Building Reserve and Using KWH

[bcroe]

We are seeing -7 F. The 6 Heat Pumps installed 2018-2020 are
all doing their jobs, which is usually heating buildings. They can
AC, but very little of that is required here. 5 are in the house, like
one in each corner and 1 in the area of the basement with an
outdoor wall. Starting with 3 HPs temps were a little uneven and
a fan helped one room. Now with more units and the house
blower circulating the air every hour, things are pretty good.

Some would say I have way too much HP capacity. But if one were
to fail, the others could just work a little harder, no crisis like a
furnace failure. What they call RIGHT SIZING I call JUST BARELY
ENOUGH FOR MOST SITUATIONS. And the minimum HP capacity
would be backed up by a resistive heat system with a COP of 1.
With my capacity the HPs can cover that too, automatically,
even if their COP drops pretty low for well below zero F. The
COP will pick up immediately as temps rise a bit. The factor
driving the above is initial cost. But mini splits are easily DIY,
bringing costs to less than half.

2023/4 saw some tree growth dropping sap on on one
panel string, which only gets removed with a scraper
(razor blade). The tree got cut back summer 2024, but
unfortunately a 250W panel was damaged by a falling
branch. It was replaced (in the dead of night) with my last
spare, better find some more.

The solar plant has been doing very well, with absolutely
minimum maintenance. I clear the snow off part of the array
about 4 times a year, the rest pretty much clear themselves.

In the switch over to straight electric water heating, I have
done some manual control of the previous propane unit. I am
suspecting after 13 years of our hard water, the high efficiency
is not so high. At my previous house with similar water heater,
it did not seem to run sooo long. And that unit could be
unplugged for several days before I ran out of hot water, this
one completely cools off in a day even with the circulator
turned off. PERHAPS mineral buildup on the heat exchanger is
interfering? This problem would go away with the electric heater,
the heat cannot go up a vent not present, it will find its way to
the water. If that strain eventually burns out the resistive
element, it is easily replaced. With 2 elements I would still have
service.

Bruce Roe

[bcroe]

Rollover.jpg

The solar system builds up kWh reserve in Net Metering, starting in April.
I use a minimal amount in summer, so most generation then goes to the
reserve. It generally tops out at the beginning of Nov, then begins dropping
as generation decreases and heating use increases. There is quite a bit
left over on the next reset in April, seems to be increasing. This though I
suspect the actual panels are loosing a bit of capability every year. Good
reason to over panel.

Here is a list of reserve beginning Nov each year, primarily controlled by
the weather. With comments.
2013 3,339 incomplete starting year
2014 12,389 1st complete year
2015 12,389
2016 12,919
2017 13,947
2018 13,991
2019 12,116 E facing panels added
2020 13,448 heavy intra building cable reduces losses
2021 13,665
2022 11,478 fires smoke?
2023 13,824
2024 14,067
2025 14,605

Lately it seems to be rising, I suppose due to warmer weather? Also last year
and 2025, the peak seems to occur later, more like 15 Nov. This is easily seen
on my bi directional, spinning disk kWh meter. Bruce Roe