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grid independance=inverter :)

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nanotech1

Jan 1, 1970
0
i have some ? to ask

1)is there some people in the north america
who are running a house with battery backup and PV cells
on one big inverter with size in the 10 to 30kw range
is it reallity or fiction

2) what kind of prices we are talking about for an inverter in those
range

3) is it better to use multiple inverters than a big one
ex( 4 smaller 3000 watts or one big 12000 watts unit )

PS dont worry about the size of inv in the above ?
i want to use some power for a shop ( arc welder electric motor ,ect
ect)
 
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Vaughn

Jan 1, 1970
0
nanotech1 said:
i have some ? to ask

1)is there some people in the north america
who are running a house with battery backup and PV cells
on one big inverter with size in the 10 to 30kw range
is it reallity or fiction

2) what kind of prices we are talking about for an inverter in those
range
The cost of that big inverter is nothing compared to the price of the
battery bank and PV cells you would need. You would do much better to think
about a generator for occasional heavy loads such as welding or running
machinery.

Vaughn
 
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Anthony Matonak

Jan 1, 1970
0
Phil said:
I've been prowing this group, homepower etc for a year or so. I live in
the burbs of st. louis, mo on a lot 75' x 150'. I've been pondering
getting off the grid for serval years now. Primarily becuase I'd like
to kick the utility bills when I retire. I guess I see my delima is how
to get there. Looks like wind is probably not much help, I guess PV
might be the way to go. Although I'm still wondering about waiting for
the full spectrum PV's that were touted in an article last year. I
guess my first concern is running our three big loads, central air
conditioner, electric stove and dryer. I'd like to start small and
build the system up over time. Any recommendations on building a system
starting small?

Some things to consider about all this.

If you are already on the grid and it's fairly reliable (doesn't go down
very often) then your cheapest option is to go grid-tied. This way you
can either have no batteries at all or a small set of batteries that
can provide backup power just to some critical loads (like fridges).
If you live in a net-metering state then you could potentially reduce
your power bills to a small token amount (i.e. $10/month).

I wouldn't wait for a particular "breakthrough" that is "just around
the corner" or that someone has announced as being the next big thing
that makes everything cheaper, better, faster. Most of these things
either never pan out or it takes decades before they reach the market.
Even then, most of them never quite live up to their advertising.

You could consider changing your three big loads from electric to
something else. The electric stove and dryer are usually easily
replaced with gas appliances which, since gas is usually much less
expensive than electricity, would save you money all by itself.
They also make a variety of gas central air conditioners. You may
also want to do an energy audit and find out what other electricity
conservation is possible (new lights, tubular skylights, and so on).

You can start at any size you like. There are places that sell kits
that just have a couple of small panels, a single battery and one
or two CF 12V lights. Determine how much money you want to spend
and then figure out what that can buy you. It can get very expensive
very quickly though.

Anthony
 
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nanotech1

Jan 1, 1970
0
Anthony said:
Who is claiming to have such a system?

Yes, it is possible and it would probably involve stackable inverters.
I.E. a parallel array of smaller 2kw or so inverters. I have heard of
computer and business power centers which have things this big but I
haven't heard of a home doing this.

The main reason you probably haven't heard a lot about home users with
inverters this large is because the typical, ordinary, power wasting
home today uses only 1 to 2kw at any one moment. A 30 kw inverter could
run anywhere from 15 to 30 homes, depending on their power needs. This
is clearly overkill for an ordinary homeowner.

Then you have to add in the fact that PV cells and batteries are very
expensive (relatively speaking). Almost everyone that goes completely
off-grid will engage in some form of conservation simply to save money.
I've heard that $1 spent in conservation up front (more efficient
appliances, lights, etc.) can save anywhere from $5 to $10 in equipment
cost down the line. That being the case, people with such systems will
typically use much less power than an ordinary home and wouldn't need
a bigger inverter than an ordinary homeowner.

