Improved soda water bottle pasteurizer
The soda water bottle pasteurizer shown here may have better performance than the one shown at Soda bottle pasteurizer. It may also be slightly simpler to fabricate.
The cut off base, inverted, provides a stand for the blackened pop
can (or other suitable black container). The taper of the inverted
base eliminates the need for tabs--the cut off top just jams down over
the inverted base.
Performance might be better for three reasons. First, the stand raises
the pop can so that its bottom can be illuminated. (Be sure to blacken
the bottom of the pop can.) Second, raising the pop can improves its bottom
insulation. Third, the air leaks are below the bottom of the pop can. Since
all of the air in the bottle above the stand is hotter and lighter than
outside air, this stable arrangement of cool outside and hot inside
air resists air leaks. In the design at Soda bottle pasteurizer. , the air leaks are above
the pop can, promoting outward leakage of hot air and inward leakage of
A possible further improvement
As the water in the pop can gets hot, most of the heat loss will occur
from condensation of water vapor on the upper inner sloping sides of the
soda bottle. We can greatly reduce the rate of heat loss from this
condensation by double glazing the upper part of the soda bottle
using the top portion of a second soda bottle as a hat on the first soda
The hat will accelerate the final portion of the temperature rise,
or allow reaching a higher temperature (to make tea?), or allow successful
pasteuration on less sunny days.
David Delaney, email@example.com
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