We built a State of the Art off grid home to demonstrate how you can live in a Secure, Comfortable and Independent environment without being connected to the Electrical Grid.
For more informatin contact:
Kevin Gedney, firstname.lastname@example.org
Utilities are starting to "catch on" to the "green movement" and are increasing the fixed monthly connection charge instead of KWH rates. Disconnecting completely is the only way to eliminate this ever increasing fixed cost.
For homes with septic tanks that effluent can be used to grow algae using photo-bioreactors to purify the water, it only takes filters for full recycling algae are very good at cleaning water, Earthships use this effluent for outdoor landscape gardening it's worth about 1.5-gallons/6-liters of biodiesel per person per day, it's a lot of biofuel.
These units are cubes 1/2m on a side that stack 6 high and full of glass plates given light, air & climate control to grow 24x7 to keep up with volume, takes 4-6 of them per adult.
I do have a lot of work on full systems that separate solids for digesting to toxic waste, there's a need for this, and the effluent is mixed for growing algae.
Rain-catchment is part of my systems and for non-prefab cisterns for agriculture have ballast-rock cistern designs that hold an acre-foot of water on 1/2-acre of catchment for scale.
This allows a farmer to store water when it happens to use when needed, same principle for a home of course it's a strategy to gain the ability to grow crops with variable rainfall dates outside of tradition now seen globally by farmers.
For space heating & cooling, hot-water consider flat-Fresnel, east-west axis collectors insulated to capture the hot or cool air in the enclosure the pipe gives up to 300C using a thermal-fluid for hot-water, I'll be running 3d-printers with it they use 20% electricity the rest is Joules so way cheaper cost-per-unit.
To store those therms consider a ducted thermal-mass stack in the crawl space or as a deck to store & reuse daily needs; storing heat-cold for hours puts the home off-grid as it's the thermal-mass capacity with collection as a system missing from architecture.
Finally, I challenge the standard stud wall on a thermal basis, consider that sheetrock is a thermal collector, studs are conductors and sheathing is a radiator, a perfect way to pump heat to a cold outdoors, eh?
From many heat-transfer runs it became obvious insulating on the outside of the sheathing is 3-4 times less heat-loss than the standard wall.
The image below a run of 6-2/3 hours showing this, blue is 0C, white 20C, 1-1/2" of insulation board added along with furring strips to hold the siding away from condensation this also reduces radiative losses & gains. The results are rather explicit.
Hope these concepts add to others' interest in off-grid thermal energy and water systems.
How is the siding connected? In North Carolina we rely on the structural elements of outside sheathing for resistance to high winds. Can we get this same strength using the foam board layer ?
All well and good, but you still have to come up with solutions to provide electricity, space heat/cooling and HWH during the worst months of the year. I'm in a Northern heating climate so I've thought about this a lot. Seasonal storage for space heating with sand beds or Thorsten Clupp's approach are possibilities, but what about electricity?
The largest issue being off-grid is thermal energy, heating & cooling my guess 80% of needs the rest is electricity for a typical home including the hot-water & laundry.
Firstly is that Long-Wave Infrared, LWIR is conserved cloudy day or not so heating happens all day unless the clouds are truly dark in winter, for northern latitudes it takes concentrating collectors to utilize these therms, a flat plate & piping won't go very far.
Since each location is needing to be customized, installing collectors where they are best sited on the lot is today quite easy with most of the parts OTS so the next issue is the thermal battery, the thermal-mass to use to store excess heat-cold for the daily cycle plus some.
You're solving that with the sand beds, consider my latest using dirt for the thermal stack that's ducted with 3" used aluminum irrigation pipes in the dirt, that fits standard ducting to link it to an existing system, this would work with the sand & makes it easy to plug in.
The next issue is to collect the hottest air from the existing heater to go into the thermal-mass before into rooms thus capturing most of the heat lost quickly by standard systems into the mass for later release, this is a big deal.
Now add in the collection system, it gives options to use a main heater pipe to capture up to 250C/480F in a thermal-fluid and if you enclose that in an insulated collector you get hot air for space heating from the pipe to blow into the thermal-mass.
Mirrors are expensive and unsightly, consider flat-Fresnels focused on the pipe and matte-black absorption wings of sheet metal to capture heat from the air.
So the solar system only needs to supply a lessor amount of energy having the thermal-mass than assumed by most people, it's a key issue to take those Joules away from needing electricity for off-grid or to burn a fuel for them, they are expensive.
With 8-kwh and larger battery-inverter systems the generator most off-grid people have can be replaced by more panels or my fav are small vertical-axis windmills 2kw each, the wind is the high-current source for off-grid and with storage doesn't matter when it happens pick a spot that usually has wind in afternoons an example that it doesn't need to be strong if it's fairly reliable.
Now consider real costs. If you buy & install a system on a loan you pay an amortized monthly for power all kinds doesn't matter how much you use or not.
If you pay for that same power by-the-watt or need to buy fuel to get it it's not a monthly payment it's a bill based on how much you use.
As a small biz if you use a lot of power it's bottom-line profits out the door to pay by-the-watt vs ownership.
