Scott Weinberg

kees ijpelaar wrote:I have test the rocket heater.

https://www.youtube.com/watch?v=F1Xfv737CiU

Do not perform well, stinks.

Maybe the dimensions, special the vertical tube, do these need as big as the feed and rizer?


regards

Please describe what you did not like about your test burn?
What do you consider the part that stinks?
Are you saying you DID NOT follow any particular dimensions?
Are you saying your vertical tube is smaller than your feed tube?
What sound was your "bad noise"?

I am not sure there is any help for this unless you answer these questions.  AS at least this might establish a base to start.

Brandon Hands wrote:


thanks for the advice.

I'm kicking around a couple of ideas. one being to start with a Liberator Rocket Stove and add some material around the bell/flue in order to extract heat. the Liberator is nice because it's UL listed to help avoid insurance fights. so I've been thinking of ways of pulling heat off of it, but I wonder if I would be overkilling it.

Depending on your abilities,   BUYING a a Liberator Rocket Stove and BUYING pellets for the rest of it's heating days? This defies much of what heating with  a Rocket mass heater and split wood is all about.   And adding the words- "add some material around the bell/flue to extract more heat from the flue" Goes against the advice you were given in the past few replies to you.

  I think most "insurance fights" are self brought on?   Kinda like asking the question and giving a negative answer at the same time, Such as  telling your insurance man, " You probably won't insure me, because you've heard that you won't insure wood stoves?"  If you give most people a easy way out, they will take it, Seems like I often hear a home owner trying to convince the insurer NOT to insure them and often get their wish.  Probably a better way to word that, But it rings true in many cases.

                                     

Brandon Hands wrote:
the other thing I'm thinking about is a more tall masonry heater type of design instead of the long bench, so that makes some of the numbers from Peter less useful. if I were to go with this kind of design, I would also want more of a batch box, which adds another element that makes the standard ratios hard to apply

A "more tall masonry heater type"? your thinking about?  with a a batch box unit,  which essentially is a batch box with a bell ( no bench ) that is super well documented by myself, Glen in CO, Tom in MT and many others And backed up by ALL of Peter V's numbers, also well documented. or are you thinking of something else? Such as a so called Russian Masonry Stove that is much harder and way more expensive to build?

Brandon Hands wrote: does Peter have masonry heater designs?  

See above

Brandon Hands wrote:
also, for #4 (chimney cap dampers), I meant for the purpose of closing off the chimney between burns so that the stack stays warm instead of having the cold air pour back down.

For air to pour back down, would you agree that it has to have a place to go in order for this to happen? if you have your air inlet door to your stove closed as recommended by every rocket design when not burning,  there would be " NO pouring back down" to take place.

I hope this does not come across as trying to rain on your parade, But in all honestly I see few things that should cause concern, every bit of information is there for proven designs.  Best of all, before you build, you will have a plan on paper, with all of the dimensions, brick count, and final look, and you can toss this to the forum. There may be some tweeks suggested, but they will be all helpful.  Once in hand, there should be nothing stopping you. Best of success to you and all.

Brandon Hands wrote:Hey,

I have been watching videos and learning about rocket mass heaters and it seems like there is a conflict between drafting well and extracting heat from the exhaust. Obviously the colder the exhaust is out of the chimney the better in terms of efficiency, but colder flue gasses mean more issues with smoke coming back the other way and potentially with pulling enough air to burn hot.

So what is the best way to do well in both categories? I've heard insulated flue pipe is good, but then your just not getting as much heat into the house. I suppose insulated pipe outside the house is good, though.

Obviously a bypass when starting a fire is good.

How about chimney cap dampers so that the flue starts warmer?

Are there other things to consider in order to get the best of both?

Are there other philosophies on the topic?

Brandon, Tom hit a lot of the things on the nail head spot on. but I would like to add a couple of things.

1) I don't think there is a conflict with a "either drafting or extracting heat" as you put it.   Simply, if there is not enough heat going up the flue, things slow  (flue gas) Thus picture in your mind, a plane flying strait up, and simply running out of power (in this case HEAT) to keep going up. The saying "what goes up will come down" is very true in this case.   Flue gas that can no longer go up, will come down, if it is NOT OUT of your chimney, it will tumble back down. Thus as Tom stated, a bypass can be a very little used but very useful tool at times   And very hard to put in later. I use my three times per year.   Once, when I start in the fall,  2nd time, tends to be when we have the first warm up in the spring and I don't fire for a week or two.  3rd time, is when we have a second cold snap in the spring after another time off.  I wouldn't say, it is used for more than 10 minutes each time, but the help is instant.

2) So with the above in mind, Extraction of TOO much heat either from to large of bell, bench,flue tunnel even flue pipe to your chimney can have detrimental effects. but fear not,  Our testing guru, Peter V. has already figured out what works best for sizing, and these figures are out there. if you have not run across, just ask.

3) On your second paragraph, you mentioned using a insulated flue pipe to your chimney may have a lowering effect on efficiency for  your stove. (at least that is how I took it)  This can be simply said, if your connecting flue pipe is hot enough you feel it is warming a room, it is to hot... at the internal flue gas temps of 150-220F-- you will never know it is casting off "additional heat"  The temp is simply to low to be radiant into your room.

