I posted a week ago to inquire what capacity generator I might need to
power things like central heating, freezer, large american fridge
freezer. The consensus seems to be, go for a 2 kw one, Honda if
possible.

I also note that things like inverters can do some of the jobs that a
generator can. Would one be relevant in my case?

Thanks for your help in advance.

Mike

Mikeyboy wrote:

I posted a week ago to inquire what capacity generator I might need to
power things like central heating, freezer, large american fridge
freezer. The consensus seems to be, go for a 2 kw one, Honda if
possible.

I'm not sure why people recommended Honda, they are hideously expensive
for the specification. I'd recommend that you have a look at Kipor
generators which are well built, electronically stabilised and very
quiet for the capacity. Given the price differential you coudl probably
run to a 4 or 6KVA Kipor for the price of a 2KVA Honda.

I also note that things like inverters can do some of the jobs that a
generator can. Would one be relevant in my case?

In brief, no. I use an 800W inverter in a remote barn to provide
lighting only. I've tried to use it for some other applications and it
has burned out a Switched Mode PSU and has difficulty driving difficult
loads. This is because the AC output is modified square wave. Good
enough for lighting and not for much else. A proper sine wave inverter
will cost as much as a generator and you still have to buy sufficient
batteries to supply current and to maintain them between blackouts. I
you really want to have a 2KVA standby from an inverter I suspect you
will be looking at 10x110AH batteries, a 250W solar panel to charge them
with appropriate charging circuit and a 2KVA inverter or a 2VA
inverter/charger. Personally I wouldn't expect to see much change from
£3000.

In article ,
Mikeyboy writes:
I posted a week ago to inquire what capacity generator I might need to
power things like central heating, freezer, large american fridge
freezer. The consensus seems to be, go for a 2 kw one, Honda if
possible.

I also note that things like inverters can do some of the jobs that a
generator can. Would one be relevant in my case?

You would need an unrealistic sized battery to carry the same
energy as a tank of petrol, and you can't easily top it up when
it runs low and you still don't have your mains supply back on.
(The more expensive generators actually use an inverter as the
final stage to generate a good quality output, but that's fed
from the generator, not batteries.)

I've got a 17Ah battery and an inverter. In theory that would
keep my heating alone running for something like 90 minutes if
the inverter is 100% efficient (it's probably not far off, as
it doesn't get hot).

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Mikeyboy wrote:
I posted a week ago to inquire what capacity generator I might need to
power things like central heating, freezer, large american fridge
freezer. The consensus seems to be, go for a 2 kw one, Honda if
possible.

I also note that things like inverters can do some of the jobs that a
generator can. Would one be relevant in my case?

Thanks for your help in advance.


Indeed it could,

A bank of lead acid batteries and an inverter is perfectly capable of
running a whole house for many hours..days even, if you spend the money
on batteries.

Essentially is a very big UPS....;-)

Not sure how big those go, or how many batteries you can hook up to
them. I'd be definitely interested tho.

Could charge on off peak and run the house off it during the day.. ;-)



Mike

Mikeyboy wrote:
I posted a week ago to inquire what capacity generator I might need to
power things like central heating, freezer, large american fridge
freezer. The consensus seems to be, go for a 2 kw one, Honda if
possible.

I also note that things like inverters can do some of the jobs that a
generator can. Would one be relevant in my case?

Thanks for your help in advance.

Mike

Almost certainly not. The cost of inverters powerful enough, with a
suitable overhead, to run even modest devices will be great. I have
found that switch on surges mean that at least 50% additional power
handling is needed, depending on the sort of load. And of course you
will need to spend a lot on batteries to store the necessary energy if
the idea is to have more than a few minutes running time, and then find
somewhere to put them. 1kWh = 3.6 MJ. 1amp hour at 12V is 1 x 3600 x 12,
which is 43 kJ (remember ItV from physics?). Thus if my calcs are
correct you need 83 Ah, which might need to be doubled to allow for
inverter inefficiency. That's two meaty batteries for just one
electricity unit.

Peter Scott

Andrew Gabriel wrote:
In article ,
Mikeyboy writes:
I posted a week ago to inquire what capacity generator I might need to
power things like central heating, freezer, large american fridge
freezer. The consensus seems to be, go for a 2 kw one, Honda if
possible.

I also note that things like inverters can do some of the jobs that a
generator can. Would one be relevant in my case?

You would need an unrealistic sized battery to carry the same
energy as a tank of petrol,

? Not really.

Depends on what you call unrealistic.

You can get a kilowatt hour of battery for about 150 quid..

30 of them would give you enough to power a house for a day, including
things like the odd heater, shower and electric kettle, and be about the
same size as a fridge. About the same (output) energy as a car tankful
of fuel.



and you can't easily top it up when
it runs low

Jump leads and your car?

and you still don't have your mains supply back on.
(The more expensive generators actually use an inverter as the
final stage to generate a good quality output, but that's fed
from the generator, not batteries.)

I've got a 17Ah battery and an inverter. In theory that would
keep my heating alone running for something like 90 minutes if
the inverter is 100% efficient (it's probably not far off, as
it doesn't get hot).


85%-95% is fairly normal on a HF inverter.

Peter Scott wrote:


Mikeyboy wrote:
I posted a week ago to inquire what capacity generator I might need to
power things like central heating, freezer, large american fridge
freezer. The consensus seems to be, go for a 2 kw one, Honda if
possible.

