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K Nelfson

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since Nov 07, 2012
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Recent posts by K Nelfson


I think it's hard to say anything about rocket mass stoves in general. There are a lot of designs out there.

In general, it's possible to get 90+ thermal efficiency out of any heat source with the right heat exchanger. There's Mother Earth News article from a while back where they built a masonry stove and got 93% on their first try. Just takes a convoluted flue that's matched in length to the heat-transfer rate and capacity of the flue materials. The heat source could be in engine, a fire, thermonuclear system, etc. So efficiency is largely controlled by the flue, regardless of the heat source.

A clean burn is another part of the efficiency. High-efficiency stoves usually have some sort of way to circulate the gas inside a stove. I don't see anything about the rocket mass stove that makes this happen. I suspect that we're all getting excited about a carefully managed fire. That's great but let's not over-sell it.

I've still to see any data that's credible and reasonably accessible.

Also, a 200 $ test is no big deal. Most standards labs cost 1000's for any battery of tests!
2 years ago

Roger Taylor wrote:

K Nelfson wrote:

Kevin MacBearach wrote:What about just putting an electric fence around them?



Well, you need fence posts, which cost time or money. You also need a fencer or an engineering degree---again, time or money. Electric fences need to be maintained. If you're a proper dairy farmer, "walking the fence" is a real thing that takes up a lot of time. Also, fences around trees would take a lot of time and effort. It'd be a lot easier to smear some gooy bad-smelling stuff on the bark every year.


I look at the trees around me, and the cows will strip the leaves from low-hanging branches and also rub the bark off the trunk by rubbing against them. I can see the oil or equivalent stop them eating from the branches, but I've yet to see anyone say it will stop them rubbing against them. Sheep are much the same, I have damage to two younger apricot trees from rams scratching up against them. Sure they've eaten the low branches and leaves from my plum trees, but the scratching/rubbing damage is worse.

There's two fir trees which cows have practically ring barked by rubbing against it in the neighbours field.

At some level, I don't think that dippel's oil can ever be an acceptable solution for cattle for me, unless it were proven to prevent rubbing. Deer or something that does no rubbing damage, perhaps.



I understand it's a repellent and it works for some people. Haven't tried it myself.... Don't have many trees on the acreage that could be rubbed---they're still in danger of trampling and deer damage. I also don't have any cows, either, which is a sad state of affairs.

3 years ago

Kevin MacBearach wrote:What about just putting an electric fence around them?



Well, you need fence posts, which cost time or money. You also need a fencer or an engineering degree---again, time or money. Electric fences need to be maintained. If you're a proper dairy farmer, "walking the fence" is a real thing that takes up a lot of time. Also, fences around trees would take a lot of time and effort. It'd be a lot easier to smear some gooy bad-smelling stuff on the bark every year.

3 years ago

Roger Taylor wrote:

K Nelfson wrote:
I read something about painting something on trees to protect them from cattle rubbing the bark off. Well, I don't know if this is exactly what was used, but it sounds like Dippel's oil is similar.

http://en.wikipedia.org/wiki/Dippel%27s_oil



Tree protection is a quite commonly discussed topic here, and if you search for it you can see lots of references to Dippel's oil.



Oh. Thanks for letting me know.

I had saw a post a while back about something Sep Holzer did involving a iron kettle, bones, and building a fire over it. A few years back. I always wondered about that and it all came back when I stumbled on the wikipedia page for Dippel's oil. Suddenly it all made sense... Sounds like you people have had it figured out the whole time!

3 years ago

I read something about painting something on trees to protect them from cattle rubbing the bark off. Well, I don't know if this is exactly what was used, but it sounds like Dippel's oil is similar.

http://en.wikipedia.org/wiki/Dippel%27s_oil
3 years ago
Interesting observation, David. I wonder how much of the heating you've seen is due to cheap seals and other sources of friction.

My understanding is that pneumatic cars are possible. But, as with so many of the non-hydrocarbon based vehicles, compressed air has a relatively low energy density.

The only real solution to hydrocarbon fuels is to slightly lower your expectations and deal

Further reading:

http://www.popularmechanics.com/cars/news/auto-blog/the-air-car-rides-again-14543822
http://en.wikipedia.org/wiki/Compressed_air_car
4 years ago
Tractors are an interesting case. They benefit from weight. So a pneumatic storage system wouldn't be the best solution but a lead-acid battery powered electric system works well. In normal ground transport, light weight is needed for stops and starts and pneumatics are a good for that.

4 years ago

Those certainly look like better quality than what I've seen in the US. And I don't mean to pick on you in particular. Just sayin'

Back to the issue at hand: Can you do a post/beam construction and use the pallets as wall panels?
Search "coconut and salinity" on the interwebs. There's lots of information about soil types, salt types, etc. I don't know if any of it is specific to your location but it's a starting point.
4 years ago

The internet's obsession with pallets, IMHO, has gone too far. Buy yourself some proper lumber.

Lumber usually isn't the main cost in building, so I wonder how much you will save.

Pallets are generally* made from low-quality wood and they're fastened together ferociously. When I've taken pallets apart, it's always been a lot of work or you end up with a lot of waste. Even if you leave them whole, it's still low-quality material and looks it.

IMHO. Just offering some healthy skepticism about the new-conventional wisdom.

--K15N1


*Yes, there are some that are made of higher quality wood, especially for international shipments. But that's usually not what the internet is talking about.