podcast 459 - Annualized Thermal Inertia Test

Would a rocket mass heater have any downside in a Wofati? Is it for purity of the experiment that you are going without a heat source entirely or is the design somehow incompatible with a RMH?

Ask me that again in about three years.

Some partial fractional solutions / ideas :

I'm working through a similar design problem.   I'm trying to estimate how much external heat (or cold) a space will require.

I accidentally figured this out by running a propane heater in the space.

If a 4k btu / hour heater heats the place, it's losing less than 4k btu /hour at the current temperature difference.


The heat loss equilibrium would be  heat_added =  heat_lost_to_environment + heat_put_into_the_mass + heat_added_to_the_wafati_envilope.


If the wafati human envelope is at a stable temperature, and the mass is at a stable temperature then the result is the amount of heat lost to the environment at that temperature difference.  ( it gets complicated because there is air and ground temperatures to deal with, ignore it for a bit ).


By finding several equilibrium points with different amounts of added heat, the system should be characterizeable.   If there is measurement of how many BTU is required to change between equilibrium points in mass temperature, that should be usable to help inform how many BTU are stored ( and thus available for use later ).


Also,  If I had my maths with me ( I forgot them long ago apparently ),   The shapes of the curves in the temperature graphs would help : e.g.  https://permies.com/t/180/120233/permaculture-projects/Jen-Boot-Camp-Allerton-Abbey  https://permies.com/t/120233/a/96786/F5DF010F-A925-4E0B-BEA5-664886DA0EA7.png ,   The Un heated temperature graphs show a logarithmic decrease.   They should be asymptomatic to the temperature of whatever is driving the system ( presumably the mass and energy losses to the cold cold outside ).  


The front wall clearly shows this sort of shape : https://permies.com/t/120233/a/96787/0D2EEB72-EC99-4555-9D23-C31D4FEDE5E7.png   Though it's probably responding to the outside temperature more than than the thermal mass charging.


Is there a temperature sensor in the floor?

Is there a reticence to using temporary portable propane or kerosene heaters?   If the voltswagon isn't doing anything  3kw of solar turns into 10k btu of heat with an extension cord and a resistance heater.  ( just don't run it on the batteries cuz' it's abusive ).

We should be able to math this out some.... humm..

I haven't finished reading your post and I need to comment on the propane heater.   I have two big concerns:

    - it uses up the oxygen in the space (and i am also concerned about the invisible exhausts)

    - it puts a huge amount of water into the air

Is there a temperature sensor in the floor?

Nope.

I feel like we did good to scramble to get the tracking thermometers that we do have in operation.  

Is there a reticence to using temporary portable propane or kerosene heaters?

There it is!  Yes!  See my notes above.  

Mostly, my feelings are that I would like to have the mass fully and properly charged.   And then do the REAL ATI test next winter.  At the same time, I very much like seeing the abbey get better prepared for next year with window quilts and the like.  

In the meantime, if we are going to explore adding a heat source, I far prefer something wood based rather than something petroleum based.  But I do think it is quite excellent that the mass is not  charged, but just people living in there and doing some simple cooking is doing pretty good.   I would like to see something much warmer, but as we add heat, the mass will pull it out of the space - as it is designed to do.  

I guess what I am saying is that I think we can simply dodge a heat source.

If the voltswagon isn't doing anything  3kw of solar turns into 10k btu of heat with an extension cord and a resistance heater.

The voltswagon ...  I am kinda wondering if the thing we need to consider is something a bit different.   The voltswagon has issues.  I wonder if the plan could be to take out the six year old lead acid batteries (which do poorly in the col) and the inverter that takes a lot of power even when nobody is using power ...   and replace all of that with a tesla powerwall.  We could even pop it down to basecamp and charge it up, bring it back and we could run something with a bit more power for a few days - if needed.

paul wheaton wrote:I haven't finished reading your post and I need to comment on the propane heater.   I have two big concerns:

    - it uses up the oxygen in the space (and i am also concerned about the invisible exhausts)

    - it puts a huge amount of water into the air

No worries.   The oxygen issue (e.g. killing things with lack of it ) can be solve by the Mr. Heater  Big Buddy  it's got an low oxygen shutoff.  Maybe not something to _only_ trust, but it's something.


