Indeed. Cant find the German name. Biomeiler is dutch. Search and you wont find any heat you can use to heat your home. A lot of work for nothing. I heard of a guy that bought a house in Germany and wanted to keep the frost out when not there. A mixed succes, but heating your house? Maybe further then France, Marocco?
Jean Pain did put permaculture on the map
I have linked this site before. If you are interested in perma-culture, they have pretty much covered it. The site is too big for me to follow unless I am searching for a specific thing. Information overload. I tried a smaller scale Jean Pain many years ago. unimpressed. I think unless you are able to work with the sizes he did then it’s not nearly worth the effort. For hot water, the way Kristijan describe makes much more sense. Also I never figured out how Jean Pain was capturing that methane. Solar in my area is very problematic. We get very little winter sun. Always heavy grey overcast. I see real potential in this heater Paul Robinson built. As a base course for the perimeter of an hoop house and with enough available manure, I thing it would be excellent.
https://www.google.com/search?client=firefox-b-1-d&q=Paul+Robinson+compost+heater