I also note that things like inverters can do some of the jobs that a
generator can. Would one be relevant in my case?

Thanks for your help in advance.

Mike

Almost certainly not. The cost of inverters powerful enough, with a
suitable overhead, to run even modest devices will be great. I have
found that switch on surges mean that at least 50% additional power
handling is needed, depending on the sort of load. And of course you
will need to spend a lot on batteries to store the necessary energy if
the idea is to have more than a few minutes running time, and then find
somewhere to put them. 1kWh = 3.6 MJ. 1amp hour at 12V is 1 x 3600 x 12,
which is 43 kJ (remember ItV from physics?). Thus if my calcs are
correct you need 83 Ah, which might need to be doubled to allow for
inverter inefficiency. That's two meaty batteries for just one
electricity unit.

Peter Scott

Well,. it all depends..

Here is a data point..3500Watts, 5KVA, around £1500...

http://www.morecomputers.com/extra.asp?pn=SUA5000RMI5U

Now I am not sure about this particular model, but many others will take
external batteries..

I would think around £6000 might easily get you a 24hr+ electricity
supply, at normal sorts of loads.

With off peak being about 8 times cheaper than on peak, its an
interesting calculation..

If your quarterly bill is more than around £150, its probably worthwhile..


THEN use a genny set to charge the batteries.. ;-)

On Sun, 16 Dec 2007 05:07:44 -0800 (PST), Mikeyboy
wrote:

I posted a week ago to inquire what capacity generator I might need to
power things like central heating, freezer, large american fridge
freezer.

http://tinyurl.com/yumrys looks about right.

The Natural Philosopher wrote:
Peter Scott wrote:


Mikeyboy wrote:



Well,. it all depends..

Here is a data point..3500Watts, 5KVA, around £1500...

http://www.morecomputers.com/extra.asp?pn=SUA5000RMI5U

Now I am not sure about this particular model, but many others will take
external batteries..

I would think around £6000 might easily get you a 24hr+ electricity
supply, at normal sorts of loads.

With off peak being about 8 times cheaper than on peak, its an
interesting calculation..

If your quarterly bill is more than around £150, its probably worthwhile..


THEN use a genny set to charge the batteries.. ;-)


If you read down the spec, at full load of 5kW this only provides just
under 10 mins of power. For 24 hours, at say 1 kW load, you would need
about 30 of these beasts. As the tech data says these are for giving
enough time for safe shut-down. Even if you use external batteries the
question of storing enough energy still remains. On a slightly different
issue, I am a great advocate of photovoltaics, but storing enough
electrical energy for overnight remains the major problem.

Peter Scott

On Sun, 16 Dec 2007 14:00:18 +0000, Peter Scott wrote:

Thus if my calcs are
correct you need 83 Ah, which might need to be doubled to allow for
inverter inefficiency.

I find my invertor is about 80% efficient. It draws 10A @ nominal 12V
for every 100W of 240Volts it pushes out into a resistive load, so no
power factor stuff is taken into account.

--
.................................................. .........................
.. never trust a man who, when left alone ...... Pete Lynch .
.. in a room with a tea cosy ...... Marlow, England .
.. doesn't try it on (Billy Connolly) .....................................

The Natural Philosopher wrote:

You can get a kilowatt hour of battery for about 150 quid..

Less - I've seen 110 Ah 'leisure' batteries advertised at GBP65 recently.

There again one litre of petrol gives you about 10 kWht (thermal) or,
say, 3 kWhe (electrical) and costs just over one pound.

--
Andy

In article ,
Andrew Gabriel wrote:
I've got a 17Ah battery and an inverter. In theory that would
keep my heating alone running for something like 90 minutes if
the inverter is 100% efficient (it's probably not far off, as
it doesn't get hot).

I've never needed it in anger, but my tests showed a standard large car
battery (IIRC 75A/hr) ran mine for 12 hours and still had enough charge to
start the car. Of course it depends on how often the pump runs and things
like motorised valves operate - mine was a pretty basic system with no
boiler electronics.

--
*I get enough exercise just pushing my luck.

Dave Plowman London SW
To e-mail, change noise into sound.

In article ,
The Natural Philosopher wrote:
30 of them would give you enough to power a house for a day, including
things like the odd heater, shower and electric kettle, and be about the
same size as a fridge. About the same (output) energy as a car tankful
of fuel.

It makes no sense at all to use batteries for some of these applications.
Far better (and cheaper) to use a portable calor gas etc ring for kettle
boiling - and the same for local heating.
An inverter only really makes sense to run central heating. Even a freezer
is better off run from a small genny.

--
*If at first you don't succeed, then skydiving definitely isn't for you *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
30 of them would give you enough to power a house for a day, including
things like the odd heater, shower and electric kettle, and be about the
same size as a fridge. About the same (output) energy as a car tankful
of fuel.

It makes no sense at all to use batteries for some of these applications.
Far better (and cheaper) to use a portable calor gas etc ring for kettle
boiling - and the same for local heating.
An inverter only really makes sense to run central heating. Even a freezer
is better off run from a small genny.


Oh. it depends on what you want.

I would simply LOVE a system that when its cold and wet and the trees
take out a power line, did not require me to have to fiddle around
starting up motors and rewiring the house..to get the TV and the lights
back on. Cooking we can do on te aga...and having te oil boiler work
would be fine..

AND if it almost paid for itself by using off peak electricity overnight
to charge batteries I ran off during the day, it would be magic.