Anthony

what would be the max peak power usage in a house with typical
electrical appliance

ex( running the electric oven range ,the electric water heater ,the
clothe dryer ,ect ect, ect all at the same time)

i know it sound silly for asking a question like that
but why in the name of God most houses have main breaker box
with the main breaker at 100 or 200 amps

you bet this one puzzle me
 
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Anthony Matonak

Jan 1, 1970
0
nanotech1 wrote:
....
what would be the max peak power usage in a house with typical
electrical appliance

Not all houses are all electric. In fact, in most places the cost
of electricity vs. natural gas makes most people choose gas whenever
they can. Gas stoves are also preferred by most cooks although electric
ovens seems more preferred as well.
ex( running the electric oven range ,the electric water heater ,the
clothe dryer ,ect ect, ect all at the same time)

In a typical house these appliances don't all run at the same time.
You could simply add up all the loads. Yes, it'll max out at more
than 2kw but then an all electric house is going to consume more
electricity than one that has gas appliances, isn't it?

Do you want to add in the power used by the plasma cutter, arc
welders and the kiln? These also are not found in a typical house
but they would consume a lot of electricity if you turned them
all on at once.

Say your using 220V 20A circuits for the oven, stove, water heater,
space heater, etc. Each circuit could supply 4.4 kw of power. If
you have 5 of these circuits loaded down at the same moment then
your house is consuming 22 kw. Obviously if you are generating
your own electricity then perhaps a little conservation might be
cheaper than buying all electric appliances.
i know it sound silly for asking a question like that
but why in the name of God most houses have main breaker box
with the main breaker at 100 or 200 amps

Because they are building the house with no idea what appliances
are going to be used. For instance, a large air conditioner could
use 20 or 30 amps at 220V easily. Add in 10 to 20 amps at 220V
for a dryer, cooktop and oven and you're up to 80 amps or so right
there. Then if the homeowner does something unusual, gets an electric
car, welds metal sculpture or the like then you can easily throw in
another dozen or so amps. They have to make the breaker box and the
wiring big enough to handle this kind of unusual situation because,
although it happens rarely, it does happen. Besides, the bigger
wire and breakers don't cost that much more.

One advantage of being your own power company is that you can decide
what kind of loads you want to have on your house and only pay for
what you need.

Anthony
 
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nanotech1

Jan 1, 1970
0
Anthony said:
nanotech1 wrote:
...

Not all houses are all electric. In fact, in most places the cost
of electricity vs. natural gas makes most people choose gas whenever
they can. Gas stoves are also preferred by most cooks although electric
ovens seems more preferred as well.


In a typical house these appliances don't all run at the same time.
You could simply add up all the loads. Yes, it'll max out at more
than 2kw but then an all electric house is going to consume more
electricity than one that has gas appliances, isn't it?

Do you want to add in the power used by the plasma cutter, arc
welders and the kiln? These also are not found in a typical house
but they would consume a lot of electricity if you turned them
all on at once.

Say your using 220V 20A circuits for the oven, stove, water heater,
space heater, etc. Each circuit could supply 4.4 kw of power. If
you have 5 of these circuits loaded down at the same moment then
your house is consuming 22 kw. Obviously if you are generating
your own electricity then perhaps a little conservation might be
cheaper than buying all electric appliances.


Because they are building the house with no idea what appliances
are going to be used. For instance, a large air conditioner could
use 20 or 30 amps at 220V easily. Add in 10 to 20 amps at 220V
for a dryer, cooktop and oven and you're up to 80 amps or so right
there. Then if the homeowner does something unusual, gets an electric
car, welds metal sculpture or the like then you can easily throw in
another dozen or so amps. They have to make the breaker box and the
wiring big enough to handle this kind of unusual situation because,
although it happens rarely, it does happen. Besides, the bigger
wire and breakers don't cost that much more.

One advantage of being your own power company is that you can decide
what kind of loads you want to have on your house and only pay for
what you need.

