Building Reserve and Using KWH

[J.P.M.]

Indeed it is the system as a whole that is optimized. It is easy for someone to cherry pick the individual components output and try to infer that your system is suboptimal.

Ampster, if you think I'm cherry picking Bruce's array, you're exhibiting an example of your ignorance of the basics of PV and solar energy in general, and I have no inclination to instruct you.

Bruce's array is optimized for what his goals and intentions are. Big AMEN on that. I share more than a bit of what appear to be his eccentricities.

Bruce and I do not share all opinions about the best way to apply solar energy.

IMO, Bruce's array is most likely not something that a knowledgeable PV designer would come up with in most any common semirural, grid tie application if cost effectiveness or optimal use of materials or resources were design goals.

You want to be helpful, buy a decent textbook and find out what solar energy is really all about before you criticize and misconstrue and attempt to twist what I write. You might be able to contribute something technical rather than repeat what you read or heard someplace that fits your view of things. You also might begin to understand some of what Bruce and I respectfully disagree about rather than more of the same blather that doesn't contribute much of anything to the discourse except that you agree with someone and disagree with someone else for unspecified reasons.

[bcroe]

Indeed it is the system as a whole that is optimized. It is easy for someone to cherry pick the
individual components output and try to infer that your system is suboptimal.

Oh, critical analysis is welcomed. If I can not answer that, its time to go back to the drawing
board. Have had to explain that to some new guys on the job. I have stories....
Bruce Roe

[Ampster]

......

Better to design a PV system that does well every day, sunny or not. A close look at my actual numbers reveals more output on EVERY day than a pure south facing array. My original south facing array would have much deeper valleys than this
chart.

Indeed it is the system as a whole that is optimized. It is easy for someone to cherry pick the individual components output and try to infer that your system is suboptimal.

[bcroe]

Yea, it is. And I don't have data or literature to comment one way or the other, so I'll not do so.

NOMB or concern, but to be clear, your inverters may be running to capacity but because of your less than optimal array orientations the panel portion of your system is not. If you had ~ 25-26 STC kW of south facing panels at a 45 deg. tilt, instead of ~ 35 STC kW you do have spread in varying orientations as you have, you'd produce about the same output on a sunny May day. You'd probably need bigger/more inverter capacity and that would cost a bit, but I'd wager you'd save a lot more than that cost by having only about 75 % as much STC kW in panels to pay for. But I do appreciate the reasons behind what your doing and the fun you're having.

Also, humidity is the amount of water vapor in the atmosphere or in a gas. What you see is condensed water vapor, or simply condensate.

Respectfully,

PV15May19.png

Will try to say condensate next time.

That is fine for the one fully sunny day on this chart of my recent daily outputs. Better to design a PV system
that does well every day, sunny or not. A close look at my actual numbers reveals more output on EVERY
day than a pure south facing array. My original south facing array would have much deeper valleys than this
chart. Just so any comparisons make sense, there needs to be a common element. Since I cannot change
my 15 KW inverter capacity, I am declaring that the fixed point. It may be used with a DC/AC ratio. Bruce Roe

[J.P.M.]

Its all a guess of course. I can run at capacity even with very light clouds, an ideal sunny
day may do 158 KWH. When our weather person says no clouds, but smoke from Canada
is causing the haze, I credit the 135-140 KWH lessor day production to the smoke.

I see a heat pump automatic switch over to cooling today, humidity is dripping out the other
(inside unit) drain. Bruce Roe

Yea, it is. And I don't have data or literature to comment one way or the other, so I'll not do so.

NOMB or concern, but to be clear, your inverters may be running to capacity but because of your less than optimal array orientations the panel portion of your system is not. If you had ~ 25-26 STC kW of south facing panels at a 45 deg. tilt, instead of ~ 35 STC kW you do have spread in varying orientations as you have, you'd produce about the same output on a sunny May day. You'd probably need bigger/more inverter capacity and that would cost a bit, but I'd wager you'd save a lot more than that cost by having only about 75 % as much STC kW in panels to pay for. But I do appreciate the reasons behind what your doing and the fun you're having.

Also, humidity is the amount of water vapor in the atmosphere or in a gas. What you see is condensed water vapor, or simply condensate.

Respectfully,

[SunEagle]

I didn't hear/read of any big fires west or NW of you, but I'm curious, how do you do the estimating of losses due to atmospheric turbidity/smoke ?

As Bruce mentioned, I have seen a number of weather forecasts that show the smoke from Canadian fires drifting South on the satellite radar images..

[bcroe]

I didn't hear/read of any big fires west or NW of you, but I'm curious, how do you do the estimating of losses due to atmospheric turbidity/smoke ?

Its all a guess of course. I can run at capacity even with very light clouds, an ideal sunny
day may do 158 KWH. When our weather person says no clouds, but smoke from Canada
is causing the haze, I credit the 135-140 KWH lessor day production to the smoke.

I see a heat pump automatic switch over to cooling today, humidity is dripping out the other
(inside unit) drain. Bruce Roe

[J.P.M.]

There is so much smoke drifting from other parts of the continent, its costing me one
or two dozen KWH a day. That is about the limit of our grief, while others suffer one
disaster after another.

Meantime the car shop is well along in the installation of a 16,000 BTU mini-split
heat pump, pictures soon. This RLS3H 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.

There are some summer days when a little AC will be nice too.

The above can be supplemented with a 7.5 KW electric heater while working, if my
KWH reserve is generous. The low temp Minis in the house are giving me a big
KWH saving to make this addition still completely solar powered.

The shop is 1080 sq ft, with basic level insulation. Meantime I am considering
burying a 500 foot loop of 1/0 out to my inverters, to preserve several percent
of my generation. The question is, if to bury 18 inches deep in conduit, or
24 inches deep with direct burial wire? Bruce Roe

I didn't hear/read of any big fires west or NW of you, but I'm curious, how do you do the estimating of losses due to atmospheric turbidity/smoke ?

[bcroe]

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.

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. Bruce Roe

There is so much smoke drifting from other parts of the continent, its costing me one
or two dozen KWH a day. That is about the limit of our grief, while others suffer one
disaster after another.

Meantime the car shop is well along in the installation of a 16,000 BTU mini-split
heat pump, pictures soon. This RLS3H 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.

There are some summer days when a little AC will be nice too.

The above can be supplemented with a 7.5 KW electric heater while working, if my
KWH reserve is generous. The low temp Minis in the house are giving me a big
KWH saving to make this addition still completely solar powered.

The shop is 1080 sq ft, with basic level insulation. Meantime I am considering
burying a 500 foot loop of 1/0 out to my inverters, to preserve several percent
of my generation. The question is, if to bury 18 inches deep in conduit, or
24 inches deep with direct burial wire? Bruce Roe

[bcroe]

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

[SunEagle]

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.

[bcroe]

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

[bcroe]

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

[bcroe]

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

[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.


https://www.google.com/url?sa=t&sour...dqgYrRPKJcGjqI