04-26-16, 11:44 AM | #31 |
Lurking Renovator
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The hybrid system is and interesting idea. What I had initially imaging was a compressor consuming all the solar energy available and basically functioning as a solar ice maker. This would be paired with a hydronic air handler. Of-course the ice storage would need to be able to absorb all the power on the sunniest day beyond what is consumed by cooling during those hours. A couple tons of ice, perhaps about 500 gallons for a large system. With a hydronic system, zoned cooling could greatly reduce night time demand.
I don't see it working to well in the winter without supplemental heating since the solar power and heating needs peak at different times. Also, an alternate use would be needed at times when HVAC demand is low. It would pair nicely with a geothermal system since it could be used to recharge the ground loop when not needed. |
04-26-16, 02:29 PM | #32 |
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Well... humm...haww... nobody ever said too much about a ground-source exchanger.
That changes everything...please tell me why. |
04-26-16, 07:38 PM | #33 |
Journeyman EcoRenovator
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Great ideas! I live in probably one of the most prefect places ever. So my case is different than most. In my case I can run the AC when the sun is up and curse through the night without any AC. Also as mentioned the hot water heater only has to run during the day too (as long as the sun shines for that day) Not the mention the hot water heater is now doubling as a small AC/dehumidifier when it runs.
Lights and a very few other appliances would be the only thing really needed at night. (assuming bright days)
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04-27-16, 03:02 PM | #34 |
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An insulated soil bed could be used instead or along side of ice as a cold storage mechanism, or it could be located after the indoor air coil. The water/glycol could be pumped through pex coiled within the soil. It wouldn't need to be that big, just an extra buffer for when solar power is exceeding AC demand over a longer stretch of time.
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05-17-16, 02:33 AM | #35 |
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You want mass , in a small volume , your not going to move it .
Stone is cheap , immersed in glycol will work just fine, fill a tank with stone insulate and away you go. |
05-17-16, 04:35 AM | #36 |
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Started an intro thread today , will start linking my future projects to them as I go .
Total independence from grid and some self sufficiency food wise along with income from home planed. http://ecorenovator.org/forum/introd...html#post50122 |
05-17-16, 07:14 AM | #37 |
Journeyman EcoRenovator
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Hi Guys,
I've addressed this before here so please excuse my redundancy. I'm sort of a prepper myself and my original thoughts, ten or so years ago, were that I would go autonomous and completely turn off the grid. After living with PV, off and on grid, I've modified my original thinking. The best solution is to have an off grid/intertie system. This way the grid keeps your batteries charged an when the grid fails the batteries take over and run your house. You get to sell energy back and still have fully charged batteries when you need them and even LA batts can last a very long time. With that said, if you still want to go completely off grid you will need more than just PV because batteries, regardless what kind, simply won't cut it. I have about 10Kw's of PV, this summer (hopefully!) I'm putting in wind and micro hydro. You have to look at your land in its entirety and extract every bit of power you can from it. If you live on a 100 x 100 lot you're not going to make the power you need and your best option is the off grid/ intertie system. I can tell you this after building battery boxes, an off grid only system and an off grid/intertie system. And I have 16 acres with a stream and good wind I've monitored for several years. Wind compliments PV and microhydro trumps them both ( sorry for the trump word!). Microhydro is the best because you get power 24/7 and your batteries only come into play for surges like motor starts. Even if the stream doesn't provide all the power you'll need it will get a boost from PV and wind if you calculate your system right. That's the way you have to figure and look at it. Land is power, we've forgotten that with the advent of fossil fuel but, as most of you know, fossil fuel is not our friend! Rob |
05-17-16, 10:00 AM | #38 |
Journeyman EcoRenovator
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I've been living full time off grid for five years now. I love it. So here's a few things I've learned.
