I'm trying to optimize the combustion efficiency of a kerosene-fired
absorption-cycle chest freezer.
It uses a Alladin brand kerosene-lamp wick mechanism to produce the
heat needed to distill ammonia. I think this is basically a candle.
It's possible to retro-fit woodstove-type catalyzers into the flue to
be a sort of after-burner for the un-combusted kerosene vapors.
But at its heart... that's closing the barn door after the kerosene
vapors have escaped..
active devices exist, such as the babington burner. But then you're
into a whole new chapter of piping, measuring, adjusting, maintaining,
aside from the customary eyeballing methods, does science teach us
anything about how to adjust a wicked burner, to optimize combustion
I think that you are stuck with the mark-1 eyeball together with your
factory-fitted general pupose digital adjusting tools (aka fingers!)
You need to make sure that the wick is well trimmed so that combustion is
uniform around/along its length/circumference. The paraffin (what we call
kerosene) burners I have been familiar with have had cylindrical wicks and
came supplied with a cutting tool that shaved the burnt end of the wick down
so that a constant length was protruding - for maximum efficiency (and
minimum smell of unburnt fuel) it was very important to trim the wicks
The important factor is the ratio of air to fuel. You probably can't do
much about the air supply, apart from ensuring everything is clean and free
from obstructions, so for maximum combustion efficiency you should reduce
the fuel supply by winding down the wick to reduce the luminosity of the
flame. Ideally the flame would be pale blue and almost invisible - the
luminous yellow colour is caused by incandescent carbon particles, which of
course represent wasted fuel - but you probably can only achieve this using
a pressure burner (Primus- or Tilley-type), which vaporizes the fuel and
pre-mixes it with air. Problem is that at its most thermally efficient the
wicked burner may not be supplying enough heat to properly drive the
refrigeration cycle so you will probably have to trade decreased combustion
efficiency against increased cooling efficiency, to obtain optimum
performance from the freezer.
We had an old Elextrolux refrigerator of this design when we owned a village
shop in North Wales. It was running on mains electricity when we bought the
shop but I later found its original paraffin burner out in the stable. I
was always disppointed that we never had the opportunity to try it out!
You might try preheating the incoming kerosine with a heat exchanger in
the exhaust gas path, or changing the burner to one that vaporizes the fuel
that way, if such a thing exists. Be careful. Aladdin lamps have a thermal
runaway problem. If unwatched, they can make big sooty 3' flames that
threaten to burn down the house and boil the kerosine and melt the solder
holding the wick adjustment knob on its shaft. Getting close enough to turn
the wick down with vice-grips is dangerous.
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On 4 Jul 2005 23:35:45 -0700, alanh email@example.com wrote:
I see a pun coming, so I'll refrain...
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