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Off grid?

Post in 'The Green Room' started by cmonSTART, Dec 9, 2007.

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  1. cmonSTART

    cmonSTART Minister of Fire

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    Out of curiosity does anyone here live completely off grid - independent of public utilities? My wife and I are very interested in it. While we don't have plans to undertake it for at least a few to several years, we would love to buy a plot of land and build our off grid home there. It's a self sufficient thing for us I guess. So does anyone have any experience with it?

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  2. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    Personally, no, but I know some folks who live mostly off-grid. I'm also working on designing heating systems and electrical generation that will work for off-grid homes.

    Joe
  3. cmonSTART

    cmonSTART Minister of Fire

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    Catskill, we saw his one hour documentary a while ago on it, which is one of the things that got us interested. Worth a watch!
  4. WILDSOURDOUGH

    WILDSOURDOUGH New Member

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    Not off grid... but the only 'utilitys' we have are electricty ( $75-125/month), Satilite Internet (49.00/month) and Dish TV (35.00/Month)- thats it.
    Thinking about a wind turbine to reduce some of the eletricial dependence, but won't go 'off-grid'.
    Solar is still to expensive and not very practical in our northern lattudes.

    One can become more self-reliant, but it is almost impossable to become 'self-sufficent' !
    (Everyone needs 'something' produced by someone else- and somewhere else).
  5. SteveJ

    SteveJ Member

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    cmonSTART,

    We are totally off-grid. I do have a 1000 gallon propane tank but hopefully have almost eliminated the need to fill.

    We have a 4.4kW PV array and a 3500AH battery bank (48V) with a Xantrex 4kW inverter.

    We now have a Seton W-130 wood gassifier boiler and are working on storage.

    In CO, the PV array and battery bank is great almost all the time. Last year we had to run a generator for about 100 hours - only when there is about a week of cloudy days. NH - solar resource may not be great but can be done. Also, check out hydro or wind.

    A good resource of renewable energy sources is the National Renewable Energy Laboratory.

    So, what are you thinking for power? for heat?


    Joe,
    What kind of systems are you developing for off-grid? DC pumps? etc.?

    My heating system is outlined in this thread.

    I am trying to use minimum electricity by minimizing pumps in the system.

    The wood boiler without storage is a definite obstacle...

    Thanks,
    Steve
  6. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    DC pumps are useful, but AC allows for variable-speed pumping, which is likely more useful. A pump that automatically speeds up and down as zone valves open and close can be a good savings. There are also little tricks like removing the transformers in the controls... most heating system controls contain a 24V transformer, and having multiple transformers is just a waste. A single high-efficiency transformer can power all the controls.

    Mostly, though, the plan is to design some CHP systems and such, so folks can get heat and power from a single wood-fired appliance.

    What type of zone valves are you using?

    Joe
  7. Nofossil

    Nofossil Moderator Emeritus

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    I'm very interested in reducing power consumption for my heating system so that I can run on batteries for longer. I'm testing the Taco Electronic Ball Valves, which use essentially zero power when open.

    Right now, I have a single Taco 007 running at any given time. Variable speed pumps would be a good thing in my system for many reasons. I've gotten a Grundfos three-speed pump to play with. Do you have specific suggestions for other cost-effective variable speed pumps?

    You speak of 'efficient' transformers. I've never seen those words on transformer packaging. Is there a 24V transformer that is significantly better than a standard box-store 24V unit? I'm using a single transformer for all my 24V relays, thermostats, and zone valves.

    Thanks for any suggestions.
  8. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    The EBV's are a very good choice for reducing power. That's why I asked him what he's currently using for zone valves.

    The Grundfos three-speed pumps are nice, however the multi-speed option isn't the same thing as variable speed. A variable speed system uses a controller that monitors the pressure in the pipe (or temperature, or other input) and varies the pump speed up and down automatically. Right now, the best way is to use a separate controller that performs those functions.

    Toroidal transformers seem to be a tad more efficient. They also reduce EMI.

    Joe
  9. Nofossil

    Nofossil Moderator Emeritus

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    Thanks. The 'separate controller' is exactly the approach that I wanted to use. The 007 seems to be a strange motor type called a permanent split capacitor, and I can't figure out how to control it as a variable speed. Taco makes a variable speed with a built-in controller, but it's really procey and I want to use my own controller in any event.