ONE: Build it: Solar. It's easy. And cheap. (this could also be called ignore the trolls) Yup. Even a humble fella like myself can stumble through a solar build. It's cheap. I built my starter system for $5k. I've grown to around $8k and I have an electric everything. Except my stove and some hot water. I have propane for that. By choice on the stove. I prefer cooking on a gas stove. I also have plans for solar augmented hot water. But, at less than a 40 lb propane tank for hot water every year. No rush. TWO: Don't be afraid to grow I've grown my system. It was a pretty bare bones 1 kw system when I started out. I've added a second kw of panels and a second controller. Put in a better inverter. Added a battery charger. An ATS. All as I learned I needed them. THREE: Buy modern stuff This means Lithium batteries. If you can get/jury rig a Volt or Leaf battery. Huzzah! But lithium is cheap compared to the alternatives. So even some nice big fat expensive Lifepo4 1000 ah with a bms will pay you dividends for many a year. Again, this could be called ignore the trolls. I don't know why. But mention any battery chemistry but Pb and the rocks start to shake. It also means look to Europe. Inverters and chargers from Europe are currently (ha. never gets old) the way to go. FOUR: be flexible. Yes, living off grid on a humble solar system like mine means I have to wash dishes in the dishwasher (electric hot water) when the sun shines (tho that will change when i get my lithium battery pack). FIVE: It's easy. Really. There are so many folks who have been doing this for so long. You'll find a plethora of quality info online. I have discovered "bokashi" for making my waste management (composting) easy. Building "perfect walls" to keep house heating costs down (combo wood/propane). "Texas cool roofs" to lower cooling needs. SIX: Experiment Perfect for us experimental types. I've been running a variety of experiments. Most very successful (texas style cool roofs before they were popular. now on rev C). Solar. Perfect wall. Wow. Some less successful. Pole style building on clay soil? Ha^%@#. SEVEN: The benefit list is long. And goes well past energy use One of the best things about living off grid is the extra time you get. I deliberately set out to build a lower overhead lifestyle. I spend my money travelling. Meeting people. Writing. Doing art. Surfing the web. Cooking. Being active. My quality of life has gone way up. To sum up. Off grid is awesome. Go for it. |
05-17-16, 11:54 AM | #39 |
Journeyman EcoRenovator
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Creeky,
It depends where you live. The hardest thing to do is to heat and cool. Heating in Northern US climates like mine where it can get to 20 or 30F below means that you need alternative heating methods, you can't do it on PV alone. It's the middle of May now and we had a frost two nights ago with several days of overcast. There's no battery that can cover that. You can burn wood sometimes but if the outside temp gets too high you'll get a back draft. Living off the grid means greater expense for batteries and a shorter life. Why not let the grid charge your batteries and only use them when the power goes out? I'm over $500.00 ahead on my electric bill and I use it to my advantage. In the winter I use electric heat to supplement my oil and reduce costs while my batteries don't get overworked. What are you gaining by not letting the grid work in your favor? As for time, being off grid doesn't save you time or give you any extra time. In fact it takes more time to live off grid. And it's not a breeze either when those batteries get low on an overcast day and that genset has to kick in. I guess you're in England and Europe is easier for you as far as inverters but there are good inverters in the States. Outback, like mine for example which are very highly rated. I agree that you can start slow and build but you still have to know where you're going as building for off grid involves different equipment than off grid/intertie. What you want is flexibility and that means land. Can you put in a microhydro? Probably not, how much land do you have? Enough for a windmill that will actually accomplish something? That takes real estate, you can't put up a windmill on a 1/4 acre lot, well you can but you can't get it high enough to do real work. Sure you can shut off the grid but you'll have to spend more on other resources to heat, cool and cook. Rob |
05-17-16, 12:34 PM | #40 |
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I'm about a mile from hydro. No intertie option. Putting in just the poles to run the grid in would have cost $35k. I have six acres. I'm north of you in Canada. The wind maps show this is a poor area for wind. Not to mention turbine maintenance. My creek by the property is too slow for useful hydro.
So as for heat and cooling. Situating your building(s) for shade is a good idea. Building properly insulated structures is key. I use around 500 lbs of propane and 1 face cord of wood per year. When I expand my system I plan on putting in an ASHP. I do use a small electric a/c unit in my studio. The only building that gets too hot (not as good insulation/strong west late day sun exposure). I have never had trouble with back draft using my wood stove. Batteries. Pb is dead. Lithium is the new standard. Talking about anything else is not time efficient. I'll point out that most people say off grid electric is too expensive. And then they use absurd comparisons. Ie., my electric is .07/kw. Not taking into account the electrical system/grid hook up costs that are on their mortgages. Because if they can't see it, it doesn't exist right? Due to heavy cloud in the late fall I use a genset. Two years ago I used $50 in gas. This year was more, but I was building. So $80? Big deal. A season for one week of truck use. Last year I went from Jan 3 to Oct 16 without any genset use. I run the genset a max of 2 hrs maybe twice a season. I expect this to drop with a lithium battery pack. Usually an hour in the a.m. suffices. And that is typically/rarely more than one or two days a week. Again. I actually live off grid. So, from 5 years experience: Once your systems are built they are completely reliable. For ex. I emptied my composting toilet facility last fall for the first time in 4 years of use. It took me an hour. Cost. .25 in diesel using the tractor to move the material to a secondary composting area. (Note: Now no trace of the material remains. Completely returned to the earth.) My electrical grid has been up and running for 3.25 years without interruption. It's funny, as many people "in town" know I'm on solar, they delight in telling me about the latest grid interruption. Two years ago the "big game" was interrupted for 20 minutes by a grid shutdown. I saw the whole game. Many laughs were shared. Because I don't have the overhead costs of living on grid (taxes, mtg etc) I have a great deal of "free" time. And living in a rural area where I get to do some light farming and kayak, hike, fiddle fart. I'm in terrific shape. My life is wonderful. You make your own decisions as to consumption. I traded excess material consumption for time. This makes me happy. Now, this is my experience. Results may vary. |
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