Jean Pain, swadust, and urine

Have been thinking about the Jean Pain method of heating water by composting. Say you had an unlimited supply of woodchips, and a urine diverter, and lots of visitors...

If you set up a system where you continually added small quantities of sawdust and urine into a big container with the pipe coil allready laid (into open space with sth holding it in place). I'm thinking of a "sawdust flush" essentially: one for feces, another with the coils for urine. Would that produce hot water?

Would you perhaps need to set up a pile initially, and keep laying your urine-sawdust on top?

You should be able to set it up as a self harvesting compost bin, with a grate at the bottom for finish compost to be removed.

To be "legal" here you would need double wall pipe, which reduces efficiency somewhat, and an on demand water heater to boost the temp past Listeria temps when needed.