We've taken away the old solar panels to redo the back terrace and intend to buy new vacuum tube solar panels very soon - well as soon as we have a roof to put them on!
In the meantime with five of us in the house we need hot water and although we just have to light the fire to heat the cauldron which heats the hot water, the fireplace is designed to retain heat so the house stays too warm for too long afterwards.
So we made a new rocket stove from an old bucket and a few tin cans, put it directly under the cauldron and it does the job perfectly. This isn't a very efficient design for a rocket stove but the bucket already had a hole in it so we used it.
Here's a little video by a guy called Vavrek which shows how to build these efficient twig-powered cooking stoves from scratch.