Building Reserve and Using KWH

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  • J.P.M.
    Solar Fanatic
    • Aug 2013
    • 14939

    #31
    Originally posted by bcroe

    About all I have is the high temp for each day. Maybe someone recorded degree days. I
    can't reference one year ago, because the not yet discovered leak in my well was covering
    up the other energy uses. Best guess I have is the internal leak started about Dec, got worse
    for weeks till I finally figured it out. For the other years there is a range of usage, but this time
    I am under all of them.

    Conservation wise, a lot improved 2010 to 2013, but the only notable thing lately is running
    a dehumidifier part time. Bruce Roe
    Thank you.

    Just wondering if you had noticed any correlation between HVAC usage and daily/weekly/monthly (inside-outside) temp. diff., or correlation with other factors such as conservation measures.

    BTW, Happy New Year.

    J.P.M.

    Comment

    • azdave
      Moderator
      • Oct 2014
      • 765

      #32
      Originally posted by bcroe

      About all I have is the high temp for each day. Maybe someone recorded degree days.
      My POCO updates a 30-day span online report each morning with the last day's activities. It 's a quick reference for graphing Net Energy, Generation and Usage. It also overlays the average temperature for the day. I can also view it by the week or by the year. Pretty handy reference to glance at while eating my bowl of oatmeal each day.

      On the Net Energy screen you can certainly pick out a cloudy day instantly.

      Webp.net-gifmaker.gif

      Dave W. Gilbert AZ
      6.63kW grid-tie owner

      Comment

      • bcroe
        Solar Fanatic
        • Jan 2012
        • 5203

        #33
        I do write down several numbers once a day, but not average temp. Inside temp not uniform and not recorded.
        I hate to think of what J. P. M. would say about my thermostat settings. The PoCo is trying to get me to have
        an online account with them, auto pay, but I am not playing. Bruce Roe
        Last edited by bcroe; 01-06-2019, 10:20 PM.

        Comment

        • J.P.M.
          Solar Fanatic
          • Aug 2013
          • 14939

          #34
          [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.

          Comment

          • bcroe
            Solar Fanatic
            • Jan 2012
            • 5203

            #35
            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

            Comment

            • Ben25
              Solar Fanatic
              • Jul 2014
              • 135

              #36
              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

              Comment

              • J.P.M.
                Solar Fanatic
                • Aug 2013
                • 14939

                #37
                Originally posted by Ben25
                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.

                Comment

                • bcroe
                  Solar Fanatic
                  • Jan 2012
                  • 5203

                  #38
                  Originally posted by Ben25
                  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

                  Comment

                  • bcroe
                    Solar Fanatic
                    • Jan 2012
                    • 5203

                    #39
                    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, 04:12 PM.

                    Comment

                    • Ben25
                      Solar Fanatic
                      • Jul 2014
                      • 135

                      #40
                      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.

                      Comment

                      • bcroe
                        Solar Fanatic
                        • Jan 2012
                        • 5203

                        #41
                        Originally posted by Ben25
                        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, 09:42 PM.

                        Comment

                        • Ben25
                          Solar Fanatic
                          • Jul 2014
                          • 135

                          #42
                          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, 11:23 PM.

                          Comment

                          • bcroe
                            Solar Fanatic
                            • Jan 2012
                            • 5203

                            #43
                            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

                            Comment

                            • bcroe
                              Solar Fanatic
                              • Jan 2012
                              • 5203

                              #44
                              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, 05:27 PM.

                              Comment

                              • bcroe
                                Solar Fanatic
                                • Jan 2012
                                • 5203

                                #45
                                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

                                Comment

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