John Michaels - Modern Desert Cave Dwelling

[Johnus]

I'm new to the scene (I don't know a thing about architecture!), and I'm not sure if I'll be able to finish, but here's my entry to the Off-The-Grid Challenge 17.

I plan on placing this house in a high desert mountain local, and built into a (mostly) naturally-formed cave. Excess material removed from the cave walls can be re-used in the building materials for counter tops, floors, or even the exterior walls to help blend it into the environment. I still need to research the strength and stability of such material before I decide where it will be used. Landscaping will be lush and colorful, but native to the region and will require no forced watering, other than what I will detail below.

To stay off the grid, I have devised a series of processes which will complement each other, all fed by a desert spring. The spring's resulting stream will feed into an intake box that drops to a Micro-Hydro Turbine. With a 6-foot intake plus a planned drop in elevation in the system, this should provide enough water velocity to output the turbine's maximum of 2kWh 24 hours per day. This power will feed into a charge controller, which will keep a battery bank charged (which will in turn provide all electrical needs of the house). Since the power flow will be mostly constant - depending on rate of flow in the stream - there will be excess energy created once the batteries are topped off. This "dump load" will be diverted to power a geothermal heat pump. The heat pump will be a liquid-to-water system, utilizing the water from the turbine's outlet. The interior temperature will be regulated not only by the cave's natural thermal insulation, but radiant underfloor heating/cooling via the water loops.

The exhaust water from this system will be quite a bit warmer than the spring water (the literature for the heat pump I was researching claims up to 50 degrees Celsius, depending on location), and will be fed into a thermally protected underground storage tank. From there, this warm water will be diverted to three places:

1. An electrolysis machine. This will use power from the turbine to separate the water's Hydrogen and Oxygen atoms, and store them in separate high-pressure tanks as needed. The preheating of the water by using the exhaust from the heat pump requires less power for electrolysis than with cold water.
2. A tank-less water heater, powered by Hydrogen. Hydrogen burns slightly hotter than Propane, and since it's effectively free (other than occasionally using energy to top off the high-pressure tanks) this should be a very efficient system. The preheating of the water will result in an additional 25-50% energy savings.
3. A natural swimming pool. Since the flow of warm water is constant, the thermal storage tank will need somewhere to put the over-flow. This way, the pool (which requires no chemical treatment and is safe for both people and the environment) is heated year-round at no additional energy cost. The pool's water level will be maintained through both natural evaporation and underground channels that will dispense the excess water much like an agricultural irrigation system. This will provide any necessary watering for the landscaping.

As for lighting, I plan on using a hybrid solar lighting system. This uses a roof-mounted (or in this case, cliff-mounted) light collector, optical fiber, and efficient low-wattage LED lighting. Normally these systems use fluorescent tubes, but LED's will last longer, use less power, and will be able to more closely match the incoming light's color temperature. The LED's are attached to transparent rods connected to the optical fiber cables. Almost no energy is consumed for daytime lighting, and as it gets darker outside, the LED's slowly ramp up their brightness so there is no discernible light difference during the transition from day to night - other than what you get through the windows.

For sewage, I will use a MicroFAST Waste-water Treatment System. A blower pumps air into an airlift, which forces waste-water over a medium covered in bacteria. These bacteria feed on the solid bio-waste. After they have digested everything consumable, the excess solid waste settles on the bottom where it will eventually have to be pumped out (although I believe it needs to be pumped out far less often than a typical septic tank). The treated waste water is then allowed to drain back into the stream. The treated water is apparently safer than most municipal water sources.

If any additional heating is desired, the house will also have an indoor fireplace and an outdoor fire ring, powered by the stored Hydrogen and Oxygen. The Oxygen is added to make the flame more visible. Because of the Hydrogen's clean burning nature (the fires should only expel Oxygen and a small amount of water vapor - both good for your health in the high altitude desert), there is no chimney required - which would be a hassle in the cave anyway. The stove and oven in the kitchen will also be powered by the Hydrogen mix.

Exterior lighting will consist largely of self-contained solar rock lights that illuminate at sundown.

Since one of the guidelines is to keep the assigned structure mostly intact, I believe I am going to bury the garage level, so from the surface it will appear to be a one-story home embedded in the rock face. There will be a ramp leading down into the garage. This way a greater portion of the house is naturally insulated and also more protected against any natural or unnatural disasters (Nuclear Holocaust, anyone?). Even the lower, buried level will be able to make use of the Sun's natural lighting via fiber channel.

To protect these technologies against the elements and for longevity (many components have duty-lives of 50+ years), everything except the solar collector will be buried and invisible to the home owner or viewer. I think this is one of the best things about my plan besides the efficiency, (almost) no unsightly green technology (solar panels, water wheels, wind turbines) to interrupt a natural desert oasis.

I will follow up this post with a few sample images of some of the technologies involved, as I'm saving this one for the final picture.

[Johnus]

If anyone has any questions (or recommendations...I'm not quite sure how I'll do all this yet!), let me know!

[AubreyM]

Welcome to the forums and the challenge.
Good to see that you put some thought into this. Now take that process and plan out your scene. Make a sketch, rough it out in 3d, which ever your preference so you have an idea how you want it to look.
You can do it

[Russell L. Thomas]

Very nice, I had actually thought about playing with a cave house concept for fun, mine was going to come out of a cliff face! Really like how much thought you have put into this, we wish you good luck with it!

[Johnus]

I'm going to start out small and work my way up, building it piece-by-piece. I've never done anything this complex before. It's quite overwhelming when I think about what's going to have to be created from scratch... Here's the beginnings of a solar-powered rock light for the front yard.

[O'Neill]

Welcome to the challenge, and very nice idea! Look forward to seeing more.

[Johnus]

I still have some tweaking to do and a spotlight to add (plus I'll probably modify the texture to better match the final image), but here's the solar-powered rock light with shaders and deformation.



EDIT: I was playing around with some atmospheric lighting and added a temporary ground shader just to see if the light reacted as it should. I'm adding it to this post because I didn't feel it deserved its own.



Unfortunately with the darker photos, a lot of the image fidelity and quality is lost when uploading to forums.

[AubreyM]

Nice textures.
That is the way to do it, manageable chunks. A little here a little there and you'll get'er done

[Johnus]

Been busy, and I wasn't able to access the site for several days, but I worked on a couple things. First up, a Parabolic Grid Antenna. Gotta get internet access and phone to the OTG house somehow...



Shaders will be tweaked when I put it in the scene. I'll likely camouflage it in some fashion.

Next up, the Solar Collector:



I'll get some shaders on that after I've finished a Battlefield 3 gaming session later today. There's a lot more detail that can't be seen without transparency.

[Rod]

Being a hermit at heart I've always been intrigued with cave dwellings. Light into the rear is always a real challenge. Good luck on your progress, and welcome to the challenge.