TerraLiner:12 m Globally Mobile Beach House/Class-A Crossover w 6x6 Hybrid Drivetrain

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4. Different possible locations for diesel heater exhaust flues in motorhomes


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Now in contemporary caravans and motorhomes the diesel heater's exhaust pipe usually slopes downwards, and most are fitted with a muffler to make things easier for neighboring campers in terms of noise – see http://www.lets-getaway.com/heating-gas-diesel-rv.htm , http://www.ukcampsite.co.uk/chatter/display_topic_threads.asp?ForumID=12&TopicID=331737 , http://www.doityourself.com/stry/3-different-types-of-gas-furnace-vent-pipes-explained#b , and http://www.dieselheat.com.au/ttwp/wp-content/uploads/webasto_AirTop_FAQs.pdf :







Alde also manufactures a product that it calls a "side flue" -- see http://www.alde.co.uk/itemdetails.php?itemId=4 and http://www.southdownsmotorcaravans....ll-terminal-for-3010-compact-boiler-flue.html :








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But there do still exist very "vertical" water boilers that have exhaust outlets on the roof, again, some made by Alde -- see https://www.leisureshopdirect.com/v...ageid=-1&productid=-1&pdfid=15856&iframe=true , https://www.leisureshopdirect.com/v...ductid=-1&pdfid=15856&heightp=948&widthp=1855 , https://www.leisureshopdirect.com/g...e-comfort-2928-boiler-and-spare-parts#ppSpecs :








This is at least one of the applications served by the Alde roof flues pictured in post #2245 above -- see http://alde.se/uk/products/mobile/?page=3173 and https://www.leisureshopdirect.com/g...arts/alde-compact-3010-water-heater-roof-flue .


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Alde also manufactures roof flues as exhaust outlets for its more boxy boiler-heaters -- see https://www.leisureshopdirect.com/v...ageid=-1&productid=-1&pdfid=15856&iframe=true , http://www.alde.co.uk/downloads/alde_cat_22.pdf , and http://www.alde.co.uk/downloads/alde_cat_mobile_19.pdf :

Side or roof flue terminals are available, linked to the boiler by a flexible flue which cools the exhausts gases giving further installation possibilities.

And they even come in brass (!!) -- see http://www.aquafax.co.uk/html/product_details.asp?ID=28412 :









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5. How the Cinderella solves the Backdraft Problem


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In the case of the Cinderella toilet, however, when it is not running, what happens? If the flue pipe were open, it might become a major “backdraft” entry point, a point where very cold Arctic-winter air would enter the toilet, the bathroom, and then the rest of the motorhome. So this may be another function of the big plate that seals the Cinderella's combustion chamber. It closes off the toilet when not in use, so that cold air can't travel though the toilet into the bathroom:







I wonder how the Incinolet used on the South Pole traverse deals with this "backdraft problem"?

In closing, one thing seems fairly certain. A diesel heater does not need a vertical exhaust pipe; again, in contemporary motorhomes diesel heaters are often installed with exhaust pipes that slope downwards – see http://techwebasto.com/redirect/heater_main/5000994A.pdf . But it would be very desirable for the TerraLiner's Cinderella incinerating toilet to have a vertical exhaust pipe. Because it's best for the toilet's exhaust to come out on the roof, as far away from people on the ground as possible. That's the central design issue suggested by Cinderella's remark about a “bundled winter chimney”.

I am just speculating out loud here; let me know what you think.

All best wishes,




Biotect

 

[Haf-E]

Here it is - the Terraliner Prototype!

https://youtu.be/FfYmv9dK_fs

 

[biotect]

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Also see https://www.youtube.com/channel/UCNMLCK1ASzD-IRaPStHFvFQ and https://www.youtube.com/user/cybert00/videos?sort=dd&view=0&shelf_id=3 . Very Art-Deco and CBE, so that it can have a rear deck with steps descending.

Inspiring.....:sombrero:
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[Haf-E]

Interesting discussions on "composting" toilets. Not sure if there has been a discussion of a couple of other options... the search function on this Expo Forum is pretty poor - sorry if this is a repeat of information...

I've lived with composting toilets on and off for the last 20 years and now have my own third generation of self-built toilet system running at my shop building - it is based on a principle called "Enclosed Long Term Composting" (ELTC) and it is the best solution I have found so far - for more info check http://www.compostera.org/

Its based on the idea that, given enough time and the right environment, the solids will reduce to about 1% of their original volume...

Not really an option for an overland rig though since the volume of the container needs to be large and there is still liquid that needs to be disposed of...

But another toilet option - the Sanitizer Toilet - a sort of a cross between a composting and an incinerating toilet design - just evaporates the liquid and heats the solids until they are sterile... allowing safer disposal.

http://cuaproducts.com/the-sanitizer-toilet/

This particular implementation of the idea is fairly basic / crude - it is really designed for applications with AC power available - I discussed with them the energy consumption and it appears to be about 2 kWh per day based on one heating cycle (about 1 hour) and a fan running 24 hrs a day. For a rig with a engine running it is possible that you could run the heating cycle from an alternator powered by the engine - but I don't think this unit's design is made for bumping along on bad roads etc.

I've often thought about a similar design for a vehicle which would use the hot engine exhaust blown directly over the liquid and solids to dry it out and sanitize it - sort of like the system which was offered on the GMC motorhomes in the 70s... The Thetford Corporation's "ThermaSan Waste Destruction System"

http://www.bdub.net/manuals/Thermasan-Brochure.pdf

The ThermaSan was fairly complex with lots of relays and interlocks - which is probably why it never was successful. With today's tech it might work better - perhaps even using a DPF type exhaust with regen to eliminate any particulate / ash emissions.

Since the Terraliner will require daily generator operation, perhaps a ThermaSan or a Sanitizer type system would be a viable option.

 

[biotect]

Hi Haf-E,

Excellent links and thinking. The argument for composting -- that it might be a good way to return essential nutrients to the soil, resulting in better food -- is a powerful one. See http://www.compostera.org/chem.html . It's also great that this website demonstrates awareness of the problem of pathogens, which composting can only address via time, hence, "long term composting". The Wynns do not seem sufficiently aware of the safety problem downstream. After all, they are just putting their humus into garbage bags. They are not returning it to the environment as pathogen-free, nutrient-enhancing fertilizer. As near as I can tell, the Wynns' primary commitment to composting toilets in motorhomes is aesthetic: they hate dealing with blackwater. Which I can most definitely sympathize with. But the disposal of human waste needs to be thought through more systematically, in terms of environmental safety and environmental ethics, not just aesthetics; which is one of the main reasons why I have inclined towards incineration.

For instance, even the disposal of urine separated from poop is more complex than people tend to imagine. They will write glib things like "Urine is completely sterile and pathogen free", which is simply not true. It was only ever thought true of urine inside the human body, in the bladder, although this myth has now been debunked. But it has always been conceded that once urine is outside, it becomes an ideal breading ground for bacteria, which is precisely why toilets that have not been flushed and contain just urine, quickly smell so bad. This is why the articulate woman in the very graphic video I posted earlier about composting toilets, reports that the smell of collected urine is a big problem:






Urine doesn't even have to hit the toilet wall to pick up bacteria. It already acquires a load of bacteria when it passes over the labia in women, and the foreskin in uncircumcised men -- see http://urologygroup.com/blog/2012/10/23/separating-urinary-tract-from-fiction/ , http://www.thenakedscientists.com/forum/index.php?topic=39150.0 , and http://www.theguardian.com/notesandqueries/query/0,5753,-2473,00.html :

Urine is sterile when it leaves the bladder (in a healthy person) but, depending upon the gender and anatomy, picks up bugs on the way out. In women, as the stream passes over the labia, it inevitably collects a rich menagerie of bacterial flora that naturally congregate in that area. This is why when females are required to provide a urine sample they are always encouraged to part the labia, pass some urine into the toilet to flush the urethral opening clean and then to pee into the pot to achieve a "clean catch". In uncircumcised men the foreskin carries a substantial bacterial burden of flora and should be retracted before providing a specimen. Circumcised men, in the absence of a UTI or other infection, generally have as close to sterile urine as it's possible to get.

The most recent studies suggest that bacteria are also present in the bladders of healthy people. So even in the bladder, urine is not in fact sterile -- see http://www.dailymail.co.uk/health/a...finding-healthy-people-bacteria-bladders.html , http://www.sciencedaily.com/releases/2012/04/120409164156.htm , http://www.livescience.com/45800-confirmed-urine-not-sterile.html , and https://www.sciencenews.org/blog/gory-details/urine-not-sterile-and-neither-rest-you . But even before this recent research, it was simply obvious that we can and do get urinary tract infections, where the primary culprit (but not the only one) is E. Coli. In other words, when suffering an infection our urine is most definitely not sterile, not even inside the body, because it contains pathogenic bacteria.


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The bacterium E. Coli is uniquely adapted to thrive inside human and animal bodies, and normally is not problem in our guts. Most strains of E. Coil are actually beneficial, and help us process food. But some forms of E. Coli (there is not just one) can cause diarrhea, which is one major reason why dumping our waste into the watershed is such an issue. When we do so, we assist in the potential spread of the "bad" kinds of E. Coli, which are then picked up downstream by people who do not have expensive water filtration, and especially by children -- see https://en.wikipedia.org/wiki/Open_defecation .

