|
Post by martinm on Nov 7, 2019 20:45:27 GMT -8
First firing of this heating structure. smaĺl fires will burn for few days to aĺow for dtying. It starts with the cold start valve open and ten minutse later the gasses could turn into the the full path . youtu.be/-wBz-MKNAWk
|
|
|
Post by martinm on Nov 6, 2019 23:26:18 GMT -8
Here is an update on the stove build> Between the lower part (second bell) and the main bell I did build an archway at lower point , because the heat exchanger is 140 cm high and quite huge (external surface 3,8 m2 ) By adding this water heat exchanger the ISA is more than the suggested by the batchbox site creators. I did that because there was a consideration that the stove would burn longer than usual rocket stove with such size - to provide heat to the heat exchanger and further to supply hot water to the insulated buffer wessel on the upper floor (500 liters). While building it I also added a small oven in front of the internal chimney and with valve opening next to and bellow the "cold start valve" . The stove is still wet so I put a hot air blower every night in front of the fire box to turn the air inside. We did put a small fire to test if there is draft . with the cold start valve open the fire goes through the port with no hesitation ! The top of the main bell is covered with 5cm aluminum silicate insulation which compensates for the ISA over-sizing . I think that by adding insulation on top will provide more heat for the water heat exchanger. Will see- we need to carefully condition it with the hot air blower and then few samll fires before the real test . Thank you all for the interest and comments .
|
|
|
Post by martinm on Oct 30, 2019 1:21:25 GMT -8
I am on tbe way to cast few "plates" from clay-sand mix . any advice for percentage of shrinkage to expect ? Plan is for 24" x 15 " by 2" thickness. Thanks
|
|
|
Post by martinm on Oct 4, 2019 21:16:39 GMT -8
Here is update on the 20cm batch box masonry heater with hot water heat exchanger: Batch box completed - it is with the size for a 20cm system on top it will be covered with two layers of volcanic stone plates each 3cm thick . In front I am considering the extended part of the batch box from the main body of the stove to be covered with Ca silicat insulation and then covered with another 3cm stone plate. The stove as for today : We ordered the heat exchanger for water heating for the upper level : here the issues are with the amount of heat and the dynamics of the firings ... we did some consultations with hydronic heat specialists and we end to the conclusion that the heat exchanger should be over sized - with more water in it and more exchange surface. I hope that after the fire is dead there will be enough heat to keep the water moving with considerable temperature for few more hours. Heat exchanger size and layout : I am still thinking about lowering the separation wall between the two parts of the stove - in a way to make a two bell system . I want the heat to stay for a while around the heat exchanger ... Position of heat exchanger ": The wall , opposite to the batch fire box will be partially insulated from the outside - because there is a staircase behind this wall , thee is wood structure next to the bricks and in this part inside there will be the water heat exchanger - the intention is the heat to "stay " there longer. In regards wiith this heat exchanger : I left the refractory wall with a vertical "gap" on the side of the heat excchanger - for easy instalation and eventual repairs. Unfortunately this decision lead to another issue - long part of the back wall will stay as a staight wall , disconnected from the perpendicular other walll. I put few brackets in between the firebricks and screw the ther end to the wood post behind. I also put ceramic wool ther for some added insulation . Hopefully the bracket will not heat up so much to set the wood on fire... in The lower part of the stove the refractory core will be surrounded by "klinker " type face bricks. Up from the level of the face bricks we are planning on adding ~5-6 cm thick layer of cob. Peace and Prosperity !
