Joined: May 12, 2013
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Off grid solutions
Follow-up from thread 5778 and moving here: Challenge is a small cabin > 5km from grid and no motorised access (too steep, wild). It works well already with wood, candles and water from a stream (if not exactly family friendly). To increase modern comforts, planning is now:
Small photovoltaic system, 50w panel, 100 Ah battery capacity. (for 8 LED lamps + radio + charging mobile/gps)
Small power generator for topping battery and use of tools/water pump.
Additional self contained solar lamps for exterior lights.
Solar thermal collector (air) to raise base indoor temperature, improve ventilation and reduce humidity/condensation. Will reverse in summer and draw cool air from vent on North wall (shade).
Hot water coil in wood-burner to provide for hot showers. (Possibly with 12V pump. Or maybe just air pressure camping shower filled from 25ltr tank on top of wood stove. Solar Camp Showers, the black bags, did not work: too flimsy and hard to keep clean.)
Cooking on gas (minimal consumption)/wood stove in winter.
The modest capacity is just a result of every component having to be carried several km in steep and rugged terrain. For now, a few ideas have been abandoned that could be good elsewhere:
Wind turbines (too noisy, relatively low output, vibrations, turbulence, too many moving parts and bad for bats/birds).
Pico hydro systems (stream too far away, components too heavy, too much maintenance, frost proofing). Yet, some very attractive systems are being developed.
Water tank heating from solar collector in combination with wood stoves even if there are some very good maritime and residential solutions available (too complicated, requires frost proofing, constant electricity for pumps).
Roof water collection (requires frost proof tank, filtering system and a new roof...).
A mobile phone (gsm) remote controlled gas/paraffin stove to pre-heat the cabin before arrival (feel uneasy about starting a flame without knowing whether a bird has snuck in the chimney and built a nest on top of the stove, and I dislike carrying gas/paraffin).
Gas/12V fridge (too heavy, energy consumption too high, using snow or cold stream water in a cold box in the shade is usually sufficient).
Heat pump, also for refrigeration (too complicated/heavy).
A modern wood burning stove to install in open fireplace. Would increase heating efficiency enormously, but they are just too heavy.
TV/Computer deliberately left out, not worth disturbing the silence and a lot more weight electric capacity needed.
The main challenge is actually sewerage/septic. Solutions exist, but I would prefer a flushing toilet (e.g. marine style), but environmental requirements makes it almost impossible to create a legal, composting septic system. Even so, the bottom line is that, yes, it is possible to create a comfortable living environment with pretty simple technologies. So, if anyone has any experience with such or other alternative technologies, please share. SH3D is a brilliant canvas, but ideas for optimal solutions would be welcome.
Joined: Mar 18, 2015
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Re: Off grid solutions
Here we are in the core of the subject ! I’ll be giving a good thinking about all items you listed and share my experience here. I just need a few days for it as I’m busy finalising my container-bio-farm-off-grid project :) For now, I’ll point out one important aspect of the off-grid concept: it's very hard and complicated to adapt or transform a pre-existing “traditional” house into a self sustained unit. Full efficiency from alternative energy can only be achieved when starting from scratch inclusive of rethinking home design and raw structural material in use. The key word in this field is: Insulation !... before any other consideration. Thanks again for opening this thread.
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Re: Off grid solutions
Yes, insulation and material use come first. Useful videos (note that one is Australian, so when the video says North, that would mean South in the Northern hemisphere). There are really two different issues here. Neither is black magic. Pretty basic considerations (before starting your SH3D design) run like this:
For anyone designing a new home, net zero (or zero energy or passive house) should/must be considered (legal requirements are getting stricter). That has - as the videos show - profound effects on construction. Thicker walls, floors and roofs. E.g. traditional houses here are built with outside walls in wood some 15+ cm thick. To satisfy modern energy requirements, the same building technique now implies walls twice as thick. Also, orientation of the house, roof angles etc. must be calculated. BTW: What I dislike most about these buildings is that they need to be more or less airtight, which again implies a (mechanical heat exchange) ventilation system to get a half decent indoor climate (and there is still a feeling of being a canned sardine).
For existing buildings, as you say, it is in practice impossible to achieve the perfect: a zero energy building. But, there is still very much you can do with an existing building to reduce energy consumption (and/or switch to renewable). To take our own (on-grid) example: We put new panelling on the house, added extra insulation/wind-proofing, changed a couple of windows and sealed a few cracks (infrared camera useful). Switching to LED lights and letting two new efficient wood-stoves provide most of the heating was revealing: hot water (long showers) now account for most of the electricity bill. That means we are considering pre-heating hot water via solar thermal collector (water) and/or the use of heat pumps. The long and short of it is a considerable reduction in carbon footprint and considerably lower energy bills (admittedly in part thanks to cheap access to firewood). And all this before we have sacrificed any comforts. If we could kick a teenager out of the shower at half time, the saving would be in the order of € 500 annually. While it will take some time to recover the cost of the investments, it has increased house value, improved environmental conscience, made us more flexible in changing energy sources, reduced our grid drain by half (so far) and we are less vulnerable to power shortages.
All this clearly quite simplified. What is exciting though, is the development of new techniques related to energy and housing. And for planning with SH3D, there are implications to consider: ranging from thicker walls/floors to making room for energy storage (batteries/thermal). Point is, keep such issues in mind before getting distracted by the details of the plan.
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Re: Off grid solutions
A relevant post turned up in thread 5829 - house made with straw - seems that house has many of the qualities of the houses in the videos. See also the previous posts in thread 5643 which give more background on location and a couple of links to relevant videos. ok
Joined: Mar 18, 2015
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Re: Off grid solutions
Awesome ! There’s definitely people interested in the off-Grid field. I suggest that we funnel all these posts to the present thread to avoid the scattering of dedicated members in the myriad of this Forum threads.
on the thermal and sound insulation straw is a great even better than the isolates used in building insulation. the bad thing is you need certain requirements for straw does not degenerate over time, humidity etc
in Germany was tested fire resistance of a wall of straw. The test consisted in raising the temperature inside the wall slowly up to 1000 degrees Celsius to watch the wall behaves. I spent 30 minutes inside wall is 800 degrees Celsius when the outer wall is at a temperature between 35 ° c
this documentary is very good and interesting I saw on youtube in Spanish , try to look for in your language . here comes the test of fire resistance as commented in the previous post