E. Coli is symbiotically beneficial to us, and simultaneously it is a very dangerous and frightening bacterium when it is not beneficial. E. Coli is very hard to kill, because it is both "creiophilic (can survive freezing, so watch those ice cubes when you are on holiday abroad), and thermophilic (can survive boiling, so that towel may not be as clean as you think...)" -- see https://www.sweet-cures.com/e-coli-bug.htm . We can pick up harmful forms of E. Coil not just from water, but also from meat that has not been sufficiently cooked (160°F, or 71°C), unpasteurized milk, and raw vegetables that have come into contact with human faeces. Which again is one of the reasons why one should not use the humus produced by composting toilets as fertilizer in a vegetable garden. E. Coli has a special affinity for human skin, and can even survive on soap. It can thrive in highly acidic environments like human urine, which is precisely why urinary tract infections are possible.

A urinary tract infection occurs when E. Coli in faeces migrates from the bowel to the urinary tract, and infects the bladder. It's not just a matter of numbers, i.e the quantity of E. Coli in an infected bladder. Some forms of E. Coli have become very drug-resistant, and urinary tract infections can also be caused by other pathogens. See http://www.everydayhealth.com/e-coli-infection/symptoms/urinary-tract-infection/ , http://blogs.discovermagazine.com/8...re-now-resistant-to-antibiotics/#.VrA_Nnlclsg , and http://www.webmd.com/a-to-z-guides/e-coli-infection-topic-overview .

There is no question that urine is an even better potential fertilizer than human faeces, because urine contains 88 % of the nitrogen and 66 % of the phosphorous in human waste. Urine collection will prove even more critical to the planet's future than compost collection, or the manufacture of biosolids from sewage -- see http://www2.buildinggreen.com/blogs/urine-collection-beats-composting-toilets-nutrient-recycling and https://en.wikipedia.org/wiki/Biosolids . But because urine can also contain pathogens, the direct use of urine as a fertilizer is problematic. It's often written that household urine needs to be allowed to "age" for at least a month in order to deactivate all pathogens, and non-household urine at least 6 months -- see http://www.motherearthnews.com/organic-gardening/gardening-techniques/human-waste-zmgz11zrog.aspx , http://www.treehugger.com/bathroom-...en-pee-cycling-greener-composting-toilet.html . For an excellent discussion thread that tries to tie all of this together, see http://www.permies.com/t/722/composting-toilet/urine-sterile .

Most people do not have the patience and sufficient background in biology and ecology to understand such complexities. For instance, they can't understand how E. Coli might be simultaneously our friend as well as our opportunistic enemy; how "bad" forms of pathogenic E. Coli have mutated because we changed the terms of our symbiotic, hunter-gatherer contract with the bug. About 10,000 years ago we began providing E. Coli with environmental conditions -- the intensive concentrations of human and animal faeces that appeared with the advent of agriculture -- such that it became in the bug's own self-interest to mutate into the harmful strains that now cause us so much grief. One needs a fairly sophisticated understanding of biology to appreciate this. One needs to understand how parasitical bacteria and viruses will quickly mutate into forms that are most beneficial to themselves, forms that strike just the right balance between virulence and deadliness relative to a given environment (host + ecosystem), something known as "optimal virulence" -- see https://en.wikipedia.org/wiki/Optimal_virulence :

Optimal virulence is a concept relating to the ecology of hosts and parasites. One definition of virulence is the host's parasite-induced loss of fitness. The parasite's fitness is determined by its success in transmitting offsprings to other hosts. At one time, the consensus was that over time, virulence moderated and parasitic relationships evolved toward symbiosis. This view has been challenged. A pathogen that is too restrained will lose out in competition to a more aggressive strain that diverts more host resources to its own reproduction. However, the host, being the parasite's resource and habitat in a way, suffers from this higher virulence. This might induce faster host death, and act against the parasite's fitness by reducing probability to encounter another host (killing the host too fast to allow for transmission). Thus, there is a natural force providing pressure on the parasite to "self-limit" virulence. The idea is, then, that there exists an equilibrium point of virulence, where parasite's fitness is highest. Any movement on the virulence axis, towards higher or lower virulence, will result in lower fitness for the parasite, and thus will be selected against.

This is basic university-level Biology 101. But most people do not have university-level Biology 101. So once we begin delving into the details of composting toilets, they will not have the ability to understand such issues with sufficient discrimination. I only took the time to write the above, because I know that you do have the ability.....


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With that said, if composting's potential to yield ecosystem-enhacing fertilizer could be combined with incineration's promise to truly kill all harmful pathogens, then such a solution might work well in an expedition motorhome. We might specify the comprehensive design goals of a toilet in an expedition motorhome as follows:


(1) Should not use water. Not only because in more conventional motorhomes without watermakers and RO, this would negatively impact the time available for boondocking..... That's one of the Wynns' main arguments. But primarily because combining water with human waste creates sewage, which is unsafe for humans, especially vulnerable children in Second and Third-World countries.

(2) Should produce end-products that can be easily disposed of, and that are safe. Short-term composting does not do this, because it does not kill all harmful pathogens. Even the disposal of urine separated from poop is more ethically problematic than people tend to imagine, for the reasons given above. But if "slow-cooking" composting poop and evaporating the urine would leave behind pathogen-free waste, then I might be in favor of a composting/incineration combination. Evaporating urine will release the nitrogen as gas, so the residue will not be quite as useful as fertilizer. But perhaps one can't have everything.....:ylsmoke:

(3) Should be aesthetically acceptable. Pure incineration still wins hands-down over any kind of composting toilet on this front. Yes, personally I know that composting humus is not the same thing as poop straight out of a bowel, or sewage. Composting humus is more like dirt, and apart from the urine-stench problem, a composting toilet should smell like a greenhouse. But as a designer, I can imagine it remaining very difficult for most people to combine intelligence with the willed recalibration of their emotions, such that they can use a composting toilet without reluctance. When using a composting toilet, most people will still imagine themselves taking a poop on a pile of poop, and that's just not something that most people want to do.


Again, many thanks for the thoughts and the links. You've raised the quality of the discussion another notch, as is your habit....... I just hope that those who contribute further will appreciate that the biology and ecology here are not as straightforward as one might suppose. And I hope that the responsible, pathogen-free dispersal of human waste will be recognized as a major TerraLiner design goal, because it is an important ethical goal.

Also, very interesting link to ThermaSan, and the idea of using hot exhaust to dry out or "incinerate" waste. But blowing directly over liquid and solids? If the container that holds liquids and solids could be reliably sealed, sure. But wouldn't there be a potential problem of leakage, and then the danger of carbon monoxide poisoning? Venting the exhaust of the TerraLiner's diesel generators directly into the TerraLiner's living space, in order to dry out poop and urine, seems a bit precarious, doesn't it? Or am I missing something?

All best wishes,



Biotect

 

[Haf-E]

The issue of directly using hot exhaust to incinerate the solids and dry the liquids really isn't any different than what is being done with the other incinerating toilet systems - they just burn propane just for that purpose. If the generator's exhaust was used instead then you would get more usefulness from the amount of fuel used as it would generate electricity AND dispose of the waste. It also greatly simplifies the issue of using diesel fuel in place of propane since the generator would use diesel most likely.

As far as the risk of carbon monoxide - again, its the same issue as with the other incinerating toilets. A well sealed flap or sliding seal, along with a ventilation fan should provide more than enough enough protection. Its really just a stainless steel box located under the toilet - perhaps there would be two compartments with two flap seals - the first one as a short term storage if the toilet needs to be used while the generator is running and then a second compartment below it where the actual incineration occurs that would be "outside" of the actual living space. The deposits in the storage compartment would be transferred (by gravity) to the incineration compartment prior to running the generator or afterwards once it has cooled down sufficiently. If the toilet seat was a urine separating type the urine could flow into the incinerating compartment all the time, reducing the issue of smells caused by mixing with the solids and a small fan would ensure any smells were diluted and sent outside continuously.

If the Terraliner is going to be dependent on running a generator for 1 or 2 hours a day, then it would seem like that could be a very good match to the amount of time required to incinerate the "waste" products. The issue of any smell or fumes would probably be less of an issue since the generator would be running as well which would dilute the smell and I would think a vertical telescoping exhaust pipe / chimney might be helpful in reducing the impact on the immediate area by allowing the exhaust to mix and disperse over a larger area away from the vehicle.

 

[Libransser]

Hey Biotect,

Well, that's got to be it, then.

So, side flues have the advantage of not being blocked by snow, but they make the problem of burnt smell at startup more notorious.

But if you opt for the roof flue, the burnt smell at startup still happens but it's more difficult to perceive due to the height and a faster dispersion by the wind, but it requires that the flue cap is high enough to clear the accumulated snow.

The flue cap itself then is nothing special, doesn't seem to differ much from a vent rain cap.

