How toroid transformer dissipates the heat generated by inner windings ?

[BravoV]

As its buried and encapsulated deep in the middle, and also sometimes with another layer/s of inter winding isolation added ?

When it comes to heat dissipation, does the common EI core has more advantage ? As it has much more openings and exposed slits.

Scope of discussion is mains transformer, say common step down.

[Zero999]

Toroidal transformers tend to be more efficient than EI core transformers, so there's less heat to deal with.

[T3sl4co1l]

Yes, the core and inner windings have to conduct their heat through the outer layers.

A good reason for transformers to be impregnated with varnish, to reduce thermal resistance.

Toroids also have more surface area than shell type transformers.

Tim