Upgraded flowerpot heater... thoughts?

Kelpie

Kelpie

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For once, not a wind-up.
As my heater has died I'm going to try out a flowerpot heater, as inspired by KTL industries et al. Heat source will probably be something more gutsy than the fork handles previously suggested. Perhaps a home-made wick burner, or a camping stove, or even my 2.5kW paraffin stove. I'm also wondering about buying a primus stove as a heat source, partially because I would like one anyway, and also because I have a large quantity of fuel for it.

I want to use the old flue from my dead heater, so that I can run the flowerpot at higher power without adding any condensation. I'm envisaging connecting it up using a length of eber exhaust.

The question is, where to connect the flue? To the top of the big flowerpot? Or make a bigger hole in that flowerpot and connect to the little one? That way the flue is directly over the burner. Someone who understand the magic behind the flower power may have to explain to me which one is better...
 
A bit of balancing act I would think. The input energy is from the candle wax on a flowerpot heater. The pot itself only stores and re-radiates some of that heat, instead of most of it heading for the ceiling. One candle pollution of the interior atmosphere is maybe acceptable. More input heat will require more ventilation and soon a proper chimney, which lets a lot of heat exit up the flu and draws in the same volume of cold air. I am not sure you will get better or safer results with flower pot derivatives than having a properly designed and installed liquid fuel heater, like say the Reflex ones.
 
I am frankly horrified at any design which risks emitting CO direct to cabin atmosphere, let alone the the nano-scale carbon pollutants given out by any hydrocarbon based fuel.
 
Well I'm not expecting this to be equal to, or better than, a proper heat. But I do hope to have it up and running this week, at very little cost. Which rather outweighs most other considerations.
I'm aware of the problems inherent in a non-vented combustion heat source. Which is why I plan to hook this up to a flue. Just trying to work out the best way of arranging that.

And it goes without saying, the CO monitor will be to hand.
 
Are those storage heaters still made? A piece of the material used inside them has a much greater thermal capacity than a flower pot. Maybe a scrap yard would have some discarded ones. Heat quickly over the paraffin stove and then let to cool slowly.

Just had a look at Wikipedia on heat capacity. Iron or water are pretty good. A saucepan of water might be your cheapest bet. Or a lump of pig iron.
 
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On my first boat, which had no electric, & had a simple GAZ light operating from a small container
I found that it gave off a lot of heat as well as light. So much heat that it had to be hung 2 ft from the ceiling to avoid damaging the paint
 
MASH said:
Why not use the gas stove you already have? (and put a flower pot on it too if you must...)
Click to expand...

I don't have a gas stove- the galley uses paraffin. Although yes, I may use this as the heat source initially. I am also considering using my Trangia meths burner as a more gentle heat source.
The problem with just using the galley for heating is that there is no flue. OK so I can open the main hatch but that is rather defeating the purpose. And, as I said, I have a perfectly good flue ready to use, so it's a case of hooking it up.

I was under the impression that the purpose of the flowerpot was not exactly the same as the bricks in a storage heater. There will be a certain degree of thermal inertia, but I think it's more to do with creating a larger surface area to transfer heat to the surroundings. And I think that the reason for nesting the pots inside each other is that you create an air chamber that boosts this effect even more. My concern is that by putting a flue onto the bigger pot I will simply suck away all the hot air that I am trying to create.
 
On a previous boat we had a Taylor's paraffin heater. It was essentially a primus stove inside a stainless cabinet with a chimney at the top. Above the burner was a metal construction of baffles that harvested the heat before it disappeared up the chimney. In view of this, your chimney should be on the outside flowerpot otherwise you are just losing the heat before using it.
 
Getting back to the basic physics of heat and away from majic flower pots. If you are to safely use the cooker as the heat source then you must take away the combustion products. I think you are right to use the existing flue. You need to make sure it will suck out the gases. A small computer fan in the outlet might be worthwhile.
OK the heat you want is in the gases. You need to extract the heat by having a section of chimney made of copper or Aluminium. It will get hot on the outside. This can be moved into the cabin by painting it black for radiated heat and putting lots of fins on the outside to conduct the heat as warm air.
Remember that more heat is collected and again transfered to cabin air by area of fins or metal in the exhaust stream and fins on the outside.
The biggest problem is that it is the air around the chimney that gets hot when you want warmth down low at your feet. Hot air rises naturally. So you might consider a fan or even ducting to get hot air down lower. You might also be able to use some of the chimney radiated heat to dry clothes ec.
Anyway good luck with the experiments. If you cna get a really good heat exchanger working then exhaust gas should be barely warm but do make sure you get the bad air out. olewill
 
The Victory heater I has consisted of a primus stove in a fancy chrome cylinder with a flue on top - 28mm by memory - much along the lines of the Taylors described by alahol2.
I improved it by adding a teracotta field drain section, cut to fit. It held the heat quite well.
The big problem was with the noise of pressurised paraffin. Eventually went on to a charcoal heater.
 
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