However, I have my doubts that owners of Cabby campers can freely switch between using a side vent or a roof vent. The translation of this link suggests it's one or the other: https://translate.google.co.uk/tran...vintercamping/s/Alde_skorsten.asp&prev=search

After thinking it strikes me that it is the chimney which is covered in snow on the roof. On this model a chimney led through the roof, while at the other Cabby models are led out through the side.

It's curious that in this case the toilet uses a direct vent, taking the combustion air from outside through an air intake vent running alongside the exhaust flue.

The special at this chimney on Alde fired is that it is not only the chimney, but also intake of air to the lighthouse.

The translation came out a little funny...



Correct me if I'm wrong, but the Cinderella PDFs doesn't seem to indicate this as an option, isn't it? Maybe it's just an option for Cabby Loo or an adaptation for Cabby campers?

Anyway...

Here it is - the Terraliner Prototype!

https://youtu.be/FfYmv9dK_fs

Lol :sombrero:

 

[biotect]

If the Terraliner is going to be dependent on running a generator for 1 or 2 hours a day....

Hi Haf-E,

Thanks for the explanation as to why using generator exhaust might be no different from using diesel or propane in an incinerating toilet. But it would be different from using electricity for an incinerating toilet, wouldn't it? I was imagining the TerraLiner as having an electric Cinderella incinerating toilet, not a gas (LPG) powered one -- see http://www.cinderella-toilet.nl/en/?p=4770 , http://www.cinderella-toilet.nl/en/?p=4799 , http://www.merford.com/media/191463/cinderella.pdf ,n and http://www.siriuseco.no/Portals/86/Media/Cinderella_2014_eng_WEB.pdf.

I also want to catch something before it multiplies. You may not have seen where safas and I discussed how the TerraLiner's primary 300 KW driveline generator would work in combination with a large battery pack, also 300 KW. Even in a high energy-usage scenario (100 KW per day, primarily to run Air-Conditioning), and even if no solar were available, the TerraLiner would only have to recharge the battery pack once every three days, running the generator for less than two hours. But if solar were available, and if the TerraLiner could be designed such that its various surfaces when fully deployed would produce on average 50 KW per day, even in hot-rainy equatorial climates, then more like 6 days without running the generator would be possible. Hence, "mostly silent" camping. And in climates with excellent DNI, but where little or no A/C might be required (e.g. Lake Titicaca), the generator may not be needed at all. The power generated by the solar arrays might be sufficient to run all camper systems, even if the TerraLiner has "electricity intensive" systems like an RO watermaker, far-infrared thin-film heating panels, and an electric incinerating toilet.

So thinking it through a bit further, using the generator's exhaust gas as the primary source of incineration energy does not strike me as all that compatible with at least one central TerraLiner design goal: to maximize the amount of silent camping. I want to maximize silent camping, even though the the TerraLiner will be a large, "high energy usage" sort of motorhome, at least when compared with expedition motorhomes that don't have A/C. I am truly committed to "mostly silent camping" as a design goal, if only for logistical and security reasons: so that the TerraLiner is not a noise nuisance, and farmers will be amenable to having the TerraLiner camp on their land for months near their homes. But I don't want this to mean that the TerraLiner's owners will find themselves living in a camper that's not much better than a tent; for instance, a camper without A/C, or a camper that expects severe water-rationing when boondocking.

With that said, I am still quite interested in the composting/incineration combination, which is different from the exhaust-incineration idea? The Sanitizer looks very promising -- http://cuaproducts.com/why-the-sanitizer/ , http://cuaproducts.com/the-sanitizer-toilet/ , http://cuaproducts.com/sanitizer-faqs/ , and http://cuaproducts.com/wp-content/uploads/2016/01/SanitizerBrochureOct2015_updated.pdf .

By the way, the videos about long-term composting on Compostera's website are inspiring. When looking at them, I felt that I was watching design-thinking by people who have carefully worked things through on all fronts -- ecologically, biologically, ethically, and aesthetically:






I really liked it when Compostera writes:

The flush toilet is by far the greatest source of water-pollution. Only a system based on being more attractive to the user, could work as a replacement for the WC. Guilting users to use a different technology has not and will not work. Here is a video showing a waterless toilet that pleases all our senses: eyes, ears, nose and touch: a good place to start.

That's a great active verb: "Guilting". It's a verb that accurately describes what environmentally-minded, politically-correct types will often do rhetorically, when they try to make a case for their own particular favored type of technology. They will try to condemn those who disagree with them as eco-sinners; they will engage in rhetorical "guilting". But if some people get very turned off by the idea of taking a poop on what they imagine to be a pile of poop, then no amount of "guilting" is going to convince them to use composting toilets. "Guilting" may seem very high-minded by the eco-virtuous who use it as a rhetorical tactic. But it amounts to little more than emotional blackmail.

Compostera's insight in this quotation is fundamentally correct and important, an insight that advocates of various composting toilet solutions often do not seem to "get". They want to just dismiss the psychological and aesthetic sides of taking a poop as trivial and unimportant, as mere details that truly eco-virtuous people will not care about. They could not be more wrong, or more lazy. It takes intelligence and genuine effort to come up with eco-virtuous solutions that "work" in all ways, not just some. So "guilting" those who remain unsatisfied with a lazy, aesthetically and psychologically inadequate design solution, is just plain nasty.

In any case, as made clear by the videos -- and as you also suggested -- long-term composting requires too much space to be viable solution for the TerraLiner. Instead, some combination of composting and incineration as per the Sanitizer seems worth exploring further.

All best wishes,


Biotect

 

[biotect]

Hey Biotect,

Well, that's got to be it, then.

So, side flues have the advantage of not being blocked by snow, but they make the problem of burnt smell at startup more notorious.

But if you opt for the roof flue, the burnt smell at startup still happens but it's more difficult to perceive due to the height and a faster dispersion by the wind, but it requires that the flue cap is high enough to clear the accumulated snow.

The flue cap itself then is nothing special, doesn't seem to differ much from a vent rain cap.

However, I have my doubts that owners of Cabby campers can freely switch between using a side vent or a roof vent. The translation of this link suggests it's one or the other: https://translate.google.co.uk/tran...vintercamping/s/Alde_skorsten.asp&prev=search .

It's curious that in this case the toilet uses a direct vent, taking the combustion air from outside through an air intake vent running alongside the exhaust flue.


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Correct me if I'm wrong, but the Cinderella PDFs doesn't seem to indicate this as an option, isn't it? Maybe it's just an option for Cabby Loo or an adaptation for Cabby campers?

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1. Alde's Direct-Vent Double-Pipe Boiler/Heater


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Hi Libransser,

The "Direct Vent" in a motorhome application may be an Alde innovation. It seems that they (or some other company?) deliberately developed the idea so that the air-intake of their diesel boiler/heaters would be the same as the exhaust. They use a kind of "double pipe" and/or double hose, in which an outer pipe (air intake) wraps around an inner pipe (exhaust):






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See http://www.alde.co.uk/downloads/alde_cat_mobile_19.pdf , http://www.alde.co.uk/downloads/alde_cat_22.pdf , http://www.alde.co.uk/downloads/alde_3020_install.pdf , http://www.alde.co.uk/downloads/alde_3010_instruct_marine.pdf , http://alde.se/usa/products/mobile/?page=3175 , and the Alde Youtube channel is at https://www.youtube.com/user/aldeheating .

Perhaps Alde does this so that intake-air is "pre-heated" by exhaust air? Or perhaps there is some other way in which a double-pipe boosts the energy efficiency of an Alde boiler/heater? Alde is a very smart, reputable Swedish company, so there must be some good reason why they do things this way. I am calling it a "double pipe", but there is probably a technical term to describe such a hose or pipe? Perhaps Haf-E might know the term?



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2. Cabby's ThermaSan-inspired Incineration Solution?


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So as far as I know, Cinderella toilets used in residential applications -- and hence, in applications that have nothing to do with Alde or Cabby -- will have air-intakes and exhausts that are completely separate. As you suggest, it would be kind of foolish if they did not? Although I am not certain about this. If the exhaust and the air-intake of an incinerating toilet were one and the same, then this might further mitigate outside smell, because some of the vented air would be immediately sucked back in as air-intake. The Cinderella combustion chamber is completely sealed, so this would not present any problems for smell inside the caravan or motorhome. So maybe that's why the Cabby Loo is so compatible with the Alde intake/exhaust double pipe, and why in a Cabby caravan the Cabby Loo's flue and the Alde heater/boiler's flue become one and the same?

The only question then would be whether this would be dangerous, because of the heater/boiler's exhaust? Even when the Cinderella/Cabby Loo is not running, its plate seems to remain completely closed. It only opens briefly when one discharges poop into the combustion chamber. So for that short period, exhaust gas from the Alde diesel heater that had found its way into the Cinderella combustion chamber, could escape into the bathroom. But again, I am not sure about this. When the Cinderella/Cabby Loo is not running, presumably its air-intake fan would also not be running. So it might be difficult for exhaust gas from the diesel heater to make its way into the toilet?

