Eric Hroboni wrote:I've made a few more upgrades. They are definitely making the greenhouse more evenly heated. I put a box around the blower to draw air lower to the floor. And also put inline duct fans in .
paul wheaton wrote:
Steven Kovacs wrote:Thanks for this, Paul. You've clearly put a lot of thought into the issue.
More like: my brain is infested with a huge amount of thoughts on a lot of topics. Lovely people then ask a simple question like "What do you think of LED lights these days?" and I am instantly tongue tied because my answer is not a simple "I still prefer incandescent." My answer is huge. In fact, my answer is even larger than what I provided, but I need to stop at some point.
thomas rubino wrote:Hi Neil;
No, Peter did not OK my burn tunnel being longer. I did that all on my own!
Originally I built an 8" J tube using perlite and clay. A Walker cast core. and a Walker style cast riser as well.
Worked beyond awesome! Barrel top temps of 1100F!
What did not hold up was the feed tube. By the end of the 2013 season, my feed tube had enlarged to the size of a 5 gallon bucket.
I decided to build a heavy brick core to replace it.
I located a source of free firebricks....
I made the burn tunnel roof apx. 13" - 15"" long. (Don't remember the exact number)
I did that because I did not have a clue... just like any first timer. Bigger must be better right?
And besides it made setting the barrel much easier...
Remember in 2013-14 information was not as easily available as it is now. There was one book by Ianto Evans and there was Permies!
I loved my new core, for the fact that wood had no effect on it. My feed tube started out at 7.5" and stayed there! Hooray we are rocketing now!!!
Long about the middle of winter I started having draft issues??? Why, I was keeping my burn tunnel cleaned out?
It quickly progressed to not burning worth a damn... smoke back was a daily problem! That was not acceptable!
My barrel of course has a removable lid, a quick look inside showed no issues in the riser.
As stated earlier, my transition area was almost full and my 8" horizontal pipes had maybe 2" left open... for the entire horizontal run! That's over 20' of pipe filled with ash!
That was when I discovered that a leaf blower can blast out your mass...BUT it make's one huge pucking mess!
A core rebuild happened in the middle of winter that year... let me tell you, it was very scary taking apart your only source of heat in a Montana winter.
That was when I learned all about WHY we use clay not refractory to mortar our bricks... A piece of cake to tear into that core. All the cob went in a bucket and was rehydrated to be reused. A scraper cleaned the bricks up in moments. Within 4 hours of walking in the greenhouse that morning I had my core rebuilt and was lighting a new fire!
Moral of the story here. The innovators, Peter Berg , Matt Walker , The Wisners , Ianto Evans. They tried all the configurations they could dream up.
They quickly learned what would work and what did not work. Eventually high dollar test equipment was utilized to fine tune their results.
They have openly shared this information with the world... we all owe them a huge thank you for telling us how they accomplished everything.
I do not believe there is a post showing that core rebuild. I may still have photo's on my computer.
Joe Danielek wrote:
Another assertion that of the ‘push–pull’ theory doesn’t make sense that Thomas indirectly dispels himself by stating “... however you need to start and keep a steady draw thru the entire system.”, thus the bypass blastgate for sale on your site. For me the secret to system efficiently is at the feed tube by fuel size and rate of feed to assure a complete burn up the riser.
Fox James wrote:
I was hoping one of the more experienced designers would chime in as it is an interesting subject….
Glenn Herbert wrote:Re "overfeeding an RMH" - a properly designed J-tube system cannot be overfed; there is not enough space for more wood than the system can handle.
Glenn Herbert wrote:Ernie and Erica Wisner have vast practical experience with RMHs (hundreds of systems built), and their experience is that these factors do matter. Do you have experience to refute that?