Building An Off Grid Home In TN

nu2solar
nu2solar Solar Expert Posts: 28
My husband and I are building a berm, covered by earth on 3 sides, off grid home ourselves. I am posting the entire process with pictures on another forum. Chapter 10 includes our solar set up and prices. If anyone is interested check it out.

http://www.city-data.com/forum/tennessee/359683-going-off-grid-east-tennessee.html

I hope you enjoy.

Lisa

Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building An Off Grid Home In TN

    thank you for the link and i will take a look at it. it's always nice to see things like this as it can give ideas and general knowledge to others.

    ok i looked it over and enjoyed the step by step process you detail. i can relate to much of it in a general sense from having to do construction work on my own home. could you also be more specific with the components used even though the brands i can deduce for much of it? pv make and model, quantity total and how wired? outback inverter model and any other pertinent info would help our better understanding of what you have and can expect?
    i find that the pvs mounted right against the roof is going to present a problem. generally you should have at least 6 inches of space between the roof and the pvs to allow the excess heat from the pvs in the summer to be cooled by the air circulating underneath them. they need alot of air to do this well, but you may be able to hold off on doing this as the world won't come to an end just yet if you don't jump. that excess heat will lower the voltage and you lose a bit of power. i'm not sure if you have the pvs oriented to true south or not and when you go to add the extra space between the roof and pvs it is an opportunity to consider an adjustable mount so that you can add a steeper angle that will allow better collection for the winter months and allow for the snow to roll off better. height is needed for the snow rolloff too as the snow will collect at the lower end of the pvs. during the winter the sun will sit lower to the horizon and for far less time than your summer months. with the bad winter angle and adding snow on top of them too and you'll find you won't have much electric produced just when you may need it the most.
  • Telco
    Telco Solar Expert Posts: 201 ✭✭✭✭✭
    Re: Building An Off Grid Home In TN

    Putting the panels at a higher angle might also improve the electrical output through reflection off that white roof. Folks have reported seeing more juice when there's snow on the ground than when there is no snow on the ground, your roof would be like year round snow in front of the panels. You should be able to use the existing hardware to raise the panels as Niel advises.

    Aside from that I'm extremely jealous of your place. Wish my wife was more willing to live in the hills, but she's a Florida girl and likes being in a place so flat you can see the curvature of the Earth off in the distance. I was raised where there's mountains and don't feel comfortable if I can't see them. Our retirement plot in Arkansas is a compromise, flat land at the base of a mountain :D.

    How are you heating the place?
  • nu2solar
    nu2solar Solar Expert Posts: 28
    Re: Building An Off Grid Home In TN

    Niel- Thank you for your concerns and comments. I posted all of our components, brands and prices in Chapter 10 including close up pictures. All of our wiring and boxes came from Lowe's. Mike wanted to specifically keep this system simple. It should be clear but if you have any more specific questions just ask.

    The panels are mounted on the ridges of a slanted metal roof(our roof is not flat). There is one inch of space under the panels which is all Kyocera suggested. If there is a problem we will modify. Since our house is basically underground and the panels are at the back highest part of our roof we should have no problem keeping the panels clean and snow free. We can just reach over and get any snow off, thankfully we don't get much snow.

    Telco- Thank you. I am the opposite of your wife. I don't like FL. Too flat and way too hot, JMO. We will be heating our house with a wood burning stove and we will also have a propane fireplace. It is definitely overkill as I am always hot. Since our house is basically underground, with 10 inch thick concrete walls, and awesome spray foam insulation we will not have heating issues. That was never a concern for us that's why we aren't facing south. Our biggest concern was keeping cool in the summer. We seem to be opposite of everyone else but that's pretty normal for us. Good luck with your future plans.

    Lisa
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building An Off Grid Home In TN

    ok it was late and i overlooked this as i read much of what was there by you in the thread and not just ch10. i don't see the battery ah rating listed or did i overlook that too? from you on the other site:


    That is basically our whole set up. We will be adding 5 more solar panels for a total of 8 and possibly one more invertor for more amps.

