Black Ice


Black Icicle
This one’s for Pablo who asks for more ice carving. It was such beautiful black ice I hated to break it but I absolutely had to. It was the middle of the winter and I wanted to check our chimney. Avoiding chimney fires is on my to-do list. Note this is an ice sculpture, not creosote, and it is on the outside of a concrete wall. The black color comes from tiny amounts of wood ash from the smoke. It is not a real fire hazard and ice does not burn.

The woodstove chimney is divided up into three sections, a tall vertical portion which stays very hot, a horizontal section that loses most of the heat before exiting the cottage and then the short vertical section that goes upward again above the roof. Most of the chimney is inside the house. This helps the chimney stay warmer so it doesn’t cool the smoke too fast and it lets the heat go into the house rather than being wasted to the outdoors. This convoluted path provides turbulance which enhances the burn. There is also a high turbulance area right after the fire box in the vertical chimney section that also enhances flue gas burning.

Based on measuring the starting and ending temperature our woodstove and chimney are about 88% efficient. That is to say that about 88% of the heat has been removed from the flue gases before they exit the house. Once they exit the house they hit the outer metal chimney and air which is much colder which provides lift. On a cold day that may be 20°F or more below zero, sometimes as low as -45°F. This causes the water vapor in the smoke to precipitate catching some of the soot particles making this glorious black ice. I just need to figure out a use for it.

So what’s with the weird shape of the ice??? Wind! The wind comes from the north, the back of the house, over Sugar Mountain. We’re pretty protected by the ridge line, the north field tree line, the home field tree line and then an embankment. The turbulence right there near the peak of the house must be interesting because it has roiled the icicle as it froze creating the weird alien tentacle thing shape to it.

Outdoors: 49°F/26°F Partially Sunny
Farm House: 31°F/30°F
Tiny Cottage: 65°F/55°F

About Walter Jeffries

Tinker, Tailor...
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9 Responses to Black Ice

  1. Brian says:

    freeze it it bears a surprising resemblance to Batman shrouding his face with his cape

  2. Ooo… I can just imagine how Holly would react to me taking up freezer space with that! :) I have put some strange things in there… I don’t think I’ll push it with this! :)

  3. Pablo says:

    Yes, indeed, that’s a fine ice sculpture. Pablo is pleased.

  4. Pook says:

    thaw it dry it & burn it

  5. That looks like something straight out of a science fiction movie…Just make sure that it doesn’t take on a life-force of its own!

  6. Anonymous says:

    I see the batman. Took me a moment to find it. Pretty cool in every way!

  7. MableMamma says:

    Very interesting black ice but in all your winter did you not have any real ice pictures?

  8. Jacob Clark says:

    Would the pigs find a use for this or just put it in garden space. I would think that the mineral content would be pretty good.

    • I’m not sure. It is an interesting question. Animals like to eat the charred wood from our bonfires out in the field. Charcoal, the kind made from wood, not fossil coal, is used as a source of minerals and detoxifier by many cultures so it is a possibility.

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