Dumb questions

SystemSystem adminPosts: 2,511 admin
I am in the process of building a 3000 sq ft Insulated Concrete Form house in Daggett, CA. Why? Damned if I know. I can see SEG's 1 and we have 6.6 hrs/day. I have the option(s) of connecting to the grid, grid tie or off grid. House has the following so far:
2 x 4 ton heat pumps (ac/heat) 220v single phase.
2 x Takagi TK-3 propane water heaters.
Wood burning fireplace.
Water softener.
2 x 3/4hp garage door openers.

Will have:
Fridge/freezer
Gas range
Microwave
Washer
Electric drier
4 computers, sat/cable tv, 3 big screens (two teenagers)
4 x security cameras and video system
Normal ancillary electrical appliances, lights, fans etc.

From SCE planning I glean the following information:

11kW
vd:2.09%
Flicker: 4.58%

Proposed: 75.0 kVA kVA 12.2 %Load16.3

The transformer they propose is a: 75kV/120/240v 1p

Running around the various sites, a 36KW generator came up as ROM.

As I read somewhere else on the forum, most of the companies/people out here are new, most are just salesmen who tell you what you want to hear, rebate, rebate, rebate. First question is "We need to see your electricity bills", as soon as "I don't have any" is heard they might as well be in the middle of the Pacific Ocean doing the backstroke.

Most folks on this forum seem to be at the pointy end of this tech stuff, whereas I can't even qualify as a spearchucker.

$64,000 question, can I go "off grid?" is it actually doable without alchemy, or am I better off doing something else?

Would ground mount, plenty of room (7 acres), but VERY high winds usually in March.

Comments

  • audredgeraudredger ✭✭ Solar Expert Posts: 272 ✭✭
    Re: Dumb questions

    IMHO off grid for this home is not feasible, Grid tied would help but won't be cheap.

    The off-grid killers are: 2-4 ton heat pumps, electric dryer and the 2 teenagers. LOL Off grid doesn't mean doing without but, it does mean discipline. I'm off grid, my daily electric use is ~1.6 KWh most days, 1.7 KWh when we run the dishwasher. 2 LCD TV's, 2 satellite receivers, microwave, energy star refer, small freezer, coffee maker, toaster, gas range, 1 tank less water heater, wood fired in floor hydronic heat, evaporative cooler, all fluorescent lights and.... no teenagers.

    I have ~ 34,000 invested to produce that 1.6 - 1.7 KWh. If I read correctly you project 11 KWh a day. Grid power is around 1/2 the price of off grid. Though there are some economies of scale, they won't cut the price by half. off grid does not have any rebates either.

    My advice is to reduce your loads then, look at grid tied.
  • newenergynewenergy ✭✭✭✭✭✭ Solar Expert Posts: 291 ✭✭✭✭✭✭
    Re: Dumb questions

    Edison is heavily tiered. The more power you use the better grid-tie will be for you economically. It doesn't mean you'll generate some giant % of your usage, but you'll get a quick payback if you're only displacing top tier power.

    I haven't done the rebate work on new construction in Edison territory, but from what I see in the New Solar Homes Guidebook the max size for rebate is 7.5kw AC and they don't offer any guidelines other than that for sizing.

    I did the rebate work for a new construction project in LADWP and they don't make you do load calcs if it's under 2 watts per square foot, so I guess that's a bit of a rule of thumb - at least for the low side.

    As far as what you'll actually use, who knows? I see people living next door to each other with similar properties and usage that differs by a factor of 5. You sound like a pretty heavy user, so you should probably feel free to go for the whole 7.5kw AC if you want. Or keep the price down, just hit the top tiers and be more conservative, like 6kw or less.

    As far as off-grid vs. on-grid, the economics for grid-tied are a lot better if you have access to the grid (don't have to pay to have it brought to your street or something). Whether or not you want to pay extra to have back-up is really just going to be up to how much you value that and then perhaps whether a less expensive alternative like a generator works better for you. Some people just don't like hooking up to the utility and it's just worth the extra money for them to be independent of it.
  • Ralph DayRalph Day ✭✭✭✭ Solar Expert Posts: 887 ✭✭✭✭
    Re: Dumb questions

    Mike,
    I can hardly believe 1/6-1.7kwh per day! My loads are much the same...fridge, freezer, flourescent lighting, 1lcd tv, no satellite, one laptop, a uv light for water treatment, very little water pumping load (less than 1kwh per week measured). How do you do it??!!!