I was just curious to do the sums on a completely 'battery powered' house.

It is NOT as expensive as I thought..if you can cope with only about 24
hours continuous battery usage.

Obviously if its a mini hurricane and loads of lines are down (as
happened the other year), one expects delays, and goes very economical
on the batteries.

The Natural Philosopher wrote:

I would simply LOVE a system that when its cold and wet and the trees
take out a power line, did not require me to have to fiddle around
starting up motors and rewiring the house..to get the TV and the lights
back on. Cooking we can do on te aga...and having te oil boiler work
would be fine..

A remote start generator and a changeover switch can make it painless.
Some generators can be configured with an automatic changeover switch
and automatic starting.

The last time I looked at sucha s system is was about £800 for a 6KVA
generator with remote/auto start and £80 for the changeover switch.
That's a lot cheaper than an inverter/battery system.

In an earlier contribution to this discussion,
The Natural Philosopher wrote:


I would simply LOVE a system that when its cold and wet and the trees
take out a power line, did not require me to have to fiddle around
starting up motors and rewiring the house..to get the TV and the
lights back on. Cooking we can do on te aga...and having te oil
boiler work would be fine..

AND if it almost paid for itself by using off peak electricity
overnight to charge batteries I ran off during the day, it would be
magic.

Anyone know what the efficiency is likely to be of going mains--battery
charger--battery--inverter--mains?

In other words, how many kWhs need to go into the charger to get 1kWh out of
the inverter?

As long as the overall efficiency is better than about 50%, you *could* be
better off by buying all your electricity at the off-peak rate and storing
it in batteries - but you'd have a hell of a capital investment (and
probably maintenance/replacement costs) to contend with.
--
Cheers,
Roger
______
Email address maintained for newsgroup use only, and not regularly
monitored.. Messages sent to it may not be read for several weeks.
PLEASE REPLY TO NEWSGROUP!

In article , Steve Firth
scribeth thus
The Natural Philosopher wrote:

I would simply LOVE a system that when its cold and wet and the trees
take out a power line, did not require me to have to fiddle around
starting up motors and rewiring the house..to get the TV and the lights
back on. Cooking we can do on te aga...and having te oil boiler work
would be fine..

A remote start generator and a changeover switch can make it painless.
Some generators can be configured with an automatic changeover switch
and automatic starting.

The last time I looked at sucha s system is was about £800 for a 6KVA
generator with remote/auto start and £80 for the changeover switch.
That's a lot cheaper than an inverter/battery system.

When you find a good 'un for that sort of money let us know please;!...
--
Tony Sayer

tony sayer wrote:

In article , Steve Firth
scribeth thus
The Natural Philosopher wrote:

I would simply LOVE a system that when its cold and wet and the trees
take out a power line, did not require me to have to fiddle around
starting up motors and rewiring the house..to get the TV and the lights
back on. Cooking we can do on te aga...and having te oil boiler work
would be fine..

A remote start generator and a changeover switch can make it painless.
Some generators can be configured with an automatic changeover switch
and automatic starting.

The last time I looked at sucha s system is was about £800 for a 6KVA
generator with remote/auto start and £80 for the changeover switch.
That's a lot cheaper than an inverter/battery system.

When you find a good 'un for that sort of money let us know please;!...

http://tinyurl.com/2k4mwt

That one's sold, but they get more in from time to time.

This one's only 5KVA but autostart and a bit cheaper.

http://www.peakgenerators.co.uk/product.asp?id=476

Roger Mills wrote:

Anyone know what the efficiency is likely to be of going mains--battery
charger--battery--inverter--mains?

IIRC it's around 75%.

Peter Lynch wrote:
On Sun, 16 Dec 2007 14:00:18 +0000, Peter Scott wrote:
Thus if my calcs are
correct you need 83 Ah, which might need to be doubled to allow for
inverter inefficiency.

I find my invertor is about 80% efficient. It draws 10A @ nominal 12V
for every 100W of 240Volts it pushes out into a resistive load, so no
power factor stuff is taken into account.

Duly noted. I didn't realise that they were that good. Still means a lot
of UPSs for a steady power supply though.

Peter Scott

In article , Steve Firth
scribeth thus
tony sayer wrote:

In article , Steve Firth
scribeth thus
The Natural Philosopher wrote:

I would simply LOVE a system that when its cold and wet and the trees
take out a power line, did not require me to have to fiddle around
starting up motors and rewiring the house..to get the TV and the lights
back on. Cooking we can do on te aga...and having te oil boiler work
would be fine..

A remote start generator and a changeover switch can make it painless.
Some generators can be configured with an automatic changeover switch
and automatic starting.

The last time I looked at sucha s system is was about £800 for a 6KVA
generator with remote/auto start and £80 for the changeover switch.
That's a lot cheaper than an inverter/battery system.

When you find a good 'un for that sort of money let us know please;!...

http://tinyurl.com/2k4mwt

That one's sold, but they get more in from time to time.

This one's only 5KVA but autostart and a bit cheaper.

http://www.peakgenerators.co.uk/product.asp?id=476

Thanks .. I'll have a good look at that..
--
Tony Sayer

Roger Mills wrote:
In an earlier contribution to this discussion,
The Natural Philosopher wrote:

I would simply LOVE a system that when its cold and wet and the trees
take out a power line, did not require me to have to fiddle around
starting up motors and rewiring the house..to get the TV and the
lights back on. Cooking we can do on te aga...and having te oil
boiler work would be fine..