The water might be the solution to get the mass more charged.

A pool heater, that circulates warm water around coiled tube inside the wafati.    ... They seem to be costing in the kilo dollars. well fooie on that.    a home brew solution might work well enough temporarily enough to charge up the mass.

...

The volts wagon.   It might be possible to hook up a heater (or some lights) without the inverter or the batteries.   (depending on the details of everything)  A dump/diversion controler => 3k worth of lights or resistance ; done. ( :) )

....

The power wall will be something like $10k ( and they _really_ might not like it being used as in a mobile installation ), for 13.5 kwh .   13.5 turns into about 46k btu, and each round trip is going to take 3-4 hours.  I'd guess the cook top is doing more.

....

heat water with the cook top?    That might help the heat transfer better... maybe...

....

5kw of propane generator (outside) and a bunch of halogen lights (inside) ?    It's temporarily icky, but might be worth it for science. ( and the cheapest/ simplest/ fastest solution ) .   And I can see not being happy with that one; I'm not.

...

Tank hot water?  Is there a large hot water heater on the lab?   a 55 gallon barrel of water at 210 degrees has about 50k BTU usable in it.     4 of them might be a good start, though driving that stuff around is going to be dangerous and getting it all moved around is going to be burn inducing.

...

That being said, it's a good problem to solve.    having to wait 3 years to _realy_ get a place happy is a larger ask for the general human populations.

...

Build the sauna.  Put it down hill of the floor of the abby.   Add some water heating coils to the sauna heater.   Thermosyphon up to tank(s) in the abby.    Daily sauna activity.  ?    

...

As a first data point it's probably a good idea to start recording wood weight.  It'll put an upper bound on BTU required to increase the air temperature in the space.   Adding more BTU than that number is just going to be wasted.  (Should! hA!  I almost should'd Paul, I need some sleep I think).  A week or two of watching the temperature loggers and recording wood weights, we can go back and get the temperature rises per weight of wood.    Two burns a day, one when it's getting warmer and one when it's getting colder ( and dark) would be helpful.  Is there an exhaust gas temperature for the typical burn on the cook top?  ( getting an approximate idea of cook top thermal efficiency might be helpful too ).  

...

I'll ponder it more after some sleep.

Good luck with it!

tesla power wall - I got the impression that they are about $7000.  And they supposedly will do fine down to 4 degrees.   It seems that the the thing to do, for a portable solution, is to have them in a super, tiny insulated room with an incandescent light bulb that comes on when temps are below 20.

Out of all of the solutions that you listed, the one that seems the quickest and I am the most comfortable with would be the propane generator and a conventional portable electric heater.

BUT!

I think the best thing this year is a series of simple, indicative tests.  

Even if we ran the generator for a week, holding the interior temp at 85 degrees F for a week and then observed what happened in the following weeks - all of that would still be nothing more than indicative.  

The real test is a year from now.   Hence the challenge with "annualized" - it takes a year to do proper tests.

If we had more people in the bootcamp the last few years, we might be two years ahead on this testing.   Which is why I have placed so much emphasis on the bootcamp and the BRK for boots.

paul wheaton wrote:tesla power wall - I got the impression that they are about $7000.  And they supposedly will do fine down to 4 degrees.   It seems that the the thing to do, for a portable solution, is to have them in a super, tiny insulated room with an incandescent light bulb that comes on when temps are below 20.

Out of all of the solutions that you listed, the one that seems the quickest and I am the most comfortable with would be the propane generator and a conventional portable electric heater.

BUT!

I think the best thing this year is a series of simple, indicative tests.  

