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Post by burnclean on Dec 29, 2017 8:31:01 GMT -8
You've got a lot of mass (thermal storage) you aren't using. Fix the design problems and get the benches warming so you can store heat in them, you will get a much longer heat cycle. Also, that bypass is so high in your bell, I recommend not using it at all during the heating season. Thanks Matt. You're right. for some reason we thought the bell and chimney had to be much hotter in order for it to flow properly through the bench. previously if I closed the bypass when bell was lower than 300 F, it would have tiny streamings of smoke very subtle but visible, coming from top of bell. Now I closed the by pass and the bell is reading 100 F and it is functioning. Not sure if that was early steam off, or just some off gasings or something from mortar. Anyways heres some readings for today: now 31 F here, high of 42 today, dropping into high 20s tonight. We put our first batch in today, the bell reads 100 F, the bench 77, 72, 68 F (next to bell, mid bench, and bench tail respectively) Room surface temp about 60-62 as we get the fire going today. About 70 F floor/ wall surface temps within 4/5' of the bell. Lets see how hot I can get the bench today, as I will leave the bypass closed all day. When you recommend , do not use the bypass at all during heating season, is that another way of just saying "keep your stove hot" - because if the stove is out for some time and temps are cold enough, we definitely require the bypass to get it going - at least I think ! Our chimney is about 30' of brick give or take.
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Post by matthewwalker on Dec 29, 2017 8:56:02 GMT -8
In my opinion bypasses are useful for starts when the weather outside is warm and the stove is cold. If you have outside temps in the 30's you should not need the bypass regardless. A heater the size of yours should have plenty of thermal storage to go 24 hours between firings with enough left over heat to prime the chimney. I believe you have some design issues that need to be addressed. Smoke from the top of the bell should never happen in my opinion.
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Post by burnclean on Dec 29, 2017 10:09:47 GMT -8
yea, what's your exit temp (bench to the chimney)? That will tell you if you're using the mass. I'm not sure how to accurately measure that, as my chimney is so tall - will try the infrared laser at the top of the chimney and see if anything seems relevant. The outside is 32 F, the base of the chimney up to about heads height is 32 F, then the middle of the chimney is higher about 40, the top back down to 32, theres no noticeable smoke or vapors coming from the chimney. That was a bit earlier. Heres our current read out: 1pm 1.5 batches burned (burning) 37 degrees outside top of bell 188 F top of bench 85 F, 78 F, 74 F (start middle end of bench respectively) interior wall temps 75 floor temps 65 (raw cement slab) Overall comfy right now. I am getting ready to load another full batch here, and we are going to post some bench temps today.
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Post by burnclean on Dec 29, 2017 10:15:55 GMT -8
In my opinion bypasses are useful for starts when the weather outside is warm and the stove is cold. If you have outside temps in the 30's you should not need the bypass regardless. A heater the size of yours should have plenty of thermal storage to go 24 hours between firings with enough left over heat to prime the chimney. I believe you have some design issues that need to be addressed. Smoke from the top of the bell should never happen in my opinion. Okay now I have a better understanding. Yes when we were first test firing the weather was warmer outside than inside (haha) so im sure thats why we got tiny streamings of smoke or vapor from the top of bell. Now I understand that if its colder outside that wont be the case and you're right theres enough residual heat here. So now we are warming the bench ! Yes, our design could be improved but, there is some room for stratification under the bench, it could just be more, im aware of that...
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Post by matthewwalker on Dec 29, 2017 11:05:24 GMT -8
Did you build your core to Peter's spreadsheet specs?
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Post by Orange on Dec 29, 2017 12:47:50 GMT -8
the base of the chimney up to about heads height is 32 F is that temp of the chimney metal pipe or brick chimney or?
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Post by burnclean on Dec 29, 2017 15:25:01 GMT -8
the base of the chimney up to about heads height is 32 F is that temp of the chimney metal pipe or brick chimney or? It is an all brick chimney that was on the barn already, we were attempting to retro fit it with this heater.