AND if it almost paid for itself by using off peak electricity
overnight to charge batteries I ran off during the day, it would be
magic.

Anyone know what the efficiency is likely to be of going mains--battery
charger--battery--inverter--mains?


mm..probably around 90% each way. Say 81%


In other words, how many kWhs need to go into the charger to get 1kWh out of
the inverter?

As long as the overall efficiency is better than about 50%, you *could* be
better off by buying all your electricity at the off-peak rate and storing
it in batteries - but you'd have a hell of a capital investment (and
probably maintenance/replacement costs) to contend with.

Well I reckoned about 5 grand..batteries SHOULD do what? 10 years? Hmm.
Not as attractive as I thought ;-)

In article ,
The Natural Philosopher wrote:
Anyone know what the efficiency is likely to be of going
mains--battery charger--battery--inverter--mains?


mm..probably around 90% each way. Say 81%

I'd be amazed if it was anything like that high. Charging Ni-Cads at a
1/10th capacity constant current takes 14 hours. More difficult to work
out with a lead acid as the charge current varies with state but my
reasonably new 8 amp (says 11) charger won't *fully* charge a 75 amp/hour
battery overnight - takes about a day. A good inverter is about 90% though.
I'd guess at more like 60%.


In other words, how many kWhs need to go into the charger to get 1kWh
out of the inverter?

As long as the overall efficiency is better than about 50%, you
*could* be better off by buying all your electricity at the off-peak
rate and storing it in batteries - but you'd have a hell of a capital
investment (and probably maintenance/replacement costs) to contend
with.

Well I reckoned about 5 grand..batteries SHOULD do what? 10 years? Hmm.
Not as attractive as I thought ;-)

Caravan types would know how long a leisure type battery lasts - I doubt
it averages at 10 years.

--
*Dancing is a perpendicular expression of a horizontal desire *

Dave Plowman London SW
To e-mail, change noise into sound.

Dave Plowman (News) wrote:
In article ,
The Natural Philosopher wrote:
Anyone know what the efficiency is likely to be of going
mains--battery charger--battery--inverter--mains?


mm..probably around 90% each way. Say 81%

I'd be amazed if it was anything like that high. Charging Ni-Cads at a
1/10th capacity constant current takes 14 hours. More difficult to work
out with a lead acid as the charge current varies with state but my
reasonably new 8 amp (says 11) charger won't *fully* charge a 75 amp/hour
battery overnight - takes about a day. A good inverter is about 90% though.
I'd guess at more like 60%.

Thats why Nicads are not ideal: Lead acid or Lithium polymer are far
better in the charge cycle. You CAN fully charge Nicads in about 6
minutes..BTW. At even worse efficiency.

The inefficiency of the charge cycle is related to how much the voltage
needs to rise above the off load voltage..with a lead acid its never
more than about 10%.






In other words, how many kWhs need to go into the charger to get 1kWh
out of the inverter?

As long as the overall efficiency is better than about 50%, you
*could* be better off by buying all your electricity at the off-peak
rate and storing it in batteries - but you'd have a hell of a capital
investment (and probably maintenance/replacement costs) to contend
with.

Well I reckoned about 5 grand..batteries SHOULD do what? 10 years? Hmm.
Not as attractive as I thought ;-)

Caravan types would know how long a leisure type battery lasts - I doubt
it averages at 10 years.


I know, but here we are not talking massively deep discharges or
massively high discharge currents, nor are we talking extremes of
temperature. In a house, these things would be running at around a 20-40
hours discharge rate, and about a 1/10th capacity charge rate (i.e. a
110 AH battery charged at 11A or so.

I feel fairly certain that batteries can be optimised for various
duties..car batteries are for short duration high peak output. Leisure
batteries for lower output but deeper discharge. Here we are talking
about optimizing for cycle life. I think 10 years is not unrealistic.
Certainly few car batteries will not - if not allowed to go totally flat
- fail after 5 years.

On Sun, 16 Dec 2007 14:04:35 +0000, The Natural Philosopher wrote:

30 of them would give you enough to power a house for a day, including
things like the odd heater, shower and electric kettle, and be about the
same size as a fridge. About the same (output) energy as a car tankful
of fuel.

But it's not that simple. Your battery bank couldn't realistically operate
at 12v. The current demand would be so high that it becomes impractical.

I quite like the idea of using E7 to charge a battery bank then use that
for the rest of the day. But in an all electric house you'll need a 10kW+
invertor assuming you want to have a shower and have other things on at
the same time. 10kW @ 12v is 833A, it comes down to a more manageable 83A
with a 120v battery bank or about 60 wet lead acid cells in series.

Assuming an average load of 1kW/hr you need capacity of 24kWhr for each
day, which, (if my maths is right) roughly 200A/Hr per cell. Cells of that
capacity are available. Of course you'd need a proper Battery Room (acid
proof floor walls, fittings, ventilated etc) for the cells and a fairly
rigourous electrolyte testing routine to ensure that all the cells are
preforming equally.

Then of course can you thump in enough charge in the available 7 hours to
last 24hrs? (You'll still be wanting to draw power during the charging
period...). I guess so, assuming 50% effciency raw mains to invertor
output and the 1kW average load that comes out at a 7kW charger, small fry
for E7.

--
Cheers
Dave. pam is missing e-mail

Dave Liquorice wrote:
On Sun, 16 Dec 2007 14:04:35 +0000, The Natural Philosopher wrote:

30 of them would give you enough to power a house for a day, including
things like the odd heater, shower and electric kettle, and be about the
same size as a fridge. About the same (output) energy as a car tankful
of fuel.

