Intrigued, I've been surfin' and there seems to be two basic designs, using bamboo canes for each column of cut off bottles and securing them to frames vs. wrapping wire on both sides of 4"x4" corner posts and 2x4 studs at regular intervals to corral the columns of cut off bottles. Some advise stacking the bottles upside down and others right side up. They are also making hot water heater panels (copper tubing instead of bamboo) and sand-filled plastic bottle brick structures out there.
I'm starting to noodle ideas for combining the designs.... The hotwater heater panel might be ideal for thermal mass and sand-filled brick might be good for north side and lower walls....
