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Building Reserve and Using KWH

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  • bcroe
    started a topic Building Reserve and Using KWH

    Building Reserve and Using KWH

    My PoCo earlier mass customer emailed me that adding PV solar might be advantageous if I had the
    roof space. Now a similar suggestion came with the latest bill, it also mentions community solar. A
    little snooping indicates the terms may be similar to mine from 5 years ago, don't know
    about gov rebates or what inspired this.

    Fine, but my net metering annual reserve reset to zero about 1 April. So with cold weather, clouds, and
    no reserve, April is my hardest month to stay ahead and avoid buying any KWH. A look at the weather
    reveals that reading the meter on today, the last day of April, would really help with maybe 400 more
    KWH added to my reserve in the last 3 days. Just as if to make it harder, the PoCo read my meter
    remotely, 3 days before the end of April, but I managed to be ahead by 600KWH anyway.

    The major conservation effort for a while will be about adding enough mini split heat pumps to take care
    of the house almost all year. The electrical distribution center is prepared, more about that later.
    Bruce Roe

  • azdave
    replied
    I want to be like Bruce! (sort of)

    Mini-split installed here too but a cooling-only unit to maximize our solar reserve in the summer heat. Working out nicely now that it has hit 110 here in Phoenix. Keeps the master bedroom and bath a very comfortable temperature while we sleep. There rest of the house is not cooled overnight. Usually, this is the time of year where we start eating into the small reserve that unfortunately gets reset on May 1st. Yesterday was 110 and yet we still banked 20kWh. July and August, when the monsoon season is upon us, will reveal the real value of not cooling the entire house all night long.

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  • Ampster
    replied
    Originally posted by bcroe View Post
    ............
    Just what is the right amount of annual
    generation is hard to say, because winter weather is so variable. Bruce Roe
    That is a good reason for an aggressive design.

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  • bcroe
    replied
    The mini split R410A inverter driven compressor technology has such a long list of
    improvements over what proceeded it, it ought to be replacing equipment (where
    applicable) on a huge scale. But there seems to be some resistance in the US HVAC
    industry to them. I am doing some volunteer work on a century old solid concrete
    mansion, now on the nat register. I just got the job of an extensive energy audit of all
    the buildings. Have not started yet, but high on my hit list is a huge old AC unit sitting
    on an intermediate roof, to supplement some rooms in the steam heat main building.

    These units run 450psi high side, 240psi low side, more than double my R12 stuff.

    My place has been highly experimental, but it feels like solutions to all main issues
    have been found. Perhaps once all my HVAC equipment is updated and the rest of
    the panels are remounted, it will be finished. Just what is the right amount of annual
    generation is hard to say, because winter weather is so variable. Bruce Roe
    Last edited by bcroe; 06-12-2019, 10:36 PM.

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  • Ampster
    replied
    Originally posted by J.P.M. View Post

    For most folks - not Bruce - rather than looking for ways to utilize overproduction, some might think it might be better yet to size the equipment so that the excess production isn't generated in the first place.
    I don't get the impression that this project has been completed yet. I has been going for at least 15 months with a stated goal of being Net Zero. I think it is too early to say that long term there will be excess production.
    Last edited by Ampster; 06-12-2019, 09:41 PM.

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  • frankge
    replied
    jumping on the minisplit bandwagon. In Tampa we run AC 24x7 in the warmer months which is a good part of the year. I installed a 12000btu Pioneer minisplit for our master bedroom which allows me to basically turn off the new 2 stage heatpump with ECM blower I just installed. That along with a heatpump water heater has given me a net-zero electric consumption. They raised our rates and electric s still cheap compared to some of you - 14 cents per Kwh, but I've already seen it raise from 12 cents. Btw the cost to install the minisplit myself end to end was about $800.00

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  • J.P.M.
    replied
    Originally posted by Ampster View Post
    Sounds like a good plan to utilize some of that 4 gWhrs of energy your system produces over and above your consumption..
    For most folks - not Bruce - rather than looking for ways to utilize overproduction, some might think it might be better yet to size the equipment so that the excess production isn't generated in the first place.

    Leave a comment:


  • ButchDeal
    replied
    Originally posted by Ampster View Post
    Sounds like a good plan to utilize some of that 4 gWhrs of energy your system produces over and above your consumption..
    I think you mean 4MWhs not 4GWhs

    4000kWh = 4MWh
    4000MWh = 4GWh

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  • Ampster
    replied
    Sounds like a good plan to utilize some of that 4 MWhrs of energy your system produces over and above your consumption..
    Last edited by Ampster; 06-12-2019, 08:34 PM. Reason: Correct math to reflect megaWatthours.