So part of the economy of alt power is that they are way cheaper to own so worth the effort.
This all to fit existing homes I do have an integrated design I call the Spartan Farmhouse that combines all this with indoor growing for basic greens & sprouting, another thing is taking the septic tank effluent to grow algae for biodiesel at the home so your waste becomes a biofuel for the car, works at home, farm & ranch scale.
It's an all-electric small home so the kitchen, hot-water backup an inline on-demand heater, and the air heating backup much smaller than for a typical home. This has 3kw of panels on the roof that uses the panels to heat air and keep them cooler roof is angled for solar gain.
You will definitely use your generator more but with the thermal properties of the building shell your Energy Use will be manageable with a good size Solar PV and Thermal System.
In the North, when the heat is needed most is at night and on colder, cloudy days. PV won't work, hence storage is necessary. Tons of batteries, or water thermal or masonry thermal. How much? depends on the house and the weather. This is a tough nut to crack, but falls under the rubric of "seasonal storage" Or you have wood/propane backup.
Integrating it all is hard if the design didn't have that in mind & few homes do other than Earthship Biotecture's designs, there are few to claim such.
I have an integrated all-electric off-grid design, the Spartan Farmhouse, that simplifies everything a reaction to complex piping in a always-custom no-standards world and suggest to everyone to have Earthships do your water & power systems, they build a package to your spec & have standard ones and importantly have it down on permitting games & all.
I will use their packages, from-scratch versus turn-key with decades of refinement on reliability.for off-grid they've done rain-catchment to cistern the whole time with re-use of water based on septic-tank systems to 20-gallon/day/person usage for modern living.
To overcome all this with an existing home is why to use collectors and a thermal-fluid high-temp storage in a cold climate where on bad days a flat-plate will hardly heat at all and a strong reason to go to the hassle of installing it.
Their experience has a simple low-temp collector for hot-water but they are mounted with max solar gain, why I know most people will need elevation tracking on collectors mounted east-west to cover a large spec home in a fancy neighborhood.
Either way it heats hot-water to a 150-gallon heater, oversized is more thermal-mass so draw-downs take a smaller percentage of the tank, next person has hot water even with company few times require the on-demand.
Backup is an inline electric on-demand, rarely needed great for passing code and a heat-exchanger to heat air when needed any time any reason maybe you want to crank it up to thaw out, passive systems can't do that having the high-temp offers the option.
That's the payback for high-temp collectors and they are needed for higher latitudes in a modern home not designed for off-grid as they have a huge surface-area penalty and don't insulate from the exterior.
Earthships learned to add a layer of soil-contact insulation to separate the thermal-mass associated with the home and grade. I was taught that by example with my first passive-solar in 1980, the building gained too much so we never hooked up the thermal-mass, a pile of rocks with difficult ducting.
From the heat-transfer modeling it obvious to insulate on the exterior of walls, conduction is the enemy and studs transmit too much heat, apply that principle to the foundation first as it's the thermal key to least input energy home, literally one can expect to need more heat if your crawl space & foundations are at grade temperature.
For cold climates my dream location a mountain pass has a year-round soil temp of 43F/6C not far below the surface, this sucks heat year-round from a home. It pays to use soil-contact on the outside of the foundation to the footings to deal with this especially with a basement below grade I found it would pay to use R-30 to wrap the concrete walls.
That changes entirely the feel to the rooms they have a cold floor but the walls aren't cold and have far less condensation and fungal problems. Adding the board you backfill with ballast rock for 12" to drop pore-pressure in soils and drain any water to the footing level there tiles or ballast to carry it away from the building. The footing rock vents radon from under the crawl-space thermal mass.
This is the stack, it shows a water bladder tank for where to store that many kJ's it'd take too much space for only dirt, specs to design one listed. Once you have a way to store air heat-cold it changes the ballgame. [Missed updating some text from the earlier idea of using cement blocks sideways for ducting now that's used 3" irrigation pipe the blocks took custom manifolds the pipe fits standard 3-1/4"x10"].
First off, check the laws in your area. Drought prone areas often prohibit on site collection / retention as hoarding a resource the gov't needs to amalgamate and manage for the good of all. Many areas prohibit on site treatment and re-use of waste water.
Utility independence is a tall order as the homeowner needs to be as responsible as the managers and government regulators are to provide constant elec, pure water, and safe sanitary disposal of wastes. In urban / suburban areas where risk of contamination from poorly treated wastes, and spread of diseases from contaminated water can effect many quickly, we are no where near ready.
I would urge people to do the best they can to reduce water and electric use, waste generation first and foremost. Undertake what on site re-use is simple, proven, safe and with short paybacks, such as composting in drums or with worms, COVERED rain barrels at downspouts, recharge "water gardens". Then invest your money in what has the most environmental impact per buck, be it PV on site, Community Solar off site, buying "green electricity" from your utility (try to ensure they aren't just selling you the hydro they've had on line for 75 yrs already), or sponsoring forest preservation. Building an expensive eco - ego statement isn't the best way to save the planet.