Building Reserve and Using KWH

[bcroe]

May arrives, one month into a Net Metering year. Many typical April
clouds, but did manage 151KWH the last day from the 15KW inverter
plant. Kept them flat out over 10 hours, literature says 4 sun hours are
about right for this area.

After 8 years of inverter abuse, thoughts on failures were that the most likely
failure mode might be, caps filtering the switching currents gradually lose
their ability. Then the transistor switches are caused to fail. The thought is,
a scope on the cap waveform might be able to detect the degradation before
anything blows up. Replace the critical caps (like oil changes) and avoid a
more serious failure.

There are a pair of identical spare inverters here, one shelved, the other
mounted next to those operational. Just move the DC input wires, close a
breaker, and the spare could take over. What might be done, is examine
critical power circuitry, and measure filtered noise on an 8 year inverter,
switch power over to the spare, and see how they compare. If operational
cap noise starts to creep up on annual check, time to switch to standby
and replace caps?

One thing that might be built, is the CLIPPING METER. The idea is to put
a panel out there with no load to provide an open circuit voltage reference.
A quick measurement should reveal the MPPT voltage as the inverters
are approaching (but not reaching) clipping. Will need to divide that voltage
down by the number in my strings (12), to compare to a single panel. The
difference between open circuit and inverter input voltage should be a good
indication of clipping, a fairly straight line transfer function I hope. Not sure
where that display should reside, or the type of display. Bar graphs are popular
here.

Major pushes in past years have left a lot of lower priority stuff neglected,
this may be a mostly catch up year. Planning will continue, I will need to get
some of the new design in place before the time the (experimental) wood
supported array falls down. Bruce Roe

[Mike90250]

I've heard that the water drain ones, get layered up with goop pretty fast - others say they don't

I'm heard of household sized heat recovery devices, and as long as you make provisions for the system to be accessed to clean out lint, or use a furnace filter as a pre-filter, it could work

[bcroe]

Just wondered , in the quest to save precious solar energy, has anyone had
experience with drain water heat recovery devices?

Another is the ventilation heat recovery device. This house is too loose to
make good use of it generally, but perhaps it could be useful on a clothes
dryer? Bruce Roe

[peakbagger]

I just picked up a table top induction cooktop unit. I pulled a couple of knobs off my run of the mill electric range and plopped it on top of one of the calrod elements. I had enough pots and pans in my collection that works with it. I think cast iron works the best. I am impressed. Almost instant heat and very responsive. I have relearn a few ingrained cooking techniques and a careful simmer is tough as the power is on off

My cooktop is a flip up for cleaning under the elements and if I wanted to get creative I could probably cut up some sheetmetal and set two of the them flush with the old cooktop. Much more likely I will leave it the way it is. The one downside to the high end cooktop units is they do not have great long term rep for reliability and when they do break or act up, its rare they can be repaired and replacements if available are pricey.

[Ampster]

........

I read of induction stove tops cooking more efficiently. But they are expensive
with far more failure potential, and apparently require a new set of utensils. The
70s electric range here has been seen to consume about 0.4 KWH a day for a
couple people, the potential improvement seems hardly worth the cost in my
situation. And the range has proved highly maintainable in the long haul.
Anyway, in the past the old range has demonstrated ability to provide extra heat,
as have my (only occasionally used) incandescent bulbs.
..

I agree with your sentiment regarding replacing an entire range just to get an induction cook top. I did replace just a cook top and the economics were different. The WAF was increased because it was easier to clean and more responsive than the old elements on the other cooktop with traditional elements. Most of our pans worked because they were either cheap stainless or clad ware which had enough iron to be excited by the induction. I don't have hard data on energy efficiency but I liked the fact that only the pan got hot and the surface of the cooktop below the pans stayed cool.

[bcroe]

The PoCo marked my 2020/21 Net Metering year as ending 30 March.
Energy generated by the inverters was 30,100 KWH, about 11% more than
was consumed. This may be a record, probably brought by considerably
more sun (less clouds) over the winter than usual. The whole month of
March actually produced more than was used. The winter sunny days were
on the cold side, so consumption went up too, how convenient.

