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Imagine a device which consists of 2 nested pipes - a pipe inside
a pipe. The inner pipe has a fuel/oil burner at the bottom of it,
able to draw in air from below. The bottom end of the outer pipe
is lower than
that of the inner pipe. The top end of the inner pipe vents out
air. The gap between the inner and outer pipe is sealed at the
top end. There is however a spout (like a teapot spout?) which
protrudes from the upper portion of the outer pipe.
Lighting the burner results in a thermosiphon. Air will be sucked in
from the bottom end (inlet), and will leave via the top. But while
smoke will exit from the central pipe orifice at the top, what
emerges from the spout will be clean smoke-free warm air. That
warm air is coming out of the spout due to thermosiphon effect,
with air in the outer pipe being warmed by the inner pipe,
an updraft, after being drawn in through the bottom inlet.
Imagine this contraption hanging by its spout off the crack of your
slightly open car window, to send in warm air into your car, while
you're stranded in the cold weather due to a breakdown. Or else,
imagine similarly heating your tent while camping, by positioning
this contraption just outside your tent, and having the spout poke
through some tent flap.
The goal of this portable device is to efficiently provide fresh
warm air into some interior compartment via fuel burning,
you to inhale smoke as well. Otherwise, people do go camping in
tents equipped with interior stoves for heating, but there's always
the danger of smoke inhalation from the burning fuel in the stove,
so that carbon monoxide detectors are often recommended for
Heating Tent With Torch & Thermosiphon
[sanman, Jan 28 2021]
[sanman, Jan 29 2021]
2021 Texas Ice Storm
[sanman, Feb 23 2021]
||One of the most ingenious heating devices I ever saw was in a rustic rural cottage in France, it was a cast iron grate which stood in the fireplace and which you lit a fire on as usual. But the iron grate was actually a serpentine hollow tube, with nozzle fittings at each side. On the front side was attached a tube that acted as an outlet nozzle pointed into the room, and on the back side was a hose fitting which ran to an electric blower. Cold air blown into the device came out the nozzle as a lovely stream of warm air which heated the entire building up pretty quickly from a small smouldering fire that looked utterly inadequate.
||// looked utterly inadequate. //
||Ah, the "Keir Starmer" look ...
||[+] for the idea, although wrapping the outer tube in an insulating material - such as blue asbestos - would improve it considerably.
||Without liquid, it's not really a thermosyphon, more a form of
facilitated convection. You'd get more efficiency if you could
power the flow in the reverse direction for a countercurrent
setup... possibly more convenience too, since it's nice to have
war air down low.
||You might want the bottom of the outer pipe higher than
the inner pipe, otherwise the 2 pipes are drawing air from
the same direction (inner sucks from the air already
contained by the outer) which could be detrimental for
one or the other (losing airflow to your burner, or less
flow getting heated). Outer higher lets it draw from
"outside" while the inner draws from "below" (more-or-
Things get interesting when it's cat vs. (small) dog... since
cats are so much more powerful (per kg).
(Long story short) my cat & my flatmates Papillon dog
were playfighting (they grew up together from very
young); my cat performed a move a WWE wrestler would
be proud of, diving over then rolling under the dog then
launching it a metre or so, airborne, across the lounge. I
wish I was filming it...
||to pocmloc: regarding your description of the fireplace
siphon heater in the French cottage, I've just added a link to
the "Franklin Stove", which was invented by Benjamin
Franklin. Apparently it has some kind of baffle designed to
siphon air and output it into a room.
||Looking at what's been happening in Texas, it seems like
my idea suggestion was quite timely. Going forward, if this
type of product could be designed and built, it might have
many takers. I was reading about people who've lost their
lives in this terrible Texas storm tragedy -- people who
died from carbon monoxide poisoning while trying to keep
warm in their car, a young child who went to sleep and
never woke up because they died of hypothermia. The
concept being discussed here may sound primitive and
basic, but in certain circumstances, the fundamentals are
what we need to hang onto life. (Added another link for
||A thought: you would also want the air supply to come from
"outside". Probably the "fresh" air (for breathing) but I
||@neutrinos shadow: Well, that's the entire point of it. Your
siphon is sucking in fresh air from the bottom of the device,
which could be hanging from the outside of your car window,
or hanging from the outside of a tent flap.
||Ah... for some reason I was visualising the device INSIDE,
with the smoke exhausting outside (which would need
But (now I read it more carefully) with the device
OUTSIDE, only the clean hot air goes in. Makes more
sense (except when you need to feed the fire...).
(More thinking...) with the burner "outside", you lose the
direct heating effects (relying only on the air heating).
Have the burner inside, drawing air from inside &
exhausting outside. Fresh air from outside goes through
the heating chamber to inside (driven by both
thermosiphon & the fact that the burner is sucking the air
out of the space). 2 pipes but more heat, & better to
control the burner.