4 ms·

Well, what's an interesting question about these systems is, "In a modern context where we understand science much better and have much more sophisticated mater

Well, what's an interesting question about these systems is, "In a modern context where we understand science much better and have much more sophisticated materials available, could we use these principles?" The real trick here is using available materials for heat storage, using air convection to circulate heat but not waste gas, and tightly limiting oxygen flow to make the most of minimal materials. It's definitely not bad, from an efficiency standpoint, to be compared to rocket heaters. They're still some of the most efficient systems we have.

adrianN 8y ago
We could probably improve the dimensions quite a bit if we used something other than granite for heat storage. Something that changes phase, like in those pocket warmers, would probably be more effective.
- yetihehe 8y ago
  There is fireclay [1], and I have fireplace with several bricks made from it. When fired in the evening for 2-3h, will keep warm until morning. [1] https://en.wikipedia.org/wiki/Fire_clay https://en.wikipedia.org/wiki/Fire_clay
xenadu02 8y ago
“High efficiency” water heaters and furnaces use similar principles to this (and the glazed tile oven mentioned). A winding network of passageways to get maximum contact with the flue glasses and thus extract as much heat as possible. By contrast a traditional straight chimney wastes a lot of heat by dumping it outside.
- Retric 8y ago
  That can be a feature in the summer when you wanted to cook inside.
  - Yetanfou 8y ago
    I cook on a wood-burning stove year round. Here in west-Sweden it can get quite warm in summer (with last summer being an extreme example with a maximum of 37°C and a period of around a month with daily temperatures between 25°C and 30°C, we did most of our cooking outside on an electric plate as open fire was prohibited due to the extreme drought). When firing the stove just for cooking I use quick-burning wood (spruce, fir, etc) and it doesn't really add that much heat to the kitchen, the thing is quite efficient. Come the colder months I light the stove a bit earlier, using heavier types of wood (birch, elm, oak, etc). I have yet to fell a living tree for either the stove or the heating stove (which, between the two of them, heat the whole house) as every year there is enough windfall to keep up with the demand (between 3 and 5 cubic meters of split wood per year). Felling, hauling, cutting and splitting wood is about 2 weeks of exercise per year, it is the fuel which keeps you warm twice - once while harvesting, the second time while burning it. Yes, this might be more work than just flicking a switch, touching a zone on an induction cooker (which I used before I moved to Sweden) or turning a knob but it is more reliable, more sustainable, more useful and more fun than the alternative (electricity).
    - Retric 8y ago
      37C is really not that hot. 40C with 90% humidity is IMO where things start to get unpleasant. Growing up I had access to basically free wood and we used it regularly for heating and occasionally cooking. However, at scale it takes fewer resources to use solar power than a wood stove. It just does not seem that way when you have ready access to plentiful trees.
      - Yetanfou 8y ago
        In west-Sweden 37°C is hot, this region normally sees temperatures around 20°C in summer, -15° to -20° wintertime. The highest temperature ever measured in Sweden is a paltry 38°C, lowest -52°C [1] so that 37°C was... hot. [1] https://www.smhi.se/kunskapsbanken/meteorologi/svenska-temperaturrekord-1.5792 https://www.smhi.se/kunskapsbanken/meteorologi/svenska-tempe...

adrianN 8y ago

We could probably improve the dimensions quite a bit if we used something other than granite for heat storage. Something that changes phase, like in those pocket warmers, would probably be more effective.

yetihehe 8y ago
There is fireclay [1], and I have fireplace with several bricks made from it. When fired in the evening for 2-3h, will keep warm until morning. [1] https://en.wikipedia.org/wiki/Fire_clay https://en.wikipedia.org/wiki/Fire_clay

xenadu02 8y ago

“High efficiency” water heaters and furnaces use similar principles to this (and the glazed tile oven mentioned). A winding network of passageways to get maximum contact with the flue glasses and thus extract as much heat as possible. By contrast a traditional straight chimney wastes a lot of heat by dumping it outside.

Retric 8y ago
That can be a feature in the summer when you wanted to cook inside.
- Yetanfou 8y ago
  I cook on a wood-burning stove year round. Here in west-Sweden it can get quite warm in summer (with last summer being an extreme example with a maximum of 37°C and a period of around a month with daily temperatures between 25°C and 30°C, we did most of our cooking outside on an electric plate as open fire was prohibited due to the extreme drought). When firing the stove just for cooking I use quick-burning wood (spruce, fir, etc) and it doesn't really add that much heat to the kitchen, the thing is quite efficient. Come the colder months I light the stove a bit earlier, using heavier types of wood (birch, elm, oak, etc). I have yet to fell a living tree for either the stove or the heating stove (which, between the two of them, heat the whole house) as every year there is enough windfall to keep up with the demand (between 3 and 5 cubic meters of split wood per year). Felling, hauling, cutting and splitting wood is about 2 weeks of exercise per year, it is the fuel which keeps you warm twice - once while harvesting, the second time while burning it. Yes, this might be more work than just flicking a switch, touching a zone on an induction cooker (which I used before I moved to Sweden) or turning a knob but it is more reliable, more sustainable, more useful and more fun than the alternative (electricity).
  - Retric 8y ago
    37C is really not that hot. 40C with 90% humidity is IMO where things start to get unpleasant. Growing up I had access to basically free wood and we used it regularly for heating and occasionally cooking. However, at scale it takes fewer resources to use solar power than a wood stove. It just does not seem that way when you have ready access to plentiful trees.
    - Yetanfou 8y ago
      In west-Sweden 37°C is hot, this region normally sees temperatures around 20°C in summer, -15° to -20° wintertime. The highest temperature ever measured in Sweden is a paltry 38°C, lowest -52°C [1] so that 37°C was... hot. [1] https://www.smhi.se/kunskapsbanken/meteorologi/svenska-temperaturrekord-1.5792 https://www.smhi.se/kunskapsbanken/meteorologi/svenska-tempe...