Grid-tied solar

[Tig]

Thanks for the advice Dave. I would go with UL/CSA approved components.
During the ice storm we went 10 days heating the house with a single bag propane lantern. We powered the well pump once a day with a generator and filled the bathtub. We then used a pail to flush.
In the new house we have a wood heat option. The DSL modem, ThinkPad and ip phone are the only essential electronics.
Currently I get by with a 300 W inverter and a deep cycle (trolling motor) battery. If on solar, I'm thinking about a 2KW inverter and minimal batteries with the intent of riding out a one day outage with nonessential equipment turned off at the breaker panel. In a longer outage I wouldn't mind if I had to fire up the generator for an hour a day to pump water, cool the freezer or run the furnace blower to move air.

 

[dave1949]

If you have the following setup: Solar Panels > Inverter > Breaker Panel > Transfer Switch > Meter
You could run something like a little Honda Inverter generator and/or a separate battery bank/inverter as the second power source and thus use their "approved" inverter AND get more bang for your buck (in the daytime) with backup power.

Aaron Z

That is basically what I have, minus the battery bank and the transfer switch. To connect my generator, I use a manual backfeed breaker that can't be closed unless the main is opened.

I was warned to be certain to never allow the inverter to send power TO the generator, I guess that is ruinous to some types of generators. I have to open the backfeed breaker used by the inverter before using the generator.

To add batteries to the system that will be recharged from the solar system, a charge controller would be needed, and I think those are usually powered from solar panel DC. I guess a stand-alone combination small generator and battery sub-system could be used somehow. Run from the batteries until they need a recharge from the generator, or if power is present, recharge from the inverter output. Sounds complicated and keeps a generator in the picture.

As the market for this stuff broadens, probably more flavors of standard systems will become available. As it is now with utility sign-off, off-the-shelf components and support, you can do it this way, or you can do it this way :laughing: seems to be the case.

 

[DarkBlack]

As meburdick pointed out, all places on earth receive equal hours of potential sunshine over a year's time. QUOTE]

Equal hours yes. Equal intensity, no.

 

[BobRip]

Thanks for the advice Dave. I would go with UL/CSA approved components.
During the ice storm we went 10 days heating the house with a single bag propane lantern. We powered the well pump once a day with a generator and filled the bathtub. We then used a pail to flush.
In the new house we have a wood heat option. The DSL modem, ThinkPad and ip phone are the only essential electronics.
Currently I get by with a 300 W inverter and a deep cycle (trolling motor) battery. If on solar, I'm thinking about a 2KW inverter and minimal batteries with the intent of riding out a one day outage with nonessential equipment turned off at the breaker panel. In a longer outage I wouldn't mind if I had to fire up the generator for an hour a day to pump water, cool the freezer or run the furnace blower to move air.

You cannot keep most freezers cold on one hour a day. Mine needs abou 12 hours.

 

[meburdick]

As meburdick pointed out, all places on earth receive equal hours of potential sunshine over a year's time. QUOTE]

Equal hours yes. Equal intensity, no.

Help me understand your thoughts on "intensity". I realize that an area with lots of clouds and such would likely yield lower output, but is this the sort of the thing you're thinking of when you mention intensity?

If that's what your thoughts were, then the concept of "potential" sunshine would take that into account. If your weather is very sunny all of the time, you'll realize full potential out of the sunlight hours over the course of the year. If you live in a notoriously foggy / cloudy / rainy region, then your potential sunshine is going to be a lot higher than your realized sunshine.

 

[DarkBlack]

It's the same reason it's hotter the closer you get to the equater. The photons are penetrating the atmosphere the closest to perpendicular at the equator. The further from the equator, the more angled they arrive, producing more bouncing off to space and a longer atmospheric path that absorbs some of the energy before it can be used at ground level.

 

[meburdick]

It's the same reason it's hotter the closer you get to the equater. The photons are penetrating the atmosphere the closest to perpendicular at the equator. The further from the equator, the more angled they arrive, producing more bouncing off to space and a longer atmospheric path that absorbs some of the energy before it can be used at ground level.

That's all very true as it pertains to *heat* energy. I'm trying to understand how that factors into *light* energy.

