Solar Backup Generator

[Lizw]

Re: Solar Backup Generator

If your friend has a grid tied solar system, it's failure or shutdown should not make the power go out. That would happen with an off grid system, but not with a grid tied one without batteries.

That's what I thought too, but he said the fault in his system caused the main breaker in his panel to trip.

Air conditioning is the worst power hog and one that is difficult to substitute for, at least until direct absorption fueled air conditioners become common. Absorption fueled air conditioners use heat (from the sun or other source) to drive the heat pump instead of a electrically powered compressor. In areas that cool off at night, more insulation and thermal mass would reduce air conditioning load, but some places like Phoenix, AZ (where it can often be 100 degrees at midnight) are nearly hopeless unless one wants to live underground or in a cave.

Only trouble with absorption cooled anything (and I've had plenty of experience with them in refrigerators) is that they're far less fuel-efficient than compressors. But of course if they're solar heated, that's not a concern.

But I'm always amused at the idea that it's not possible to get by without a/c. I lived in Phoenix once, as it happens, in a small travel trailer with no insulation in the late summer, and the heat didn't kill me. Sleeping at night was less comfortable than if we'd had a/c, but we managed. And I spent my teen and young adult years in Florida, also without a/c. The notion that a/c is somehow a basic human need is a relatively recent one.

 

[Zac]

Re: Solar Backup Generator

That's what I thought too, but he said the fault in his system caused the main breaker in his panel to trip.

There is likely a design or installation problem with the equipment if that happens. But, there should be a breaker dedicated to the solar grid tie inverter(s). Shutting that breaker will isolate the solar equipment and allow grid power to be restored by resetting the main breaker.

Only trouble with absorption cooled anything (and I've had plenty of experience with them in refrigerators) is that they're far less fuel-efficient than compressors. But of course if they're solar heated, that's not a concern.

But I'm always amused at the idea that it's not possible to get by without a/c. I lived in Phoenix once, as it happens, in a small travel trailer with no insulation in the late summer, and the heat didn't kill me. Sleeping at night was less comfortable than if we'd had a/c, but we managed. And I spent my teen and young adult years in Florida, also without a/c. The notion that a/c is somehow a basic human need is a relatively recent one.

It depends on the climate of a particular location. In San Francisco, or along most of the northern California, Oregon, or Washington cost, AC is not essential. I couldn't survive in Phoenix in the summer without AC. I'm unfortunately very heat sensitive and get sick with migraines and other nasty things when it gets too warm. I currently live in the Sacramento area (101 outside now) and the AC issue has been on my mind the last couple years. I don't think I could survive here in the summer without AC and it's not nearly as severe a climate as Phoenix. This is probably why most of the areas with lousy climates like Phoenix were very sparsely inhabited until AC became affordable and common.

To run more than the most modest AC system (like a small room air conditioner) would require a large solar system. Running it off grid would require very large batteries. For example, my 3 ton air conditioner eats about 5 kw when the compressor is running. Running a sustained 5 kw load would require around 100 kwh (such as 48V @ 2000 Ah) of batteries if they are to last 10+ years.

 

[Lizw]

Re: Solar Backup Generator

It depends on the climate of a particular location. In San Francisco, or along most of the northern California, Oregon, or Washington cost, AC is not essential. I couldn't survive in Phoenix in the summer without AC. I'm unfortunately very heat sensitive and get sick with migraines and other nasty things when it gets too warm. I currently live in the Sacramento area (101 outside now) and the AC issue has been on my mind the last couple years. I don't think I could survive here in the summer without AC and it's not nearly as severe a climate as Phoenix. This is probably why most of the areas with lousy climates like Phoenix were very sparsely inhabited until AC became affordable and common.

Yes, exactly. Though when I lived there, it was a haven for people with asthma, whose doctors had sent them out there for the dry air.

To run more than the most modest AC system (like a small room air conditioner) would require a large solar system. Running it off grid would require very large batteries. For example, my 3 ton air conditioner eats about 5 kw when the compressor is running. Running a sustained 5 kw load would require around 100 kwh (such as 48V @ 2000 Ah) of batteries if they are to last 10+ years.