    Does anyone make a reasonably priced variable speed pump that takes a simple control signal to set the speed?
  10. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    If your utility has interconnect agreements, its hard to justify the cost of being completely off grid. Off grid systems need batteries, which need maintenance, can be dangerous, and are not environmentally friendly to dispose of. Its much more economical to allow the grid to serve as the "battery bank" and has almost zero maintenance. The problem is, with grid tie systems, if the grid goes down you go down. That can be solved by adding a small battery backup system to your grid system. The batteries for that type system are much less expensive, and the reserve is small. you loose a bit of efficiency going with a battery back up system, but not much.
    Off grid systems are around 80% efficient of converting the power from the array to usable energy in your home. Grid tie systems are about 94% and grid tie with battery backup is about 90%.
    Off grid systems are usually reserved for people that dont have access to grid power, or the grid power is to cost prohibitive to install. I had a client recently that was 1 mile away from the grid, the utility company quoted 250K to get power to her home. The off grid system cost her 90k to install. IF she where on the grid, that same system would have cost her 60k and only 24K after rebates.
  11. cbrodsky

    cbrodsky Member

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    It's also a very "green" idea to tie your solar into the grid so any excess capacity can be utilized to help offset firing up coal plants to meet peak demand periods.

    Still, I understand the idea of going completely off-grid has its own emotional value :)

    -Colin
  12. MountainStoveGuy

    MountainStoveGuy Minister of Fire

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    i hear ya about it being all emotional. It becomes less emotional here in colorado if it saves you 60k, or 30k out of a non rebate area. :)
  13. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    I'm not a EE, but I don't recall there being anything special about controlling PSC motors.

    Joe
  14. SteveJ

    SteveJ Member

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    MountainStoveGuy,

    I agree about net metering when available - use the grid to store your excess energy and get all the rebates possible...

    In my case, the inverter and battery bank and six panels were installed when I purchased the house.

    Xcel wanted $3500 a pole for 11 poles to run the grid to my house ($38,500).

    I added 18 more panels for a cost of $20,000 of which I got $11,000 back in rebates.

    So, off-grid worked in my case.

    Inverters and batteries are a pain but have been fine to date.

    Steve
  15. SteveJ

    SteveJ Member

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    Joe,

    Zone valves are Honeywell V8043E1012 - one for each of the three zones.

    The propane system (225kBtu) is used for the thermostat controls - single 24V relay and single Taco007 that only is on with thermostats.

    The Seton W-130 has been plumbed in series (picture below) with the propane boiler and the hot water heater to keep both warm. A Grundfos UPS15-58FC circulates the W-130 hot water through the heat exchanger (DHW pre-heat) and the propane boiler. The GrundFos is on low speed (0.5A) until the Seton goes below 130 and then the pump stops. So, the system works as the original (before the W-130) when there is no fire.

    The goal is to turn the GrunFos off more often and conserve electricity while minimizing propane use. I used less than 20 gallons last month (W-130 install was 11/1/2007) down from about 250 gallons during November of last year.

    Any suggestions on how to improve the system?

    How much to fly you out here and consult :question:

    Attached Files:

  16. SteveJ

    SteveJ Member

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    cmonSTART,

    Sorry for derailing your thread...

    A good initial screening tool for PV is the Solar Advisor Model available at SAM.

    Let me know if I can provide any additional info,
    Steve
  17. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    I'm not sure exactly how you have it piped, from that picture. I presume the two larger pex lines are to the Seton... is the plate heat exchanger on the supply or the return?

    By the way, kudos on the CO detector. I hate having to try and convince homeowners that they need one. Someone might spend $10k on a heating system, and then argue about not wanting to put in a CO detector because they'll have to buy batteries or pay for electricity to run it... If there's fire in your house larger than a candle, you need a CO detector...

    All my gas-fired installs now will have a CO/combustible gas detector wired to an automatic gas shutoff valve.

    Joe
  18. SteveJ

    SteveJ Member

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    Joe,

    Sorry for the lack of description on the plumbing.

    Yes, the two larger pex (3/4") are the supply and return from the Seton.

    The supply runs through the heat exchanger and then to the return from the radiant and the through the propane boiler back to the Seton.

    The heat exchanger does have parallel rather than counter flow so exchange is not as efficient as could be. However, the hot water heater does not use propane as long as the Seton is on and circulating. Also, the heat exchanger does not require a second pump as it is tied to the cold water into the water heater.

    The picture below shows the plumbing on the Seton in the garage. Three Aquastats, 1. control GrundFos - shuts off at 130F, 2. Controls draft - shuts draft door at 180F, and 3. Overtemp, opens largest zone valve and turns on Taco 007 when water temp above 190F.

    Is there a way to use a variable speed pump on the Seton loop and use less energy than the GrundFos running at low speed (about 0.5A draw - for reference, the Taco007 has a 0.7A draw which adds up when almost always on).