|
|
|
Post by martinm on Oct 4, 2019 20:08:01 GMT -8
Best construction I've seen (and built) so far: the opening as large as the complete height and width as the bench. In effect, the bell and bench will combine at the level of the bench so gases will be moving much, much slower there. Good for heat extraction, ... Thank you peterberg < I do undesstand the concept of keeping the fluids "calm" and slow in the bell, however I tend to lower the wall between the two parts - with the intent to keep the higher part with stratified hot gasess to lower part - beacause we want also to extract some heat with teh water heat exchanger. I will post an update further in the tread >
|
|
|
Post by martinm on Oct 4, 2019 20:02:10 GMT -8
...What is the second bell for? In order for the gas to move, we select dry heat in the first bell and install a heat exchanger in its lower part. As a result, the gas can be very cold to be removed by the chimney.In my bell, the gas temperature reaches 600 degrees Celsius, and below after the heat exchanger it does not exceed 65 degrees. Under such conditions, gases move very well. The lower part of the stove (second bell) was designed because of the specifics of teh interior - low wood construction element , proximity of kitchen countertop on this side etc. second thought was the intention to slow down the movement of gases in the first and by doing so allow for more heat to be extracted from the water heat exchanger. Thank you for sharing your experience . I kept building the inner refractory brick walls and considering your and peterberg advice I didnt build the low arch separating the two "bells"(колпак?)р However after a consutation with an experienced piping water heating craftsman I am re-considering building a partial separation in the higher part of this wall between the low and high part. The main reason is to concentrate the heat in the higher part of the bell (first bell). Beacause of concerns about the quantity of heat which will be pumped to the water heating system for the second floor we oversized the heat exchanger - now we calculate it as 7 pipes 2" each H=120cm connected at low and high level with square tube 10 cm . PLus tehre will be extensions on every tube sideways ... total volume of water= 4.2 ltr. Outer surface 4 m2 . There will be a insulated hot water buffer container at above second floor to compensate for the fluctuations . We are considering 300 ltr or perhaps 500 ltr ... ? alarin - from your experience - how long after the fire is gone , the water heat exchanger keeps pumping hot water for radiator heating ? and my second worry is that oversized heat exchanger will take longer time for the water to start turning into hot water. It is for first time in my life dealing with such complex stove ... but my intuition is that the more water contains teh system , the better will performm in regards with te specifics of teh firings of massive masonry stove - a lot of heat for few hours and then just accumulated heat , so teh water will heat extensively for few hours and afterwards the heat from the surrounding walls will radiate and provide few more hours for the hot water to be usable for heating the socond floor ... will see . Further down I will put an update to where I am now in this project. PS : Извините меня но мой руский не очен хорош . Здес мого лудей оворят английский поетому я пишу на английский. Спасибо за ответа друг !
|
|
|
Post by martinm on Sept 9, 2019 21:28:37 GMT -8
I see your layout and was just wondering if you are planning on the brick being separated by the cement board that will just lay on the MDX wood subfloor? ... . Also if its a multi story house there could be draft issues due to the stack affect. One other thing is all the weight on the floor joist. Just a couple of thoughts I had - you may have already addressed it but I just wanted to mention just incase. I would rather say something now while you're just getting started. I'm looking forward to see how it progresses. Thank you for your input. Actually the whole stove sits on a separate concrete base - it was planned in such way with the owner. The level of the concrete base was lower so we had do lay down few concrete bricks and we put cement board on top to make it even. As for the draft - the two storeys are separate and there is a door betwween the staircase and the living room where the stove is located.
|
|
|
Post by martinm on Sept 9, 2019 6:56:31 GMT -8
Thank you peterberg for the timely input ! I already mortared the first layer of bricks and fortunately took a short break before advancing further. So somehow the flow pattern on both sides of the secondary air duct gets disrupted being directed by the beveled corners - interesting . For sure I will continue building with the bricks straight to avoid this terrible effect. Hopefully soon will try to make a dry fit model and test this situation.
|
|
|
Post by martinm on Sept 9, 2019 6:50:17 GMT -8
I finally went on building a Batch Box Rocket Stove for a friend, here is the plan: The heat riser is on the side to allow for incorporating on the back a water heat exchanger for gravity fed hydronic heating of a second floor above. On the side of the first bell there will be an elevated bench"or something like a second bell. between the two bells in the middle there will be an ""inner chimney" which leads to a opening on the top of main bell to a real chimney. There are story and a half above the stove. All the walls of the stove will be build out of fire bricks and some are receiving outer shell of "clinker" type of well fired solid bricks or adobe layer , covered with lime. I have few issues haven't resolve and I keep reading here for references to similar situations/ details : 1. The height of the entry / opening to the bench/second bell so far I chose to make it is five brick layers or around 36 cm. Knowing that this will affect the performance of the system I wonder what will be better height? 2. The "Inner chimney" opens to the very low point of the second bell , faced out of the entry point of this bell. Hope this will create the effect of a open plan bench which a see here being build. My issue here is with the two sides of this inner solid stack of bricks , between the two bells - it will get a lot of heat from the first bell , which is good for securing draft , but perhaps I will loose too much heat ? should I put an insulation layer on the walls of this inner chimney faced to the heat riser ? How crucial is that ? I tend to think that I should put insulation there . Plan : dry fit of the layout : Schematic sections, explaining the relation between the two bells: front view: Greetings from the Balkans !