Even if we ran the generator for a week, holding the interior temp at 85 degrees F for a week and then observed what happened in the following weeks - all of that would still be nothing more than indicative.  

The real test is a year from now.   Hence the challenge with "annualized" - it takes a year to do proper tests.

If we had more people in the bootcamp the last few years, we might be two years ahead on this testing.   Which is why I have placed so much emphasis on the bootcamp and the BRK for boots.

Totally fair and right.  

My understanding with the power walls,  $7-8k cost, + installation ~= 10k.

( I just found these) Slightly better than strait propane would be something like a cozy cabin propane heater, they are sailboat heaters that send flue gasses out the chimney.   Neat!

Also, they make the same thing but for diesel.   Diesel heaters : flue gasses go out and the heat stays.    And diesel. :/

These are probably both cheaper / better than a generator and lights, but would be more single purpose tools.

And yes, artificially loading up the mass is testing, and possibly testing things that are not the most important.

Good luck!

> [keep batteries at a good temp]

Put them in a vault in the ground below frost line. Insulate the top of the vault and the top of the hole (because you're not going to backfill and that space above the vault will want to follow out door temps). Wire as needed. Beware ground water.


Regards,
Rufus

What about a portable rocket that heats liquid that travels down flex pipes to send the heat into the abbey?  Could be used for all kinds of heat needs around the lab...

https://permies.com/t/131988/Portable-Rocket-Space-Heater

i use to use a gas engine attached by belt to a truck alternator to charge my battery bank (36 volt golf car with custom built wires and anderson connectors to quickly change from 36 volt to 12 volt and back again) that was a mobile battery bank, also had a solar panel on its roof.

back to the gas engine part. i had a stainless steel pot with a hole in the side with some broken fire brick inside to hold another stainless steel pot above the hole inside the first pot . the outside pot sat on a concrete block to give it the correct height to run a piece of pipe from the exhaust pipe (the muffler had a small pipe exiting the gases)
this allowed me to heat water in the inner pot (with  a stainless steel lid) with the waste  heat from the engines exhaust!  we lived in a camper in rural south dakota for 3 straight years. minus 30F temps.
we used a M1950 (extreme tent heater) surplus wood stove to heat the 2000 year model 31 foot long camper with a 12 foot slide out. the stove is a real piece of crap but will burn not only wood, but also gasoline fed from a jerry can. i never used anything but wood in it. i went through 2 grates in just 1 winter burning the maple flooring i scrapped/salvaged from the old house on the property that needed burning down because of the raccoons living in it. the lack of air tightness would cause the thermometer on the wall of the bedroom (at opposite end of the trailer) to reach 105F around 2am with -30F temps outside. i would throw both doors open to cool the trailer down, even in a blizzard!!

engineer775 has an old video on youtube about endless hot water. if i remember correctly it uses a rocket stove to heat water in a copper coil . cold water in and steaming hot water out!  and it also used a hot water tank for the storage of the hot water.

i also use to buy 35 yard dumpsters of lumber scraps and sawdust mixed from a garbage hauler that got it from a TRUSS FACTORY, i think i paid around $185 for it with delivery. lots of 2x materials even up to 3 foot long. i used a screen made from chicken wire at an angle to remove the small pieces of wood from the saw dust, would store these in plastic bags i got from a neighbor (wood pellet bags) and burn the small stuff in the M1950 , just throwing the chips in by hand, leaving the lumber for when my wife  was feeding the stove. a person could actually lay the lumber scraps flat and nail/screw them down to build a house with 3 1/2 inch thick solid wood walls (article about this in an old mother earth news magazine. i got 3 foot long 2x12 in those dumpsters too.

thought this info might give you some ideas on heating allerton abby with hot water. if a person were to put hot water lines in the soil battery portion when constructing the wafati using big rolls of PEX pipe, the heat battery could be charged even with a solar water heater using thermo siphon to pump the hot water to the top and gravity flow back to the heater, to charge it during the summer months.