Note that if the Cabby Loo's flue and the Alde heater/boiler's flue in a Cabby caravan are one and the same thing, or somehow connected, and if this means that the Cabby Loo incinerating toilet might be sucking in some Alde heater/boiler exhaust gas when it goes through its burn cycle, then Cabby caravans would in fact be employing the "exhaust gas incineration" idea of ThermaSan, at least to some extent. If they are, and if this is safe, then gosh, that's some pretty sophisticated engineering!!! It also gives new meaning to the phrase, "bundled winter chimney". Bundled indeed!! Double-wrapped double-usage is what we're talking about here.....:sombrero:

That's my best-guess answer to your question, and it ties in nicely with Haf-E's thoughts about ThermaSan. One would expect that Cabby caravan's engineers were thoroughly familiar with the ThermaSan solution, and that they explicitly had it in mind when they developed the Cinderella Motion/Cabby Loo (one and the same product), so that it could share use of the Alde heater-boiler's exhaust/air-intake double-pipe.



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3. The TerraLiner's semi-ThermaSan Solution?


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So Haf-E, back to you, and some modification of my earlier thoughts. Although I would not want the TerraLiner's generator to run daily, on the other hand when the TerraLiner is camping in cold climates, it may be advantageous from an energy consumption point of view to have a diesel heater/boiler supplementing the far-infrared thin-film panels. In a very cold climate it's quite possible that such a diesel heater/boiler might be running continuously, and hence venting exhaust gas continuously. Having its air-intake/exhaust pipe be one and the same as the air-intake/exhaust of an electric Cinderella incinerating toilet, might then be a very good idea. That way, the hot exhaust of a diesel heater/boiler would be re-absorbed immediately as air-intake for the Cinderella toilet as well, and would reduce the amount of electricity that such an incinerating toilet would require. The air drawn in would be "pre-heated".

So something like what the ThermaSan system did would occur, but not completely. The TerraLiner would still be able to run its electric incinerating toilet in a hot climate, when the diesel heater/boiler is switched off, and when the primary driveline generator (300 KW) is also not running. The TerraLiner's electric incinerating toilet would still be compatible with "mostly silent" camping, in which the primary 300 KW generator would run at most once every third day for less than two hours; and at best, when solar DNI is really good, not at all.



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4. Outside versus Inside Air-Intake


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By the way, carbon-monoxide poisoning from a diesel heater can be an issue. The "Big Red Kress Truck" at McMurdo station, for instance, has a passenger cabin that is so tightly sealed against the Antarctic cold (which seems a good thing), that it can't run its diesel heater, because apparently carbon-monoxide then builds up in the passenger cabin. See posts #42 to #44 in Camper Thermal Engineering, at http://www.expeditionportal.com/for...Arctic-Antarctica-Tibet?p=1655487#post1655487 and following. Granted, this is a bit surprising, because in the Alde heater/boiler, it's very clear that that the air-intake/exhaust is completely separate from the heating system, which is hydronic. So there's no reason why a motorhome diesel heater should have this end result.

Perhaps those who designed the cabin on the "Big Red Kress Truck" made the mistake of installing a heater that uses a "Power Vent", drawing air from inside the cabin for combustion? So there is probably a backdraft problem with the truck's heater, a common problem in furnaces that draw air from inside a home -- see http://www.doityourself.com/stry/3-different-types-of-gas-furnace-vent-pipes-explained , and post #2447 at http://www.expeditionportal.com/forum/threads/124789-TerraLiner-12-m-Globally-Mobile-Beach-House-Class-A-Crossover-w-6x6-Hybrid-Drivetrain?p=2016643#post2016643 . "Power Vent" seems like a rather euphemist, overly optimistic term for what is more commonly called a "Natural Vent", a form of furnace venting that has always been known to have a backdraft problem, and hence, may prove dangerous for users:

1. Natural Vent

It operates on natural air convection and is also known as the Type B vent. Type B vents are a standard design that most modern gas furnaces use. It draws air from within the house for combustion. Gases produced during combustion are very hot and as such, easily rise through the flue. The air is then vented outside through a B-vent pipe which is set vertically to expel combustion air through the roof. Natural vent pipes can be installed fairly easily, and costs are fairly modest, making them a popular choice. However, back-drafting is more common with natural vent pipes than other varieties. The indoor air can easily pull combustion gases back indoors. This detracts from the efficiency of the B-vent piping. The tendency to back-draft also raises questions over furnace safety where such pipes are used. Back-drafting can affect the health of household occupants through inhalation of toxic emissions if it remains a consistent problem.

2. Direct Vent

This type is an ideal alternative to natural vent systems. This piping system incorporates two pipes of different sizes in one unit. The outer pipe draws air for combustion from outside, and the smaller pipe occupies the inner position and is used to vent the exhaust fumes. Piping can be set horizontally to allow venting through a sidewall, or vertical installation can also be undertaken to allow venting through the roof. Direct vent systems have versatility to their installation that natural vents do not. Also, no chimney is needed regardless of whether horizontal or vertical installation is used. Installation of direct venting is fairly easy, but more costly than the B-vent type.

Less environmental pollution occurs with direct venting since they extract most of the combustion heat and expel it outside. They also do not spoil the quality of indoor air unlike the B-vent type, so safety ratings are higher for direct vent furnaces than natural vents.

Put another way, the diagram that you posted, Libransser, may be a bit propagandistic. It seems like an example of visual rhetoric being used to try to sell a cheaper, "natural vent" system. Whereas "power vent" refers more generally to the idea of using a fan to expel exhaust air, in either a "natural vent" or a "direct vent" configuration:

3. Sidewall Power Vent

This is also referred to as an induced draft fan. A fan is placed at the end of an exhaust pipe that runs through a sidewall which draws out combustion gases and expels them outside. The fan works in conjunction with the furnace, usually turning on before the furnace starts. Sidewall vent systems are especially great for replacing old chimneys, and it is one of the more affordable options to consider when installing a venting system for your gas furnace. Sidewall power vents also rate highly in efficiency and safety.

For instance, one could describe the Alde boiler-heater when using a sidewall vent, as a "direct sidewall power vent" furnace, because it draws combustion air from outside with a fan, and also expels exhaust with a fan.

Comparative diagrams and descriptions produced by manufacturers are always a bit dangerous to use, because they tend to bias their descriptions in favor of whatever product they happen to be selling. Even a "natural vent" furnace that uses a fan to expel exhaust may still have backdraft problems, and hence, may be venting carbon monoxide into the living space, as per the heater in the "Big Red Kress Truck". But calling it a "power vent" instead of a "natural vent" furnace makes it does sound better.

The most important distinction from the end-user and safety point of view, is whether a furnace or heater draws air for combustion from inside the living space, or whether it draws air from the outside. That's the most important distinction, but one gets the impression that manufacturer descriptions of the possible range of furnace and RV heating products are deliberately designed to hide or obscure this distinction. More honest descriptions would run something like this:


1. Inside air-intake heater/furnace that's cheap, and may poison you and your family, even if it has a "power" fan.

2. Outside air-intake heater/furnace that costs more, but is much safer, and won't poison you even if the "power" fan stops working.


Unfortunately, this degree of honesty won't sell the cheap, low-end, inside air-intake product. So it's much better to call it a "natural vent" heater/furnace; or even better, if it has a fan, a "power vent" heater/furnace. Because consumers think that "natural" or "power" must mean "good".....:ylsmoke: .. Here it also has to be conceded that low-end consumers may be tacitly concluding in the creation of such confusing nomenclature, because nobody on a budget wants to think or be told that they are buying an "Inside air-intake heater/furnace that's cheap, and may poison you and your family, even if it has a "power" fan." Even from the point of view of some consumers, it's much nicer to call their cheap furnace or heater a "natural vent" or "power vent" model, instead of an "Inside air-intake model that's unsafe, and may kill."

Note that even sidewall direct power venting as per some Alde boiler/heater installations is not such a good idea:

What Issues Can Arise from Sidewall [Venting]?

Improper sidewall venting can have serious unintended consequences that must be recognized and addressed. A number of different elements can be impacted:

• Building envelope
• Attic moisture and mould
• Air quality and health
• Noise


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Building Envelope Damage

As discussed, the moisture generated by the gas combustion in winter can both condense on and be absorbed by building envelope materials, which can lead to damage. In winter, the exterior building envelope materials are already at or nearly at saturation moisture content. With very little drying potential, the additional moisture can impact building envelope durability.

Icing problems on building envelopes due to sidewall venting have been observed on the Prairies and have prompted some authorities in Saskatchewan and Alberta to introduce local requirements for larger spacing requirements between houses with sidewall vents. Minimum distances as great as 8 feet between a house and property line are being proposed.


Attic Moisture and Mould

The flue gases moving up the house can enter the attic through the soffit vents where they can condense on the framing and underside of the roof sheathing. There have been reports of moisture and mould on the underside of roof sheathing in houses with sidewall vented appliances and also on adjoining houses. Some builders have even reported condensation and mould growth in new houses that are still under construction – where the water vapour from an adjacent home’s gas applianceis blown into the attic. Similar problems have been observed inolder homes that have been retrofitted with new high efficiency gas furnaces where the venting has been put through the wall rather than keeping it through the roof.


