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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

  • bcroe
    replied
    We passed the reset date, once again without buying any KWH for the year. I did burn
    down some surplus with the car shop resistance heater, mostly left its propane heater
    off. I would really like to find time to put a somewhat larger mini split there, -25F rating
    to keep things more comfortable year round. The house could use another for the worst
    of winter (set a new low record this year). The bi directional disc KWH meter is doing
    well in indicating day by day surplus down to the reset.

    For the first years I noted one inverter always produced one or two more KWH a day than
    the other. Observation showed that is was because of the shadows at day extremes from
    a pair of trees. Those trees were trimmed in 2014, but had regrown worse (from a PV
    perspective) than ever. With prospects getting worse, they finally got the axe about a
    year ago. Since then the OTHER inverter has been out producing a KWH or 2, which
    means the system is producing several more KWH a day.

    There is the possibility of saving nearly 1000 KWH a year losses by replacing the rest of
    the 4 gauge wire out to the inverter building, with 1/0. I now have a trencher to ease
    getting this done, but it is not getting much priority. More likely is to start upgrading the
    early panel mounts to the same standards of the latest, but that will take quite a while.
    If the HVAC plant reaches its final operational status this year, I might start in on the
    optional upgrade stuff.

    The PoCo now asks me to pay them $25 a shot to take my old WORKING appliances.
    Of course I can just break them down to the scrap metal and get paid for it, like previous
    decades. Bruce Roe

    Leave a comment:


  • SunEagle
    replied
    Originally posted by bcroe View Post
    My solar system is proclaiming the spring equinox. The inverters were up for almost exactly
    12 hours. And also, production (130 KWH) exceeded consumption for the first time in 2019.
    Hope I can average that balance in April after my net metering reserve is reset to zero. Today
    there is still plenty left over from last year. Bruce Roe
    +1. Great job Bruce.

    Leave a comment:


  • bcroe
    replied
    My solar system is proclaiming the spring equinox. The inverters were up for almost exactly
    12 hours. And also, production (130 KWH) exceeded consumption for the first time in 2019.
    Hope I can average that balance in April after my net metering reserve is reset to zero. Today
    there is still plenty left over from last year. Bruce Roe

    Leave a comment:


  • bcroe
    replied
    The PoCo bill for 28 Feb 19 shows an energy reserve of 58% of my peak of 14,000 KWH
    after the beginning of the cold. It is pretty obvious I am not burning through all that in the 31
    days of March before my 1 April reset day. Rather than humbly give such a generous gift to
    the PoCo, I installed a 7.5KW electric heater in the car shop, setting it to keep the temp
    about 42F. That had been done in other times with propane, but I am trying to limit that.
    This makes the building so much more pleasant to pop in and out of in winter, than 0 F
    temps seen so much lately (as a consequence of global warming I hear). Snow and water
    dragged in by the 44 inch snow blower soon disappear. From there a quick blast of propane
    achieves the desired 65 F when serious vehicle work is to be done. Turns out this heater
    really does not run that much in most weather.

    In the house the mini split heat pumps made this the easiest winter to get through since PV
    solar went in. The propane furnace functions only as a generator powered emergency
    backup. No need to turn on every incandescent bulb in the house 24/7 for the worst below
    zero temps. From this learning experience, I will probably install a couple of minis rated to
    cover -25F in return for slightly poorer efficiency. The exact ducting arrangement is still
    being contemplated, using multiple indoor air units for a compressor might be the best, but
    is another adventure into areas I have not visited. Another -25F mini may find its way into
    the car shop, then only turn on the electric 7.5K as a supplement rarely used.

    Looking back a bit, methods here are close to the reverse of the usual recommendations.
    Most of the examples I see exalted are brand new construction using the very latest tech
    to avoid losses. Fine but everything here is old, I did spend a lot of resources reworking
    things up to my version of Energy Star performance. Then I should put in super windows,
    run around turning off LED lights, and learn to live like a monk in my sweater. Then I am
    allowed to put in barely enough PV solar to cover minimum annual consumption, and
    save as many $ as possible to be invested for my descendants.