    Here is a breakdown of our system components and the costs:

    12 6volt batteries $940.00
    Battery cables 40.00
    8 135watt each Kyocera PV Panels 5200.00
    Outback Flexmax 80 Charge Controller 650.00
    Air Breeze Wind Turbine 600.00
    Poles and anchoring for the wind generator 85.00
    Outback VFX2812 Invertor 1950.00
    All wiring, panels, and electrical parts 500.00

    Back up Honda generator 1800.00


    as to what kyocera said, yes they will work at 1 inch, but reduced as you will see by any output curve for a pv with higher temps. and it is true that you will need a better angle than that to properly capture the sun's energy as it should be your latitude degrees for the overall average or your latitude +15 degrees that many like to go with for improved wintertime collection. the angle i see you have may work ok for summer use only. you also did not say the direction the pvs face either as i had asked.
    i am only trying to let you be aware of some aspects that would allow for better operations for you and your husband and a better understanding for us as to what you have, but as my concerns have been duly noted by you you may do as you wish and continue to just say all is there when you failed to address concerns of mine that still aren't listed there that i asked about.
    you can keep it somewhat simple, but the simplest isn't always right or best or your husband would've also gone with straight pwm ccs as well rather than a quality mppt cc if he was keeping it that simple. do know there's nothing really that simple about solar power generation or everybody could make and build their own pvs, controllers, inverters, etc., but for appliance operators (you know those that know nother more than flipping a switch) i suppose the light=power concept will work well enough for them as beyond that they have difficulty. most of us are to varying degrees somewhere far above keeping it that simple. i'm not implying anything here either, but you and your husband need to up it a notch to make it work better or you may find yourselves not producing very much power in the winter no matter if it never snows.
    i'm also curious as to why you elected to go 12v rather than 24v for the batteries? that would be the same number of batteries, but losses can be lower by upping the voltage. in fact i also asked how the pvs were to be wired and that wasn't answered as initially you were going to go with 2 strings of 3 in a post here on this forum a few months back, but you have opted for 8 pvs i see and there's no mention of the wiring arrangement that i saw for the pvs. being you have 3 in now you either have them all in series or all in parallel. having all 3 in series would mean you'd need 1 more pv to have 3 paralleled strings of 3 in series so i'm guessing all are in parallel. wire losses can be lowered by placing series strings of 2 pvs and then paralleling the 4 strings together for a 12v battery setup. if you go to 24v on the battery arrangement (inverter already at 12v and no change possible without 24v version of the inverter) then either a 36v or 48v arrangement on the pvs may be done.
    the wire is important too as we do not know the gauge from the pvs, battery interconnects, or the battery to inverter or their lengths and there's more wired stages i didn't mention, but i hope you get the drift that all of the wired stages need addressed. did he figure in the voltage losses or did he kiss it and let lowes tell him what to put in? i hate pulling teeth so please volunteer what we need to know as all isn't there.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building An Off Grid Home In TN

    supplemental:

    has anybody been following them on this project as i've popped in a few times to read what they are up to? i saw they had 2 wind turbines at one point and finally settled with the wisper 100 i think it is and the pvs have been upgraded to 6 more pvs. anybody notice the direction these pvs are facing in comparison to the direction the first set of pvs face? yup they are facing 90 degrees east of the first ones and we still don't know what direction the first ones are facing.:cry: another thing is the angle these new pvs are at with 15 degrees mentioned there. it should be their latitiude or their latitude + 15 degrees.:cry: if they are at guessing say 35 degrees latitude then this should be the minimum angle they should have with a possibility of up to another 15 degrees to that for a better winter production total of about 50 degrees. i wish them well, but they don't take advice well and we've been accused of "not thinking outside of the box" in addition to a few other solar places.:confused: yes, they are right and the rest of the world is wrong and i've even seen someone tell them it needs to be angled better. i also saw an nec wiring violation, but i'm not saying.
    i couldn't quite tell very well, but it appeared that during the wisper's installation that he may have been stepping on one of the pvs.
  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Building An Off Grid Home In TN

    Interesting. From the pictures and the various sun angle, I guess their house is facing east. The new 6 PVs are facing south probably around 35-degrees, not bad. The first set on the roof is a few degrees facing east. Some one reminded them to check on the angle of the first set to maximize power production but it seemed to be ignored. Similarly with the dripping loop on the PV wires. I wonder what made them decided to get the 2nd PV set, whether they did estimate on their daily power usage to size the PVs and the battery. The first PV set on a tracker probably gives them enough power boost from the angle they placed it. So now thay have ~1600W PV on a 12V system i.e. 135A charging. She mentioned they are using some DC lighting. That's probably what they decide to use 12V inverter. They did replace the fused breaker box with MN DC disconnect. The batteries are 12 225AH GC2 type, probably not enough for off-grid to last more than a day without sun and the batteries probably won't last long with daily charge/discharge. She mentioned they will move them away from the house eventually. Hope they realize the power loss with 135A DC going from a distance and the cost of copper wires to support that high current. In one post, she mentioned they are in a county where building codes are not enforced. They were in contructions in NY, NC, FL, so I think they follow codes but not to the Ts.
    GP
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building An Off Grid Home In TN