|
|
|
Post by martinm on Sept 9, 2019 5:47:56 GMT -8
Helllo , on secondary air floor channel : considering the chance of the top , vertical part of the feed tube to deteriorate, also thinking of the option to change the geometry of this part by replacing it : I will try to make it in such way : the floor channel will have a hole with size a mm or more larger than the profile of the vertical part. in the refractory plate which is the bottom of the fire box there will be a square opening to receive the vertical part of the sec. air tube to go through . the two parts will not be welded , instead - the horizontal tube is "buried underneath the floor of the firebox and the vertical will be inserted in both the square hole in the refractory floor and the horizontal tube. A steel"sleeve"around the lower part of the vertical tube will be welded , so the part will "stay "on top of the refractory floor and thus will be easier to be replaced. Any one tried something similar ? Here the square hole in the floor of the fire box is seen : a cardboard dummy in place , beveled walls of port , so air supply could be closer to Heat riser while keeping the air flow of the sides of the ,metal tube going through the same area as above. : drawing explaining the "sleeve"
|
|
|
Post by martinm on Jul 16, 2019 5:02:16 GMT -8
Hello Planning on single bell Batch box rocket stove. On site we have 50 cm drop between concrete base, on which the stove would be build and finished floor. Considering this and the option to build more ISA by building on top of the concrete base (underneath there is basement which could also be heated a littlevia the concrete base ) I am exploring the option of having lower exhaust exit flue , while having the heated bench on top of the finished floor . I have seen Peter experimenting with three barell rocket stove which apparently worked OK having such drop between the fire box and the lower exit. On MHA meeting I have also seen the two bench model of a stove where there was a baffle inserted on the way of gasses to better the flow. my question is : what should I consider or design to be sure that the heated bench will extract heat in this layout . drawing is schematic ! Any thought and shared experience would be highly appreciated . alchemyarch.files.wordpress.com/2019/07/2019-07-16-11.09.36.png
|
|
|
Post by martinm on Jul 10, 2019 1:29:12 GMT -8
Nice Looking . love the adobe blocks . Few questions : your firebox looks white - did you use insulating firebricks or some other composite insulating mtrl? I see in the middle on the wall an insulated pipe ? is this where the heat exchanger is ? did you use it for thermosyphon type of water heating ? regards
|
|
|
Post by martinm on Sept 9, 2018 0:14:30 GMT -8
Hello I am working on plans for a double bell masonry heater with a batch box. Intention is to heat a two story woodframe house ( 2 x 65 m2). House is designed with stove centrally located on first floor , adjacent to the wall of a staircase. Unfortunately my friend (and client ) resisted with the idea the mass heater to be fitted with a water heat exchanger , similar to this one: heatkit.com/html/lopezs.htm so we could heat the second floor with hidronic radiators. Instead my frend insisited that "we should keep it simple " and instead of hidronic transfer of heat we should think about transferring heat to the second floor with air ducts- somehow .... here is my last update before the idea for the ducts : donkey32.proboards.com/thread/2171/double-masonry-heater-suggestions-welcomeI am not confident that ducts are good solution. I would appreciate any input and info on systems - mass heater , coupled with ducts carying hot air to other floors spaces. Regards Martin M
|
|
|
Post by martinm on Nov 8, 2017 14:20:12 GMT -8
Help needed! we are few "rocket builders" and we will have a meeting with the local government staff in a major city in eastern Europe, presenting them the concept of rocket stoves. The reason for such mission is that there is need for teaching people in poor neighborhoods to use efficient stoves. I need reliable data on emissions of rocket stoves and emissions + efficiency comparison with typical "traditional'' wood burning stoves. Our aim is to start staging workshops and show and build few simplified versions of efficient wood burning stoves (doesnt have to be the typical gravity fed - and barrel on top of heat riser + bench design. The main concern of the local authorities is the polution from the stoves of poor people burning anything in whatever stove they have a hold on. Climate here (Bulgaria) is moderate and some pooor people are entitled for government assistance for heating in form of certain amount of wood for heating. Will appreciate any input. W here or via email : martinmikush@gmail.com. thank you
|
|
|
Post by martinm on Jan 8, 2017 23:45:34 GMT -8
Thank you Peter !
I will change the scheme accordingly . I was also thinking on reducing the "second bell" to size which makes it an updraft channel. Many reasons for that. The reason to decide on the bench not to be a cross-flow channel was the fear that such channel so close to the first bell will heat too much and too fast, perhaps by adding more mass - double brick skin, adobe render on top and by building a wooden grate on top of the bench for sitting will mitigate such effect. And I have to definitely insulate the back wall , particularly important is in the area of first bell. Couple of years ago I built an oven which hearth stands on wood beams - similar situation but in horizontal direction. I added few layers such as perlitte , aluminum foil and light cob. I know how to do it it will be more difficult since it is vertical and bigger area. adding Lightweight refractory bricks would be nice but more expensive. Have to think about it. The reason to place small oven on top of firebox - white oven means some can bake while fire is going on and it stays clean. Black oven could be used only after full cycle of burning fire inside . Masonry heater builders have good examples of small ovens which are fed with fire from the firebox underneath, but that makes sense when such oven is slightly bigger and needs more precise brickwork.
The house is two story = it is a small one but we need to think of heating the second floor. I am thinking on adding heat exchanger in the updraft channel or somewhere in the first bell and heat water for gravity fed water heating system for the second floor. Saying gravity fed - I have to be sure to make it in such way that no boiling could occur, therefore such heat exchanger should be further out and away of the heat riser discharge.
and yes - I may consider 8" system dimensions.
|
|