the university of iowa published a 8 1/2 x 11 paper back book in the 1970s with ways actual old farmers were getting free heat and electricity etc.. one dug a big hole where his shop was going to be and filled it with large rocks, then built his shop on top, on a slab. he built a solar air heater and used a fan to blow the heated air down to heat those big rocks , then in winter they heated  his shop by circulating air around those rocks and blowing it into the shop

another used old iron edison batteries from a train and a wind generator for his electricity , he was in his 80's and HAD NEVER HOOKED TO THE GRID IN HIS 80 SOMETHING YEARS!!  lots of good ideas in it that actually worked and low cost DIY

paul wheaton wrote:Ask me that again in about three years.

Your three years are up.  :)

So how did it all work?  There's 38 pages in the other thread which is alot to catch up on and I wasn't sure if that's the only thread on the topic.

We have been short handed these three years.  There have been some improvements and some tests.  I would like to see some bigger improvements and some very solid tests.

At the 58 minute mark on the podcast, it was mentioned that there was condensation, that some of it froze on the windows, and it would likely be better if the temperature was closer to an even 70, rather than the 50 it tended to be the first year.  It was mentioned perhaps to put a dehumidifier in there and run it off the volts-wagon.  

I have a thought inspired by these two videos.  This engineer experimented with making a desiccated air-conditioner.  The idea was to dry the air by blowing it through water drops saturated in Calcium Chloride (used as a food additive or de-icing sidewalks, etc) which absorbs humidity.  This raises the temperature as it drys the air; you have a different setup to do a swamp cooler effect to cool it.  

But, elements can be used from this to just dry the air.  I was thinking of trying something like this, a different element in this system, to evaporate sap to make Maple Syrup.  

He shows you can run this just off of solar, and there might be a way to just run this off the wood stove.  

Edit: (This is a recognition to make this post more useful, a brief description would cut down on a lot of time)

The mechanics of this is basically three tubes with air being blown in from the bottom, and water droplets being dropped from the top of the vertical tubes.  

One tube would have air coming in from your living space, and have water saturated with sodium chloride at about room temperature.  When the air passes the droplets humidity is drawn out of the air.  This also has the effect of warming the air, because water vapor is condensing to liquid.  

The second tube could have normal water dropping through the air from the first tube with air dropped to room temperature, which would cool the air like a swamp cooler.  

The third tube would be outside, and have the diluted water from the first tube to heat it first, either by a solar panel or perhaps a wood stove, and use outside air to take the moister away, thus leaving the sodium chloride solution less diluted.  

It was the first tube that I thought would be good for using as a dehydrator for the Wofoti, and the third tube to complete the cycle for the water.  

It was this third tube that I wanted to think about doing it for Maple Syrup.  I think it would take a lot less wood thank a conventional evaporator.  

This is just a rough idea what the videos show.  I am probably making an error somewhere.  


https://www.youtube.com/watch?v=R_g4nT4a28U&t=580s

https://www.youtube.com/watch?v=7w4rg3UcsgI

Well it's all interesting.  I wish there were examples of houses using the annual storage technique that we could see, i haven't been able to find any online, strange.  Hopefully you get yours working. It sounds like you dont really have insulation in the roof, it wont work until you get that straightened out.  Thats very well your biggest heat loss zone.  If your woods have deciduous trees, you could rake up piles of leaves and pile them on top the building for now.  I'd get a cheap roll of painters plastic and some tape and cover over those windows just for a simple temporary solution for your window problem.  I'm wondering what the humidity range is you are experiencing and if vapor barriers were used in the walls and floor.  Fungus growing on a wall is not good, you might have a leak.  My biggest problem with the oehler type construction is this very issue.  A simple design change could easily eliminate the worries of wood rotting on the walls, you are worried about air quality from smoke, what about air quality from mold.  I appreciate what y'all are doing and salute your efforts and especially your honesty about what's really going on.