Air Quality and Health

There are also potential health impacts associated with sidewall venting. Indoor air quality can be negatively affected if there are operable windows near a sidewall vent that are left open when the gas appliance is operating. Similarly, if there is a ventilation air intake in the area, the indoor air quality could be compromised as the combustion gases can be drawn in.

Because the gas-fired appliance is often located in the basement or crawlspace, the vent is taken directly out the sidewall of the building. The vent gases are often dispersed near the ground in narrow confined spaces between buildings – a less than ideal situation.

Malfunctioning equipment could produce higher levels ofcarbon monoxide and other harmful combustion gases that could affect occupant health.


Noise

Another issue that has been raised by some building officials is that of equipment noise. The fan motors of some power vented quipment can be loud, even when installed according to manufacturer specifications. These noise levels can exceed allowable noise limits set out in municipal noise by-laws.

See https://hpo.bc.ca/files/download/BuilderInsight/BI10.pdf . This is a PDF produced by a consumer safety group, the British Columbia "Homeowner Protection Office" (see https://hpo.bc.ca ), so it will be honest in a way that most manufacturer literature won't be. All of the above considerations will also apply to a motorhome, especially a motorhome like the TerraLiner that will have an "upstairs" floor. Even though the TerraLiner will not have an attic, it will have a pop-up. So the first two considerations will apply as well, even though at first they may seem relevant only to fixed-home residential construction.


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CONTINUED IN NEXT POST..
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5. The Ideal TerraLiner heating-incineration Air-Intake/Exhaust Vent: A Co-Axial Roof Chimney


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Of course in the case of the TerraLiner, given that it will have an incinerating toilet, a roof chimney would be strongly preferred for that reason alone. But it's interesting to learn that there are lots of additional reasons why sidewall venting in a motorhome may not be such a good idea.

Instead, the TerraLiner's ideal air-intake/exhaust format will be a "direct power co-axial roof chimney". There are no images on Alde's website describing diagrammatically what this looks like. So I "cheated" a bit, and using Haf-E's post which appears next, I inserted phrases like roof co-axial Type L direct power vent chimney , roof co-axial direct power vent chimney , co-axial vent , L-type vent , type L vent , type L vent systems , etc. into Google image search. The key words here are "co-axial" and "vent", although "Type L", "direct", and "chimney" may have helped -- see http://inspectapedia.com/chimneys/Type_L_Vent_Chimneys.php , http://inspectapedia.com/chimneys/Direct_Vent_Chimneys.php , and http://www.mtlfab.com/media/L-Vent_Installation_Instructions-L2147.pdf :









Also see http://woodensun.com/showroom/what-to-bring-with-you/ , https://basc.pnnl.gov/resource-guides/condensing-boilers , http://www.slideshare.net/Wermbo/b-i-g-e-p-e-l-l-e-t-s-t-o-v-e-p1000-2009-manual , http://coalbasket.com/coal baskets Direct Vent.htm , http://www.woodstove.com/pages/pdffiles/Woodstock Gas Brch.pdf , and http://valorfireplaces.com/media/Horizon/specs/534I Horizon Co-Axial Venting Jan-10.pdf .

There are complete Duravent catalogs of co-axial or "concentric" venting systems (pipes and chimneys), intended for use by gas or propane stoves and fireplaces, at http://www.duravent.com/docs/product/L820_DVP_W.pdf , http://www.duravent.com/docs/product/directventpro_L820_2012-sep_w.pdf , and http://www.duravent.com/docs/product/L915_W.pdf .

Note that the TerraLiner venting system could start out co-linear, and then become co-axial nearer to the chimney -- see http://gadgetsgo.com/Z-Flex-Coaxial-Termination-indoor-tankless-hot-water-heater-ventilation.html , and http://www.duravent.com/docs/product/directventpro_L820_2012-sep_w.pdf :







Indeed, the TerrraLiner's venting system could become co-axial right at the chimney -- see http://valorfireplaces.com/media/Generic Title PDF manuals/English/530_colinear_venting_Oct09.pdf and http://valorfireplaces.com/media/Generic Title PDF manuals/English/530-Colinear-Venting.pdf . In the image above I circled in green various chimneys that function simultaneously as co-axial adaptors.

This is important, because Alde's heater/boiler system will not be ideal for the TerraLiner, if only because it uses LPG. And as near as I can tell, even though Alde is a major force in the motorhome industry in Europe, and sells more heater/boilers than anyone else, all of them are LPG. Alde seems relatively uninterested in diesel, although I could be wrong about this. Hence, one cannot necessarily count on the idea that the pipe that exits the TerraLiner's heater/boiler, will be a co-axial pipe as per the Alde. It may in fact be co-linear, depending on the brand of heater/boiler used.

There is a good short article about the difference between co-axial and co-linear at http://thehomestylecollection.com/C...ollinear-and-a-coaxial-direct-vent-system.cfm:

What is the difference between a collinear and a coaxial direct vent system?

There are two types of direct vented appliances: co-linear or collinear, and co-axial. The term "direct vent" is used interchangeably between the two which sometimes adds to the confusion. 

In a co-linear system, the vent and the intake liners run parallel to each other, hence the name co-linear. Co-linear systems use two continuos flexible aluminum chimney liners as the venting system. Nearly all co-linear installations occur in a masonry chimney. A bottom view of a co-linear termination is below. 

In a co-axial system, the vent and intake pipe are nested into one another or share the same axis, hence the name co-axial. Co-axial systems use two rigid single wall pipes as the venting system. This configuration allows for air flow through the pipe to prevent heat transfer to the surrounding combustible structure. Unlike the continous co-liner liner, co-axial pipe is installed in sections. Most co-axial installations occur in a chase. A bottom view of a co-axial termination is below. 
 


What's really wanted is a dual-energy, diesel/electric boiler-heater, one that heats both hydronically (for under-floor heating), as well as circulating air, as per a "forced-air" heater like the Webasto Air-top. But such a thing probably does not exist. One probably has to choose between hydronic versus forced-air circulation.

"Forced-air" is a British expression that seems very descriptive and precise, and I prefer it to "central heating", the North-American expression -- see https://en.wikipedia.org/wiki/Forced-air and https://en.wikipedia.org/wiki/Central_heating . Central heating can also mean hydronic, heating via the circulation of water. So "central heating" does not have the degree of precision one needs in order to talk about motorhome heating in a clear way. Now given a choice between the two, I would probably opt for "forced-air" instead of hydronic, because I would view forced-air as supplementing thin-film far-infrared panel heating, i.e. heating by electricity. As already indicated a number of times in this thread, instead of the standard kinds of hydronic radiators placed under furniture and along the walls, radiators that heat through convection (this is what Alde uses), I would like the TerraLiner to have thin-film far-infrared panels. This may even mean that under-floor heating is far-infrared/electric, and not hydronic.

Truma, Webasto, Eberspracher, etc. all make diesel heaters that come in various combinations. And Aqua Hot, the system of choice for high-end Class-A motorhomes in the United States (Newell, Liberty, Marathon, etc.) makes a heater that can use either engine heat, AC electricity, or diesel fuel -- see http://aquahot.com/Products/RV.aspx , http://aquahot.com/Products/RV/675D.aspx , http://aquahot.com/Products/RV/600D.aspx , etc.






The Aqua Hot system seems to be only hydronic and not forced-air, whereas the Truma Combi 6 D E and the Webasto Dual Top 7 and 8 are forced-air as well as having hot-water boilers -- see https://www.truma.com/int/en/heating/diesel-heater-combi-d-6-e.php , https://www.truma.com/int/en/heating/overview-truma-combi-heaters.php , https://www.truma.com/downloadcenter/combi_d6_e_cp_plus_ready_installation_de_gb_fr_it_nl_dk_se.pdf , http://www.webasto.com/int/markets-...ng-solutions/integrated-heaters/dual-top-evo/ , http://www.webasto.com/gb/markets-p...ng-solutions/integrated-heaters/dual-top-evo/ , and http://www.webasto.com/fileadmin/we...ternational/rv/data-sheet/rv-dual-top-evo.pdf :



[video=youtube;SbkpWYHy7vo]https://www.youtube.com/watch?v=SbkpWYHy7vo [/video]


But whether having hot-water boilers means that these heaters could also provide under-floor hydronic heating, is an open question. As near as I can tell, the answer seems to be "no". Please correct me if I am wrong. On the other hand, for a vehicle like the TerraLiner these heaters are very interesting, because they can also heat the water in their boilers via electricity alone. In the Truma, "D" stands for Diesel, and "E" for electric; and in the Webasto range, the Dual Top 7 and 8 specifically can heat electrically. I am currently leaning towards these two heater/boilers, because they seem like they would complement far-infrared thin-film panels most successfully. But I would need to speak with a heating expert in order to nail all of this down even further.

For a very thorough discussion of dual-energy diesel/electric heaters, and a discussion that also factors in the problem of altitude, see page 4 in the ExPo thread "What is the BEST....High Altitude Solution for Heating?" at http://www.expeditionportal.com/for...BEST-High-Altitude-Solution-for-Heating/page4 . It gets very technical, but has tons of links to all the relevant manufacturers and their products, including some of the more obscure ones, like ITR, which makes military-grade heating systems that can run on a variety of fuels, including kerosene -- see post #32 at http://www.expeditionportal.com/for...de-Solution-for-Heating?p=1598613#post1598613 .

