starting to plan our home... a solar question

Discussion in 'Alternative Energy' started by cindyc, Aug 8, 2006.

  1. cindyc

    cindyc Well-Known Member

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    We have a large family. We would like to go "solar". Is it unrealistic to think we could generate most of our own power? We have 5 kids. The amount of laundry we do is pretty big. We are homeschoolers, so we are home ALL the time, which, I'm sure would increase power consumption. We usually buy meat in bulk, which means we need a freezer. DH is a programmer who sometimes needs to work from home, so computer with DSL that is on a lot of the time is not optional etiher. We could go natural gas on a lot of things, but that seems to me like just switching one "bill" for another, though I am not against it if it is truly a "cleaner" energy source. We also don't mind going non-electric for somethings. We have talked about wood-burning radiant floor heat, for example. Don't mind using oil lamps at night either... A/C is a problem. It had been in the 90-100 degree range around here lately, and humid, so I would like to have SOME type of A/C... We will try to have a smart design that uses thermal mass, and has all the south facing windows, etc., etc... but I am not sure that would be enough to take the edge off of the heat here. Also... because of the heat, is it worth it to have a metal roof for a rain water cistern or will that COST us too much energy in the long run? Because of the age differences of our kids we probably need 4 bedrooms...
    We do have an architect that we are going to work with who has experience in alternative building and solar, but we want to have thought all of this through when we go back to him... (That is if he is still doing this. I hear he was running for office or something).
    Also, has anybody build a solar system "along-and-along"? We are building without a mortgage, and so we will not be able to afford to do ALL of our solar system at one time. We will just have to keep adding as we go along. If you have done that, how did you do it? Where did you start? (besides basic components of the system I mean... I know I need batteries, PV panels, inverter etc... etc...) I mean where did you APPLY your solar power FIRST? (Lighting, Heating, Fridge etc...)
    Am I asking too many questions? :) Sorry, I am trying to learn... Hope ya don't mind.
    Cindyc.
     
  2. Tango

    Tango Well-Known Member

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    I will leave the planning questions to the more experienced minds here. This last question is something I can tackle since I am doing it now. I started when I moved to live in my travel trailer as I built my current home. The initial system was 240 watts of panels, a 12v shurflo pump to bring water, a small rv type charge controller, 3 marine batteries, a 600 watt true sine wave inverter, and a trimetric meter to keep tabs on the batteries. That cost about $27-2800. My needs in the trailer were lighting, water, laptop, and charging power tools. My son played his psp and watched movies on the laptop and we never ran out of power. At the time I was going to build on grid but as things progressed the desicion was made to build off grid. Now I wish that I had purchased a larger inverter from the beginning and a larger charge controller, both things I will need to replace , well I already replaced the controller.

    You can easily add on if you plan to add on from the beginning. Look into energy saving, alt. energy appliances, not just energy saving appliances. For example, I have a tankless propane water heater that ignites on demand -does not burn a pilot light all the time and never runs to heat water unless the hot water is turned on. Our propane stove has not clock and no glow bar. It ignites with a match. The staber washer is the most cost effective washer out there (on my wish list). Heating will be wood when I can get my fireplace done. Lisa on this board has a/c in her bedroom. Dunno if you can run a swamp cooler instead of a/c where you are at.

    Natural gas is going to go sky high. Solar, wind, or hydro power has high up front costs but is then inexpensive to run and maintain relatively speaking. I think a large family can live comfortably on solar but attitudes adjustments need to be made. That is probably the most important part of going solar. Adjusting our attitudes so that we don't think we're so entitled to be wasteful. I'd love to hear as you progress with your plans! :)
     

  3. mightybooboo

    mightybooboo Well-Known Member

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    Think active(hot water) and passive(earth sheltered,proper site orientation for solar heat gain,shading) solar in the house design,thats where the savings will really pay off,in the design.

    Wont pay off if you are thinking a conventional home with solar panels.The big savings is in heating and cooling by proper design,not add on electrical stuff in a conventional home.Like appliances,think waaaaaay outside the box unless you have LOTS to spend on solar electric.

    You are lucky in that you can? design a home to take full advantage of all solar offers,not just electric.

    Im sure Solar Gary can really give you a rundown in that area.

    Me.earthship design with passive solar,active solar H20,solar electric,solar refer and freezer.Thats the plan anyhow,this year very disappointing in land search unfortunately.