And of course there's the start-up surge. The recent work with capacitors to even that out may help the situation, but absorption units are probably still the way to go in hot humid climates. Or earth-sheltered homes--I have a friend here whose electric bill is almost never more than the minimum, and his home is all-electric. It's also built into a hillside with only two faces exposed.

I put up trellis mounted on 4 x 4's along the western face of the 70 foot mobile home I live in, and grow hops and maypops on the trellis. The vines shade the trailer in the summer and die back in the winter so the sun can hit it (I mounted the trellis panels on hooks so I can take them down in the winter). There's about a ten degree differential between the temperature on the sun side and on the shade side, and that really makes a difference in the amount of a/c we use. Given my druthers, I'd turn the a/c off, open the windows and install a solar-powered ventilation fan in the roof, but it's not my property.

 

[Rocky]

Re: Solar Backup Generator

Attached are some quotes for installing a grid tied solar system without batteries in Arizona. That provides an example of the rebate and tax incentives.

The rule of thumb is a solar system mounted at a fixed angle will produced the rated power for about 2.5 hours per day in the winter and 5.0 hours in the summer. (it's perhaps 10% less at high latitudes) Fixed angle mounts can be mounted to optimize for winter production or for maximum annual total production. A steeper angle increases winter production, but decreases summer production. More grid tied applications just use the angle of the existing roof for aesthetics.

so a 5.oi is a 5 KW system costing ~$13K which will produce 25KW in the summer, about half of what a normal household would use?

Imagine if the $19,000 in electric company, state and federal incentives were spent a little differently...

my 25KW system runs 24/7 expected life 115,000 hours and costs $20K including the grid tie... and that isn't counting what the state will pay in incentives much less the energy being sold to the electric company beyond usage...

A 12'x12'x18' room in a school could hold 900+ units and sell enough energy back to the electric company to pay for the school...

I'm trying to hurry...

PS RV batteries are great backup systems, I have 8. Now if you really want to store some juice, get an electric forklift battery ... weighs half a ton, but it'll power your office...

 

[Rocky]

Re: Solar Backup Generator

And of course there's the start-up surge. The recent work with capacitors to even that out may help the situation,

Ultracapacitors for the electricity you will need are outrageously expensive...

They load up quick and discharge instantly, perfect for applications like electric trains but still way to pricey for a household...

 

[Flufreak]

Re: Solar Backup Generator

I thought this was a serious thread, not the fantasy room.
Rocky, IF you have the solution to the the world's energy and economic needs, get serious and save the planet. I'll quit my job and help you! We'll be rich and famous.

Of course, the earth might explode because we are sucking away the gravity flux, but we'll be long gone by then!

 

[Zac]

Re: Solar Backup Generator

Ultracapacitors for the electricity you will need are outrageously expensive...

They load up quick and discharge instantly, perfect for applications like electric trains but still way to pricey for a household...

Ultracaps are not suitable for mass energy storage because they don't provide energy density (kwh/pound) that is competitive with conventional chemical batteries. They are not needed for a typical off-grid solar power system as adequately sized batteries would provide plenty of surge current capacity. A adequately sized inverter should also have enough surge capacity to handle motor starting and so forth. Keep in mind a small to medium sized inverter as might be found in a typical off grid solar system does not have the surge current capacity of the utility grid so some short duration (milliseconds to perhaps a few tenths of a second) voltage drop and waveform distortion when starting motors is expected. Most electronics are not sensitive to this. If you have electronics that is, the easiest solution is run those items on a separate inverter.

 

[Rocky]

Re: Solar Backup Generator

I thought this was a serious thread, not the fantasy room.
Rocky, IF you have the solution to the the world's energy and economic needs, get serious and save the planet. I'll quit my job and help you! We'll be rich and famous.

Of course, the earth might explode because we are sucking away the gravity flux, but we'll be long gone by then!

lol... when someone asks what I am using I always say gravity because it spins their mind with the possibilities...

I've been working on grants for several years and always end up getting kicked out in the final decision...

I'm getting closer to final prototype funding I've raised on my own...

once it is complete, it will be a few months before full production...

