylinder. Heat is rejected back to atmosphere via forced air from the package. As a rule of thumb, a 50 HP compressor rejects approximately 126,000 BTU per hour.
An air-cooled air compressor uses ambient air to bring down the temperature of compressed air. This is by far the most common form of aftercooler for rotary screw or rotary vane air compressors.
- Compressed air moves through a series of coils inside the aftercooler.
- A fan blows cool ambient air over the coils, carrying away excess heat.
- Cooling fins provide additional surface area for air to move across, increasing the heat transfer capacity.
- For self-cooling air compressors with built-in air cooling, an alternative to mounting a fan with its own motor, a belt guard air aftercooler (used on some piston-style compressors) uses airflow generated by the compressor’s belt system, which can save some space.
Air aftercoolers provide effective cooling for most industrial compressed air applications. They are also simple to maintain.
- An air aftercooler cools air to within roughly 15-20°F of ambient temperature, also known as the approach temperature. If the ambient temperature is 85°F (29.44°C), you can expect the air cooler to reduce outlet temperatures to about 100°F (37.78°C).
- At the same time, some of the excess water vapor drops out of the air as it cools. Condensation must be removed via a drain valve.