Remember that "cotton is rotten". Make sure none of the donation clothes coming in are cotton. Cotton soaks up water like a sponge and then that water gets cold, sapping your body of heat. If you sweat, cotton will absorb it and keep you cold.
There are a few elements to staying warm in a survival/homelessness situation:
Avoiding evaporation
Stopping airflow
Generating heat
Trapping heat
Evaporation kills attempts at staying warm. Things need to be dry or you're just swimming upstream constantly. Spare layers of clothes help as do waterproof layers.
If you have a team and some resources, this method to produce waterproof tarps is ideal. You can use this as a shelter, as a cloak, or as an outer layer for bedding.
Stopping airflow is tricky and it's very contextual. Layering up clothing is a big factor here.
Generating heat is rightly emphasised but I think it's somewhat overemphasised. Unless you have taken efforts especially to prevent things getting wet and thus evaporating and to mitigate drafts, generating heat can require a ton of resources. Bodies themselves generate a significant amount of heat and ideally you want to trap this as your primary heat source since it's just the cost of doing business for mammals. You can get fairly cheap yoga mat-like material that has a layer of foil (I'm guessing it must be Mylar) and this is going to go a long ways to reflecting the radiant heat that is generated back to your body rather than allowing it to be absorbed by the ground. Emergency blankets are also really good at doing a similar thing, although they aren't very durable.
Trapping heat is what tends to get overlooked. There's the reflection of heat, as described above, but developing ways to store heat is an important consideration. Unfortunately materials that work as heat batteries are heavy and bulky. One exception to this rule is stuff that relies on a chemical reaction like sodium acetate, although I'm no materials scientist so hopefully a person who actually paid attention in high school chemistry and physics will chime in here.
a rocket stove type design
Don't take this personally because it's not aimed at you but rocket stoves are so fetishised by certain groups that it drives me to distraction. There are certain design principles necessary for a rocket stove to be a rocket stove and most of what you find being referred to as a rocket stove is just something that is a J-tube.
Honestly I don't think that a true rocket stove is the right option for people who are homeless because they require a significant amount of space and they are heavier than an alternative like a wood gasifier stove that almost certainly archives an equivalenly efficient burn in less time as it doesn't require the burn chamber to reach a high enough temperature in order to achieve recombustion. A wood gasifier stove isn't bound to the same design principles that require a rocket stove riser to be rather high and as they do not require insulation, they are much easier to disassemble and pack down vs a rocket stove.
Don't be an asshole about it with people who are trying to do good work but the next time you see someone touting a rocket stove ask them about the ratio between the diameter of the burn chamber and the length of the riser or what they are using as the insulation and you're going to get blank stares like 75% of the time. This is bad news because a poorly designed "rocket" stove burns inefficiently and the riser will develop a creosote buildup that will become a fire risk over time, all other considerations aside. You also see people wrapping heat exchanges around the burn chamber of rocket stoves which further reduces the efficiency of a "rocket stove" in the most infuriating way - it's like driving while your parking brake is on.
I am consistently impressed by your posts.
There are certain design principles necessary for a rocket stove to be a rocket stove
Yeah honestly I don't think a rocket stove is actually what I meant to discuss here anyway. It might have been a rocket mass heater that we were discussing, although we also discussed trying to employ ondol heating which might be a bit easier.
Admittedly, I need to read more on the pros and cons of all of these options. Just wanted to check with people here to see if there was anything else I should explore - or if people have had experience with these projects in the past, what pitfalls to avoid.
Thanks for your taking the time to write this all out, it's helpful.
It's really hard to say without knowing the conditions of the people you're targeting for aid but ondols, kangs, and rocket mass heaters are a really good solution for creating thermal mass to use as a thermal battery but they are also quite permanent so its much less suitable as a solution for people who are homeless/housing insecure that are more transient (i.e. compared to living in slums or shanties which are permanent or semi-permanent.)
If you are intending on using this sort of heating method for people who are unfamiliar with safe operating, a rocket mass heater is going to be the safest based on the fact that you are able to build this above-ground as opposed to it being underfloor. (Kangs are usually raised platforms but due to construction there are specific considerations for fire safety so I'll put them aside for simplicity's sake.) The only caveats are that a rocket stove needs to have a clear outlet free from combustible materials nearby. For people who are unfamiliar with operating a rocket mass heater who may have impaired judgement due to things like severe mental illness or substance use disorder, I would strongly advise having a straight exhaust as one which curves creates corners that creosote can accumulate upon. Suboptimal operation of a rocket stove will also create more creosote. Straight exhausts are far easier to clear and to visually identify when there is buildup. Realistic worst case scenario you're probably going to have is the exhaust shooting out a few feet of flame as the built up creosote ignites so you want clearance especially with suboptimal operating conditions and a lack of routine maintenance.