But it's not that simple. Your battery bank couldn't realistically operate
at 12v. The current demand would be so high that it becomes impractical.

I never said it should. Actually it could and can. 15KW is only 1200
amps or so.

Quite doable on an inverter. Not efficient tho.




I quite like the idea of using E7 to charge a battery bank then use that
for the rest of the day. But in an all electric house you'll need a 10kW+
invertor assuming you want to have a shower and have other things on at
the same time. 10kW @ 12v is 833A, it comes down to a more manageable 83A
with a 120v battery bank or about 60 wet lead acid cells in series.


Yes. I actually went for about that.

Assuming an average load of 1kW/hr you need capacity of 24kWhr for each
day, which, (if my maths is right) roughly 200A/Hr per cell. Cells of that
capacity are available. Of course you'd need a proper Battery Room (acid
proof floor walls, fittings, ventilated etc) for the cells and a fairly
rigourous electrolyte testing routine to ensure that all the cells are
preforming equally.

Yup. Within a few percent we are talking the same numbers.

Lithium cells would technically be a better solution - no electrolyte to
speak of - but those sorts of capacities are about 10 times the price of
lead acid currently.




Then of course can you thump in enough charge in the available 7 hours to
last 24hrs? (You'll still be wanting to draw power during the charging
period...). I guess so, assuming 50% effciency raw mains to invertor
output and the 1kW average load that comes out at a 7kW charger, small fry
for E7.

charger should be 90% efficient or better.

As would be the inverter. 120VDC is just about perfect for modern
switching MOSFETS. Now there will be a lot of RF interference, but the
thing - the inverter/charge - could be in a shielded grounded box.

I think that an installation like this is on the cards in the next 20
years actually.

If we do go nuclear - and I think we must - the ability to use off peak
cheap electricity to power cars and houses is very great.

Owain wrote:
Dave Liquorice wrote:
I quite like the idea of using E7 to charge a battery bank then use
that for the rest of the day. But in an all electric house you'll need
a 10kW+ invertor assuming you want to have a shower

Why woulndn't you just store the E7 heated water?


Indeed.

Thats possible a very effective way - do storage heaters 'properly'


Owain

On Fri, 21 Dec 2007 11:09:11 +0000, Owain wrote:

I quite like the idea of using E7 to charge a battery bank then use
that for the rest of the day. But in an all electric house you'll need
a 10kW+ invertor assuming you want to have a shower

Why woulndn't you just store the E7 heated water?

My telly doesn't run on hot water... but yes splitting the E7 across a
water based heat bank and a battery bank probably does drop the required
invertor size to sub 10kW. How ever add up the breakfast routine, kettle
(3kW), toaster (1 or 2kW), hob (1kW) for porridge plus lights and
fridges/freezers, breakfast/kids telly. The peak demand of a single house
can be surprisingly high, if short lived, even if 24hr average is less
than 1kW.

--
Cheers
Dave. pam is missing e-mail

The Natural Philosopher wrote:
I think that an installation like this is on the cards in the next 20
years actually.

If we do go nuclear - and I think we must - the ability to use off peak
cheap electricity to power cars and houses is very great.

Indeed, but I don't think we should overlook the amount of energy
required by, and the amount of "hothouse" gases emitted during, the
manufacturing processes for heavy duty batteries and electronic control
systems, not to mention heavy gauge wiring with plastic coating and
large copper terminals. SFAIK, metal smelting processes alone require
huge amounts of power and produce toxic gases. Then there is the issue
of recycling heavy metals and plastics when the batteries and control
gear have reached the end of their working lives.

In other words, supplementing the direct consumption of electricity with
stored energy systems in every home will create problems for the
manufacture of sufficient plant irrespective of how the electricity is
generated. In fact the use of wind and wave power by its very nature
implies the installation of large stored energy systems somewhere.

I don't want to appear a doom merchant but I do believe that such
matters are significant. I suspect that I am only now beginning to
grasp the scope of problems created by an exponential growth in the use
of energy by mankind. If I am totally misguided, I would be grateful
for correction.

--
Dave N

N.B. Mail to nospam is rejected. Use the Reply-To which does work.

Dave Liquorice wrote:
On Fri, 21 Dec 2007 11:09:11 +0000, Owain wrote:

I quite like the idea of using E7 to charge a battery bank then use
that for the rest of the day. But in an all electric house you'll need
a 10kW+ invertor assuming you want to have a shower
Why woulndn't you just store the E7 heated water?

My telly doesn't run on hot water... but yes splitting the E7 across a
water based heat bank and a battery bank probably does drop the required
invertor size to sub 10kW. How ever add up the breakfast routine, kettle
(3kW), toaster (1 or 2kW), hob (1kW) for porridge plus lights and
fridges/freezers, breakfast/kids telly. The peak demand of a single house
can be surprisingly high, if short lived, even if 24hr average is less
than 1kW.

Yep. I reckoned 15KW was about right for peak, and 30KWH for a 24 hour
usage.


Actually this got me thinking when I was taking the dogs for a walk..

Tow massive lumps of concrete with holes in, and water pipes (or a
working fluid anyway) buried in the ground under the house in loads of
insulation..and a third under the lwan..heatpump from one to the other
or to teh third..so you have one hot block for heating, one cold block
for cooling..and source or sink the difference into the soil..


