Radiator design contains no water

[darlo]

I have moved into a property which has a convential boiler and system but the radiators appear to be pressed panels that contain no water.
The water pipe containing hot water arrives at the bottom centre inflowand then follows to LH side to top RH side and out from centre bottom outflow.
It seems to work by heat transfer.
I know little about Central heating so wonder if anyone has any experience of such radiators.
They work slowly and slowly meet any requirement for temperature change.

 

[Madrab]

The ribs in the rad have to be what will carry the water through internal waterways by the looks of it, no other way it could work.

TBH though , cant say I've ever seen that actual type before.