Note that one of the main reasons why I want the TerraLiner to have electrically powered, far-infrared thin-flim heating panels, is precisely because of the altitude problem that some diesel heaters may face. Although the Truma and Webasto are diesel-electric, in electric mode they generate much less heat. So boondocking for months on the Tibetan plateau may well require that the TerraLiner have the capacity to heat its living space mostly by electricity alone. Sure, there are various "fixes" allowing one to rejigger a Webasto, Truma, or Eberspracher heater beyond its operational specifications, enabling it to work at high altitudes; fixes also discussed in the "What is the BEST...." thread. But having far-infrared thin-film panels seems like a simpler and much more reliable solution, and would be desirable for other reasons as well. There are health benefits to far-infrared heating, and there may also be energy benefits. The South Pole traverse only uses electric heating, and so that's also something to consider.

When designing the TerraLiner's combination heating system + incinerating toilet, one would then probably want their air-intakes/exhausts to fuse and culminate in a "direct power co-axial chimney". However, a Truma, Webasto, Eberspracher, Aquahot, or ITR diesel/electric heater may not be set up to discharge and accept air to/from a co-axial pipe, as per the Alde. For instance, schematic drawings of the Truma and various Webasto products suggest that, while the Truma heater-boiler has a coaxial air-intake/exhaust, even in the Webasto Dual Top Evo the air-intake and exhaust outlet are quite separate -- see https://www.truma.com/int/en/heating/img/combi_d_aufbau_xl.jpg , https://www.truma.com/downloadcenter/combi_d6_e_cpplus_ready_operating_de_gb_fr_it_nl_dk_se.pdf , http://www.ersatzteilbox.com/media/products/0955282001290383186.pdf , http://www.webasto.com/fileadmin/we...ternational/rv/data-sheet/rv-dual-top-evo.pdf , and http://pbautoelectrics.co.uk/wp-content/uploads/2014/02/Webasto-Dualtop-EVO-Datasheet-PB.pdf :







Hence, one would want the co-linear pipes from a Webasto heater to be able to eventually fuse, and become a single co-axial chimney pipe, or chimney fixture. One would also probably need the same for the Cinderella incinerating toilet, whose air-intake and exhaust outlets are separate and co-linear, at least in the electric models (Classic and Comfort). Furthermore, to minimize the problem of exhaust gas from the heater venting into Cinderella toilet's combustion chamber when it's cold and not in use, one would probably want to be very careful and clever about how pipes from the Cinderella connect to the co-axial pipe that finally culminates in the roof chimney. Last but not least, one would want to locate the TerraLiner's diesel heater right beside or very near the primary 300 KW diesel generator, so that as per the Aquahot system, the TerraLiner's heating system could recover heat from the operation of the ICE-driven generator.

It's good to know that manufactures like Duravent exist, manufacturers who can provide co-axial pipes in a wide variety of sizes -- again see http://duravent.com/Product.aspx?hProduct=5 , http://www.duravent.com/docs/product/L820_DVP_W.pdf , http://www.duravent.com/docs/product/directventpro_L820_2012-sep_w.pdf , and http://www.duravent.com/docs/product/L915_W.pdf . Indeed, Duravent even produces a co-axial pipe that telescopes, with O-rings that seal off any possible exhaust leakage!!

However, my intuition tells me that the best solution for the TerraLiner will be having two co-linear hoses running up through the Pop-Up, separate hoses that only culminate in a short co-axial pipe + chimney on the roof of the TerraLiner. Further, it may even be possible that there should be four (4) hoses running through the Pop-Up, not two. On the one hand, when the incinerating toilet is going through its burn cycle, one would want it to draw in the hot air of the diesel heater's exhaust. However, if one merely had a "Y" junction much lower down in the TerraLiner from a single air-intake hose, nearer to where the incinerating toilet and heater will locate, then it seems much more likely that exhaust from the heater might "bleed" into the incinerating toilet when it's cold and not in use. The big plate in the Cinderella would be sealed, to be sure. But once one took a poop, for a brief moment when one lets the poop fall, any carbon monoxide that had collected in the toilet from the running the heater might enter the bathroom.

I don't know if "carbon monoxide bleed" or "backdraft" is a significant worry, and only fairly detailed discussion with Cabby and/or Cinderella could settle a question of this kind.

There's the added complication that one of the main advantages of co-axial pipes, is that the outer "intake" layer serves as insulation for the interior "exhaust" layer. Such pipes still need to be insulated, but less, because the inner exhaust layer is separated by fast-moving air drawn from the outside, air that is presumably cold. At least that's how Alde co-axial pipes are set up, and it's how co-axial pipes used in residential applications typically function. When renovating an old building with fragile masonry, for instance, if one wants to install a stove where before there was a fireplace and chimney, it's best to put a co-axial pipe inside the chimney. That way old masonry will be more protected from the heat. But I came across the following diagram, which seems to get things backwards:







In motorhome applications, the exhaust will most certainly be on the inside, and the air-intake on the outside.

So to add another layer of engineering intelligence (or complication), it may be best if the rigid pipes that lead vertically upwards from the incinerating toilet and the heater/boiler were co-axial in the camper box below. They would then become four co-linear flexible hoses inside the pop-up; and they would become completely co-axial again only at the final terminus on the roof, where the four hoses would merge to become a single co-axial chimney. That sounds complicated, but it's really not, because all the hardware already exists "off-the-shelf", as suggested by the images posted above, or a quick perusal through the Duravent catalogs. Including the culminating co-linear-to-co-axial roof chimney. Seems rather incredible that such stuff exists off-the-shelf, but it most certainly does.

Cleaning might be an issue. But on the other hand, a chimney broken down into "segments" that could be detached would be much easier to clean than a single unitary vent/chimney. The segments would just need to be connected in a very reliable, leak-proof way. Having flexible hoses that could detach inside the Pop-Up, for instance, would provide excellent cleaning access from above for the rigid co-axial pipes that lead down to the incinerator and heater/boiler. And the four flexible hoses could be taken outside for cleaning.

Finishing off this section, it's quite possible that Cinderella mistakenly translated the Swedish equivalent for "co-axial", as "bundled". So perhaps "bundled roof chimney" really means "co-axial roof chimney" -- see http://www.hearth.com/talk/threads/cleaning-coaxial-pipe.120298/ . In any case, this seems by far the best form of venting. And if what I have written above is correct, then it will prove the most energy-efficient as well, contributing significantly to the power of the heater, and the speed of the incinerating toilet.



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6. Cabby Caravans: a well-deserved innovation prize at Düsseldorf 2013


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I am not an engineer, but when writing these posts I sure felt like one, albeit only very temporarily, using my very primitive level of pseudo-engineering reasoning. :sombrero:.. Many thanks to you both for your replies, because they sure got us thinking!! All of this also demonstrates how when exploring novel engineering solutions for an extreme-boondocking-capable motorhome, one needs to think "holistically", constantly going back and forth between systems, imagining how one system might dovetail with another. Hence, the complexity of this thread.....

Because the Cabby caravan/Cabby Loo/Cinderella Motion/Alde boiler-heater solution has become so exemplary, I now feel kind of duty-bound to insert all the images in the posting series a few pages back about the Cinderella/Cabby Loo incinerating toilet. That way others can refer to this material easily, and will know what we're talking about. What I just wrote above seems complicated to follow, even for me; even though I've been all over this material. So having Cinderella's and Cabby Loo's PDFs and images visually "ready to hand", and easily back-referenced in the course of further discussion, seems important. It's going to take a while to insert all that stuff; processing PDFs and inserting images always does.... So if the two of you respond to these three posts, as well as the one before addressed to Haf-E -- which I hope you do! -- and if I don't respond for a while in turn, that's because I am trying to complete the Cinderella/Cabby Loo posting series by inserting all the visual material.

This discussion has become extremely interesting. But it will only be interesting for others, beyond you two and myself, if I provide enough visual material such that others can wrap their brains around what seems to be a very sophisticated engineering concept, developed co-operatively by Cabby caravans + Cinderella + Alde. I still don't know how Ecotech fits into all of this, but apparently Cabby caravans had help from Ecotech as well.

If I am right about all of the above, then Wow. Cabby caravans sure came up with a very sophisticated solution, and no wonder it won the innovation prize at Düsseldorf 2013. The camper-capable "Motion" version of Cinderella's incinerating toilet then seems to be only one part of the solution. The "bundled winter chimney" shared with an Alde heater/boiler is also important, and perhaps contributes significantly to the efficiency of the whole system? For instance, when the incinerating toilet is running, its exhaust might in turn contribute to the heat of the intake-air used by the Cabby caravan's Alde boiler/heater. Thereby improving the efficiency of the boiler/heater even further?

What do you guys think?

