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, yadda yadda.
aside from the customary eyeballing methods, does science teach us anything about how to adjust a wicked burner, to optimize combustion efficiency?
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 regularly.
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.
HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.