Mary Fisher wrote:
"John Rumm" wrote in message
et...
Mary Fisher wrote:

I read a post from a bloke however who did install a solar thermal
system, where its only used to heat water. He said he noticed a big
drop in his bills, maybe as much as a third. It did cost a heck of a
lot to install though and that's when he still did a lot of the work
himself and got a grant. Plus he will have to stay put for 20 odd
years for it to repay itself and have been worth it.
Not true. But payback isn't an issue.
Says who?

Says me and all the people I know who have invested in such devices.

Do you consider the payback time on everything you buy?

Yes. I may ignore it, but I don't fail to consider it.


If it never pays back in financial terms, there is a fair chance it will
never pay back in environment ones either.

At my previous house, I estimate my annual hot water costs were about
£100. Say a solar system could save me 70% of those costs over the year -
it would take ten years to recover the costs if the system cost £700. Many
of the commercial systems cost more than double that.

And power prices are more than double :-)


My FIL has been quoted and paid a deposit on a £4000 installation
system that *by the manufacturers own brochure*, operating at 100%
efficiency, will save him at most £200 a year.
The salesman claimed it would halve his domestic heating oil costs,
running at around £2500 a year.

So did all the 'satisfied customers' who acted as reference sites.

I wonder how much of a service contract they sting him for as well. I
bet it will be 200 quid a year..

David Hansen wrote:
On Mon, 28 Jul 2008 09:38:05 +0100 someone who may be "Mary Fisher"
wrote this:-

Not true. But payback isn't an issue.
Says who?
Says me and all the people I know who have invested in such devices.

Do you consider the payback time on everything you buy?

Indeed. People who would probably never consider the simple payback
period on other items, double glazing, car, kitchen and so on do
claim to be interested in the simple payback period for renewable
energy "generating" items.

Thats why ther e are so many poor peole and rich double glazing salesmen.

In my view many have an emotional
opposition to renewables, or at least some forms of renewables, but
try and disguise this by bringing in other arguments.


Quite the revers: so many people have an emotional bias towards
renewables that they are easy meat for any salesman. I guess that's what
your line must be,.

That is certainly the case on a large scale. For example when all
the other arguments have been countered opponents of large scale
wind farms generally resort to their real objection, an emotional
argument about appearance.



On the contrary, that is a complete lie: as you know I spent a long time
pointing out why they are an expensive waste of time and only work when
highly subsidised by the taxpayer, who gets no benefit whatsoever.

Huge wrote:
On 2008-07-28, Bob Eager wrote:
On Mon, 28 Jul 2008 09:43:24 UTC, David Hansen
wrote:

In my view many have emotional support for renewables, or at least some
forms of renewables, but try and disguise this by bringing in other
arguments.

Was that Bob or David?

Whatever ...

Hell, even I have emotional support for renewables, but they have to *work*. In
the cruel hard light of economics and physics. If they don't, there's no point
ot them, no matter how nice the idea might seem.


I've only found one domestic technology apart from super insulation,
that has any real impact in the UK climate and that's heat pumps, and
the snake oil salesmen have already moved in on that one.

"John Rumm" wrote in message
...
Cerumen wrote:
"Mary Fisher" wrote in message
t...
"Dave Liquorice" wrote in message
ll.net...
On Sun, 27 Jul 2008 11:49:57 +0100, R D S wrote:

I have been thinking about getting a solar panel to keep a fridge
runnning and keep a battery charged while camping.
It'll have to be a *big* (expensive) photovoltaic panel to run a fridge
even under bright sunlight conditions.

Not a caravan fridge!

That depends if it's a peltier type which uses a lot of power or the more
expensive but lower consumption compressor type.

Other way round I would have thought? I would not have expected many
compressors to run on 75W or less...

I have a 12 volt compressor that runs on 3 amps and of course it has a
thermostat so is not continuously pulling power as peltier units do.
According to the manual to maintain 5C at ambient 20C it runs 10% of the
time


--
Chris, (on tour)
Intellect is invisible to the man who has none.
Schopenhauer

On Tue, 29 Jul 2008 03:44:27 +0100 someone who may be The Natural
Philosopher wrote this:-

That is certainly the case on a large scale. For example when all
the other arguments have been countered opponents of large scale
wind farms generally resort to their real objection, an emotional
argument about appearance.