Energy reserve from the previous summer hit a peak of about 13,500 KWH
on 1 Nov, dropped to about a low of 3000 KWH before leveling in March. A
surplus of 3034 KWH was gifted to the PoCo on 30 March trueup. Without
increased generation, I hope to soon see a slight increase in reserve with
about a 2.5% increase in energy arriving at the PoCo meter, through more
efficient local wiring for the first full year. See reserve graph.

The energy setup has continued to evolve each year. The same 15 KW inverter
plant continues in service. Energy generated has somewhat increased via better
panel placement and gradual reduction of shading (tree removal). Transmission
loss is reduced with better wiring. More efficient equipment has saved energy, but
this has been largely consumed by increasing service equipment. The standby
central furnace blower (with new motor) is run regularly so that the electronic air
filter can do its job, and summer humidity is limited.

The conversion back to all electric by now includes 6 heat pumps in 2 buildings,
a 70s electric range, and a ventless clothes dryer. Energy sights are set on
electric (or some other hybrid system) water heating, but the intended heat pumps
are not yet available. Even before PV solar here, some 60 circuits were monitored
for wasteful appliances. Many were replaced, others modified to avoid waste.
The theme continues to be efficiency (avoiding waste) along with generous KWH
generation, definitely NOT any human deprivation or discomfort. Ever in mind,
just a 1 watt vampire load wastes 8.766 KWH a year.

I read of induction stove tops cooking more efficiently. But they are expensive
with far more failure potential, and apparently require a new set of utensils. The
70s electric range here has been seen to consume about 0.4 KWH a day for a
couple people, the potential improvement seems hardly worth the cost in my
situation. And the range has proved highly maintainable in the long haul.
Anyway, in the past the old range has demonstrated ability to provide extra heat,
as have my (only occasionally used) incandescent bulbs.

In general things are running with minimal maintenance or operational attention.
The Heat Pumps are a blessing, allowing entirely comfortable temps year around
without switching around equipment, regardless of humidity. They are nearly silent.
The first winter HP demonstrated what somewhat limited capacity could do. Two
more winters have passed, and I have since doubled HP capacity to cover the
second building, and the the possibility of a really severe winter. This while
evening out temps better in the many zones, and achieving the goal that no single
failure would produce a desperate winter situation. That was always a worry in
my propane furnace era. No reset is necessary after a short outage.

My belief is that more HP capacity here just means they run less, maintaining or
even increasing overall efficiency. Some will say HPs are expensive, but cost can
be drastically cut depending on how much of the work can be done on a DIY basis.

This electric bill contains a sheet for reliability, says I was only down 110 minutes
in the last year, that was the suicidal raccoon affecting just my transformer 30 July.
99.97% reliability, guess that came off their super duper electronic net meter. I
suppose my neighbor was 100%. We are just around the country block from the
area sub station, which in turn is very few miles from the Nuke. The outage
occurred in the dark of night, no solar operation affected.

Inverters here have been fine for 8 years, I have spares just in case. No
longer pushing the already high line up another 9V at the inverters, no
need to reprogram the V monitors. The original experimental wood array
that I expected to last for 5 years (and hoped for 10) is starting to look its
age. The final array is planned, present config is lacking a second west
facing section to maximize high output hours and KWH. I could now start
putting in permanent foundations to finish. Bruce Roe

Reserve 21m.jpg

[SunEagle]

Yes the subject of the power is worthy of mention in prayers these days. It
has been totally reliable here, and at least we are used to some -10F every
winter. If TX was mostly nuke, at least the power would be available, keeping
it distributed is another problem. Just how does a wind turbine freeze up,
too much blade ice?
Bruce (in cold, boring, but no disasters ILL) Roe

I don't know the details yet but based on how Texas was distributing primary power through wind & solar and other forms of power generation distribution was secondary. When the primary generation failed due to the snow and cold the secondary could not keep up with the demand.

I think it was too many eggs in the same basket scenario.

[Mike90250]

You use Jet-A to power the de-ice system

De-Ice Wind turd blade.png

[bcroe]

As they say the weather is changing and we have to change with it. Look at all those poor people in Texas without power during the worst cold snap most have ever seen in their lives.