    I do not see it that way, solar should go in right away to start providing energy. That
    energy should be large enough that I can enjoy year around temps anywhere I set,
    operation of a dehumidifier, and a much higher minimum temp in the occasionally
    occupied car shop (she calls it the Garage MaHall). It should be large enough to
    entirely free me of all the utility manipulations of one of my largest costs, keeping
    warm. My electric energy budget went up by a factor of 5 with solar.

    Zero carbon footprint for house heat and electricity was achieved a while ago, have a
    lot of other projects (mostly not energy related), not sure when these awful windows might
    get replaced. The interest saved by never being in debt has been a big investment.

    Overall, I think I am much closer to the end, than to the beginning, of achieving sustained,
    green, automatic, generous home energy use. Bruce Roe

    7500heater2.JPG
    Last edited by bcroe; 03-06-2019, 04:27 PM.

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  • bcroe
    replied
    Originally posted by Ben25
    Here's some data I just found from heat pumps in VT. I haven't read the whole
    thing yet, but very interesting stuff.
    That is a lot of info and processing, for a smaller sample. More than some of us want to know.
    I was sorry to see that hardly anything was said about outdoor temps lower than -5F. Interesting
    that a 9000 BTU unit put out as much heat as a 12,000 BTU unit. And, the largest indoor head
    could put out a maximum of 15,000 BTU heat.

    Meanwhile, the PoCo seems to have stopped sending me those messages that my energy use
    is very high or very low compared to the neighbors. Useless since they only saw inflow, not my
    net metering outflow. But I am getting messages about putting in new heating plants that are
    very expensive and half as efficient as what I now have. The rebates would not begin to save
    what DIY would, with no rebates allowed. Apparently these are just ads passed along from the
    HVAC industry under their name. And some other appliances. Bruce Roe

    Leave a comment:


  • Ben25
    replied
    Here's some data I just found from heat pumps in VT. I haven't read the whole thing yet, but very interesting stuff.


    https://www.google.com/url?sa=t&sour...dqgYrRPKJcGjqI
    Last edited by Ben25; 02-06-2019, 10:23 PM.

    Leave a comment:


  • bcroe
    replied
    Originally posted by Ben25 View Post
    Who makes the -25 mini split? I've been running my new pellet stove a lot this year, mostly when its below 20f, so haven't run my mini splits nearly as hard. I've been getting very bad feedback from the hyperheat multi zone Mitsubishi units (MXZ-C series) people have been reporting a COP of near 1.4 for heating.
    I would expect the heating COP would drop with outside temp, do not have all the numbers. From
    what I see its better than 1.4 above zero F, at some negative it could drop to 1 which is still as good
    as resistance. Even if it reached that level, having the system take care of every temp with no
    action from me would be valuable. I am quite sure the best COP possible is delivered at any time,
    winter temps go all over here.

    The pump was part of the family of Fujitsu RLS3 rated -21F 16000 BTU heating 29.3 SEER.
    RLS3H rated -25F, maybe they added a heater because no SEER listed. That is fine, saves
    me turning on a heater. Bruce Roe
    Last edited by bcroe; 02-06-2019, 08:42 PM.

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  • Ben25
    replied
    Who makes the -25 mini split? I've been running my new pellet stove a lot this year, mostly when its below 20f, so haven't run my mini splits nearly as hard. I've been getting very bad feedback from the hyperheat multi zone Mitsubishi units (MXZ-C series) people have been reporting a COP of near 1.4 for heating.

    Leave a comment:


  • bcroe
    replied
    Got the PoCo bill today, well into winter, and this time covered some serious cold (below zero F)
    temps including a couple record breaking days. The general experience has been, the 3 mini
    splits (around 3 tons total heating) will handle any cold down to zero F. What I needed to know,
    is what to expect for below zero. More equipment will be needed, but how much?

    Jan included below zero, and even a couple record breaking -30/-31 nights. The minis seemed
    to be still putting out serious heat down to -12F, but losing effectiveness below that. As we
    headed down to -30F, some 3 tons more heat was turned on of the previously unused resistive
    heat elements. This seemed to do the job, in fact it was more comfortable than years the minis
    were not helping. I know, this is far from laboratory precision.

    Seems like the mini outdoor units tended to make more noise with extreme cold, defrosting
    themselves I think. Sort of like the engine of a rather distant heavy truck.

