No Propane!

[G Dub]

"Hydronic heating" is by definition Hot Water circulating/radiant heat. OK. So you're not going to use propane to heat the water, fine, you still need to make hot water. WHAT FUEL DO you intend to heat the water with?

All hydronic systems that I am familiar with use one or more of the following:

• Diesel Fuel
• Propane
• Electric Elements (shore or battery/solar)
• Engine Heat
• Add Gasoline

They all use some form or other of having the plumbing from the hydronic system coming in contact with the plumbing of the water system. The biggest flow I've seen so far is 3 gpm for hot water. These are extremely expensive. A flow of about 1.5 gpm is a little cheaper.

Thanks for the great question.

G Dub

 

[kazetsukai]

Quite a few replies here don't attempt to answer the question. Propane is not compatible with the OP's design goals... People should stop critiqueing the no-propane choice and instead focus on solving the engineering problem at play here.

Power/Weight ratio and safety-wise, propane is a great choice. The problem here is that propane is not something just any of us can readily produce. No amount of advocacy is going to change that.

Here's my suggestion to the OP if they're looking for off-grid heat with maximum ease of acquiring new fuel: Get a decent sized wood stove, modify it by lining the firebox with several water pipes. I planned on doing this myself, using a heat-tolerant putty-like substance to cover the pipes themselves.

Then I'd use solar energy to run water through the pipes and into a hydronic heat system. Some isolated pipes could be used for heating water for faucet/shower, but for the hydronic heat I'd use antifreeze.

Wood is the most freely and easily obtained fuel source available, period. Modifying a wood stove/rocket stove to heat water seems ideal given the hypothetical scenario where conventional fuels are unavailable.

Another solution would be to use a solar water heating solution, however the limitations are clear: Only usable during daylight and some extraordinary engineering efforts would have to be made to make it viable in winter, where you would need it the most.

Possibly more useful would be solar-powered electric water heaters, but given today's battery capacities and lifespans it doesn't seem practical except for on-demand applications.

 

[G Dub]

Quite a few replies here don't attempt to answer the question. Propane is not compatible with the OP's design goals... People should stop critiqueing the no-propane choice and instead focus on solving the engineering problem at play here.

Power/Weight ratio and safety-wise, propane is a great choice. The problem here is that propane is not something just any of us can readily produce. No amount of advocacy is going to change that.

Here's my suggestion to the OP if they're looking for off-grid heat with maximum ease of acquiring new fuel: Get a decent sized wood stove, modify it by lining the firebox with several water pipes. I planned on doing this myself, using a heat-tolerant putty-like substance to cover the pipes themselves.

Then I'd use solar energy to run water through the pipes and into a hydronic heat system. Some isolated pipes could be used for heating water for faucet/shower, but for the hydronic heat I'd use antifreeze.

Wood is the most freely and easily obtained fuel source available, period. Modifying a wood stove/rocket stove to heat water seems ideal given the hypothetical scenario where conventional fuels are unavailable.

Another solution would be to use a solar water heating solution, however the limitations are clear: Only usable during daylight and some extraordinary engineering efforts would have to be made to make it viable in winter, where you would need it the most.

Possibly more useful would be solar-powered electric water heaters, but given today's battery capacities and lifespans it doesn't seem practical except for on-demand applications.

Thanks for the logical, measured approach and your respect for my intentions.

I have considered a few types of wood-burning options. The main thing about wood burning is it creates heat all the time - even when it's 102° outside. While hydronics radiate heat as well, it is contained in the basement (which is separated and insulated from the living quarters). And the amount surely is less than an in-your-face, in-the-living-space stove.

So, while it may be warm outside (not in the dead of winter), I may still want to have some heated water for my shower. The hydronic systems I am looking at are more responsive than a wood stove as well - but at a substantially higher price.

I like your thinking process. Thanks for the post.

G Dub

 

[kazetsukai]

Thanks for the logical, measured approach and your respect for my intentions.

=)

The main thing about wood burning is it creates heat all the time - even when it's 102° outside.