Yes the subject of the power is worthy of mention in prayers these days. It
has been totally reliable here, and at least we are used to some -10F every
winter. If TX was mostly nuke, at least the power would be available, keeping
it distributed is another problem. Just how does a wind turbine freeze up,
too much blade ice?
Bruce (in cold, boring, but no disasters ILL) Roe

[SunEagle]

About 11 am Tues we got some temp considerably above zero, combined with
good sun. I went out and worked on solar panels, cleaned off the latest snow.
First got all the fluffy stuff off so the sun could get at them. Then made another
pass, started getting ice off. Then went back to the beginning, this time the sun
helped me get the last of the ice off. Running at maximum 15KW again, will need
the additional energy. Bruce Roe

As they say the weather is changing and we have to change with it. Look at all those poor people in Texas without power during the worst cold snap most have ever seen in their lives.

[bcroe]

about half an inch of ice was frozen onto half the panels

SOMEDAY we ought to get an adequate combination of sun and higher temps to
get rid of the rest of the ice, it still covers parts of enough panels to inhibit those 6
strings. Bruce Roe

About 11 am Tues we got some temp considerably above zero, combined with
good sun. I went out and worked on solar panels, cleaned off the latest snow.
First got all the fluffy stuff off so the sun could get at them. Then made another
pass, started getting ice off. Then went back to the beginning, this time the sun
helped me get the last of the ice off. Running at maximum 15KW again, will need
the additional energy. Bruce Roe

[bcroe]

We are now at the coldest part of winter, -12F has been seen, around 0F much
of the time. Gortex insulated mittens are a big improvement in the cold. Nearly
2 weeks ago we got a warm melting snow, but got hit with a hard freeze before
I went to clear it in the morning. As consequence about half an inch of ice was
frozen onto half the panels, the original install, unadjustable, lower angle ones.
Some snow has occurred more nights than not, keeping the later install half of
my panels clean has required very little attention. In this situation it may hit 4 to
8 KW output depending on clouds.

SOMEDAY we ought to get an adequate combination of sun and higher temps to
get rid of the rest of the ice, it still covers parts of enough panels to inhibit those 6
strings. I could use the energy, the heat pumps are keeping inside temps just fine
but eating away at the summer KWH reserve. That load can hit 8KW. Clearly I
will not be giving the PoCo a free 5000KWH surplus at this 1 April true up. That
was the original plan, use most of it up, staying in the black will depend on the
weather till then. I am down perhaps 500KWH because the new cable was late
July getting into operation.

I believe I have mastered using the snow blower to clear panels. Today inches of
fluffy stuff did stick to the 72 near vertical panels, I just directed the snow blower
to the top edge of the array, and all the snow immediately slid off. That 4WD
tractor with traction tires does so well, I have not been using chains. But it
can be hard to keep pointed in the right direction with the snow blower down,
I may try chains on the front wheels to help that.

Seeing the snow advantages of the adjustable panels, I am more inclined than
ever to rebuild most (or all) of the array to that standard. It will not be the rush
before winter of the last time, but now I have all the big tools and knowledge to
move it along over several years. The next adjustable array will be a 2 sided
version of the last one, more bang for my efforts.

Thank goodness everything is working now, here and other places. Bruce Roe

Feb21ice.JPG

[DanS26]

The Podcast was informative. they see California as a significant market because of the energy regulations. I was especially intrigued with how he described it as a Distributed Energy Resource (DER) making the grid more resilient.

Yes, heating water with excess electricity at the right time so that you do not have to heat that water at the wrong time.

I use the same concept with my two ETS (Electric Thermal Storage) systems only I am heating ceramic bricks rather than water.

[Ampster]

Last I heard was the Nyle Geyser for residential applications would be available Spring 2021, but their website just says "Coming Soon".
..........

The Podcast was informative. they see California as a significant market because of the energy regulations. I was especially intrigued with how he described it as a Distributed Energy Resource (DER) making the grid more resilient.

[DanS26]

Thanks, I heard that when they sent me a note. I was hoping they were announcing availability.

Last I heard was the Nyle Geyser for residential applications would be available Spring 2021, but their website just says "Coming Soon".

The older model I have has been running very well for 8 years. I've taken the cover off once just to see what was inside.....very well built, heavy duty relays, solid weld and solder joints, good insulation, etc. The compressor appears sturdy and runs with little vibration or noise.