 

[DarkBlack]

I see where you are getting confused. Ponder this... How can the temperature be just barely above absolute zero at a distance midway between the warm earth and the inferno crazy hot sun? Why isn't it warmer in a high altitude plane flying 8 miles closer to the sun than the ground?
The short( I'll be very breif ) answer is that the heat you are talking about is from the enrgy transformation of the light ( photons ). Energy can not be created or destroyed, it only changes forms. A typical pv panel takes the photons that made it through earths atmosphere and of the light a few percent remain as visible light reflected from the surface, about 15% are converted to electric energy, and the other 80+% are converted to the heat you are talking about. The real "cool" thing is that what you "see" as light is actually just in the range of radiation spectrum that your eyes can see. If you had better low frequency vision you could also "see" lower frquencies ( infra red) that your body intreprets as "heat"
OK done..

 

[DarkBlack]

If you understood what I posted, then the next "cool" fact is that the 80% heat is actually still the energy of the photo radiation, it has only had it frequency lowered below the "visible" range of your eye.... to a frequency that the pv's plastic can vibrate at and absorb the energy.

 

[meburdick]

I see where you are getting confused. Ponder this... How can the temperature be just barely above absolute zero at a distance midway between the warm earth and the inferno crazy hot sun? Why isn't it warmer in a high altitude plane flying 8 miles closer to the sun than the ground?
The short( I'll be very breif ) answer is that the heat you are talking about is from the enrgy transformation of the light ( photons ). Energy can not be created or destroyed, it only changes forms. A typical pv panel takes the photons that made it through earths atmosphere and of the light a few percent remain as visible light reflected from the surface, about 15% are converted to electric energy, and the other 80+% are converted to the heat you are talking about. The real "cool" thing is that what you "see" as light is actually just in the range of radiation spectrum that your eyes can see. If you had better low frequency vision you could also "see" lower frquencies ( infra red) that your body intreprets as "heat"
OK done..

The counterpoint to the "sunshine is more intense in the equatorial regions", though, is the fact that significantly increased amounts of heat in a PV panel will cut efficiency / output by 10-15%. So, while the sun may seemingly "have more energy to give" near the equator, it is offset by the panel's loss in efficiency because it's so much hotter.

 

[DarkBlack]

The counterpoint to the "sunshine is more intense in the equatorial regions", though, is the fact that significantly increased amounts of heat in a PV panel will cut efficiency / output by 10-15%. So, while the sun may seemingly "have more energy to give" near the equator, it is offset by the panel's loss in efficiency because it's so much hotter.

That's a catch-22 isn't it? Hmm.... what to do with all that wasted 80% energy... hmmm..

 

[dave1949]

Solar Energy and Energy Independence
Every hour, the sun radiates more energy onto the earth than the entire human population uses in one whole year.

http://www.nrel.gov/docs/fy12osti/51946.pdf
Rooftop PV
Total annual technical potential for rooftop PV is estimated at 818 Terra-watt hours. States with the
largest technical potential typically have the largest populations. California has the
highest technical potential of 106 TWh due to its mix of high population and relatively
good solar resource. Figure 4 and Table 4 present the total estimated technical potential
for rural utility-scale PV.

http://www.ipsr.ku.edu/ksdata/ksah/energy/18ener7.pdf
Total US electric consumption in 2010: 3,754,493 giga-watt hours, or 3,754.5 terra-watt hours

Using solar PV, the existing residential and commercial building rooftops in the US are technically capable of producing 21.8% of all US annual power consumption. Since these buildings already exist, the additional environmental footprint required to achieve this is minuscule.

Of course it is important to achieve the best possible affordable efficiency in solar panels, but the meaningful measure is the cost per solar watt versus the cost of carbon-based fuels.

 

[Tig]

You cannot keep most freezers cold on one hour a day. Mine needs abou 12 hours.

We keep our freezer in an unconditioned area. It rode out the 10 day ice storm outage without any power. But then again, even the house was only 55 degrees during that time.

 

[Tig]

Using solar PV, the existing residential and commercial building rooftops in the US are technically capable of producing 21.8% of all US annual power consumption.

At some point, I'd like to see that mandated by the building code. It would help take the peak demand out of air conditioning season.

 

[dave1949]

At some point, I'd like to see that mandated by the building code. It would help take the peak demand out of air conditioning season.