    BooBoo
     
  4. Guy_Incognito

    Guy_Incognito Well-Known Member

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    It's quite do-able, but a little expensive. But if you're going to spend a couple of hundred thou on a house, whats another chunk'o'cash in the big scheme of things?

    As an indication, this is the system that I'm in the process of designing.
    It's for a four-bedroom house in the tropics with no grid power available. No heating required,but maybe A/C if I'm lucky. Solar hot water. This may vary if I hit any major stumbling blocks, but the numbers work out generally ok so far. This is a big system, but it improves the Wife Approval Factor (WAF) by a large amount. :)

    Panels - 12x 130W kyocera's - 1500W output.
    Batteries - 40 x 1.2V x 400Ah nickel-iron cells - 19.2kWh storage.
    Inverter - 2 x 2300W Outback Power inverter/chargers linked together.
    Max power point tracker and charge controller - for max efficiency.
    Genset - Listeroid 6hp / 3KVA - for when it's cloudy and topping up system.

    I've got a spreadsheet here with the appliances, average sun hours for summer and winter there, battery capacity and efficiency estimates, etc. But the rough numbers are as follows, prices are in Aussie dollars (about .75USD) :

    Worst-case load for the house is about 6-7kWh a day. That's giving a "reasonable" estimate and adding another 50%. All standard appliances (the WAF), fluorescent lighting throughout, gas stove. Washing machine doing 1 load every 2 days, dryer once a week (maybe, again, WAF).

    Panel output is about 6 to 11 kWh a day, depending on the season. Less in summer than in winter, as it's cloudier in summer (monsoon season).

    With those two figures, there's normally a surplus of 1.0-4.0kWh on average a day left over to charge up the batteries from any previous discharge. The battery bank is sized that it can run for 3-5 days without any input to charge it up.

    Panels - Kyocera have a pretty good rep, and are warranted for 25 years on output. The max power point tracker for the panels gives another 20-30% power output, which is always good. About $14,000 for me here.

    The generator, at 3kWh, will charge the 19kWh bank from completely flat to full in about 10 hours running. Full load uses about 1.5 - 2.0 litres (about half a gallon) an hour of diesel. The old lister diesel design is a slow-running, long life engine - 50,000 hours between rebuilds is not unheard of. Looking at a heat exchanger for the genny to heat the hot water system as well, as it's quite likely that the times that I need to use the genset, I might need to boost the hot water system as well. If I run the generator, I can have a small split-system A/C unit in the bedroom without drama, so I might consider that for those hot humid nights. If we went all-out with the power conservation during the day (or we weren't home) we could probably run it for a few hours in the evening to cool things off a bit. Again, a big increase in the WAF. About $3000 for the genset here.

    The nickel-iron batteries are a bit lossy, but have a reputation for being indestructible and long-lived. You can also abuse them (run them dead flat,etc) without any loss in capacity, which is ruinous for a lead-acid battery.This is important for me as the place might be unattended for a week or so at a time, and I don't want some hiccup flattening and ruining a set of batteries early. Good batteries are expensive and you can factor in a replacement set every 7-10 years if you're going to get lead-acid ones (for the equivalent to my size bank, about $20,000). $12,000 for the nickel-iron ones for me.

    The inverters are pretty large, but I wanted two. They're linked and smart enough that if there only needs to be one running for a load, the other one will go to idle. They fail-over as well, so if one dies the other will carry on. This is my main reason for having two, as it's fairly remote, and I don't want to be sitting around in the dark (or on the genset) while another one's shipped to me. There's all the usual features, remote display for monitoring it in the house, genset start, load-shedding outputs (drop big loads if the batteries are getting low), etc. About $9,000 for the twin inverters + display,etc.

    Price for all that for me is about $40-45,000 once you include wiring from the inverters to the house wiring, which I'm getting an electrician to do. I'm doing the rest of it myself - as I'm an auto electrician by trade.

    It turns out that the fridge and freezer are the biggest loads in the house, so I'm looking at adapting a marine system to suit. All the 'normal' DC fridges are expensive here - about $2500 for a reasonable sized fridge, and they don't save that much power anyway. A marine fridge-freezer with 4" of insulation uses about 1/5th of what the "normal" fridges do, and you can build them to whatever shape you like. Up-front costs are about the same really, so might as well.

    As for building as you go along it's relatively easy - you need the batteries (or *some* batteries), an inverter, and some panels to kick off with. The rest can be added as you go along. As a start, I'd probably suggest :

    - A battery bank that can keep you going for a day or so.
    - A single inverter/charger that is able to be paralleled later on with more inverters as your needs grow. Or a cheap one for the first 12 months until you've got the cash to get the next step up, like one of those outback power units.
    - A few panels. You'll need at least enough panels to match your battery voltage. As you go along you can simply add more panels in parallel to increase your charging current.

