Even in a world where mass transit is the norm, we think there is a place in a sustainable culture for motorhomes and travel trailers. In brief, we see a hybrid electric motorhome getting 50-plus mpg, that uses no fossil fuels, never needs to be plugged in, never needs to visit an RV dump station and almost never needs to be filled with water. Here are the details of the ultimate green traveling machine we are building toward:
- Engine: hybrid diesel electric or onboard hydrogen fuel cell
The hybrid diesel electric will include four electric motors mounted over the wheels, which will be powered by a large battery bank that replaces the engine. The batteries will be charged by a combination of the alternator, solar PV panels, regenerative braking, and when necessary, the onboard vegetable oil powered diesel generator.
- The hydrogen fuel cell motorhome will produce hydrogen onboard with electricity coming from a battery bank powered from the same sources mentioned above. The batteries will provide the electrical juice to convert water into hydrogen, which will then power the engine. The water will come from the greywater recycling tank, which will convert sink/shower water into usable water. Fuel mileage becomes a thing of the past.
- Body construction: recycled steel or carbon fiber chassis, recycled aluminum or carbon fiber frame with an aerodynamic molded shell of recycled aluminum or composite. Instead of a literal brick on wheels, this motorhome will take more of a bullet nose shape, with the cockpit still providing enough headroom but built in a much more aerodynamic shape. We believe that with this more aerodynamic, lighter weight frame paired with the hybrid electric engine, fuel mileages upwards of 55 miles per gallon would be possible in a 20,000 lb vehicle.
- House electrical systems: fully solar powered
Through the use of a roof with paint-on solar paneling, solar fabric awnings, small wind-power turbine and high quality batteries, the motorhome will generate enough electricity to power all house systems, especially when paired with energy efficient appliances.
- Interior/exterior lighting: LEDs or OLEDs
With the same number of lights that put out the same amount of light as contemporary fluorescents and incandescents, the motorhome LEDs will use 97 percent less electricity, the equivalent of what one contemporary refrigerator light uses. The SolTrekker prototype has already accomplished this.
- Wall/window construction: high efficiency insulation
Using dual pane windows and nano-insulating panels and paint that triple or quadruple current industry R-values, the ideal motorhome also uses that much less energy for interior heating and cooling. In addition, snap-on interior insulating shades as well as exterior window shades provide even greater all-season comfort. The SolTrekker prototype has made significant strides in this direction.
- Interior heating: fully solar powered
Instead of using the old forced air, propane/diesel powered systems, the ideal motorhome uses solar power. Roof mounted or side mounted tilt-out solar thermal collectors coupled with a super insulated heat exchanger provide hot water for several days after receiving just four hours of direct sunlight. The hot water is used in the sinks/showers as well as in the radiant floor heat system. An electric heating coil (still solar powered) is used as a back up during four or five day stretches without sun. The SolTrekker prototype already employs this exact system.
- Interior cooling: fully solar powered
A small air-conditioner powered by the solar-generated electricity could be used, as well as a water chiller that supplies cold water to tubes in the walls and ceiling. This technology is currently employed in the residential and commercial market, and could be fairly easily adapted to the RV. This would be the priority for RVs intended for use in the Southern U.S.
- Solid waste treatment: composting/dehydrating toilet or methane digester
There are choices to make here. When dealing with solid waste, it may be ideal to mount the toilet above an onboard methane digester, which produces usable methane fuel. Another option, and the one the current SolTrekker motorhome employs is a waterless toilet that separates liquid waste from solid waste, sending the liquid waste to a separate tank where, it can be disposed of as regular sewage or mixed with 8 parts of water and used to fertilize plants. The solid waste gets fan-dried to speed the composting process. Some toilets super heat the waste, turning it into a small amount of odorless, bacteria free powder that can be stored in a vacuum bag, but these systems were beyond our current budget.
- Washwater treatment: greywater recycling
The current SolTrekker system is fairly ideal. The greywater from the sinks/shower is sent to a recycling tank where it is UV treated so that it can be used for another cycle in the sinks. Perhaps filtration technology can get to the point where it can economically filter the recycled water to a potable state.
- Greywater supply/storage: Rainwater catchment system
The SolTrekker prototype employs aerodynamic stainless steel gutters mounted near the roofline that capture rain run off and direct it to water storage tanks inside the motorhome. The water is cleared of sediment and filtered here where it could be treated to become a potable source or used in showers/sinks.
- Cooking: vegetable oil fueled range and pull-out solar oven
Instead of using propane to cook, we've gone a step further with the SolTrekker prototype and added a burner that is fueled entirely by vegetable oil in a very efficient burner. Ideally, we'd like to add a high quality solar oven in an exterior compartment that can be pulled out on nice days for a renewably fueled cookout.
- Interior materials: produced from non-toxic, sustainable sources
The SolTrekker prototype scores pretty high marks here. The material list includes: recycled denim insulation, cork flooring, bamboo wallboard and bed frames, natural wool carpet, recycled glass tile, re-used cabinets, recycled composite countertops, natural hemp fabric valances and upholstery, zero VOC paint and NO VINYL! That's no to say these are the only sustainable choices, and we're sure that there will be a bunch of future improvements in this realm.
- Interior design: efficient use of space through convertible design
The SolTrekker prototype uses bamboo framed ceiling beds (with very comfortable pillowtop air mattress) to make the best use of space. During the day, the space is usable for working/sitting/walking and can quickly and easily be converted to sleeping space at night. Future upgrades could include the addition of pop-out tent awnings that create screened in porches.
- Kitchen waste: composting worm bin
Our ideal motorhome would carry a composting worm bin below decks with a sealed trap door housed in the kitchen where scraps could be dropped in. Below decks, in an exterior compartment, the worm bin will pull out for fertilizer harvesting.
- Deep space travel: hyperdrive or wormhole generator
We're already so close to our ideal that we had to add something crazy. C'mon, who wouldn't want to bend the space/time continuum?