I guess my approach to the problem came with the presumption that you would need multiple solutions for varying climates. I think its safe to say my solution is a top contender in the dead of winter, but warmer weather I think would benefit from another solution.

Keep in mind, the wood solution may still work, even in the case you mention. During the winter you could use a stove in the cabin, benefit from the hydronic distribution of heat as well as warming water. During summer you could hook up a much smaller (think cubic mini cub size or smaller) wood stove on the outside that plugs into some inlets on the wall. It could only heat your hot water, and you'd only run it when you wanted hot water. Kind of reminds me of steel-drum hot baths. Additional Engineering Required.

As a preparedness-minded individual myself, the challenges of finding fuel during WROL or other events have crossed my mind. One of the reason I don't like pellet stoves is that pellets aren't something I can produce.

I have hydronic heat in my bus, currently exclusively from the engine for cabin/defroster heat. I'm going to put a diesel parking heater inline on that loop so that I can have cabin heat, on thermostat, without running the engine itself. The double benefit is that I can use the parking heater to warm my engine before starting it.

In terms of heating drinking/shower water: I have been meaning to play around with thermoelectric (peltier) heat pumps a bit, but so far I like the solar-powered, on-demand electric option the most. I'm putting close to 3kw on the roof and I'll have something like a 6kw inverter. I tested propane to some success but have more or less the same concern(s) as you.

#2 on my list is the diesel parking heaters. While diesel isn't ideal, at least I only require one type of fuel for the whole operation and thus have only one pit stop to make to fuel up. Algae/biodiesel is a hurdle though.

Ultimately I'd have to put at least as much thought into your use case as you have to come up with your ideal solution.

 

[coachgeo]

Great post.

I originally wanted to go the Unimog route, but the wife beat that out of me.

My 404 unimog with implanted diesel engine cost me 12 grand 20yrs ago though.. but that include shipping from Belgium. Sadly I had to let it go when economy crashed about 10 years ago.

I've looked into the methane (you mentioned urine) production thing - I don't know how it would work on a bus, er, ambulance, but it's the kind of thing I love looking into.

methane would be from food and human waste.... A LOT of it. Not possible in a skoolie or really any portable cabin. A planted foot in the ground home with several family members and animal waste... yes. Now urine is different. It would produce hydrogen same way HHO works..... but less electricity needed

It sounds like you've got (or will have) a really great rig. Will it go off-road?

That is the whole plan. base truck is military with AWD/4wd..... weigh about 9 tons

 

[G Dub]

I guess my approach to the problem came with the presumption that you would need multiple solutions for varying climates.

I'd really like to find one solution for varying climates.

As a preparedness-minded individual myself, the challenges of finding fuel during WROL or other events have crossed my mind.

I encourage you to continue to think in these terms. I hope that one day we can meet up somewhere on the road or in the country and enjoy a weekend campout in our creations. :marshmallow:

I'm going to put a diesel parking heater inline on that loop so that I can have cabin heat, on thermostat, without running the engine itself. The double benefit is that I can use the parking heater to warm my engine before starting it.

Is there one that heats water? If you have that, you have the solution, I think.

 

[Unpluggedone]

Hydronic

Hydronic is an indirect heating method. So something has to make the water hot, whatever your choice of fuel, diesel, solar, wood, propane. It's a wonderful heating method in a house where a lot of mass is what you are trying to heat. Get the floors typically toasty and everything else is toasty too. And you can insulate 4-6-12" to keep all that precious energy in. Hot Water for showers and washing is a side benefit.

Now in a bus the heat system that comes with them, uses the waste heat from the engine to circulate the same hot fluid through various heater and defroster coils to the desired effect. Without the engine going no heat so up north big rig drivers use a supplemental diesel based heater to heat the antifreeze and then you can keep the interior warm and when needed preheat the engine for those. 40 below starts.

You could use a wood fire/stove as your heat source although not when your driving. My wood stove sauna is fun but I'm not relying on it every day, heating a cabin with wood is a LOT of work, the thermostat is how many sweaters you wear, not very family friendly to be sure. So in a bus, now that would be a fire hazard with an accident waiting to happen.

