I've only been addressing most of my posts to egn, because he has been so enthusiastic about my project, and so helpful and supportive. Indeed, egn has become a kind of ersatz "client", for whom I now seem to be designing the TerraLiner.
Sorry, but we are very happy with our camper. And even we were not, and it wouldn't be a CBE design
, we wouldn't be able to afford it. :hehe:
As it is easier for me I will use metric units in all answers below.
A. The size of major tanks
It makes no sense to to put abnormally big tanks into an vehicle, because as I already have stated, we are very limited in available volume in the vehicle. So the size will be a compromise regarding the self-sufficiency which someone wants to achieve in certain environments with a specific comfort.
So your question regarding size for "two months off-grid boon-docking" is incomplete, and there is no absolute answer that is a perfect match for everyone. If you look at the sizes of freshwater, gray water and black water tanks, everything is tightly connected. The more freshwater you use, you will need larger tanks for grey- and black water, too. It also heavily depends on how efficient you are using the resources. This is not only dependent on personal comfort, but also dependent on the used appliances.
So an answer can only be given when you know all the variables in the equation and the solution is only valid for a specific user.
What I can give you are some examples regarding our camper:
1. Freshwater (2x raw water tanks a 250 l, 1x drinking water tank 150 l (filtered with 0.5 micro m, UV disinfection)
The water from outside goes into one of the water tanks, either from a pressurized source or is pumped with a build-in pump. It is only filtered regarding sand and other larger particles. The filling goes very fast as this need no large pressure and the fill rate is only dependent on the source.
The drinking water tank is then filled with a regular pump through the trinking water filter, with about 10-15 l/min. The drinking water filter can filter particles as small as 0.25 micro m (depending of type of filter element) and is a combination of micro filter and active coal. It filters particles, biological items and a wide range of organic and an-organic chemicals.
To keep the water biological inactive in the drinking water tank, there is a UV disinfection lamp installed, which is only used occasionally for a few ours if there is not much water use.
All water inside the vehicle is taken from this drinking water tank. For two adults the total of about 650 l water is good for about 14 days, including showers every two days. But normally we take bottled water as pure drinking water, then it is good for about 3 weeks. If there is a chance to take showers somewhere else the water will last much longer.
So if we take the 14 days to about 60 days, we would need about 2.500 l fresh water tank. That is far away from practical, at least not for a permanent installation. If you want to achieve that, you have to look into saving water as much as possible and probably use it mainly for drinking, without showers and use for the toilet. With 5 l/person/day then 600 l would be enough for 60 days. But this all will not be comfortable anymore and not a concept that sells in the luxury market.
2./3. Greywater (200 l) and blackwater (200 l)
The size was dictated mainly by the available volume. We have put both greywater and blackwater tanks below the floor of shower and toilet. The sum is smaller than the total size of the freshwater, because it is not to hard to get rid of both content. In western countries you often have infrastructure available and a discharge every 1-2 weeks seems to be no problem. In all not so densely populated countries, you can discharge both without much effect to the environment.
For same reason mentioned for freshwater, for me it would make no sense to put 4 times larger tanks into a vehicle.
At start of the project we also thought about a composting toilet, especially because we had many years of experience with the cassette toilet. But with 4 persons traveling at that time, the cassette had to be discharged every two days. We had a second cassette for emergency, but it wasn't a delicate jobs to do the discharge, and you had to constantly look for a place to discharge them correctly. But finally the decision was against the composting toilet, because it didn't gain the the Wife-Acception-Factor (WAF).
We are very happy with the Sealand vacuum flush toilet. It works flawless, it can be used like a normal toilet and it has the advantage that only about 0.5 l water is normally used per flush. This reduces fresh water use considerably.
You wrote about reuse of shower water for toilet flushing. We have thought about this but dropped the idea because of the extra tank necessary and the problem with the odor of grey water. It may start to smell bad very fast in the toilet.
Regarding type of shower we see this totally different. We had a very efficient camping shower in our Concorde and were constantly annoyed that it took very long to get wet fully. Especially the ladies with their long hair needed a lot of time to get wet and to remove all the shampoo again. The total amount of water used is the product of water flow per minute and the time in minutes. You save absolute nothing by using an efficient shower head, if you have to shower longer to get fully wet or free from soap.