I could see that too. Two down and 400 million to go :laughing:

 

[madmax12]

I could see that too. Two down and 400 million to go :laughing:

Wait... Is that code for subsidies???

PS... Storyland was GREAT!!!! Parents tired after long day.
PSS.... They do NOT take monopoly money

 

[dave1949]

Wait... Is that code for subsidies???

PS... Storyland was GREAT!!!! Parents tired after long day.
PSS.... They do NOT take monopoly money

Today was the nicest weather day we have had in some time. Must have been nice to get out. I actually fired up the chainsaw for a while.
No monopoly money accepted? Dang.

Our national energy strategy gets yanked around a lot by politics. The renewable energy credits date back to 1992. They have been fairly constant with a few short breaks.

 

[madmax12]

Today was the nicest weather day we have had in some time. Must have been nice to get out. I actually fired up the chainsaw for a while.
No monopoly money accepted? Dang.

Our national energy strategy gets yanked around a lot by politics. The renewable energy credits date back to 1992. They have been fairly constant with a few short breaks.

I have strong views, that I think have validity (of course I would think my views are valid ). BUT subsidies are a frienemy to all sides. I mean no politically directional slander in mocking subsidies. I am seriously concerned about the math skills of "officials," but that again is not aimed in a political direction. And I am interested in wind and solar, and energy independence...for real.

Now, back to what matters ... the weather was PERFECT! The park was busy, but not packed. You could ride any ride, as much as you wanted, and there were just enough people for no real lines, but no empty rides. How often does something like that happen???

Was the chainsaw time as therapeutic as tractoring?

Thanks for being a great sport with me.

:drink:

 

[dave1949]

I have strong views, that I think have validity (of course I would think my views are valid ). BUT subsidies are a frienemy to all sides. I mean no politically directional slander in mocking subsidies. I am seriously concerned about the math skills of "officials," but that again is not aimed in a political direction. And I am interested in wind and solar, and energy independence...for real.

Now, back to what matters ... the weather was PERFECT! The park was busy, but not packed. You could ride any ride, as much as you wanted, and there were just enough people for no real lines, but no empty rides. How often does something like that happen???

Was the chainsaw time as therapeutic as tractoring?

Thanks for being a great sport with me.

:drink:

That does sound like a storybook day in Storyland!

The chainsaw work is a long story. I have a small 8x12 shed that is one of those mistakes I should have avoided by waiting for a better thought. It was intended to be a shelter for my wife's dogs, so I made it tall enough to stand up in under the peak, but the sides are only about 5' tall. The dogs never used it except to lay beside it in the shade it makes. :laughing: And now it is outside the new fence we put in this spring anyways.

I want to move it out to where it would be handy to store some garden and yard stuff in it, but it is back in some apple trees I want to keep. I cut some 16' logs to put under it and use like travois poles I could lift and pull with the tractor. I know I am going to put a lot of work into this, only to end up with a storage shed I will never really like. I have considered tearing it apart and using what I can salvage in new shed. I may do that yet if my moving attempt fails.

 

[madmax12]

That does sound like a storybook day in Storyland!

The chainsaw work is a long story. I have a small 8x12 shed that is one of those mistakes I should have avoided by waiting for a better thought. It was intended to be a shelter for my wife's dogs, so I made it tall enough to stand up in under the peak, but the sides are only about 5' tall. The dogs never used it except to lay beside it in the shade it makes. :laughing: And now it is outside the new fence we put in this spring anyways.

I want to move it out to where it would be handy to store some garden and yard stuff in it, but it is back in some apple trees I want to keep. I cut some 16' logs to put under it and use like travois poles I could lift and pull with the tractor. I know I am going to put a lot of work into this, only to end up with a storage shed I will never really like. I have considered tearing it apart and using what I can salvage in new shed. I may do that yet if my moving attempt fails.

Relaying to me a story like that (shed), know this: sadly, I understand completely.

At least u get to "fix" your plan with cool tools, like chainsaws and tractors! :thumbsup:

I see, too, that u totally understand why I'm waiting til I'm certain I can envision the driveway project correctly... I know I could do it, when I know what to do. Not really "seeing" it yet, makes the project more scary, right now. Like u said, about it, give it time and it will come to me.

I hope your shed move/renovation goes as safely and smoothly as possible.