Pneumatic suction unloading systems for cotton gins can be constructed as a closed loop without the high volume exhaust air discharge that causes difficulty in meeting air quality standards. Tests comparing a closed loop suction unloading system with a standard open exhaust suction unloading system showed that the closed loop system can be operated at a performance level equal to the standard suction system using 110 horsepower compared to 250 horsepower for a 30 bale per hour system. This is a substantial savings that demonstrates a big advantage of the closed loop system that would justify it even if it did not eliminate exhaust emissions. Returning the exhaust into the fan inlet eliminated the energy cost associated with entry and exit losses experienced in conventional systems. The cost savings would quickly pay for the installation and provide the gin with reduced operating expenses thereafter. The closed loop suction unloading system helps solve the air quality problem that is currently critical for cotton gins and helps to attain the air quality goals of the clean air act because it totally eliminates one major emission source.