The reason the Cabby Loo is so interesting, needless to say, is because it seems to be a rather unique example of an incinerating toilet used in a mass-production caravan. So far, it seems that incinerating toilets have only been installed in custom/bespoke motorhomes like the Maxi-mog and the Kiravan, or used in exotic applications like the sled-mounted living module on the South Pole traverse. Whereas the Cabby Loo seems to be the first example of an incinerating toilet developed for more widespread motorhome usage.

Here it's worth repeating that the toilet installed on the South Pole traverse is an Incinolet, and the end-users hate it. They despise the toilet, and needed to come up with special solutions to deal with the smell, like pooping in a plastic bag within one hour of using the kitchen:

Any similar concerns regarding your living/sleeping quarters? Or have you gone deliberately "all-electric" to avoid such worries about carbon monoxide, and because you have two big 50 KW generator available?

Everything besides the stove is electric- it's easier to maintain. Each room also has an escape hatch in the roof that we can crack for fresh air if needed. When designing the new modules we put the Incinolet inside the same module as the kitchen. This was a mistake. In the morning all 10 people use the crapatorium and that thing gets FULL. When we shut the generator off the fan no longer pulls the poop smoke out the vent and the foul stench starts leaking into the kitchen area. That smell doesn't make eating fun. So now we have to crap in a plastic bag if we are within an hour of shutting off the generator. That's not fun either.

See posts #53 to #58 in Camper Thermal Engineering, at http://www.expeditionportal.com/for...Arctic-Antarctica-Tibet?p=1655502#post1655502 and following.

By way of contrast, the Cabby Loo seems to be an incinerating toilet that actually works. Here "works" means what Compostera means by the term: an alternative toilet that is successful on all fronts, aesthetically, psychologically, environmentally, and ethically. The Cinderella seems to be very popular in Scandinavia, and seems to receive glowing reviews on Scandinavian discussion forums -- see posts #2431 to #2434, at http://www.expeditionportal.com/for...w-6x6-Hybrid-Drivetrain?p=2015800#post2015800 and following . It would then be interesting to find some web-discussions of the Cabby Loo specifically, and determine whether Scandinavian end-users think it is a success as well. That would be the next step in research. But as just remarked, first I first need to insert all the visual material in the Cinderella/Cabby Loo posting series.

All best wishes,




Biotect


PS -- Haf-E, you may have missed this in my reply to Silverado; so because you have a particular interest in toilet technology, thought I'd repost.

In the course of more research, I chanced upon what is probably the most comprehensive survey yet produced of literally every experimental, alternative, or "eco" toilet design that has been proposed in recent years. See the PDF at http://wedc.lboro.ac.uk/resources/books/Contemporary_Toilet_Designs.pdf. It must have been an expensive document to create, because it contains at least 50 custom-drawn explanatory diagrams of the toilets. These are not just lifted from manufacturer product literature, but were custom-commissioned for this survey. Perhaps paid for by the Bill & Melinda Gates foundation? Again, merely as a piece of graphic design the document looks expensive because it's so beautiful, the layout is first-rate, and the explanatory diagrams cohere. But perhaps the expense was worth it, because the diagrams are very easy to understand.

This is a document that someone like you should have, because you will be able to digest it at deep level, and then draw interesting further conclusions. Conclusions, of course, that you would be most welcome to post in this thread....:sombrero:
..

 

[Haf-E]

Thanks for the further explanation of the generator run strategy you are considering. It is worth mentioning that there are some extremely quiet generators offered primarily for the boat / yacht market which are as quiet as a typical air conditioning unit - some even power an air condition compressor directly as well - so operating a generator doesn't have to be an extremely noisy situation. Many times it is more efficient to produce the power required by large energy consuming loads (like air conditioning) continuously instead of trying to operate them off of a battery and then having to recharge the battery at a very fast rate to minimize the generator's run time. With the advancements in energy storage occurring, it will be / is possible to do what you are describing, but the cost might be excessive. However, since the very large generator and battery are also to be used for propulsion power, they would be doing double duty in a sense.

Using an electric incinerating toilet is an option - but it would be very interesting to find out how much energy that would require. I know that the "sanitizer" toilet system was said to use 2 kWh per day for limited use - such as would occur with two people in a caravan type situation - but that doesn't dispose of the waste - just evaporates the liquids and reduces the hazard of the solids. You still are "dumping" the solids some where else.

Combining the electric incinerating toilet with the exhaust of the generator would reduce the amount of electricity required - but it certainly isn't hard to also just build in enough storage capacity for the toilet system to hold three days worth of waste and have it be incinerated when the generator runs. Perhaps only using an electric heating system to evaporate the liquids on a frequent basis and then the having the incineration occur every three days or whenever required would be a successful strategy. I think that if the solids were "sanitized" by an electric heating system in a separate compartment from the toilet - it could remain there for many days or weeks without issue since it is rendered "inert" by the heating cycle. Then the generator's hot exhaust would incinerate it, reducing the volume considerably and making the resulting ash easy to dispose of into a landfill or some other suitable environmentally considerate manner. It might be possible to simply collect the ash into a 5 gallon bucket for many months based on the descriptions of the incinerating toilets operation. This would allow you to operate with "zero discharge" for long periods of time, assuming that the gray water was also recycled.

The double tube intake / exhaust systems is often referred to as being "concentric" or "coaxial" and are a way of improving the efficiency of heaters - it is often used on small "direct vent" or "sealed" combustion wall heaters which often use no electricity. I have one in my shop with that setup and it works great. They are much better than "vent free" type heaters which release the exhaust into the living space and increase the humidity due to the by products of combustion. Traditional non-sealed heaters use indoor air for combustion and therefore need to draw in cold outside air into the heated space and are less efficient / effective compared to the sealed, direct vent type heaters. I've considered installing one of these heaters into my sprinter van for winter camping but have instead insulated it well and used a large battery bank with a mattress heating pad and a small 1500 watt radiant electric heater to take the chill off the room in the morning... but I tend to not stay in one place for more than a night so the engine recharges the battery once I drive.

 

[biotect]

Hi Haf-E,

Your post was really interesting, so had to respond.....:sombrero:

Thanks for the further explanation of the generator run strategy you are considering. It is worth mentioning that there are some extremely quiet generators offered primarily for the boat / yacht market which are as quiet as a typical air conditioning unit - some even power an air condition compressor directly as well - so operating a generator doesn't have to be an extremely noisy situation. Many times it is more efficient to produce the power required by large energy consuming loads (like air conditioning) continuously instead of trying to operate them off of a battery and then having to recharge the battery at a very fast rate to minimize the generator's run time. With the advancements in energy storage occurring, it will be / is possible to do what you are describing, but the cost might be excessive. However, since the very large generator and battery are also to be used for propulsion power, they would be doing double duty in a sense.

Yes, I agree with you here. The major consideration would be whether such a silent generator could be found that produces 300 KW, or thereabouts. WhisperPower manufactures a very quiet marine generator that produces 200 KW, and that has a superb energy density (kg/KW), one that's even better than the Jenoptik -- see http://www.whisperpower.com/uk/4/21...-systems-(high-power)/m-gv-200-genverter.html . But my (very) preliminary power calculations suggest that a 280 - 300 KW primary generator is more nearly the size that the TerraLiner will need for driving. That's the size of the generator used by Oshkosh in its MVTR hybrid, for a 3-axle truck that is comparable to the main vehicle of the TerraLiner in terms of weight, size, etc. If anything, the MVTR is slightly smaller, and it normally doesn't tow a trailer:






See http://www.dtic.mil/ndia/2007power/...snasrCopyofJointServicePowerOTC42407Final.pdf , http://oshkoshdefense.com/wp-content/uploads/2013/08/ProPulse_SS_6-13-11.pdf , and http://www.dtic.mil/ndia/2011power/Session16_12834Mimnagh.pdf , http://www.dtic.mil/ndia/2009power/may6Nader.pdf . Have already posted extensively about the hybrid MTVR, so won't repeat any of that here.

If you know of any quiet boat/yacht generators that are as big as 280 - 300 KW, please post!!

This size of generator probably won't be found in the serial-hybrid bus corner, because transit bus generators tend to be much smaller, more in the 100 - 160 KW range. The biggest ones I've come across top out at 195 KW -- see http://www.kirsch-energie.de/fileadmin/user_upload/redakteur/pdf/Referenzlisten/Referenz_APU_en.pdf . So I'm on the same page as you: what's needed is a generator of the kind found in the yacht market. Wrote as much a while back in posts #2128 and #2129 , sections 48 and 50 in particular, at http://www.expeditionportal.com/for...w-6x6-Hybrid-Drivetrain?p=1974111#post1974111 and http://www.expeditionportal.com/for...w-6x6-Hybrid-Drivetrain?p=1974540#post1974540 .

As for the battery pack size, that can be finessed. If the generator really were quiet and "farmer acceptable", then the size of the battery pack would only be determined by the needs of the TerraLiner when driving. Perhaps 100 - 200 KW might suffice. Note that I am currently banking on the forecast that a 300 KW battery pack will weigh about 1300 kg in 2020. That's the figure arrived at with safas. If you think it will be possible to do better, and you have some interesting leads, please post!