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  • bcroe
    replied
    Originally posted by bcroe
    Meantime the car shop is well along in the installation of a 16,000 BTU mini-split
    heat pump, pictures soon. This 15RLS3H has a -25F degree operational capability,
    achieved with some internal supplemental resistive heat at the very lowest outside
    temps. This luxury will attempt to keep inside temps at least 40 F year around, as
    opposed to just being really cold in Feb. This will make quick jobs (oil change) easy
    and a quick blast from the propane furnace will get me 65 F for a transmission
    overhaul. The occasional, automatic use of some resistance heat at extreme lows
    is a huge improvement over using it continuously and manually.

    The shop is 1080 sq ft, with basic level insulation. Bruce Roe
    Here is the state of the 15RLS3H installation in the car shop, the inside work is
    already finished. My house mini splits past winter left me with a generation
    surplus of over 4000 KWH, so this winter will attempt to use some of it up on
    this semi insulated building, which used to sit with no heat in winter. Damaging
    levels of ice and snow slide off the high metal roof, so a small roof/shield will
    be placed a foot or so above this equipment for protection.

    The 15RLS3H will be the main energy experiment for the next winter. I do not see
    it as being in its sweet spot, trying to maintain 40 F in a substantial area with
    outside temps down to -25F, so it will be a test. It has more capacity than my
    first minis, and the heater supplement will take energy, but nothing like a pure
    resistance heater. Bruce Roe

    RLS3H1.JPG
    Last edited by bcroe; 06-12-2019, 10:33 PM.

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  • Ampster
    replied
    Originally posted by bcroe View Post
    ..........but many of us were not happy to see suggestions of here putting them on some of the best farm land, in direct violation of existing zoning......
    In California there are a number of large commercial solar farms in the desert. At other locations I have observed smaller installations on hillside pasture land and adjacent to flat farm land in the Central Valley. In the case of the hillside pasture land I occasionally see sheep grazing under the panels. In the Central Valley water is an issue and not all land appears to be utilized for farming for reasons that may relate to water allocations or cost of transporting water. I don;t know what the zoning issues are in California with respect to agriculturally zoned land either.

    In looking at some of these smaller installations I also notice that the panel angles are sometimes closer to horizontal than I would have suspected. On further research I understand that the power density per acre can be increased by using these lower angles and thereby reducing the spacing between arrays. This appears to result in a configuration that produces more AC power per acre. I would guess that these systems run higher AC to DC ratios.to optimize system performance. . I can understand that if someone looked only at the array configuration it could be argued that they are suboptimal. However from a system standpoint (array, inverter and land), they may be optimizing the ROI.
    Last edited by Ampster; 06-06-2019, 02:11 PM.

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  • bcroe
    replied
    The first results are in for the attempt to expand commercial solar in IL. Those I
    reviewed were in the 2MW to 20MW (AC rating) range. Of 900 project submissions,
    100 were approved, I do not yet know more details of the approval process. I do not
    yet know of anything close by, but many of us were not happy to see suggestions of
    here putting them on some of the best farm land, in direct violation of existing zoning
    Comprehensive Plans, by some sort of slight of hand. And I was additionally unhappy
    to see proposals where clouds and snow are so prominent. Bruce Roe

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  • Ampster
    replied
    Originally posted by bcroe View Post
    You guys ought to just stick to the facts. Bruce Roe
    The facts are that large scale solar farms average a DC to AC ratio of 1:25 to 1.That number has been increasing over the years. I don't recall your AC to DC ratio but I believe it is greater than 1 to 1.

    Perhaps the misunderstanding is whether we are talking about optimizing the array or optimizing the entire system. I won't speak for J.P.M. but he consistently refers to arrays (the panels) and I interpret your discussion on this thread to mean the entire system, including the panels, inverters and racking.
    EDIT
    As you point out in the following post, most commercial solar farms are described by their AC rating. My point in the above is that an array centric methodology is not always used by professionals to optimize systems.
    Last edited by Ampster; 06-06-2019, 01:23 PM. Reason: Mention that commercial solar installations are rated on AC rating.

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  • bcroe
    replied
    You guys ought to just stick to the facts. Bruce Roe

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  • Ampster
    replied
    I agree with Bruce because he is optimizing his system. Perhaps you might want to try to attack the argument instead of attacking someone else.

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