Because ultimately - if we take overall domestic power., about 80% is
used to heat things, about 15% to cool things (reverse in hot summers)
and the rest ends up as heat anwyay after doing whatever else it does,
like running a computer...

So if you are talkinng nuclear electric, it makes sense to store tehheat
rather than the electricity through times of peak demand.


Now how big a block of concrete represents 30KWh over say a 40C
temperature span? I found a reference of 0.2BTU per lb per degree F..who
is USING such units..ah well..anyway I get 9995 BTU per ton over a 40 C
change from that..that's 2.91768532 kWh per ton..so to get 30KWh is
about ten tons.

Cripes. That is NOT a lot of masonry at all.The storage heater to end
all storage heaters..

Oh..dunno if I did the calcs right, but WATER is the ultimate store. I
get around 400KWh per metric ton for a 40C change in temperature.

So there's your thermal store then. Bloody great insulated tank of hot
(or cold) water under the house ...

Won't do cooking, but it sure would do house heating or cooling, and
cool room stuff.

Dave N wrote:
The Natural Philosopher wrote:
I think that an installation like this is on the cards in the next 20
years actually.

If we do go nuclear - and I think we must - the ability to use off peak
cheap electricity to power cars and houses is very great.

Indeed, but I don't think we should overlook the amount of energy
required by, and the amount of "hothouse" gases emitted during, the
manufacturing processes for heavy duty batteries and electronic control
systems, not to mention heavy gauge wiring with plastic coating and
large copper terminals. SFAIK, metal smelting processes alone require
huge amounts of power and produce toxic gases. Then there is the issue
of recycling heavy metals and plastics when the batteries and control
gear have reached the end of their working lives.

In other words, supplementing the direct consumption of electricity with
stored energy systems in every home will create problems for the
manufacture of sufficient plant irrespective of how the electricity is
generated. In fact the use of wind and wave power by its very nature
implies the installation of large stored energy systems somewhere.

I don't want to appear a doom merchant but I do believe that such
matters are significant.

They are, but less than you might think.

For a start, dont worry about energy used in making stuff. If its all
nuclear generated, its zero carbon.

All this 'carbon burnt in manufacture' becomes utterly meaningless if
your energy is carbon neutral.

There is an implied shift here, form 'energy conservation' to 'carbon
emission reduction'

The actual energy used is a very small fraction of what falls on te
earth..that won't affect the climate half as much as the CO2 does.

Very little industrial process actually generates Co2..smelting does a
bit, as does concrete making. Smelting you could probably do in order
ways than using carbon monoxide aqs a reducing agent..electrolysis for
example. I suspect there is no way to make cement without releasing CO2
though. But there are other materials..

Ive actually been to a lead and zinc smelters.. the place was dripping
sulphuric acid..and the old batteries were simply tipped into the
process at some point to recycle the lead. However we went there to
install toxic metal detectors, for the outflows, to monitor mercury and
cadmium levels..they are not that bad. Most of the nasties can be
separated out, at a cost. So although there are issue, I don';t see
them as insuperable. At some level to maintain an industrial or post
industrial lifestyle means SOME form of waste will be generated. You
have to literally pick your poison..ultimately the best battery material
is lithium anyway, which is plentiful and abundant almost everywhere, it
just takes a lot of power to extract. But with power cheaper, its not
such a big deal.

AND if my last posts calcs are correct, you can keep a house warm with a
few tons of stored hot water heated on E7 overnight anyway.

So battery requirements are not huge.




\









I suspect that I am only now beginning to
grasp the scope of problems created by an exponential growth in the use
of energy by mankind. If I am totally misguided, I would be grateful
for correction.

The Natural Philosopher wrote:

Very little industrial process actually generates Co2..smelting does a
bit, as does concrete making.


Concrete making is carbon negative. Taking a large view cement making is
close to being carbon neutral, if one ignores the fuel consumption which
you seemed to be suggesting is a necessary part of your calculation.

The Natural Philosopher wrote:
Ive actually been to a lead and zinc smelters.. the place was dripping
sulphuric acid..and the old batteries were simply tipped into the
process at some point to recycle the lead. However we went there to
install toxic metal detectors, for the outflows, to monitor mercury and
cadmium levels..they are not that bad. Most of the nasties can be
separated out, at a cost. So although there are issue, I don';t see
them as insuperable. At some level to maintain an industrial or post
industrial lifestyle means SOME form of waste will be generated. You
have to literally pick your poison..ultimately the best battery material
is lithium anyway, which is plentiful and abundant almost everywhere, it
just takes a lot of power to extract. But with power cheaper, its not
such a big deal.

It is this issue which interests me because AIUI conversion to a system
based upon widespread use of stored electricity in homes and vehicles,
would lead to an increase of an order of magnitude at least (if not two
or more orders of magnitude) in the use of battery systems reliant upon
such materials. Perhaps hydrogen cells or motors would be a better
solution for stored energy, assuming that electricity isn't too costly?
However, as I inferred before, I realise that I do not know all of the
facts.

--
Dave N

N.B. Mail to nospam is rejected. Use the Reply-To which does work.