Beyond noise, there's also pollution to consider, and so too the psychological dimension. Running a generator for 2 hours to recharge a large, 300 KW battery pack every 3 - 10 days will "feel" much less polluting to a farmer and/or neighboring motorhomes, than running the same generator twice or three times as often to replenish a 200 KW or 100 KW battery pack. Sure, the generator will run for a much shorter period daily. Perhaps just 40 minutes daily, instead of 1.5 - 2 hours every three days (in the minimal solar scenario). But human psychology is a funny thing, and a nuisance repeated daily for a much shorter time-span will "feel" more onerous than a nuisance repeated only twice a week, or even once a week (in the average-solar scenario). Even if the nuisance runs 2 hours instead of 40 minutes, all those days when the generator is never running at all will have a terrific psychological impact. Being able to promise a farmer in advance -- one who lives in an area with good solar DNI -- that the TerraLiner will produce no pollution or noise for 6 or 7 days straight, and will then only run the generator for less than 2 hours, might be music to his ears.

Using an electric incinerating toilet is an option - but it would be very interesting to find out how much energy that would require. I know that the "sanitizer" toilet system was said to use 2 kWh per day for limited use - such as would occur with two people in a caravan type situation - but that doesn't dispose of the waste - just evaporates the liquids and reduces the hazard of the solids. You still are "dumping" the solids some where else.

Combining the electric incinerating toilet with the exhaust of the generator would reduce the amount of electricity required - but it certainly isn't hard to also just build in enough storage capacity for the toilet system to hold three days worth of waste and have it be incinerated when the generator runs. Perhaps only using an electric heating system to evaporate the liquids on a frequent basis and then the having the incineration occur every three days or whenever required would be a successful strategy. I think that if the solids were "sanitized" by an electric heating system in a separate compartment from the toilet - it could remain there for many days or weeks without issue since it is rendered "inert" by the heating cycle. Then the generator's hot exhaust would incinerate it, reducing the volume considerably and making the resulting ash easy to dispose of into a landfill or some other suitable environmentally considerate manner. It might be possible to simply collect the ash into a 5 gallon bucket for many months based on the descriptions of the incinerating toilets operation. This would allow you to operate with "zero discharge" for long periods of time, assuming that the gray water was also recycled.

Fascinating suggestions about a higher-capacity toilet. So here you seem to envisioning a toilet like the Sanitizer, partly composting faeces for a week, its composting aided by low-level electric heat that does not consume too much power; and then blasting it with generator exhaust at the end of the week? How could a "separate compartment" be set up? Do you have any engineering precedents in mind? Did you have a chance to look at the superb PDF about contemporary alternative toilet designs, at http://wedc.lboro.ac.uk/resources/books/Contemporary_Toilet_Designs.pdf ? Fully agreed, blasting the stuff down to ash would not only reduce volume "considerably", but massively. In the case of the Cinderella toilet, for instance, the volume of ash produced is so minimal, that the ash-bin only needs to be emptied about once every 35 days, here calculating for two people taking one poop each per day. And the ash-bin of a Cinderella seems much smaller than a 5 gallon bucket.

From an environmental point of view is there still be a worry about ash? All of the pathogens will have been destroyed, right? The only things remaining that might be questionable are trace quantities of toxic substances and minerals, which all of us now have coursing through our bodies. But even still, I figure that simply burying the ashes produced once a month should suffice? We are not talking a great deal of volume here:






In short, what would your concerns still be about ash?

Over the next week I'll try to digest the electric-Cinderella material even more thoroughly, so that I can guesstimate what the usage might be for two people per day. Note that safas already took a stab at this question much earlier in the thread, when he wrote:

Summary of claimed power consumption of incinerating toilets, electric or diesel:

Ecojohn uses 0.3 l of diesel for waste incineration which equals to 3 kWh and 0.113 l for urine (1.13 kWh).
Incinolet uses 1.5-2 kWh of electricity.
Cinderella - 0.8-1.5 kWh
Usenburn uses 0.076 l of diesel (0.75 kWh)
ADDED:
Separett Flame 8000: 0.4-1.5 kWh
ADDED:
http://www.testfakta.se/node/3244 shows results of electric toilet comparison.
ADDED:
Toamoa 0.4-1.7 kWh

ADDED:
How about burning garbage too?

The double tube intake / exhaust systems is often referred to as being "concentric" or "coaxial" and are a way of improving the efficiency of heaters - it is often used on small "direct vent" or "sealed" combustion wall heaters which often use no electricity. I have one in my shop with that setup and it works great. They are much better than "vent free" type heaters which release the exhaust into the living space and increase the humidity due to the by products of combustion. Traditional non-sealed heaters use indoor air for combustion and therefore need to draw in cold outside air into the heated space and are less efficient / effective compared to the sealed, direct vent type heaters. I've considered installing one of these heaters into my sprinter van for winter camping but have instead insulated it well and used a large battery bank with a mattress heating pad and a small 1500 watt radiant electric heater to take the chill off the room in the morning... but I tend to not stay in one place for more than a night so the engine recharges the battery once I drive.

Many thanks for the nomenclature. Good to have your confirmation that a co-axial chimney and direct venting will significantly improve the efficiency of a heater/boiler such as the Alde, or the Truma. Using "coaxial" as a key search term, I was able to research and think about the TerraLiner's venting system much further. Instead of creating a new post, I expanded post #2460 on the previous page, at http://www.expeditionportal.com/for...w-6x6-Hybrid-Drivetrain?p=2017432#post2017432 . Sure, it drives some people nuts when I expand/modify something already posted. But sometimes it's more efficient to do things that way, because I can simply add material to a train of thought or argument that's already in play. No need to restate or recapitulate. When/if you have the time, please take a look at the finished version of post #2460 (it's now complete, and the whole posting series is complete), and please let me know what you think.

In particular, it would be great to get your feedback on the following paragraphs:

....my intuition tells me that the best solution for the TerraLiner will be having two co-linear hoses running up through the Pop-Up, separate hoses that only culminate in a short co-axial pipe + chimney on the roof of the TerraLiner. Further, it may even be possible that there should be four (4) hoses running through the Pop-Up, not two. On the one hand, when the incinerating toilet is going through its burn cycle, one would want it to draw in the hot air of the diesel heater's exhaust. However, if one merely had a "Y" junction much lower down in the TerraLiner from a single air-intake hose, nearer to where the incinerating toilet and heater will locate, then it seems much more likely that exhaust from the heater might "bleed" into the incinerating toilet when it's cold and not in use. The big plate in the Cinderella would be sealed, to be sure. But once one took a poop, for a brief moment when one lets the poop fall, any carbon monoxide that had collected in the toilet from the running the heater might enter the bathroom.

I don't know if "carbon monoxide bleed" or "backdraft" is a significant worry, and only fairly detailed discussion with Cabby and/or Cinderella could settle a question of this kind.

There's the added complication that one of the main advantages of co-axial pipes, is that the outer "intake" layer serves as insulation for the interior "exhaust" layer. Such pipes still need to be insulated, but less, because the inner exhaust layer is separated by fast-moving air drawn from the outside, air that is presumably cold. At least that's how Alde co-axial pipes are set up, and it's how co-axial pipes used in residential applications typically function. When renovating an old building with fragile masonry, for instance, if one wants to install a stove where before there was a fireplace and chimney, it's best to put a co-axial pipe inside the chimney. That way old masonry will be more protected from the heat. But I came across the following diagram, which seems to get things backwards:







In motorhome applications, the exhaust will most certainly be on the inside, and the air-intake on the outside.

So to add another layer of engineering intelligence (or complication), it may be best if the rigid pipes that lead vertically upwards from the incinerating toilet and the heater/boiler were co-axial in the camper box below. They would then become four co-linear flexible hoses inside the pop-up; and they would become completely co-axial again only at the final terminus on the roof, where the four hoses would merge to become a single co-axial chimney. That sounds complicated, but it's really not, because all the hardware already exists "off-the-shelf", as suggested by the images posted above, or a quick perusal through the Duravent catalogs. Including the culminating co-linear-to-co-axial roof chimney. Seems rather incredible that such stuff exists off-the-shelf, but it most certainly does.

Cleaning might be an issue. But on the other hand, a chimney broken down into "segments" that could be detached would be much easier to clean than a single unitary vent/chimney. The segments would just need to be connected in a very reliable, leak-proof way. Having flexible hoses that could detach inside the Pop-Up, for instance, would provide excellent cleaning access from above for the rigid co-axial pipes that lead down to the incinerator and heater/boiler. And the four flexible hoses could be taken outside for cleaning.

Finishing off this section, it's quite possible that Cinderella mistakenly translated the Swedish equivalent for "co-axial", as "bundled". So perhaps "bundled roof chimney" really means "co-axial roof chimney" -- see http://www.hearth.com/talk/threads/cleaning-coaxial-pipe.120298/ . In any case, this seems by far the best form of venting. And if what I have written above is correct, then it will prove the most energy-efficient as well, contributing significantly to the power of the heater, or the speed of the incinerating toilet.

Just one last question: what model of 1500 KW electric heater do you use?


All best wishes,




Biotect