Anthony

i am asking that ? because i would like to have a house want
witch would be exclusively run entirely on electricity
(all electric appliance and all electric heating)
that wouldnt be serve by the elec utily grid
and be indepandent of any source of energy
( like heating fuel and/or propane and/or natural gaz,ect)
i would like to choose the energy source like (solar, winmill, small
hydro electric setup,ect)
and not to worry about how much electricity i am using on a normal sizes
house

so if the main breaker of my house is 200amps at 240vac
loaded at 80% load at the peak max( for a margin of inverter safety
witch it's not really often :) )


so let me see 80% 200amps=160amps and 160amps multiply by 240vac=

38.4 kw for a 200amps main service box
or
19.2 kw for a 100amps main service box

dont worry these figure they are absolutes max values

in a way i dont want to be dependant on any fossile fuel
 
A

Anthony Matonak

Jan 1, 1970
0
nanotech1 said:
....
i am asking that ? because i would like to have a house want
witch would be exclusively run entirely on electricity
(all electric appliance and all electric heating)
that wouldnt be serve by the elec utily grid
and be indepandent of any source of energy
( like heating fuel and/or propane and/or natural gaz,ect)
i would like to choose the energy source like (solar, winmill, small
hydro electric setup,ect)
and not to worry about how much electricity i am using on a normal sizes
house ....
in a way i dont want to be dependant on any fossile fuel

If you simply want to have unlimited amounts of electricity
available for anything you might ever want to do with your
house then you'll wind up spending a staggering amount of
money. Most people short of Bill Gates would faint dead away
at the sticker shock. I.e. 30 kw of solar PV at around $7/watt
installed (very conservative estimate) is $210,000. This seems
ridiculous when spending $10,000 on different appliances could
save you $150,000. Are electric appliances worth that much?

Instead of an all electric house you might want to consider solar
thermal collectors for the majority of heating and cooking with
some locally obtained biofuel (such as wood, corn, beans,
vegetable oil, etc.) as backup. You could design solar thermal
storage which can be used like a heat "battery" to provide
heat and cooking nights and on cloudy days. This would be
much cheaper than using electricity for these purposes. You
can even use solar thermal collectors to drive fridges,
freezers and air conditioners. You would have to run the costs
to figure out if this is cheaper than electric for these things.
This would fulfill your desire to be free of fossil fuels and
still save you hundreds of thousands of dollars.

Anthony
 
N

nanotech1

Jan 1, 1970
0
Ron said:
We're doing it with wind. But, having read some of your other posts, and
to put things in a similar perspective, we basically have a 60amp service.
Our average daily use in the winter is 20-24kWh/day; in the summer it is
about 15-16 kWh/day. We do not have nor require air conditioning.

We heat and cook with propane, because that's much cheaper than generating
electricity. We also use propane to run a backup 12kW generator.

I've never seen a continuous draw of more than 5kW.

We have dual inverters which supply 120VAC/60HZ each -- they are wired in
series so we can obtain either 120 or 240 VAC. Each inverter can supply
5.5kW (actually kVA) so at 11kW, we're at the lower end of your range.

Although not economically warranted, I will probably add PV to reduce the
runtime of the backup generator. If I wanted to further minimize fossil
fuel use, I would add solar heating for heat and DHW.

-- ron (off the grid in Downeast Maine)

i would like electrical supply of a house to work that way

many smaller inverters in parallel than everything in the house
at this point would be direct current supplyed
adding to this,a system witch would be manage automaticaly by a current
controller at all supply sources to the needed load BUT all in DC supply
this would be much easyer and cheaper to setup

in a way managing lyke an honda EU serie generator principle

"high freq alternator to a DC bridge and to the inverter
the load current is use to control the engine rpm depanding on the
energy use"

not lyke an full ac generator setup witch always has to run at
syncronize speed to be at proper freq


in dc you can do that more simply

in ac you always have to take care to syncronize the freq witch is much
more complicated to do

PS dont worry about the cost for now i havent build anything yet :)
 
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