    After you've got a basic system like that going, slowly increase the capacity of each section. Probably batteries first, as you can charge them as needed from the genset if you use too much juice. Consider a max power point tracker for the panels as you'll get a noticeable increase in power out of them if you install one. Once you get a (good) max power point tracker, you can simply add more panels in series and bump the voltage up - this is good as you get less loss in your wiring then.

    Anyway, hope this helps. Or if it thoroughly confuses you, well at least you'll be able to ask a heap of questions now :rolleyes:
     
  5. Fire-Man

    Fire-Man Well-Known Member Supporter

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    I agree with everyone else-----You need to put alot of effort into How your home is built, Located and Furnished(appliances etc). Get your family familiar with solar-----alot of tean age girls don't realize that a Hair Dryer cost ALOT to run off solar. I think you are thinking right about starting out with a small system and keep adding to it, but plan it so you don't waste alot of money say buying a slightly bigger charge controller each time you add panels etc. Go ahead and get a Large controller in the beginning------also keep in mind, you DON"T have to have just one solar system. I have two. I have 4-80 watt panels on a tracker. Then I have my bigger system separate. Its more to check, but I like it set-up My Way. My X GF and I were talking about having a Solar set-up just for each kids room so when they left their light on or watch tv to long--It shut down only their room. When it comes to solar---EVERYONE has to work together or the system will not work as good. If I were you I would have a the house wired for 12 volt too---At least one light in each room. Have Fun!! Randy



     
  6. cindyc

    cindyc Well-Known Member

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    I agree with you on this one I think. Thanks for all the good advice.
     
  7. cindyc

    cindyc Well-Known Member

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    Woa, Woa, Woa... Who said anything about putting that chunk o change into a house? What we have in mind is WAY simpler than that. We are building without a mortgage. It would take YEARS to build one that costs THAT much.

    Anyway... thanks for the advice in information about your solar system.

    I am sure more questions are coming. :)
     
  8. cindyc

    cindyc Well-Known Member

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    Our land search isn't going so well either. We are considering that we may have to move out of the area. We are not going with earth-ship, tho... we are going with a hybrid bale infill, I think. The architect we are working with has hepled design and put up several around here that are not any worse for the humidity, even after a number of years, because they are sealed into plaster. Post and beam frame... Yes, we will be careful to design the thing using passive solar elements, too.
     
  9. cindyc

    cindyc Well-Known Member

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    Now, there's a thought... All the bedrooms on one system, so the kids can learn what energy wastefulness costs them... hmmm... :nerd: But you do have a good point... I probably ought to be more diligent about training them to conserve in their energy useage NOW anyway, just on GP's...
    Thanks,
     
  10. WisJim

    WisJim Well-Known Member Supporter

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    We raised 3 boys in an off-grid home in Wisconsin, then moved to an old house that is grid connected, but we still produce most or much of our power, depending on the time of year, etc.

    The secret is planning a home to fit the site, and reducing your power use. The actual design, etc., is dependent on where you are, so until you have a site, it is hard to get specific.

    I have been using wind generated electricity since 1977 and PVs since 1981, so I have a bit of experience. My youngest son has been building straw bale and other super-insulated types of houses for the last 4 or 5 years, and works with a fellow with many years of construction experience in these types of building.

    First thing to do with an alternative electical system is to REDUCE DEMAND!!

    Go to one of the many energy fairs around the country, and attend some solar homes in the national solar tour in early October of every year. (try googling "energy fair" and your state, or nearby states)
    http://www.ases.org/tour/index.htm
    We plan to participate again this year, and will have our wind and solar systems on display.
     
  11. SolarGary

    SolarGary Well-Known Member

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    Hi,

    I'll put another vote in for putting most of your effort into designing a house that is efficient for your climate. It sounds like you have done quite a bit of work on this already, but there may be some materials on solar home design that you can use here:
    http://www.builditsolar.com/Projects/SolarHomes/solarhomes.htm

    If the house is going to be on the grid, I would worry less about the PV and more about good house design and conservation of energy. We have been working on cutting our energy use back by one half, and done a bunch of projects to do this from things like insulating, infiltration control, to solar space and water heating ... At the end of this we plan to do an about 1KW PV system. For all of the projects, I've done the dollars invested vs energy saved. If you add up all the 22 projects before we get to the PV system, the cost is about $9000, and this cuts our energy use down about 60% (home and car). Adding the PV system about doubles the money spent, and decreases energy use by 2.5% more -- so, it seems to me, you can leave the PV to the end -- just plan for it -- do all the other stuff first.
    Details on how much bang for the buck we got on each project here:
    http://www.builditsolar.com/References/Half/Half.htm

    I think its a good idea to take each energy saving idea and try to do a rough estimate of what it costs to do, and what you save in energy and dollars by doing it. Then include the things that pay well. I'm sure people in this group can provide some help on how to do this for each energy saving feature.