Dave N wrote:
The Natural Philosopher wrote:
Ive actually been to a lead and zinc smelters.. the place was dripping
sulphuric acid..and the old batteries were simply tipped into the
process at some point to recycle the lead. However we went there to
install toxic metal detectors, for the outflows, to monitor mercury and
cadmium levels..they are not that bad. Most of the nasties can be
separated out, at a cost. So although there are issue, I don';t see
them as insuperable. At some level to maintain an industrial or post
industrial lifestyle means SOME form of waste will be generated. You
have to literally pick your poison..ultimately the best battery material
is lithium anyway, which is plentiful and abundant almost everywhere, it
just takes a lot of power to extract. But with power cheaper, its not
such a big deal.

It is this issue which interests me because AIUI conversion to a system
based upon widespread use of stored electricity in homes and vehicles,
would lead to an increase of an order of magnitude at least (if not two
or more orders of magnitude) in the use of battery systems reliant upon
such materials.

I estimate a tripling of the national Grid in size, ( electrical use of
energy is about 30% of total use at the moment: aparet from aircraft and
military and specialised vehicles, that assumes everything else 'goes
elecvtrioc'

And each household with a car, having 30-100KWh of storage capacity -
possibly IN the car, possibly IN the home.

The latest data point I have on lithium cells is this:-

www.maxamps.com/products.php?cat=24

which is about 37 watt hours for $54.99

That puts an undiscounted 37Kwh car pack of 1000 cells at $54,995.

About £27,500 ..which is not - for the equivalent of driving a car on
ten thousand 'Rabbit' duracells, unduly expensive.

Note the peak power available from a single cell - 370 watts. so a
thousand would be capable of 370KW. Around 500bhp. For about 5 minutes ;-)

Total weight around 200kg for the pack. About what an engine and gearbox
comes in at for a small car.

Volume about 1/10th of a cubic meter.

Say 1.5 meters long, by a meter wide, by 6cm thick, tho for high power
use the cells need air cooling between them. There is a fire risk
associated with these cells, so probably under the floor in the center
of the car with a fireproof barrier is the place to put them Good for
weight distribution as well. In fact near perfect.

So the cost is about ten times a lead acid solution at the moment, for
retail 'hobby cell' prices.


I've been abusing cells like this for a few years. They are now pretty
good. At modest discharge and charge rates (which we seldom use) they
approach 95% cycle efficiency, and some I have that are rather poor at
high power - have showed almost no self discharge in 6 months.

Charge regime is really simple - like lead acid. Limit the charge
current to at MOST a one hour charge rate, and limit applied voltage to
4.2v/cell.

Dischrge shows an initial sharp drop of about .1v per cel, then an
almost linear voltage reduction down to around 3-3.3v/cell, and then a
rapid drop in voltage thereafter: That makes monitoring charge state
relatively easy.

The cell chemistry tends to be flammable - althuogh some raw lithium is
produce by lithium carbonate electrolysis, that is not the real problem.
The solvents used to get decent internal resistance are organics, and
highly inflammable. There are tradeoffs between power, longevity, charge
rates, flammability and efficiency that have yet to be explored for
automotive use.

On a estimated 500 cycle lifetime, of say 200 miles per charge, the
capital cost amortizes to 27.5p per mile.

Electricity costs on economy 7 overnight charging? Even at 10p a unit,
its £3.70 to 'fill the tank' for 200 miles..so worst case around 1.9p a
mile.

Apart from routine lubrication, tyres and brakes (and with regenerative
braking possible, less of those too) the annual service charges would be
minimal. One would expect - at least in the early days - cell failures,
so a routine test and module replace of what would probably be a modular
battery, with each module having its own regulation and safety
circuitry, would be likely to be the worst costs.

If tax incentives were added on to a car like this, it would further
reduce the overall cost per mile.

Most likely way to power the thing would be two or four hub based highly
multipole brushless DC motors, with hall effect sensing for commutation
purposes. Ironless designs MIGHT bet up around 95% plus efficiency.
However the wide speed range over which the motor has to operate would
probably not result in much better tan an overall 75% efficiency from
power station to wheel. Without a non carbon fuel based power
generation, the thing - tho cheap to run taxation wise - is no better on
emissions. (Just like the Priapus really).

Why aren;t we doing this right now?

Although te isses of a load of power electronics and chips needing to be
developed is one thing in the way - but one that companies like Lucas
and Bosh should be able to tackle effectively - the main thing holding
it back is that almost nothing of what constitutes todays car/oil
industry is of any use whatsoever in developing this technology. I
would say that an electric car might use the same steering wheel, seats,
pedals and tyres as a conventional car, and the same windscreens. The
rest? forget it. All gone.

Likewise conventional garages would be totally ill equipped to deal with
the electrical side without major investment in test equipment.

In short,. there is zero incentive to develop this technology. And very
many reasons to NOT develop it and hinder its introduction.


Nevertheless it WILL happen. As you can see under current tax regimes
its almost economic to run one.



Perhaps hydrogen cells or motors would be a better
solution for stored energy, assuming that electricity isn't too costly?


No. The hydrogen ******** - like most greeny ********, is as biased as
hell, all about 'hey, this is a fuel people *could* use in cars that
have the sort of engines we build, and would have to buy at our service
stations, and would have to be transported by a fleet of trucks which we
have exactly the right infrastructure for'

The conversion efficiencies are dire, the safety is dubious - unless you
want a tank of liquid hydrogen with the power of a medium size fuel air
bomb, in your car, it needs to adsorbed into a sintered metallic
substrate. That's not light.

You CAN make it at power substation sized plants along the M1 by
electrolysis, but you certainly wont make it at home..

As far as I can see it simply is nonsense. Its like windpower, its
possible, but the overall cost benefit doesn't make real sense.


