Heat tiny home with mini split year round in cloudy oregon?

[AntronX]

But you want a hot chimney to cut down on creosote and I’m averse to wood-fire exhaust heat recovery.

That would go against the idea of efficient wood energy recovery. Maybe a more complete combustion would help reduce creosote buildup? Using dry wood chips with propane burner assist? Another way to prevent creosote chimney fire is to place temp sensors that would detect it and automatically cut off air supply to the stove.

 

[oregonsun]

All my stuff for the mini split has arrived, about to start the install, but now I'm shopping for more batteries so I can turn it on once installed.

I'm debating either getting more amperetime 12v200ah which are below $700 now and eg4 ll which are still at a bit of a premium. Are the cells better in the EG4? Will their UL listing be of benefit when I get around to restoring power from the grid? They could pass inspection, but my amperetime won't?
I do intend to keep using my solar even after grid power is back, I'm guessing it would be nice to have it all legal parts, or would it matter?

I would consider DIY, if there were crazy savings and just installing them in my RV so legality is off the table, but it seems the prices have gone up and the gap between DIY and amperetime is not that great any more? I have the 10k of amperetime, I need 10k to 20k more, what would you guys do in my situation?

 

[12VoltInstalls]

Maybe a more complete combustion would help reduce creosote buildup?

That takes a secondary and final ‘burn’ - three stages in a masonry firebox assembly - to combust the residual gasses. Very efficient.

I view not scavenging chimney heat like I view idle consumption from the inverter running my fridge: the cost of another panel or two overcomes the ‘loss.’ The unburned energy that goes up the chimney in comparison to the low cost of a few extra chunks of hardwood isn’t a significant expense.

A good, hot fire from very dry hardwood will not creosote buildup in a chimney. Some would say (and have), “you don’t want over dry firewood because it burns too fast” but it only burns slow (and much cooler) because of the moisture content that 1) soots a chimney, and 2) reduces heat output greatly.

Learn how to run the damper, and burn dry firewood. That’s less cost in dry wood (2 or more full summers dried) than burning ‘seasoned’ wood and cleaning constantly or having a chimney fire. Same goes to harvesting chimney flue heat imho. Ymmv

That would go against the idea of efficient wood energy recovery

yes. and no.

That small amount of ‘wasted’ heat is just part of the cost of having safe, renewable, cost-effective heating.

 

[AntronX]

I been reading about catalytic combustors and they say 30% of wood energy gets wasted via unburned wood gases going up the chimney and contributing to creosote buildup. A catalytic combustor burns up these gases releasing heat and cleaning up exhaust so no smoke comes out and a lot less chimney fouling. They cost about $200 and last 12000 hours. Assuming 24 kbtu (7 kWt) average furnace that's an extra 25.2 MWh of heat from $200 investment and the benefit of cleaner air and chimney while saving 10 thousand pounds of firewood. That comes out to 2 cents per pound of avoided firewood expense. Quick googling returns dry split and seasoned firewood cost of 5 cents per pound. So it makes financial sense to run an efficient furnace and to try conserving firewood. And extra benefits are much less harmful emissions into surrounding air.

 

[curiouscarbon]

That takes a secondary and final ‘burn’ - three stages in a masonry firebox assembly - to combust the residual gasses. Very efficient.

I view not scavenging chimney heat like I view idle consumption from the inverter running my fridge: the cost of another panel or two overcomes the ‘loss.’ The unburned energy that goes up the chimney in comparison to the low cost of a few extra chunks of hardwood isn’t a significant expense.

A good, hot fire from very dry hardwood will not creosote buildup in a chimney. Some would say (and have), “you don’t want over dry firewood because it burns too fast” but it only burns slow (and much cooler) because of the moisture content that 1) soots a chimney, and 2) reduces heat output greatly.

Learn how to run the damper, and burn dry firewood. That’s less cost in dry wood (2 or more full summers dried) than burning ‘seasoned’ wood and cleaning constantly or having a chimney fire. Same goes to harvesting chimney flue heat imho. Ymmv

yes. and no.

That small amount of ‘wasted’ heat is just part of the cost of having safe, renewable, cost-effective heating.

may i ask about your thoughts on wood gasification approaches?

 

[12VoltInstalls]

may i ask about your thoughts on wood gasification approaches?

Originally it was developed in Finland like 500? years ago due to the king’s decree because of the wood shortage at the time. I think they did 4 or 5 stages of “burn” where a large central masonry ‘oven’ would be used for a short extremely hot fire in the morning and the masonry would radiate the heat throughout the day.

This type of wood heater today is commercialized under the brand name, tulikivi https://www.tulikivi.com/usa-can
Unfortunately, the several excellent resources on building these and their historical development that were easily found on the internet in the 90s have disappeared from availability following the globalizing of the brand name of the manufacturer. It’s not their technology, however.

