I saw a story on Digg about a designer (architect?) that got an award for building a house with water walls. But I could not find it again. This piece popped up and uses an older technology but you can get the idea from it.
Build a Water-Wall Home
Construct your very own water-wall home and learn about calculating water storage requirements, wall construction and solar basics.
The Morgan home in Davis, California has 14,000 pounds of thermal mass stored in its water walls, yet the containers blend in so well with the house design that they’re barely visible.
In many ways, passive solar homes are superior to those with active (mechanically assisted) heating and cooling systems. After all, passive solar systems don’t rely on auxiliary energy sources to perform (so they’ll work even when the power is off)… are generally simple and low in cost, combine energy collection and storage functions, have a long life, need little maintenance, and can often be built and installed by the home handy person, without special training or equipment.
But precisely because such “non-moving” systems have no pumps or controls to circulate warm or cool air, they typically rely on one key element: the thermal mass that stores and gives off absorbed heat or cold. A number of different items can be used to provide this energy-holding capacity, but just about the most effective and economical “To a water wall (a term that is a shorthand way of saying “contained water for thermal mass in passive solar homes”).
Go there and read. More next week.