For transient populations, it's going to be about what is most portable - so stuff that is lightweight and ideally that packs down or can be easily disassembled and reassembled.
For permanent and semi-permanent populations things like cost and safety of longer-term operation become much more of a consideration.
I'm not sure what the weather is like where you are but if you're only in the early stages of planning I think you might have left your run to late for making a rocket mass heater that uses cob as the thermal mass. I'm assuming that you don't have a location picked out yet and that this is an org that meets once or twice on the weekend before everyone goes back to their day jobs but at a very optimistic timeframe it would look like everything being settled this weekend, including site and sourcing inputs, then the next two weekends constructing with it being ready to go by mid-January. That's assuming that everyone is happy with working through Christmas on this too.
I'm presuming a level of familiarity with cob construction and rocket mass heater construction. If it's a first time job it could easily take an extra couple of weekends. So I'm not sure exactly where that would leave you with regard to the viability of the project and your time frames.
I've never fired cob directly after construction. I would assume that it wouldn't be catastrophic but you could expect to see larger, structural cracks in the cob mass as it dries rapidly due to heat and the inner parts contract much faster than the outer parts. The temp of a rocket mass heater can reach vitrification levels so I'm unsure of the implications of this for the structure of an uncured cob mass - generally speaking cob is easily repaired with patching it however if uncured clay begins to vitrify when it's right beside the burn chamber it might not be so easy to repair and I'm not really sure where to look to find out if anyone has attempted this or what the short and long term results from it would be.
Cob also takes a surprising amount of effort and inputs. I'd strongly recommend using a small cement mixer to make your cob because otherwise the labour input will be very high - this is fine if you have a lot of people and the weather is decent, especially if you are building a lot of walls so you are limited by how high each layer can be constructed before you have to leave it to cure in order to prevent sagging but it's less ideal if you are trying to turn out a rocket mass heater in one day.
Do you know the soil composition of the site that you're considering? This is going to be a major factor with costs and logistics. It's not uncommon that you will need to source one of the two main parts (either sand or clay) to get the ratio right. If you are planning on using what you have on hand then it's possible that you're going to want to use a backhoe or mini excavator to save a large amount of time that digging below the topsoil would take to do manually but it depends on the size of the project and what you have access to including labour power.
Sorry to be a downer about this. I really like cob construction - I'm a big fan of it, although the skin on my feet is too delicate (probably EDS skin) and whenever I've made cob traditionally I always find that any small stones or pebbles end up tearing up my feet so this probably my one and only true complaint that I have about cob lol. It's really not like me to try and ruin someone's enthusiasm for it.
(Ooh look at me! I'm not just a grass-toucher, I'll even brag about having touched dirt!!)
Edit: I completely overlooked my assumption that this was intended to be constructed indoors or, at the very least, in a well-sheltered location (because I figured ondol = inside a home or sheltered location).
If this construction is intended to be outdoors or in a place which is only partially sheltered then it's going to become a lot more complicated and, honestly, unless you are pretty familiar with cob construction I'd just advise against it.
Cob can be used in outdoor construction and it can work well however it comes with significant considerations about the local conditions. Outdoor cob construction in areas that have high groundwater or on low elevation like, idk, Florida sounds like a disaster for outdoor cob construction except if you built on a relatively high elevation for the local area on a site that had sufficient drainange (this is well outside my wheelhouse). Heavy rainfall is going to kill it except under certain circumstances that would take a lot of effort to describe but if you are unsure about this then take it as your sign that it's a bad idea because its really not for beginners. As for areas that get any significant amount of snow this, too, is outside my wheelhouse. My hunch is that unless the rocket stove is being operated on a daily/near daily basis that snowpack piling up on the stove could cause serious problems with getting the exhaust to draft and getting it up to optimal operating temperature - not impossible but unlikely that it would be an easy task and unlikely to be something for beginners. As for snow melt and the damage it could do to a rocket mass heater, again that's way outside my knowledge but it's possible that it could destroy the cob mass, requiring either a major repair job or even a complete teardown and rebuild. Hard to say for sure and it's never something that I've had to consider so this is just speculation.
