Sun hours

[SunEagle]

Here is a curve I plotted, of how much energy reserve (Po Co rollover) I had by date.
A few things of interest:
The system started up with south facing panels 1 Aug 13; reserve built up till cold weather
started 1 Oct. The east-west panels started working 1 Nov, but with shorter days and record
cold, reserve was gone in Jan;

The rest of winter 13/14 was run on energy being collected, a minimal amount of KWH
purchased, and some propane. I managed to conserve a single tank of propane into
the summer, to be refilled at the lowest price. The huge Feb propane price spike in Feb
was entirely avoided;

After reserve RESET in April, with longer days I managed to generate about as much
energy as was being used. In June the heat was off, and the reserve began climbing
at a considerably faster rate than 2013 (more panels);

In Oct the reserve didn't flatten like 2013, but continued to rise on a lesser slope. This
is because the new heat pump was conserving a lot of KWH;

With the unseasonably cold weather, I had to shut down the heat pump in early Nov.
I opened its circuit breaker, since it may have a compressor pre heater element (need
to check this). I am now on the reserve down slope. With 4 times the reserve of 2013,
it should last at least until the 1 April reserve reset date. The drop will be steeper,
because I'm not planning to use ANY propane for heat this year;

Come 1 April I'll have the struggle to collect as much energy as I use again. But if the
weather will allow a couple weeks use of the heat pump, it should be OK. In that case
the reserve built in 2015 should be even larger than 2014;

If I see a large surplus reserve in Feb/March 15, I'll burn some of it off with electric heat
in the car shop. It is normally kept around 40F except when working, with propane.

In another thread, someone showed a chart with (nearby) Chicago getting 3.14
SUN HOURS a day yearly average. That seems a little pessimistic, must be the clouds.
However, 90 mi west I managed 5.42 SUN HOURS for the yearly average, despite the
clouds & storms. Bruce Roe

Looking good Bruce. Hopefully you do not get a large number of snow storms or very low temps this winter.

[bcroe]

Something is in the sky!! Its... Its... the SUN! First time we in NW IL have seen it this
Dec. Depressing to hear the weatherman saying Dec has been 97% overcast. If it will
just stay for today, maybe the array will make more than 20 KWH. Good news is the
heat pump is doing well in this warmer weather. Even with it running, the meter says
I'm now banking most of the energy. Bruce Roe

[SunEagle]

Something is in the sky!! Its... Its... the SUN! First time we in NW IL have seen it this
Dec. Depressing to hear the weatherman saying Dec has been 97% overcast. If it will
just stay for today, maybe the array will make more than 20 KWH. Good news is the
heat pump is doing well in this warmer weather. Even with it running, the meter says
I'm now banking most of the energy. Bruce Roe

It must be tough to have grey or cloudy sky's for weeks on end.

My wife was up in Lincoln Il. for a week in early December and never saw the sun. The good thing was there was no snow, just some sleet.

[bcroe]

Here is a curve I plotted, of how much energy reserve (Po Co rollover) I had by date.

In June the heat was off, and the reserve began climbing
at a considerably faster rate than 2013 (more panels);

In Oct 2014 the reserve didn't flatten like 2013, but continued to rise on a lesser slope.
This is because the new heat pump was conserving a lot of KWH;

With the unseasonably cold weather, I had to shut down the heat pump in early Nov.
I am now on the reserve down slope. With 4 times the reserve of 2013,
it should last at least until the 1 April reserve reset date. Bruce Roe

Just got the electric bill; here is the extended plot of KWH RESERVE this winter. The
slope right now looks like I'll zero out before 1 April. BUT I expect production to be
much better in a few weeks, than the just past months. And warmer temperatures in
March should greatly reduce usage, with the heat pump coming back on. So if we don't
have another terribly cold winter, I expect it is on track. Bruce Roe

[bcroe]

PVOutput

I updated a year of output on PVOutput. Bruce Roe

http://www.pvoutput.org/list.jsp?p=5&id=30265&sid=29099&v=0&o=date&d=desc

[bcroe]

Just got the electric bill; here is the extended plot of KWH RESERVE this winter. The
slope right now looks like I'll zero out before 1 April. BUT I expect production to be
much better in a few weeks, than the just past months. And warmer temperatures in
March should greatly reduce usage, with the heat pump coming back on. So if we don't
have another terribly cold winter, I expect it is on track. Bruce Roe

Here is the 30 Jan version of my KWH reserve chart. 2 more months till the Po Co
resets it to zero. While the curve at 30 Jan doesn't look optimistic, the longer days along
with more sunny days, definitely improve the slope in Feb, more so in March. I have
taken last year's production, along with increasing March temperatures, and estimated
the curve to 1 April. It came out 128 KWH to spare. If this is correct, the annual energy
generate will match consumption by closer than 1%.

The next data point will be known only a couple of weeks before reset date; a decision
on how to finish will be made then. Bruce Roe

[pleppik]

2 more months till the Po Co
resets it to zero.

How does it work in your area? Do they carry forward production and then just zero out any net generation on some date?

They could at least send a Thank You card for the power you gave them.

[bcroe]

How does it work in your area? Do they carry forward production
and then just zero out any net generation on some date?

They could at least send a Thank You card for the power you gave them.

They were very vague about that last year, net metering was a haphazard, by hand
operation. It was hard to tell what happened. But this year bills are regular again.

