Most air conditioning condensers dissipate the heat that the system absorbs in the process of cooling a home with a large fan mounted under a grille at the top of the condenser (outdoor unit) that sucks air through the closely-spaced fins in the condenser coils on the sides, and blows it out the top. Combine this with the fact that clothes dryers have a filter screen to catch lint, but the screen is not 100% effective and some lint particles get exhausted at the termination of dryer vent duct, and the result is that a condenser unit near a dryer vent will suck the lint onto the fins, where it gets trapped.
As the lint builds up over time, the air flow through the fins is impeded, reducing the efficiency of the condenser and making it work harder to dissipate the heat through clogged fins. This is why some manufacturers specify that a condenser should not be installed near a dryer vent termination and also why we call it out as a defect during a home inspection—to avoid the lint crud layer on the surface of the condenser too close to a dryer vent shown in the photo above.