However, as I inferred before, I realise that I do not know all of the
facts.


Nor it seems do those making decisions about all this. And those who DO
know the facts are usually employed by companies in whose interest it is
to keep those facts to themselves.

I don't mean there is a conspiracy of silience..more like some poor
graduate does a design proposal, more or less as outlined above, it goes
to the bean counters, they take one look and say 'all I can see is
spending a billion to commit commercial suicide and invalidate the rest
of our entire operation'

Nonetheless I expect a Japanese electric car - or Korean or Chinese,
pretty soon..

Owain wrote:
Dave Liquorice wrote:
Why woulndn't you just store the E7 heated water?
My telly doesn't run on hot water...

A small one might run on some Peltier cells.

but yes splitting the E7 across a water based heat bank and a battery
bank probably does drop the required invertor size to sub 10kW. How
ever add up the breakfast routine, kettle (3kW), toaster (1 or 2kW),
hob (1kW) for porridge

A stored heat cooker could help there.

Ah. like an Aga.

6 grand of heatbank and cooker combined. ;-)


plus lights and fridges/freezers, breakfast/kids telly. The peak demand
of a single house can be surprisingly high, if short lived, even if
24hr average is less than 1kW.

If you don't use a lot of cooking appliances, and stagger the washing
machine and dishwasher (or operate them on E7), 5kW would probably cover
most things. People on barges manage with sporadic mains electricity and
gas/diesel heating, and they're restricted by the space available for
batteries.

Yup. Cooking uses surprisingly little power. Its just that rapid heating
demands a high peak output. Batteries CAN do that. They are rather good
at it.


Owain

In message , Steve Firth
writes
The Natural Philosopher wrote:

Very little industrial process actually generates Co2..smelting does a
bit, as does concrete making.


Concrete making is carbon negative. Taking a large view cement making is
close to being carbon neutral, if one ignores the fuel consumption which
you seemed to be suggesting is a necessary part of your calculation.


I don't know about carbon negative or even neutral but it's a nice way
to lock up carbon dioxide. Concrete actually works by soaking up CO2 as
it cures because it turns to limestone eventually IIRC. ISTR some
research about soaking concrete with liquid CO2 to cure it faster and
allow the manufacture of some extremely un-concrete like structures
(springs being one that come to mind, if I can find the reference I'll
post it.)
--
Clint Sharp

The Natural Philosopher wrote:

[...]

Thank you for a detailed explanation of your thinking.

Dave N wrote:
Perhaps hydrogen cells or motors would be a better
solution for stored energy, assuming that electricity isn't too costly?

The Natural Philosopher wrote:
No. The hydrogen ******** - like most greeny ********, is as biased as
hell, all about 'hey, this is a fuel people *could* use in cars that
have the sort of engines we build, and would have to buy at our service
stations, and would have to be transported by a fleet of trucks which we
have exactly the right infrastructure for'

The conversion efficiencies are dire, the safety is dubious - unless you
want a tank of liquid hydrogen with the power of a medium size fuel air
bomb, in your car, it needs to adsorbed into a sintered metallic
substrate. That's not light.

You CAN make it at power substation sized plants along the M1 by
electrolysis, but you certainly wont make it at home..

As far as I can see it simply is nonsense. Its like windpower, its
possible, but the overall cost benefit doesn't make real sense.

It will be interesting to see how Iceland gets on with its plans for
100% conversion to hydrogen fuel cell technology. Sources I've found
via the internet appear to agree that storage and transport of hydrogen
is the main technical problem.

--
Dave N

N.B. Mail to nospam is rejected. Use the Reply-To which does work.

Clint Sharp wrote:
In message , Steve Firth
writes
The Natural Philosopher wrote:

Very little industrial process actually generates Co2..smelting does a
bit, as does concrete making.


Concrete making is carbon negative. Taking a large view cement making is
close to being carbon neutral, if one ignores the fuel consumption which
you seemed to be suggesting is a necessary part of your calculation.


I don't know about carbon negative or even neutral but it's a nice way
to lock up carbon dioxide. Concrete actually works by soaking up CO2 as
it cures because it turns to limestone eventually IIRC. ISTR some
research about soaking concrete with liquid CO2 to cure it faster and
allow the manufacture of some extremely un-concrete like structures
(springs being one that come to mind, if I can find the reference I'll
post it.)
ISTR we had this discussion elsewhere, and that only true of lime based
cement. Portland doesn't work like that.

Worth double checking. But in any case its not a huge CO2 issue really.
Its just more greeny ******** 'wood good, natural organic, concrete made
in factories inorganic unnatural bad.'


Its jusdt religion really.

In message , The Natural
Philosopher writes
Clint Sharp wrote:
ISTR we had this discussion elsewhere, and that only true of lime based
cement. Portland doesn't work like that.

Worth double checking.
Of course, you're right. It is only lime based cement that works that
way AFAIK. Portland's a nasty mix of all sorts of rubbish. If anyone
wants to look up the liquid CO2 thing, it's known as SCF or super
critical fluid treatment and it's not actually liquid CO2 (my mistake)
that's used.
But in any case its not a huge CO2 issue really. Its just more greeny
******** 'wood good, natural organic, concrete made in factories
inorganic unnatural bad.'
Very likely, there's a massive amount of bull**** talked about CO2 et al
by the greeny weenies.

Its jusdt religion really.
Of course.
--
Clint Sharp