    Available is a 2 ton mini with a -25F capability. Given these result, I will see about getting one
    going in what she calls the Garage Mahal. The idea is to keep it in the high 30s all winter, with
    a quick blast of propane to bring it up to 62 F for serious work (transmission overhaul,etc). It
    would be better for things like keeping the 44 inch snow blower completely melted off for the
    next use, and so on. Some summer cooling, and maybe justify the size of the array.

    The -25F mini may not be quite as efficient as the -14F units now operating, but when added
    could lower the temp of completely automatic operation of the house. If we break the latest
    cold records, I might need to turn on the electric stove.

    The summer generated KWH reserve started a bit down (14,000 KWH) from past years, but is
    now higher than ever before this date, near double the average over several years. The reserve
    has been dropping about 62 KWH a day, was around 100 in past years. Total consumption is
    about 99 KWH a day, the difference being solar generation over the month.

    Bruce Roe
    Last edited by bcroe; 02-04-2019, 03:12 PM.

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  • bcroe
    replied
    Originally posted by Ben25 View Post
    Just read through most of this thread. Part of my job is installing Mitsubishi mini splits. Sounds like you did your research and did a good job installing. One thing: if you didn't use nitrogen to pressure test the lines, I would check all of the connections for signs of oil. Leaks can sometimes occur only under pressure, not under vacuum. If theres no oil, you're all set. When the refrigerant leaks out it brings oil with it and then evaporates.

    I have 3 units at my house. (FH-15, FH12 and FH-09)
    Even though they're rated to -13f, I've seen them running at -20f. Great units! Just make sure you keep the filters clean.

    Ben
    Thanks for the feedback. With welding and other gasses here, they did get pressure tested. A leak
    was and remains my biggest concern, and great care was taken to avoid them. None were detected.
    The below zero weather has not arrived, that will be the most serious test. Bruce Roe

    OcHpN.JPG

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  • J.P.M.
    replied
    Originally posted by Ben25 View Post
    Just read through most of this thread. Part of my job is installing Mitsubishi mini splits. Sounds like you did your research and did a good job installing. One thing: if you didn't use nitrogen to pressure test the lines, I would check all of the connections for signs of oil. Leaks can sometimes occur only under pressure, not under vacuum. If theres no oil, you're all set. When the refrigerant leaks out it brings oil with it and then evaporates.

    I have 3 units at my house. (FH-15, FH12 and FH-09)
    Even though they're rated to -13f, I've seen them running at -20f. Great units! Just make sure you keep the filters clean.

    Ben
    Seriously, it's nice to get some intelligent feedback from someone who sounds like they possess common sense and experiential knowledge. Thanx for the reminder/refresher.

    Leave a comment:


  • Ben25
    replied
    Just read through most of this thread. Part of my job is installing Mitsubishi mini splits. Sounds like you did your research and did a good job installing. One thing: if you didn't use nitrogen to pressure test the lines, I would check all of the connections for signs of oil. Leaks can sometimes occur only under pressure, not under vacuum. If theres no oil, you're all set. When the refrigerant leaks out it brings oil with it and then evaporates.

    I have 3 units at my house. (FH-15, FH12 and FH-09)
    Even though they're rated to -13f, I've seen them running at -20f. Great units! Just make sure you keep the filters clean.

    Ben

    Leave a comment:


  • bcroe
    replied
    Originally posted by J.P.M.
    I believe I'm better versed in cost effective ways to kill a utility bill and I think you leave money
    on the table ion that respect
    Pretty much right, different objectives. Bruce

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  • J.P.M.
    replied
    [QUOTE=bcroe;n389644]I hate to think of what J. P. M. would say about my thermostat settings. /QUOTE]

    Why? First and foremost, NOMB.

    Besides, some of my cold climate thermostat shenanigans would probably make you shake, or at least scratch, your head. But I learned or confirmed a lot of book learning by doing stuff.

    My sense is that you and I are about equally eccentric in residential energy matters but with different emphases. I think my ways of approaching the situation are more useful for more people, and, without being critical, I believe I'm better versed in cost effective ways to kill a utility bill and I think you leave money on the table ion that respect, but I feel that ignoring your experiential knowledge and/or what you write about with respect to the finer points of PV electronics and practical ground mounting is not in my, or others', best interests. I don't agree with you on everything, but I sure take what you write seriously and I believe you are sincere and well meaning.

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