Posted by R. Ticle on
URL: https://www.es-forum.com/Please-help-design-an-EMF-safe-off-grid-home-tp1548899.html

Hey everyone,

I've wanted to go off-grid for some time now. Financially, it's still out of reach, but I will do it some day, hopefully within a couple of years; I don't see much point in sticking around in the suburbs in a larger than necessary house, relying on an AC power supply of questionable cleanliness andreliability. Besides, off grid implies, for me, rural, and with enough scouting around, better RF-wise.

So - I want to build (with help of course!) a small, year-round, sustainable off-grid home, on wheels. I'm one person, single (not forever, I hope!),and don't take up a lot of space, so I'm probably looking at 150 to 200 square feet, with a loft upstairs for sleeping in, thus freeing up room downstairs. A design will probably be loosely based on the models of the Tumbleweed house company, you can see an example at: http://www.tumbleweedhouses.com/houses/fencl/
(Those prices, BTW, are for them to build it, not build-it-yourself).

Now, going off grid means no constant AC current running through the house - awesome. But from an EMF standpoint, I imagine the design and implementation offers its own unique considerations and challenges, which I hope you all can help me with.

The first which I think should be addressed is solar power. Obviously, my electricity is going to have to come from somewhere, and that primary source will be solar panels and a battery bank. The first thing I'm confused about is placement of the panels. Many houses mount them on the roof - however, in house designs like this, the roof is directly above the loft, and therefore above the sleeping area. Do the solar panels or the wires which run to the batteries emit anything to be concerned about so close to where you spend your time sleeping? And is there a way to address this?

The second part of solar which I'm unclear about is inverters: Someone (Bill Bruno, I think) may have said that solar panels don't necessarily use inverters, but current controllers, and the problem with them is that many controllers use PWM (pulse width modulation) - though, Bill pointed a popular model out which is PWM-free. However, all the off-grid designs I've seen specifically mention inverters. Why? Do I understand that an inverter is used to change the DC to AC? Or is it something else?

And would I need an inverter if all I'm running are DC powered things: a DCpowered computer, LED light bulbs, a pump for running water and a small motor to push hot air from a small propane marine heater as a furnace, and perhaps a small venting fan for a composting toilet?

If an inverter is necessary for these things, how does one go about filtering it (because if I understand correctly, the problem with inverters is thedirty frequencies they produce). On that note, I did see one inverter which claimed to produce a "pure sine wave" of AC power: http://www.realgoods.com/product/id/1008161.do

But again, this seems like something only to convert DC to AC (I guess if people want to run AC powered appliances in an off grid home?) Do you think such an inverter would be a good option to install in order to allow for ACpowered things to be run as a possibility?

Gah, the whole inverter thing really confuses me.

Oh - are there any unique considerations if I were to implement a small wind turbine, too? And would the wattage of the solar setup make a difference?
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Moving on from that, comes the question of wiring. If I'm talking about everything using DC, are there any considerations for wiring to take into account? Shielded, magnetically, electrically, or anything?

As for motors: Bill, you explained why DC motors may not be good because they convert DC to AC using brushes or chips, if they're brushless, but both can produce dirty AC. What about the kind of motors I'm talking about using - for an in house water pump/on demand propane based hot water heater, possibly forced air furnace, and maybe a small motor for a composting toilet's venting system - are these all going to convert DC to AC, or is it designdependent? And if they do convert, either by brushes or chips, can they befiltered, or is it not something to worry about for occasional use, or if I'm far away from them?

Should I try to have each motor on a separate circuit? (If there is such a thing as separate circuits with a DC system?)

One thing I've noticed in my mobile home (trailer) is that the water pump and the fan for the furnace is that when the water pump runs, there's a strong magnetic field a few feet away from it, in the floor of the trailer, andperhaps another spot, too. With the furnace, there's, unsurprisingly a magnetic field in close proximity to it, but also a few hotspots in walls farther away - I simply avoid these areas when it's running, but I wonder why that happens - is it simply from so much electricity, even DC, being used to drive the motors? How can one avoid this: by shielding the motors with mumetal, or shielding the wires, or what?

Also - if the house had copper pipes for running water - could a jumping ofa magnetic field from a pump motor onto the pipes be prevented by installing a dielectric coupler between the motor and the piping, and encasing the motor in mu metal (or could that pose an overheating risk)?

Regarding lights: I think LEDs are the good choice (not CFLs, of course!) for low energy and long life. Do we know which LEDs have a good design? I thought I read that some may have a ballast, or something like that?
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Now, onto another biggie: Building materials. Obviously, I want to make this thing as green as possible, ie, safe and healthy. No faux wood, formaldehyde, harsh plastics and things I have to wait two decades for to outgas! The designs I've looked at are all made of wood. I like wood. It's warm, it's natural. However, it offers little in the way of RF protection. Of course, I'm planning to go where the least RF is, but I want to be prepared for my living space not to let any in, regardless of that fact. My currenttrailer is, like all trailers, clad in aluminum. It's great for not letting RF in, and I can't say it bothered me much, but for a new structure, I don't really think I want to live in a metal box. Which if the following options do you think would be best to incorporate into a wooden structure?:

-Aluminum mesh
-"Dragon Board"
-Carbon paint
-Any other ideas?

The aluminum mesh would be reflective. The dragon board (what is it, magnesium oxide, or something like that?) and the carbon paint may absorb, rather than reflect - is that correct? Regarding absorbing RF - is there a "saturation point", where the material fails to absorb any more and begins to let it in? I'm still puzzled about this...

Do you forsee a problem with a metal roof, however? Some of the designs usethis, maybe for simplicity, durability and to keep down the cost. What ifsolar panels were mounted on it?

If there is some metal incorporated into the walls, in the form of mesh, oranything else conductive, I would assume that it'd be wise to attach a good grounding cable to the structure and drive it deep into the ground to drain away any electrical fields, yes?
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Well folks, that's all I can think of for now. I know this is a rather long message, but I need to know the best way to go about this. I think it can be done, I'm just not clear on how, yet. Thanks for all your help, and if there's anything I may have overlooked, please let me know. Many thanks!

R.