    Thanks,
    Steve

    Attached Files:

  19. BrownianHeatingTech

    BrownianHeatingTech Minister of Fire

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    Switching the flow on the heat exchanger would be easy enough :)

    Changing that 007 for another UPS15-58 would be some energy savings. Other than that, it looks to be a pretty good system, all-in-all.

    Eliminating the old-style gas water heater would be a savings, as they tend to waste heat (the internal flue acts as a chimney and extracts heat from the water, and that draft hood pulls room air up the chimney). Of course, the newer sorts tend to draw more electric power, so it's a trade-off.

    You could use only one pump and a three-way zone valve. That way, the pump would direct water to the gas boiler or the wood boiler, rather than using two pumps when the wood boiler is running. An aquastat would move the valve, and the end switch would kill the gas boiler when it wasn't being used.

    Joe
  20. Jimbob

    Jimbob New Member

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  21. amkazen

    amkazen New Member

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    Ah, a topic I know a little something about...living off-grid.

    We started building our house the end of February 2001. We had our power system installed and up & running by June 1, 2001. Our system consists of the following:
    Sixteen (16) Kyocera KC-130 photovoltaic panels, for a total of 2kW...we started with 16 KC-120 but had two fail at 4 yrs and 4 14 yrs. We called Kyocera each time to get them replaced under warranty and Kyocera shipped the 1st replacement out...had it replaced within 3 weeks of calling Kyocera. The 2nd panel went out over Christmas 2006 and Kyocera was shut down at that time. I called the 1st business day of January 2007, got the replacement process rolling and 1 week later got a call from Kyocera. Because I had more than 10% of mt array fail, they replaced every single panel in my array witht he current model, the KC-130. The KC-120 had manufacturing problems with a solder joint and this is the solution. I did not ask or anything..they paid for shipping, installation..all of it. What a fantastic company with great customer service.

    Two (2) Zomework trackers

    Two (2) Trace SW5548 inverters

    One (1) Outback MX-60 Chargeback controller

    Twenty-four (24) Interstate L-16 6-volt batteries..started with 16 and within 8 months increased to 24..have replaced 3 of them since June 2001

    One (1) Kohler 11RMY propane generator

    House: 2-story, 3,200 sq. ft. 3-bedroom, 2 3/4 bath with 4-car garage.
    1st story is constructed of Polysteel 12" ICF blocks
    2nd story is constructed of 6" classic "d" double tongue & groove, random length, cedar logs from Cedar Knolls Log Home company in Plattsburgh, NY
    Roof is green metal pro-panel pitched roof
    Windows are metal faced outside, wood inside Caradco awning windows
    Doors are metal faced outside wood inside Caradco sliding glass doors and Stanley exterior doors
    Heat is supplied by a Crown propane boiler feeding the radiant pipes in the floor
    The Crown boiler also supplies the domestic hot water which is stored in a indirect water storage tank

    1st floor has a game room, 3/4 bathroom, and dedicated theater room with a 108" movie screen and Epson front projecter and 7.1 sound. The entire house is wired for audio. The game room has four (4) 15" LCD TV's hanging from the ceiling along with a 32" Sony tube TV that the front projecter replaced. The garage is 3 bays wide (two 10' and one 8' door) with the smaller bay being double deep. There is a dedicated exercise room off the garage with a 15" LCD TV on the ceiling.

    The 2nd floor has all 3 bedrooms with two full baths. The living room, dining room, and kitchen are all one big room. One kid's room has a small walk-in closet and the master bedroom has a large walk-in closet. There is a pantry off the common area next to the kitchen. We have a large 60' x 10' deck on the south side (LR, DR, Kitchen, 1 bedrm) and a covered 16' x 10' deck off the master bedroom on the north side. This covered deck will be enclosed and added to the master beroom by Feb 1, 2008. The is a 34' x 10' covered porch on the east side.

    This description is not to brag or anything but to show people living off-grid is not something odd. A regular, large house can be powered by the sun. Our system cost $32,000 installed. I would do this again in a heart beat! All of the houses that have been built up here since 1999 are similar sized with similar features. The $32,000 price is not cost-effective given the price of electricity in Albuquerque (who knows what that is now but our friends in town average $100 for electricity per month for their similar houses). This neighborhood does not have utilities thanks to the developer not installing them in the mid-1950's when this subdivision was platted and thanks to the local Indian tribe that has millions of dollars and hundreds of attroneys at their disposal to fight any attempt to bring in utilities, that are approx. 3/4 of a mile away as the crow flies.