So we took a totally different approach by using a large rain shower. You turn it on and you are totally wet within seconds. For this we installed separate high flow pumps for cold and warm water, which is mixed by a thermostat.
The same happens when you want to remove the soap. As there are separate controls for temperature and water flow, you can easily start and stop the water flow without changing temperature. One complete shower uses 10-15 l water.
Fancy faucets doesn't save any water if you have water use in mind. If you need 1 l of water for tee than you save nothing with a fancy faucet, it just takes longer. Important is that you can control the water flow easily.
So it is more of an design decision what you finally take.
What may be interesting are appliances like the
Quooker, because you can save energy with it in every days use.
D. Water-making/Purification
Yachts can constantly use water makers because they a floating in water that can be used as source and at least motor yachts have a generator running constantly to provide electric power. Osmosis from salt waster is very power hungry and solar power collected by PV on a vehicle will not be enough, if you have to use electricity for other things also. Water making by osmosis takes a long time and is then only worthwhile when staying longer at the place where the water is available. Please keep in mind that with osmosis you can use only a certain percentage of the raw water, depending on the water quality. You also have to maintain the system.
For low to medium quality water found purification with filters is the way to go. There are a lot of systems available in the market with different performance. The most famous are Katadyn and Seagull. They are very costly and the water throughput is not very high compared to the cost, so most people use them only as poor drinking water source. In my opinion, if you want a larger volume then other filter solutions combined with UV disinfection are a better way to go.
E. REFRIGERATOR & FREEZER
We use 24 V fridge and freezer build for marine use, because
- they can run without any inverter directly from the battery,
- they are made to run in all positions seen with offroad vehicles,
- they keep the content where it is intended to be,
- they have reliable door locks.
Home appliance become more and more popular for RVs because they are cheap compared to the 12/24 V versions, which also use different compressor technology. Top modern home-appliance fridges are very energy efficient, but the necessary constantly running inverter will make the advantage negligible. Reliability in offroad-use may not be of concern, because there are already a lot of people using them off-road, and I didn't read any negative comments yet.
For me the other points are important. You don't want that all the items are flying around in the fridge. Look at the images you posted. Where does the content go when you drive off-road?
Function should go before design here. This doesn't mean that the appliances should look bad, bad you should always look for function first.
May be as next project you can design a nice looking off-road fridge.
You may find similar fridge/freezers in the commercial market, where presentation of content is more in focus then energy efficiency and functions necessary for off-road use.
What size they have to be is also heavily dependent on what cuisine you like. But the typical fridge/freezer will be always to small for two months food, if it consists mainly of fresh ingredients. Just look at home how much space you need for food for just one week. So you have to have uncooled storage space outside fridge/freezer to take enough calories and other food with you. This may be a lot of pasta, rice, flour, ... as basic carb providers, and canned food as protein and vitamin providers. Fridge/Freezer will hold only that food that really has to be cooled.
What we do for longer tips is to pre-cook and preserve main courses without side dishes in glasses, that was also done in the earlier days when fridge/freezers weren't that wide spread. The food is preserved for months at room temperature and on glass contains a main course portion for 2-3 people. You just have to heat it and cook a side dish like pasta, rice, ... . The complete meal is ready within 10-20 minutes. The storage needs no extra cooling and is done in our relatively cool cellar below the kitchen floor.
You really get the most out of the available volume if you store the base food ingredients in a way so that it needs no extra cooling. So it should be no problem to store food for 2 months outside fridge/freezer. You can the keep the fridge/freezer free for cold drinks and ice.
We never liked the idea of diesel hobs, because they are just not as comfortable as typical house-hold appliances, they do smell and they don't work at higher altitude very well. Original they were build for marine use at height zero, and at heights above 2000 m they don't work very well.
We have a normal electrical hob with Ceran surface and with mechanical switches. Induction saves energy, but adds more sources for failures. We save energy when cooking by using other appliances. I.e. we use the microwave to heat a cup of water, an electrical water kettle for heating larger amounts of water, like for cooking pasta. We use our two-sided contact grill to barbecue meat, fish, vegetables, ...
G. GE MICROWAVE / HALOGEN OVEN
We use something similar from Bosch, which combines normal oven functions with microwave. Something like this is certainly a must to make something delicious from base ingredients. It is used same as at home to bake bread and cake.
