I don't have any personal knowledge of the details of the water arrangement in a shower car, but at one time it was somewhat common to heat water with a simple loop of water pipe in the firebox of a wood stove. The water pipe would run out the back of the wood stove and
could be directed to a storage tank in the ceiling of the shower car.
The kitchen wood stove that I have used with this water heating loop had a copper pipe water loop in the firebox, but was otherwise a fairly ordinary stove. Assuming the plumbing external to the stove is arranged with a loop, the heated water would rise up to the [higher up] external storage tank via convection without any pump needed.
Edited 1 time(s). Last edit at 03/19/2017 11:00PM by Rader Sidetrack.