    Gary
     
  12. GeorgiaberryM

    GeorgiaberryM Well-Known Member

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    Oh it must be so wonderful to build a house - having some control over your home instead of coping with what you've got.

    If I were you I would start with EFFICIENCY and you have got to check out this site
    http://www.dougrye.com/

    He is an architect who designs high efficiency homes. He sells a DVD describing his techniques, and I borrowed it from a friend and watched it - well worth the $ if you are building.

    We are landscapers and we did a garden at a Doug Rye house in Texarkana TX - the homeowners are very pleased, and say that the design delivered the efficiency that was promised. They have been in the home for about three years, so long enough to see some pattern in their electric bills. They had their house designed by a different architect, then I think they paid Rye (he is based in Fayetteville AR) to consult the plan and specify insulation, sealing, and this interesting framing technique that reduces air flow and increases insulated space. He describes and illustrates it in detail on the DVD.

    Combine efficiency in homebuilding with efficient appliances and common sense power usage and you have a great place to raise kids.
     
  13. Guy_Incognito

    Guy_Incognito Well-Known Member

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    Well, you're right, it would take years. But solar isn't cheap and that's all there is to it. Perhaps mine can stand as an example of the final product. :)

    But I did mention to start small and work your way up if you're doing this on a cash basis. I need mine to be "Here and Now". Yours sounds like it can grow as you go. Just make sure that as you build it that it's fairly easily expandable. A big house (well, a house with a large family) will tend towards a reasonably large system to power it, unless you just want the bare minimum. Talk of many loads of washing indicates that your power usage overall would be fairly high. Especially since kids don't seem to grasp the concept behind "off". :)

    If you've got grid power, you're probably better off connecting to it and going with a grid-tied solar system. You can then start off small (eg. A panel + a 500W grid tie inverter) and add panels to it as finances dictate.

    At least when you're building you'll be able to design, locate and build the house as efficient as you can - you've got an advantage over a lot of people there.
     
  14. Jim-mi

    Jim-mi Well-Known Member

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    My system has grown over the years. Enough so that I did something unthinkable this summer ------I went and bought a window AC unit. So the sun (PV) and the wind really helped me survive the recent heat wave---with the AC.

    One thing to know is, tho you may add on more PV along the way you can Not add more batterys to an existing bat bank.
    ie.---adding "two more" two years from now.
    The new and the old will not be compatible.
     
  15. offGridNorthern

    offGridNorthern Well-Known Member

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    Good for you Cindy!! Building a home was fun for us.

    If you are going off the grid you need an architect who understands what this really means. So for example, living here in Northern Ontario where the winters are cold .... this house was built to take advantage of the south sun in winter, thus reducing the # of times the radiant floor heat pumps came on. In the summer, when it's hot , the architect designed large overhangs to keep the sun out of the house ..... windows are placed to take advantage of the wind. You learn to open windows at night ... close during the day to trap the cool air in the house. Consider building a slab so that the slab keeps cool and cools your house in the daytime.

    Computers --- we use a lap top because it uses less energy.

    Laundry .. again, you learn to judge the wind & sun -- today for example, when I got up the wind was high and the turbine was going so fast I couldn't see the blades. I bought dishwasher and washer that have timers.... put the dishwashe ron in the a.m. and the washer to come on 2 hours later (more to let the well recover!)

    Children: do you children leave the sink taps running??? Do they leave the doors open in winter?? No. So they have learned to turn taps off and close doors and they will learn to turn lights off.

    If your children are home-schooled I suspect that you are a parent that isn't in to the TV, games, etc. which is a good thing both from a learning perspective but also from an energy viewpoint. We don't turn our TV on until 8 p.m. which is something we started when we only had 2 panels (backordered) and have just kept doing .. and guess what ... it's wonderful. We talk or play board games with the kids!!! And then they watch TV.....

    Go for the solar .... you will be making a better world for you kids.