    The best I can seem to get down to is about 6-7kwh per day. 2.1kw pv, H80 wind turbine currently on the ground, 10kw diesel generator (130-150 hrs per year running).

    Do tell.

    Ralph
  • audredgeraudredger ✭✭ Solar Expert Posts: 272 ✭✭
    Re: Dumb questions

    Ralph, I miss spoke after rechecking my spread sheet, my usage is 6 to 7 KWh per day. Of all the things that I have lost, it's my mind that I miss the most! CRS - Can't Remember Stuff!

    Discipline. TV's & satellite receivers are on switched plugs, computer & DSL modem on switched outlet bar, kitchen GFI's are switched too, lights & TV's are turned off when you leave a room, water is via gravity, heat is from outdoor wood boiler and two 1/25 hp circulaters. House is sip construction ( 7/16 OSB + 5 1/2" Styrofoam + 7/16 OSB), ceiling has R-38 foil faced Urethane foam at the ceiling joists. A tight house.

    I would like to lower our 6 - 7 KWh usage but, haven't figured out how without doing "with out". Perhaps only one pot of coffee or no toast in the mornings but, that's doing with out... LOL
  • System2System2 admin Posts: 6,290 admin
    Re: Dumb questions

    Thank you for the prompt and informative replies. SCE would like to charge me
    $34K+ to hook up, and that's with me already having dug the trench and laying the underground pipe. Personally I would like to be independent, especially a couple of years down the road, however if that is not feasible, then grid tie would be the next best thing. Anybody out there know any "knowledgable" solar people out here in SoCal by any chance?

    If I'm going to do it, I would much prefer to do it right the first time, I hate rework.

    Thank you again,
  • Solar GuppySolar Guppy ✭✭✭ Solar Expert Posts: 1,962 ✭✭✭
    Re: Dumb questions

    Add a zero to your hookup fee and thats what your looking at to be "offgrid" with the loads listed, your probably going to be in the 80-100kwh/day range with dual AC's and teenagers.

    You could do things like have geothermal for the AC/Heat, R40+ insulation, thermal pane windows ect, but your probably doing the ready, fire , aim approach if you already building the house.

    Offgrid is about a dollar/watt when you figure in everything, and for you size loads your going to need a huge battery bank!,
  • CariboocootCariboocoot ✭✭ Banned Posts: 17,615 ✭✭
    Re: Dumb questions

    I agree with Solar Guppy; off-grid in any size is technically doable, but financially improbable. Costs don't drop significantly if you increase the size of the system: you're still looking at $1/kilowatt hour over the lifespan. Plus, the bigger it is the more maintenance (that giant battery bank SG referred to).

    Even if your daily usage was <3kWhrs per day it's too expensive when utility power is available. At twenty times that .... Bill Gates would have to fund the project.
  • newenergynewenergy ✭✭✭✭✭✭ Solar Expert Posts: 291 ✭✭✭✭✭✭
    Re: Dumb questions

    I'm in Manhattan Beach. Daggett is a little far, but I'll be happy to help if I can. Sometimes I end up out in San Bernardino or something, that's 1/2 way there anyway. Or, maybe on my way to Las Vegas!

    IMHO, if you want to be independent, think about it this way: you generate your own power grid-tie and the utility is just your battery.
  • mike95490mike95490 ✭✭✭✭✭ Solar Expert Posts: 8,415 ✭✭✭✭✭
    Re: Dumb questions
    johncw wrote: »
    Anybody out there know any "knowledgable" solar people out here in SoCal by any chance?
    ,

    Near LAX, where are you?
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • System2System2 admin Posts: 6,290 admin
    Re: Dumb questions

    Appreciate all the offers of help. The house build is ICF, R45+ on the walls, double glaze tinted windows, alum film under the roof panels. In 120 degree oat, uninhabitated last summer, iat steady 80 deg. In winter, oat 35 deg. iat 65 deg. So the build design works. It is a "green" house, as much as I hate that word. Again, I would love to be truly off the net, but, as you put it, $$/kwhr requires some sense in the equation. Maybe using SCE as a "battery" is the way to go.

    I am going to think about all the advice you have given, deliberate a short while and hopefully make a wise decision, or not, after all I am in the middle of the desert.

    Thank you,

    John
  • nielniel ✭✭✭✭ Solar Expert Posts: 10,311 ✭✭✭✭
    Re: Dumb questions

    johncw,
    i feel for you as it will cost you big $ to electrify your new home no matter what way you go.
  • System2System2 admin Posts: 6,290 admin
    Re: Dumb questions

    That was always budgeted for, I got with all the utility folks beforehand. Gas folks wanted $18K, even I can't justify that. Propane is just fine thank you. I have always toyed with the idea of solar, would really like to do it, wondered if an off grid was practical/cost effective. That is why I am here with you folks who have done it and know what works/what doesn't.