 

[Rocky]

Re: Solar Backup Generator

Zac, you are pretty knowledgeable on electricity, what is the Maximum power that can be sent from a Home into the grid without overheating the lines?

each unit maxes out the grid tie inverter - 25KW 220V

separate circuit for each unit going into the power box...

 

[Zac]

Re: Solar Backup Generator

Zac, you are pretty knowledgeable on electricity, what is the Maximum power that can be sent from a Home into the grid without overheating the lines?

That varies depending on your utility feed. For instance, my house has a 200 amp feed. So, 240V @ 200A is 48 kW which would be the best case. Older houses may have smaller feeds. The limiting factor is usually the transformer in the street. The transformers are rarely, if ever, specified for 100% duty cycle at 100% rated load so every house sending the maximum rated power upstream for hours will probably overheat the transformer. But, few of us can afford or even have space to mount a 48 kW solar system.

 

[tropical]

Re: Solar Backup Generator

#29: "what is the Maximum power that can be sent from a Home into the grid without overheating the lines"


The same it can be max. sucked from the local power source giving the house power - attached source lines thickness depending (if grid is meant to be the local power provider's source).

 

[Rocky]

Re: Solar Backup Generator

hmmmm

each unit is ~ 114 AMPs, I guess a house running normal power would absorb part of it so I should be able to max out with 2 per home...

I guess I could modify the inverter to slightly higher voltage to lower the AMPs...

 

[tropical]

Re: Solar Backup Generator

modify the inverter to slightly higher voltage to lower the AMPs...

only slightly, otherwise ...

 

[Flufreak]

Re: Solar Backup Generator

lol... when someone asks what I am using I always say gravity because it spins their mind with the possibilities...

I've been working on grants for several years and always end up getting kicked out in the final decision...

I'm getting closer to final prototype funding I've raised on my own...

once it is complete, it will be a few months before full production...

This pretty much tells me you are not on to something.
If you are doing cold fusion or knocking hydrogen atoms to a lower state, I have some bad news for you...

 

[Rocky]

Re: Solar Backup Generator

This pretty much tells me you are not on to something.

actually just the opposite, this administration is no different than any other, no matter what you are being told...


I can show you how to run a Hydrogen car with $35 dollars worth of hardware... You will never have to stop at a hydrogen station...

That's one reason the Hydrogen auto was back burnered, they realized there is nothing to tax to pay for the roads...

all electric on the other hand...

 

[Flufreak]

Re: Solar Backup Generator

actually just the opposite, this administration is no different than any other, no matter what you are being told...


I can show you how to run a Hydrogen car with $35 dollars worth of hardware... You will never have to stop at a hydrogen station...

That's one reason the Hydrogen auto was back burnered, they realized there is nothing to tax to pay for the roads...

all electric on the other hand...

If true, this information would have an Ro much greater than the pandemic flu does at 2.0, and would also be "unstopable" . If you are right about your government conspiracy theory, you posts would already be deleted! Also, why would you call such attention to yourself to post anything at all here about any of this?

 

[Zac]

Re: Solar Backup Generator

Can we please stick to the practical and dispense with the fantasies and conspiracies?

 

[Rocky]

Re: Solar Backup Generator

If true, this information would have an Ro much greater than the pandemic flu does at 2.0, and would also be "unstopable" . If you are right about your government conspiracy theory, you posts would already be deleted!

Well things are getting much better than years ago when someone speaking in public would die of lead poisoning, it is not that inventors are in danger any more, they just aren't being helped in moving forward with ideas that can change the planet.

Why do you think Pickens just rolled back his plans to open the largest wind farm in the US and moved back in the direction of burning fuel for energy production? Well beside the fact that he owns several of the largest natural gas reserves in our country...

He seriously believes America must end its dependence on foreign oil.

Where were the investors that should have stepped in to help him?

All this talk about going green, but reality is different, we are still an oil based economy.

Also, why would you call such attention to yourself to post anything at all here about any of this?

the nice thing about forums, is there is always a Zac around to point out my ideas are crazy...

When the Wright brothers went to the scientific community and told them they were going to fly...

They were called crazy by the greatest scientific minds of the time...

look at the sky and watch the 60 tons of metal flying today...

Things are only impossible, until they are done...