    if the pvs on the roof are facing east then the new ones are facing north as the new ones are to the left by 90 degrees(maybe worded wrong and is point of view for if looking at the front of their place the originals are facing you and the new ones would be on the right facing to the right) and i don't think that is that case with the original pvs, as you say, being easterly. the pics on page 61 for 10/22/08 do indicate that the original pvs may actually be facing west or northwest going by the shadows making the ones just installed closer to south as they should be. see the one with the sat dish as the sun is making the shadow hit the house in a way telling me that their house is most likely facing west to northwest as would be the original pvs. that is most likely why they bought more of them as they were not seeing much power outputted from the originals due to bad angles and bad directions. maybe we don't think outside of the box sometimes, but at least we aren't so far out to be thinking from another planet by trying to find the north star with pvs.:p
    lots of reading over there isn't it?

    edit to add:
    notice the pole for the wind genny and its shadow is cutting accross the original pvs that are facing the wrong direction? pic is hughes sat dish with new pvs. that pic says much. one favorable thing to say is that the new pvs in that same pic aren't at 15 degrees by looking at them and that's a good thing. it looks closer to about 35-40 degrees.
  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Building An Off Grid Home In TN

    You're right, the 2nd set is definitely more toward south. The first set is 90-degrees clockwise from the 2nd. That would make it westward. I was wondering if the wind gennie poles would cast their shadow on the PVs on the roof. Recent picture clearly shows that. Over the past week, they moved the 1st set off the roof to be close to the 2nd set. I guess, they are OK now. Maybe the wind would make up in the winter for that 35-degrees or so angle. With the 2 poles bracketted to the ceiling frame, the metal roof, I wonder whether the acoustic ceiling tiles could filter out the wind noise or the vibration of the pole.
    GP
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building An Off Grid Home In TN

    they must still be reading here? good deal on them moving them, but i don't think i would've overlapped them like that. in any case they'll be much better off now.
    i'm not seeing the poles bracketed to the building at all. where are you looking?
  • GreenerPower
    GreenerPower Solar Expert Posts: 264 ✭✭✭✭✭✭
    Re: Building An Off Grid Home In TN

    The brackets are shown on page 15 and 52. They probably took off the one close to the battery box recently. With that high pole, the wind gust would give quite a vibration. I wonder when they finish their ceiling tiles, the hollow attic would act like a sound box for the wind/vibration noise.
    Yeah, that slight overlap may be OK for winter sun angle. For high noon sun in summer, if the whole top cells are partially shadowed, that would cut a bit of power production.
    They put the relocated PVs on another CC, probably figuring the STC 1600W is exceeding the FM80 at 12V. And they are talking about maybe getting another set of batteries. Too bad, if she had followed up on this board on PVs and wind turbine, they probably wouldn't have had to trial and error like that. Hope they learn about battery care on those GC2s before getting serious on a set like the Trojans.
    GP
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building An Off Grid Home In TN

    that was the first wind turbine they put up and to my knowledge they didn't put it back up as the pvs went into that spot that the turbine was in. for the second one i see no such brackets to the house as i gather they realized the hard way that it wasn't a good idea to do that. i have no idea if they intend to put that first one back up somewhere else or not.
    edit to add:
    reading further on that other site i see on the 2nd of nov they decided to start to reinstall the first turbine and at the rear corner of the house near the new pvs. this is quite close to the other turbine which i wouldn't have done. if not for the possibilty of one turbine hitting the other, it will have the effect of one turbine being in the way of the other one causing a slight reduction in power reaped when the winds are southerly or northerly. it could also increase eddy currents in the wind and increase the odds of a shear being created that could destroy one of the turbines. the house is also in jeopardy if those blades fly off or fail for any reason. east or west winds would be ok.
  • System2
    System2 Posts: 6,290 admin
    Re: Building An Off Grid Home In TN

    Niel and Greenerpower,

    I'm new here. I can't seem to find where the lady asked for advice. Can you point me in the right direction?

    johnny99
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Building An Off Grid Home In TN

    johnny99,
    yes, i can point you in the right direction as i see where you are going with this and just because she didn't ask for it doesn't mean she is right in what she and her husband did. we want them to suceed and we try to help here, but if she posted only as a boost to her and her husband's ego then we will disapoint as a previous egomaniac had found out.
    now if you posted only to be using political type tactics or to develope your trickery in words then there are better forums than this one for that purpose.