I have solar hydronic as a supplement to my natural gas domestic hot water. 2. 4x10 panels gives plenty of heat for a couple showers a day in the summer, not in the winter and you would run out of usable heat energy for space heating in a few minutes. Takes LOTS AND LOTS of panels to grab enough heat as it drops below freezing.

I am reminded of how the eskimoes keep warm, they build igloos to keep out of the wind, and then they sleep under polar bear or other animal skin and furry blankets. They don't take hot showers, and they lived for thousands of years that way. Not many left make that choice anymore, instead, they stay in western houses with electricity and heat because they can. Hope this gives you some insights. Happy skooling

 

[Rivetboy]

You have to have bus that is roadworthy i.e. good tires, good brakes and is licensed and insured to bolt your dream heating system that will keep you toasty in case of zombies.
That is the much larger focus then worrying about how you are going to heat it.
With the list of parameters that are important to you, a diesel fired hydronic heater for space heating with a heat exchanger for domestic hot water will meet your design goals.

If you are saving for a bus you better set up a go fund me to pay for your heating system.
$$$$$$$$$
-

 

[G Dub]

You have to have bus that is roadworthy i.e. good tires, good brakes and is licensed and insured to bolt your dream heating system that will keep you toasty in case of zombies.
That is the much larger focus then worrying about how you are going to heat it.
With the list of parameters that are important to you, a diesel fired hydronic heater for space heating with a heat exchanger for domestic hot water will meet your design goals.

If you are saving for a bus you better set up a go fund me to pay for your heating system.
$$$$$$$$$
-

I do have a GoFundMe account but it is against the rules to post it here.

Currently, I am looking at getting a bus from our local school bus pool. The head mechanic told me all about their rigorous maintenance schedule. For now, it's easy to dive into the weeds. When I get the bus parked outside I'll be too busy (and tired) to devote the same level of energy to design - I think.

 

[G Dub]

My 404 unimog with implanted diesel engine cost me 12 grand 20yrs ago though.. but that include shipping from Belgium. Sadly I had to let it go when economy crashed about 10 years ago.

Bummer.

That is the whole plan. base truck is military with AWD/4wd..... weigh about 9 tons

You're my new hero.

 

[G Dub]

Hydronic is an indirect heating method. So something has to make the water hot, whatever your choice of fuel, diesel, solar, wood, propane. It's a wonderful heating method in a house where a lot of mass is what you are trying to heat. Get the floors typically toasty and everything else is toasty too. And you can insulate 4-6-12" to keep all that precious energy in. Hot Water for showers and washing is a side benefit.

Now in a bus the heat system that comes with them, uses the waste heat from the engine to circulate the same hot fluid through various heater and defroster coils to the desired effect. Without the engine going no heat so up north big rig drivers use a supplemental diesel based heater to heat the antifreeze and then you can keep the interior warm and when needed preheat the engine for those. 40 below starts.

You could use a wood fire/stove as your heat source although not when your driving. My wood stove sauna is fun but I'm not relying on it every day, heating a cabin with wood is a LOT of work, the thermostat is how many sweaters you wear, not very family friendly to be sure. So in a bus, now that would be a fire hazard with an accident waiting to happen.

I have solar hydronic as a supplement to my natural gas domestic hot water. 2. 4x10 panels gives plenty of heat for a couple showers a day in the summer, not in the winter and you would run out of usable heat energy for space heating in a few minutes. Takes LOTS AND LOTS of panels to grab enough heat as it drops below freezing.

I am reminded of how the eskimoes keep warm, they build igloos to keep out of the wind, and then they sleep under polar bear or other animal skin and furry blankets. They don't take hot showers, and they lived for thousands of years that way. Not many left make that choice anymore, instead, they stay in western houses with electricity and heat because they can. Hope this gives you some insights. Happy skooling

Trust me, I've contemplated going the primitive route. And who knows? It may come to that before the end.