I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy:
Wool blankets at army surplus stores are heavy. Also places that buy stock in bulk and sell it cheap like big lots or ollies, I've seen some mr buddy heaters there etc.
Yo yo yo I am homeless so I am probably the best person to ask.
First and foremost, the things they’re saying they need are the things you wanna go with. You can also get these little camping stoves on Amazon for about $5.
Cash is really useful because many of us need to buy certain things every day in order to stay well, and it’s nice to have a break from having to hustle and break our backs every day.
But also, cash gives each of us the independence to buy what we feel best suits our needs. Idk if that’s scalable of not/feasible for your group.
Of course, the people living there know best what they need, and with their current setups they mostly need wood for their stoves, or fuel for their generators, which are running electric heaters. But not all of them have stoves or generators.
So Generator -> Electric Heater is incredibly inefficient. People are likely doing this because it's all they have and they want to charge their electronics. If you want to provide equipment I would suggest:
This will allow them to connect to a standard propane tank. This setup is incredibly cheap to maintain esp. if they have access to a Amerigas/Rhino propane exchange or propane fill-up station. The buy-in here is around $140 per tent but you can get it down cheaper if you get a generic hose. The maintenance cost of exchanging/refilling the propane. On the 4000 BTU burn, this can last about half a month with a standard 20lb propane tank and should be more than enough to heat a tent. Monthly this has a cost of about $40 depending on how much propane is locally. Since the heater is radiant it's heating the person / objects in the tent not the air meaning it's incredibly effective.
This setup is really beneficial because it's easy to adapt to different living circumstances whether you're in a tent, a car, etc. In a pinch it can keep you comfortable enough in a single-wide too.
If you guys want to build something, reducing fuel costs during the day can be achieved by building a solar collector
Check out this diy thermal battery. The guy shows a cooling setup first but there's also a heating setup. Pretty cheap to make lots of the material, not 100% sure what the best way of putting it into a blanket would be, but something to get you started.
I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy:
running a generator and electric heating is dramatically inefficient. only advantage is no carbon monoxide in the tent/structure, but it doesnt take a ton of airflow to keep that from being a problem with propane, and any reasonable wood stove also doesnt have that issue. plus monoxide detectors are like $3 on aliexpress if it becomes an issue. propane can be a bit scary (tent fires and tank explosions) in an encampment scenario but it beats freezing to death certainly
is it a tent situation primarily or are there other structures that can more readily be insulated? even just a shitload of blankets makes decent insulation if done well
also all depends how harsh the winters are there.
I've seen a zine online of how to make a yurt with a woodstove for exactly this use case. but that doesnt eliminate the need to provide insulation (a tarp layer or two and then blankets mostly) and firewood. the advantage there is it can house a few people per so they can share heat, and its a much sturdier structure than a tent and is designed around the wood stove so it doesnt catch on fire.
edit: here's the zine: https://files.catbox.moe/1t9148.pdf
if there are more permanent structures in place those RVing diesel heaters might also make sense but might not be cheap enough/trivial to set up.
is it a tent situation primarily or are there other structures that can more readily be insulated?
A mix of both, but probably mostly tents. I think the generator provides electricity to multiple tents so that's the main advantage, plus it being the only option really for folks who don't have wood stoves at the moment.
yeah... tents are kinda troublesome, they're not very resistant to heat, embers, etc so I have a hard time recommending wood stoves if the structure theyre being used in is camping tents.
but I do suspect that providing wood would be much more cost effective in the long run than gasoline.
building wood stoves to the extent that people have structures that can safely accomodate them might be worthwhile but whiz bang stuff like rocket stoves are not it for an encampment in my opinion, too much complexity for something that might just get tossed by pigs next week, all to save a little bit of wood which can often be gotten for free
the yurt zine is cool, but a big project depending on the size of y9ur org. I could probably find the group that made it, they are doing similar work it sounds like to you. And their stove design is dirt cheap (half a barrel and 5 pieces of stovepipe)
If they're typical silnylon camping tents wood stoves are a huge risk.
You can safely use wood stoves for canvas tents as long as you get a good stovejack, they make great silicone ones now. The problem is that canvas camping tents are typically cost prohibitive for most homeless people.
yeah I guess I should have been more explicit about that. its no good, very unsafe. But other types of structures can accomodate wood stoves with some effort
Handwarmers are good in a pinch. Carry some in your car if you got one and pass them out if you see someone out with a sign. It's a useful thing when stepping out for a bit.
Sounds like their encampment is better than some in my area, wood stoves and all that.
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