    I think I will head down the grid tie road, it appears to be the saner route. Thank you for all your help. If you guys don't mind, I will lurk quitely in the background and try and learn a few things while I finish the rest of house. At least at that point I should be able to determine a more accurate usage figure.
  • Solar GuppySolar Guppy ✭✭✭ Solar Expert Posts: 1,962 ✭✭✭
    Re: Dumb questions
    johncw wrote: »
    Appreciate all the offers of help. The house build is ICF, R45+ on the walls, double glaze tinted windows, alum film under the roof panels. In 120 degree oat, uninhabitated last summer, iat steady 80 deg. In winter, oat 35 deg. iat 65 deg.
    John

    Your choice of dual 4 ton AC's makes little sense, I heat cool 2700sf with a 3.5 ton unit without any issues and its not nearly as tight as your new home. Who did the schedule J on the home and can up with the need for 75,000 btus to heat/cool the structure?
  • BB.BB. admin Super Moderators, Administrators Posts: 29,629 admin
    Re: Dumb questions

    John,

    And don't be shy about telling us about your conservation features in your home... We are always interested in learning more.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • audredgeraudredger ✭✭ Solar Expert Posts: 272 ✭✭
    Re: Dumb questions

    John, a hybrid system might work for you; Grid tied with battery back up. could power the essentials during an outage.

    One of the things that works in my house is switched outlets where the TV's, satellite receiver's and computers plug into. All three of these devices draw up to 80% when "off". Only way to stop there hungry ways is to unplug or switch off there power. With three of each in your household it might make a dent in your usage.

    Some brands of GFI's are "power hungry" too. My kitchen and bath outlets are on switches. (ahead of the GFI's) Arc-fault breakers in the bedrooms eat power but, I haven't figured a way around them... GFI breaker for the outside outlets is simply turned off.

    All CFL's or fluorescent lights (removed the halogen lights from the range hood), security lights are self contained solar led units.

    Every little thing helps!
  • dreesdrees ✭✭✭ Solar Expert Posts: 481 ✭✭✭
    Re: Dumb questions
    Your choice of dual 4 ton AC's makes little sense, I heat cool 2700sf with a 3.5 ton unit without any issues and its not nearly as tight as your new home. Who did the schedule J on the home and can up with the need for 75,000 btus to heat/cool the structure?
    Does it regularly get over 110*F where you live? It is damn hot near Barstow, CA. Normal high is over 100*F for about 2 months. Heat waves mean temps much higher.
  • Solar GuppySolar Guppy ✭✭✭ Solar Expert Posts: 1,962 ✭✭✭
    Re: Dumb questions

    No 100+, but the high humidity keeps the average temperatures over 24hr higher than desert climates which get colder at night. We swing 75-95 for our summers at near 100% RH. This winter we saw many nights into the high 20's

    With a tight building ( SIP ), radiant barrier like the OP is building the AC/Heat load will be quite low compared to a typical builder grade home.

    I built a zero energy home a decade ago that used a 2.5 ton AC/Heat pump that easily handled the 3400sf. That included higher near 100 and lows into the 20's
  • dreesdrees ✭✭✭ Solar Expert Posts: 481 ✭✭✭
    Re: Dumb questions

    Yeah, humidity hurts - need long run-times to pull maximum water out of the indoor air so that higher temperatures feel more comfortable. Smaller or multi-stage AC units can help with that.

    I checked the weather history in Barstow for last year - in July, it can go a week without temps dropping below 90* at night with daytime temps over 110*. If you want to maintain less than 80* inside with those types of conditions, you either need a really, really tight envelope or a lot of cooling power.

    If the John's units are multi-stage units, over sizing them a bit doesn't make too much of a difference and a lot of HVAC guys seem to like to oversize units for some reason for worst case scenarios and also to be able to cool down a horse more quickly. As long as you have the duct capacity that works OK! If not - it just makes a lot of noise. Since it's a new house, should be the former.
  • russruss ✭✭ Solar Expert Posts: 593 ✭✭
    Re: Dumb questions

    Many contractors typically oversize a heat pump as it assures them of less call backs and the cost is to the customer so they don't care.

    An oversized unit will cycle on/off more frequently which is a no-no for heat pumps as it shortens the life of the compressor.
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