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Post by burnclean on Dec 29, 2017 15:29:38 GMT -8
Did you build your core to Peter's spreadsheet specs? To my knowledge we are exactly to Peter's specs for an 8" system, including the ISA etc. Actually Brian and Joseph sort of brained this build, so I'll have to let Brian give any specifics there. Here's some current temps, I'm loading batch 4 today. Its 6:25 pm, Now 32 degrees outside. the top of bell reads 245 F the bench 116, 95, 85 F (going along the bench) the floor 77 F, walls 74-80 F range.
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Post by briank on Dec 29, 2017 16:04:15 GMT -8
I had the image of the spec sheet from batchrocket.eu/en/building#dimension saved in my iPhone and constantly referred to it during the build. All the dimensions are strictly according to Peter’s guidelines for an 8” batch rocket. (I think our riser was 60” while the specs called for 57 11/16”. Firebox is 12” wide, 18” tall, 24” deep, minus the 1 1/4” firebrick splits on the floor and rear wall.)
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Post by briank on Dec 29, 2017 16:14:45 GMT -8
the top of bell reads 245 F the bench 116, 95, 85 F (going along the bench) the floor 77 F, walls 74-80 F range. That’s the best ratio of primary bell temps to bench top temps I’ve seen from your rocket so far. I have to wonder if not using the bypass as Matt recommended forced a slower/calmer stratification of the hot gases in the primary bell and allowed the bench to fill/heat better.
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Post by burnclean on Dec 29, 2017 19:54:59 GMT -8
Here's a couple more stats from a couple hours ago, now the bell has cooled off a little I am getting ready to put in last batch. I would say these readings are from 5 batches today. It is currently 27 F / -2 C here. The read outs were looking like: 300 F / 148 C at the top of the bell BENCH temps read: 133, 103, 90 F / 56, 39, 32 C - going from closest to bell to tail of bench The room is really as warm as we would want it, any more would reach sauna status. The walls read 95 F / 35 C floors range from 70-80F, about 21 C Funny enough I don't have a proper air temp thermometer , which means I have to kind of guess the room temp which is really 75-85 F degrees its quite warm. My wife is saying its "toasty" upstairs this evening and that it feels like summer. Thats a little unnatural - but honestly I will not normally run it very very hot, I will just keep the room around 65-70 F and keep the chill off. Overall its incredible how efficient and easy it is to use this batch rocket. Truly a blessing. I think I will do some readings next week during the bottom of the lower temps we will get which is 13 F, or -10 C at the lowest in this time frame. These are the lower temps we've gotten yet this year and I'm sure more to come. Considering that I can make the room "uncomfortably" warm, I am pleased because I want to be able to off set VERY cold temperatures at any time. and I feel we've accomplished that ! Thanks I hope this is helpful...
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Post by briank on Dec 29, 2017 22:29:11 GMT -8
300 F / 148 C at the top of the bell BENCH temps read: 133, 103, 90 F / 56, 39, 32 C - going from closest to bell to tail of bench The room is really as warm as we would want it, any more would reach sauna status. The walls read 95 F / 35 C floors range from 70-80F, about 21 C Great numbers! I might be biased and I’m no expert and don’t claim to be one, but given those primary bell temps and bench top temps I’d be loathe to recommend any modification of this build in any way whatsoever at this point. I’d consider your 8” masonry rocket mass heater a successful build - including the operation of the bench. The only thing I’d recommend is to complete the skin of the primary tower.
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Post by Orange on Dec 30, 2017 0:46:50 GMT -8
well if it's an old brick chimney it's hard to guess what the temp on the inside is, you need a probe.
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Post by matthewwalker on Dec 30, 2017 7:08:50 GMT -8
5 batches in an 8" BB? This is an enormous amount of fuel, you should have much higher temps from that much wood in my opinion.
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Post by briank on Dec 30, 2017 7:53:31 GMT -8
5 batches in an 8" BB? This is an enormous amount of fuel, you should have much higher temps from that much wood in my opinion. Valid point. Hmmm...
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