Gasification was used to run internal combustion farm equipment in the early 1900s btw, with much use during WW2.

The ‘three chamber burn’ I referenced is essentially a gasification wood heater. How they figured that out without today’s tech and reference blows my mind!
In process, the science of it is leaned on with modern wood stoves that use air tubes whose output stream is directed across glass-front doors and market as self-cleaning glass features- but in reality this increases the burn of secondary gasses although not nearly as fully as a three-stage burn.
A three-stage burn will achieve 2300*F at the final burn, the ‘wash’ air types may be only 1000*F or so- not much different than a ‘normal’ wood stove. Plus, I’ve seen the wash-air types when glowing super hot and ‘gasifying’ actually accumulate these super-hot gasses and when it is windy create cyclic positive and negative pressure on the chimney and then the sudden introduction of more air will combust the gasses in the stove and chimney (explode) and blow the mortared-in chimney thimble right out with a large sooty fireball across the kitchen ceiling resulting.
Yes, I’ve actually seen this happen.

been reading about catalytic combustors and they say 30% of wood energy gets wasted via unburned wood gases going up the chimney and contributing to creosote buildup

There is no doubt that catalytic stoves can be more efficient- but they have three faults that annoy me. One: you have to insure catalytic burn only happens once the firebox is like 900*F+ Two: the catalyst doesn’t last nearly as long as typical marketing claims. Three: even the ‘automatic’ designs are fussier than a 10kW lead acid battery bank. Bonus: the catalytic wood stoves do not reach the efficiency or overall high temperature of a true gasification/three stage burn.

I’m no thermodynamics engineer but the 30% and other claims I think are opportunistic market from an unrepeatable by consumer lab test.

]~~~~~~~[

And THAT is just about the limit of my knowledge.

 

[newbostonconst]

I calculated to heat my house in lower Michigan with mini splits and just solar I needed 3 times the size to do it all in solar. If you have Net Metering it might be better. Go Big or Go Home....cold.

 

[oregonsun]

I calculated to heat my house in lower Michigan with mini splits and just solar I needed 3 times the size to do it all in solar. If you have Net Metering it might be better. Go Big or Go Home....cold.

Three times what original size solar setup? I'm only trying to heat a single room, not the whole house.

 

[newbostonconst]

Three times what original size solar setup? I'm only trying to heat a single room, not the whole house.

It is a data point you could use to help you decide how much solar you want to add. If you want to do your own heat loss calculation to calculate the energy needed for your size house, age, insulation, and sun exposure have at it.

If you took the data point to that I gave you, that you might need 4 times the solar to heat your house compare to your normal electrical usage (because electrical usage does eventually all go to heating your house) so that is part of the equation. So say this room is 1/4th of your houses total size you would need potentially double the solar because 1/4 times 4 = 1.....have a good day.

 

[12VoltInstalls]

Three times what original size solar setup? I'm only trying to heat a single room, not the whole house.

I think his point is at higher North American latitude you find out in winter that you need 3-5 times the solar panels at a minimum to make stuff work most of the time not even all of the time. So scale that to your room BTUs

 

[oregonsun]

It is a data point you could use to help you decide how much solar you want to add. If you want to do your own heat loss calculation to calculate the energy needed for your size house, age, insulation, and sun exposure have at it.

If you took the data point to that I gave you, that you might need 4 times the solar to heat your house compare to your normal electrical usage (because electrical usage does eventually all go to heating your house) so that is part of the equation. So say this room is 1/4th of your houses total size you would need potentially double the solar because 1/4 times 4 = 1.....have a good day.

I was asking what size solar setup he has originally that he thought he would have to triple to heat his whole house, so there would be a data point I could think about.
3 x ????w of solar doesn't tell me anything.

 

[newbostonconst]

I was asking what size solar setup he has originally that he thought he would have to triple to heat his whole house, so there would be a data point I could think about.
3 x ????w of solar doesn't tell me anything.

You need to do your own heat loss calculation to figure out how much power your going to need...You want an answer to your question but yet you haven't provided any information you were told you needed, but yet I am the dumb one....

I tried to help as much as possible but you are asking an impossible question to answer...Good Day.

 

[oregonsun]

You need to do your own heat loss calculation to figure out how much power your going to need...You want an answer to your question but yet you haven't provided any information you were told you needed, but yet I am the dumb one....

I tried to help as much as possible but you are asking an impossible question to answer...Good Day.

I provided all the info needed in my first post, what info do you think was left out?
I also didn't call anyone dumb, I'm politely trying to get info from people who know more about this than me, but I will keep that option in mind sounds really productive to be a jerk to people.