I believe they will reset 1 April or whenever they (manually) read the meter. The
plan was I get no credit for extra KWH, but A. I can burn extra heating the other
building, and B. It looks to be a very small amount anyway, which cost me nothing.
I can make 128 KWH in one sunny day. Or, I might run short, too close to call. Bruce

[bcroe]

As hoped, Feb production is heading way up. In other words, lots less clouds. A
week of good production topped by exceeding 100 KWH today. Bruce Roe

[bcroe]

One of the first things to notice about heating with a heat pump, the vent air isn't
very warm. Guess that agrees with the math, the energy doesn't come in great
big lumps like a propane furnace. In cold weather it pretty much keeps up, but
does so by running nearly continuously. Not that the blower uses much, but its
failure may be hastened. Perhaps I'd better get a spare blower motor and figure
out a quick change routine. Bruce Roe

[gregvet]

One of the first things to notice about heating with a heat pump, the vent air isn't
very warm. Guess that agrees with the math, the energy doesn't come in great
big lumps like a propane furnace. In cold weather it pretty much keeps up, but
does so by running nearly continuously. Not that the blower uses much, but its
failure may be hastened. Perhaps I'd better get a spare blower motor and figure
out a quick change routine. Bruce Roe

Bruce,
Not to get off topic, I have been contemplating a heat pump as well. Has it worked adequately in this cold weather? Even with it working constantly, what is the kWh/day consumption?

[bcroe]

Bruce,
Not to get off topic, I have been contemplating a heat pump as well. Has it worked adequately in
this cold weather? Even with it working constantly, what is the kWh/day consumption?

Its a 3 ton air to air, pretty quick & cheap but only half as efficient as a buried system,
and definitely limited in the coldest months. In a 2000 sq ft, not very well insulted ranch,
its a big improvement over the previous (ancient) unit. It claims a SEER of 14.5, which I
estimate to be an energy multiplier (COP) of 3.7 in the warmer 6 months, dropping down
to 1 at 0 deg F. It uses 10A @ 240VAC, which at an estimated 0.9 power factor, comes to
52 KWH a day if running continuously. Add an estimated 8 KWH for the air blower. My
array can generate double that if the sun is shining even in Feb.

Haven't written much down, but it seems to pretty much handle everything down to
around 20 deg F by increasing run time and doing more frequent defrost cycles. Below
that it couldn't maintain the thermostat setting, so I start turning on some resistance
heat to help. This could add 50 or more KWH a day as the temp drops below zero, at
which point I would turn off the pump and run maybe 150 KWH resistance, -10 F I
might "exercise" the propane furnace that normally never runs. But that usually only
happens overnight, recovering well above zero the next day.

Its definitely paying for itself pretty quickly, a buried system would use considerably less
energy but even these can run out of steam in the most severe cold. And the buried coil
system would tear up the property, take quite an effort to restore. Certainly if building
from scratch a quite large buried coil heat pump with a lessor PV system would be more
ideal, but I am working on continuous upgrades from where I am. My PATHFINDER and
I will be surveying ways to avoid PV shading this year, to increase the 28,400 KWH annual
production. A quick (very cold) preliminary look was promising, should be able to actually
estimate the benefit before work. And house doors/windows/insulation are on the horizon.

Meantime Feb produced a lot more KWH than last year, and March is looking even better.
Bruce Roe

[bcroe]

Nw il

Today was overcast, we saw no shadows, couldn't even tell exactly where the sun
was. But the "Illinois Array" turned in 113 KWH, I call that performance. Still
haven't seen an electric bill (to check reserve) from 28 Feb, guess that's Ill
performance too. Bruce Roe

[bcroe]

This is the end of my first complete net metering year, the Po Co sets all back to zero. It
would be better if they did it on 28 Feb, because with longer days, fewer clouds, and lower
heating needs, March almost certainly will run a surplus. So the issue is, will I have a
surplus or deficit KWH reserve on the Feb meter reading date? The bill will tell, but it
doesn't come, and it doesn't come. Finally I call them and they say it was mailed 24 Mar
for $400.
1. I can ignore the $400 because the people answering cust service don't
see the net metering info; that is probably how much heating I did;
2. So why didn't the bill get mailed on 5 Mar?

So its a week and no bill. I call again; it was mailed 24 Mar but now its for $15.95, that
is the base amount if I don't buy any energy. Looks like I did it, no electric energy
purchases that year; hardly any propane. Also they read the meter on 5 Mar, not 28
Feb, probably behind due to weather and a short month. That just might have helped me
make a zero energy purchase year. The extra week into Mar ran an extra 683 KWH
generated, with reduced consumption. I requested another copy of the bill anyway, to
get all the details. Curve when available. Bruce Roe

[bcroe]

Had a little problem this week, good weather, but the 3 ton heat pump just stopped. Still
covered after only 6 months (I didn't tell them how hard its been working). The main
machine seems just fine, plenty of F410A gas. Turns out the problem was no signal from
the new super fancy menu driven screen battery backup software imperiled thermostat.
A little program change and its all going again.

Can't say this surprises me much. In the vein that less complex is more reliable, I kept
my decades old environmentally illegal mercury tilt thermostat in place to run the
propane furnace; the new one just triggers the blower and heat pump. There just might
come a day when old reliable does everything.

Meantime warmer days are here, the heat pump runs very little, and I'm already piling
up KWH reserve for the winter of 15/16. Bruce Roe