Cob: breadbox water heater plans, thermosiphoning slabs, and mass walls in cold climates,

[Mark Piepkorn]

Free online plans for simple one- and two-tank batch solar water heaters
http://www.networkearth.org/naturalbuilding/heater.html

A few years ago I visited a (stick-frame) house in Minneapolis that had a 
smaller version of this kind of batch heater - about ten gallons - mounted 
onto the side of their house. As long as they didn't use more hot water 
than that at one time, they didn't need their water heater in the 
summertime. In the winter it preheated the incoming water - with or without 
sun, as it turned out, because heat leaking from inside the house kept the 
"breadbox" warmer than the incoming water (and provided the additional 
bonus of preventing freeze-ups, which - depending on how they had things 
plumbed - could have had some significantly negative repercussions...)



A good article from Backwoods home about the 'goods' as well as the 
'watch-outs' of solar thermosiphoning hydronic slabs. The number-one rule 
it cites: Use thermosiphon only in areas where freezing temperatures are rare.
http://www.backwoodshome.com/articles/hackleman64.html



Regarding uninsulated mass walls in cold climates, Chuck Learned's comments 
were on the money. Here's a well-written synopsis followed by an article 
about rammed earth in Australia, from which much can be inferred with 
regard to cob:
http://www.repp.org/discussion/greenbuilding/200101/msg00037.html