H. SPLENDIDE WASHER / DRYER
Currently don't have it on board, because for our current trips up to 6 weeks we don't need one. We have enough clothes with us and there is always a possibility to wash in between at a official camp site. Please keep in mind that washing needs a lot of energy and water, so it easier to use available infrastructure. Of course, when we will be on longer trips we will have one on board.
Here in Europe the small models of Candy are used very often. With some you can lock the drum from outside to avoid damage of the drum when going off-road.
This is a waste of space and resources for us.
We have a Webasto Thermo 90 ST diesel heater for both space heating and warm water. For warm water we have a boiler that is heated by a heat exchanger or electrically.
Currently we don't have air-condition, because we always like to adapt to the climate of the region we travel. But for redundancy regarding heating, we probably will add a highly efficient inverter air condition unit, combined with heat pump function.
L. SUPER THIN-FILM SOLAR & KIMBERLEY
For an integrated vehicle this is certainly the way to go. You can place solar panels everywhere. If the efficiency is as high as with regular panels, the only disadvantages are that the panels are not cooled very well and you get no advantage through the tropical roof effect when they are placed directly on the roof. Instead the hull of the vehicle is heated additional an the panels go up to the highest temperature with an efficiency drop of about 30 %.
The "innovation" of Kimberley is very old and has be used with stationary camp trailers for long time. With mounting regular panels on the roof you get this effect automatically. By design I avoided any holes in the roof, because they have disadvantages in hot and cold climate.
A kind of tropical roof should certainly be a design feature for the Terra Liner.
N. LITHIUM BATTERIES & FUEL CELLS
Lithium is certainly the way to go for energy storage in the future, but fuel cells are far away until they have a reliability of at least 100.000 h and the fuel can be conventional diesel available everywhere. I don't mean low-sulfur diesel, which is only available only in specific areas on the world.
For the diesel engine scenario you need approximately the same space as with lead-acid batteries. The size is dependent on the average daily energy usage less the available energy from solar, and the days you want to be only on battery without running the engine or a generator.
For the electric-hybrid scenario it depends mainly on the pure electrical range of vehicle, and whether the fuel engine(s) are capable enough to fully power the vehicle most time.
So you have to determine this parameters first to be able to estimate the spatial requirements.
O. DIESEL SCENARIO: SOLAR, BATTERIES, and GENERATOR
You know the parameters of the Shachagra Expedition vehicle, you should get the size by yourself through research with google. I don't have the numbers present and would have to research myself.
Regarding generator I would looking into water-cooled units where the waste heat could be used for space heating and warm water. Fischer-Panda is a good start. It is important to have a unit with low maintenance. Nobody would like to do maintenance in cold climate every few weeks. Maintenance once a year would be ok.
P. ELECTRIC/HYBRID SCENARIO: SOLAR, BATTERIES, and DIESEL GENERATOR
For an electric/hybrid you need 2 units of something like this.
You have to power the vehicle fully during travel. With highway speed you will need about 100-150 kW power on average. Off-road you will need much more, at least for peak power. A part can be supplied from the battery storage, but sometime you have to fill the storage again.
May be you can make an arrangement with Tesla regarding use of the super chargers. But of course, they will not be available in the middle of nowhere. :sombrero:
Q. DUAL HIGH-OUTPUT ALTERNATORS instead of a DIESEL GENERATOR?
We have done this for 5 years with an high power alternator and it worked fine as long as you move within the storage capacity of the battery. But if you stay longer than a week, in winter then you would have to run the engine, which is not accepted everywhere.
I also don't believe the numbers cited. It may be true that Ford engine is more silent and uses less fuel than the Fisher-Panda when the Ford is idling. But I don't believe that the alternators will produce the same power as the Fisher-Panda when it produces 4000 W. The power of alternators his heavily dependent on rpm. When the engine is idling, alternator normally deliver only a few 100 Watts. The transmission is normally designed to give the full power somewhere in the upper rpm range of the engine.
A comparison at idle is pretty useless. The comparison has to be done at a specific power output of generator and alternator.
Beside this, idling is not allowed in most countries.
Regarding other alternators you should look at the truck manufacturers first, because with todays electronics it may not be possible to fit other alternators, at least not if they feed the same battery.
Here you to know the power and what features you need. If you install a lot of electronic anyway, you may look into complete electrical systems from one supplier, like Victron, Mastervolt and others.
Regarding further discussion of CBE, I cannot deliver much input, because I find this concept not very attractive to me. Sorry.
