If the dryer is totally empty then there is very little material to hold the heat in the dryer chamber. A moderate amount of clothing will heat up, allow lots of space for tumbling and allow easy air flow of low humidity air through the dryer. As the low humidity air passes over the surface area of the heated clothes, the vapor pressure of the heated water in the clothing drives water molecules into the air which is then blown out of the chamber. The vapor pressure of the water in the clothes is a factor of their temperature. The counter pressure of the air in the dryer is a factor of its humidity and temperature. The reaction/evaporation happens only on a surface where wet clothing is in contact with relatively dry air.

So the ideal is to get maximum contact between heated wet clothes surface and hot dry passing air.

So don’t throw in a single sock, and don’t pack the dryer to the gills.

Moderation in all things.

Thanks
Ron