    Living off-grid is doable. A person does not need to have a small house, or a house that "screams" "I am a solar house and my owners are hippies and very extreme environmentalists". We have had people over for dinner, visits, etc., and they never knew we were off-grid and powered by the sun.

    Now, has it all been roses living uff-grid? No, and we have learned some lessons. 1st, a minimum of 3kw is what my friends and I have found is truly needed to run a house this size. As my system is underpowered, I use more propane than the others as my generator runs more than theirs do. 2md, battery maintenance is sore on my back and I have great access to my batteries, unlike some of my neighbors who have their batteries under stairwells or in racks that make maintenace difficult. But, 24 batteries have 72 cells to check and that takes about 45 - 60 mintues to clean the batteries, check the water, and replace the water. When I replace these batteries I am raising them up another 1' - 2' instead of the curent 1' off the ground they are now. 3rd, I woudl put the batteries and inverters in a room in the garage so I can get to the system without having to go outside. My bequipment is currently about 20 feet from the house in a separate building adn the only time I have had problems is when it is rainign, snowing windy, and blisteringly cold outside. And, those problems stem from my Kohler generator not starting automatically because of a bad throttle control that allows the generator to go into an overrev situation when it starts and it is very cold outside. This causes the generator to err out, the inverter keeps trying to start the generator, and fails, and then the power keeps dropping until the inverters shut power off to the house, causing me to go outside to reset everything. But, at least I do not have to wait days and weeks for my power to come back on like during a mid-west ice storm, etc.

    I hope this answers any body's curiosity about living off-grid. Joe, I am very interested in your company. I will pm you with some questions once I have read your web-site.
  22. dvellone

    dvellone Feeling the Heat

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    My home is completely off grid and I can assure you that unless your site is prohibitively far from the grid the expenses of an off grid home - system costs as well as many related expenses are much higher. You will never "break even" so to speak. And grid tie systems are considerably more costly. The purported benefits of selling back power are not reality. Inverter and grid tie costs are outrageous and the buy back rates (which don't kick in as soon as the meter reverses in these parts) are at the buyer's discretion - much, much less than the selling rates. That said, if your site is quite distant from the grid, the real estate value should reflect that fact. Your savings in that respect can go towards the system costs making that otherwise primitive homesite very appealing as far as electricity and convenience go. And if independence, your own renewable energy system, and no power outages are at the forefront of your values then none of this matters too much I guess as long as you're ok with spending some money for those goals and not having "unlimited" energy (think heating and cooling systems, refrigeration, and any other constant usage items)
  23. tnunemac

    tnunemac New Member

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    I completely agree with MountainStoveGuy. The utility company in our area gave us an extortionate bid, but with no competition and their overseeing governmental body not very helpful, we decided to investigate off-grid. We worked through some scenarios with the solar company who would later install our grid-tie PV array, and a few things kept us from sticking it to the utility company, like we desperately wanted to:

    * Batteries are expensive, and the more affordable ones require lots of maintenance and have surprisingly short lifetimes.
    * The rebates and tax credits for off-grid are close to non-existent in our area, whereas for grid-tie, they're massive.
    * Generator backup can be expensive, especially if you need pretty "clean" and reliable power, like I do, as a work-from-home computer guy.
    * We don't get any cell reception, so it was no phone or a sat phone. Or internet phone, but there's some question of latency with our setup.

    So, it was far cheaper and lower maintenance for us to go grid-tie, as unsatisfying as it was to fork over cash to the evil utility company. At least we get the satisfaction of selling them back the juice instead of the other way around, the way we sized our array.

    With varying grid-tie connection costs and rebates in your area, and depending on the size of the system you need, the numbers may work out totally differently.
  24. colebrookman

    colebrookman Minister of Fire

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    http://www.solarhouse.com. Has some great solar info on a house in Maine. Also I just recieved my first issue of Home Power magazine which deals with solar, wind, and hydro. http://www.homepower.com. These are great to see what works in the real world. As usual we can't wait for the government to take any lead because of the many lobbyist so it's up to us to make sure that our grandchildren have something more positive than just a load of debt in their future.
  25. tnunemac

    tnunemac New Member

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    I'd add that with better batteries and cheaper PV, both of which seem to be in our near future, off-grid could be practical for many more folks than it is now. PV paint, anyone?

    I'm also curious to hear if anyone here uses micro-hydro. We don't have running water on our property, unfortunately, but my in-laws in Alaska live on a mountainside with a stream through their lot. Seems like they could make some good use of that.
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