4) "chimney cap dampers"?   The stove is 100% planned to burn as wide open as possible,  As stated in #1, if you try to keep something from going up, it will come down.   That is never good.

5) I don't mean to repeat, but all the figures are out there, you will have the best of both, if you build to proven numbers. This would be like trying to build a house by looking only at the outsides of a nice house.   if the insides are not correct, it may look like a house but that is about it.

Tom, that really brought back memories, as I used a much wider one but same principal years ago,  ( use a diamond wet saw for most everything now, because of the granite work)

Anyway a short head banging story- I bent down to adjust the brick just slightly, and just reached up to pull down the handle - brick popped as it should, but being I was below the handle, instead of above, well lets say I remember where the handle went.

cheers

Scott Weinberg wrote:.

  Using alcohol inks, acrylics, some epoxy work, Poly aspartic coatings,  for very vivid colors.  All on metal.  It has been great fun for the last 20 years.
A few more.

Benjamin Dinkel wrote:Hey Scott. It’s a Wiki, so depending on the settings certain groups of Permies can edit it.
If you can’t edit it you can add a reply with all the details and someone will include it in the list.

Being I have no idea what a Wiki is, I will use this as a intro.

I live in North East Iowa, have built two different J tubes, And then went up to a 7" single bell batch rocket, which has worked extremely well from day one. The link to this build can be included and should be tagged to this reply.  Next build will be a 7" shorty with a single bell. Slated for summer 2025 build for use that coming winter.

Benjamin Dinkel wrote:Dear permies,


I added myself to the List of RMH Builders and am happy to show my brand new website RocketMassHeaters.com.

[i

How do you add yourself to the list?

Randy Butler wrote:Gentlemen - thanks for the quick response.


As to the size reason - turn out that the FB dimensions and port are very close to full brick dimensions when adding a FB Split liner.  

The divided exhaust port means I can have a center (IFB) "post" to support the middle ends of the two IFBs above and no lintel.
Castable refractory isn't cheap here, and I have more than enough K26 IFBs.

Randy, Please take the time, to consider that building a 7" shorty will require NO splits.  Enclosed is a photo up to the top of the port, thus showing only the lower burn chamber ( lower riser)  There are NO splits in this, all of 2.5" thick x 4.5"wide x  9"Long or cut derivatives of this brick, The light tans are full bricks, any other color is cut to a smaller size.

As Tom pointed out, using a tension frame, and correct cuts of brick  ( full bricks - think 22.5 and 45 degree cuts, nothing else)  will allow you to avoid the surface tension drag in the riser as  you have proposed with a split riser roof support. Adding resistance opens up a huge can of worms.

I know the casting material is expensive, but sometimes it is simply un avoidable,  a case in point might very well be the extra long cross piece at the exit port.   another area where an obstruction could have detrimental effects.    

Tom showed how he made his "castings" with the sawzall vibrator, and there are other ways as well.  All far beyond a hammer and help greatly for a finished product. While I have not looked,  Amazon Prime with free shipping (in a sense $12 to $16 a month or find a neighbor with it)  can really open up the door for a cost effective solution.

Randy Butler wrote:




     7 1/2" system: Base  = 5.43  (Chimney is 8" square clay flue tile lined)
  The Riser Exhaust - if I can maintain the height and total width per specs, can I divide the exhaust in 2?
  Lower Riser Bay - Width and Depth both system size (so 7 1/2")
  Upper Riser Bay - Width and Depth both 2*Base (2 * 5.43 = 10.86, pretty close to 10 7/8")

  BUT in one of Peters notes, he says the riser depth should be less than riser width to establish a good "double ram's horn."
  I did not find any specifics on just what the difference should be.

He also expressed concerns about minimizing the number of brick cuts required for any layout.
Other than ease of assembly, do you find that to be any issue? Mine will be done on a chop saw with abrasive blade.

Based on the numbers I have, plus PvdBs input, I made a stab at a 7.5" core in SketchUp.
Suggestions on how to post the skp file?
I'd love any feedback if you have a chance.

Thanks!

Randy
Are you asking if you can have two smaller exhaust instead one, and I presume you mean if you have the same square inches?  if I am reading this correctly, what is the perceived gain?  what friction loss calculation do you intend to use?

When you say "riser depth" and "riser width" where are you measuring for these numbers?  The first part and the second part of the riser are square each. to the best of my calculations. Left to right and front to back.

Minimal brick cuts.     it takes great planning for the least amount of cutting,  with the general rule, lesser amount of cuts equals lessor amounts of waste, thus far less cost.  I have cut 1000's of pieces, brick-marble-granite-tile, and this " least amount of cutting" is always important.

I may not have answered any of your questions, but did ask some more of you.

cheers
Scott of Iron Design.

thomas rubino wrote:I received a package yesterday afternoon from Permie member Scott, at Iron Designs in Kansas.
A gift in appreciation of the guidance I had offered him while constructing his 7" batchbox, as well as the help I offer all other aspiring Rocket Scientists.


Thank You, Scott. This is a fine example of your work that I will display for many years to come!

Very welcome Tom, Every stove puffs harder ( like a dragon ) with bling  

Scott of IronDesign in IOWA