On the contrary, that is a complete lie:

Incorrect.

as you know I spent a long time
pointing out why they are an expensive waste of time and only work when
highly subsidised by the taxpayer, who gets no benefit whatsoever.

You spent a lot of time digging a deeper hole as your claims became
ever more bogus.




--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Mon, 28 Jul 2008 17:17:36 +0100 someone who may be Andy Hall
wrote this:-

If the argument for buying this stuff is not an economic one, but a
feel good one,

It is I think revealing that the points which others have made
before on the reasons for installing such things remain unanswered.
Instead what is presented is the lie that the reason people install
these things is to feel good.






--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On 2008-07-29 09:06:15 +0100, David Hansen
said:

On Mon, 28 Jul 2008 17:17:36 +0100 someone who may be Andy Hall
wrote this:-

If the argument for buying this stuff is not an economic one, but a
feel good one,

It is I think revealing that the points which others have made
before on the reasons for installing such things remain unanswered.
Instead what is presented is the lie that the reason people install
these things is to feel good.

Given that we know that they are not economically viable in less than
their operational lifetime, what other reasons for purchase are there
other than feel good factor?

On Tue, 29 Jul 2008 08:21:52 UTC, Andy Hall wrote:

On 2008-07-29 09:06:15 +0100, David Hansen
said:

On Mon, 28 Jul 2008 17:17:36 +0100 someone who may be Andy Hall
wrote this:-

If the argument for buying this stuff is not an economic one, but a
feel good one,

It is I think revealing that the points which others have made
before on the reasons for installing such things remain unanswered.
Instead what is presented is the lie that the reason people install
these things is to feel good.

Given that we know that they are not economically viable in less than
their operational lifetime, what other reasons for purchase are there
other than feel good factor?

The look good factor.Coupled with self importance.
--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
http://www.diybanter.com

"The Natural Philosopher" wrote in message
...
Mary Fisher wrote:
"R D S" wrote in message
...
Maybe if energy prices go sky high a solar thermal system may become
an option for a lot of people. But you'd have to hope that the climate
isn't going into a cooling period and we start getting less sunshine,
and that it pays itself back a bit quicker.
Surely if we have a cooling period there will still be the same amount
of sunshine.

That's right. The temperature isn't all that important. when we connected
ours up the air temperature was 4C and we got a large cylinder full of
water at over 30C in a few hours.


You can get a large cylinder full of 30C water in a few miniutes at a
couple of shillings of electricity cost.

I reckon about 12 minutes to get 225l 10C hotter with a 3kW heater.
My boiler will do it in less than three minutes at a cost of less than 1
pence.
If that is the standard by which solar water heating is a success I won't
bother.
I expect it to give me 70C water to be worthwhile.

I priced up a ground source heat pump the other day..
about £1000 for the heat pump.
about 2000-3000 to have a 75m borehole done in the local mud stone.
I want a DIY way of drilling a 75m borehole in mud stone if anyone has any
ideas?
If I used say four 25m boreholes how far apart would they need to be to give
a suitable heat store?

On Jul 29, 3:16*am, The Natural Philosopher wrote:
R D S wrote:
I have been thinking about getting a solar panel to keep a fridge runnning
and keep a battery charged while camping.
Has anyone any experience/opinions?

Also with energy prices being the way they are has anyone gone further than
this and installed solar in the home? Likewise with wind, a local electrical
supplier reckoned he could get me a 2kw turbine for approx £1500. At one
point I would have thought alternative power was prohibitively expensive but
now it looks as though it may sense.

Neither wind nor solar make any real economic sense in a domestic
situation in the UK..


...unless you live off-grid. When I lived on a boat with no access to
mains electricity, I found that solar PV panels were far more useful
than wind turbines. I had about 5 square metres of PV panel on the
roof and this did run the lights, TV,radio and the pumps (but not
heating of course).

Robert

On 2008-07-29 10:10:36 +0100, "dennis@home"
said:



"The Natural Philosopher" wrote in message
...
Mary Fisher wrote:
"R D S" wrote in message
...
Maybe if energy prices go sky high a solar thermal system may become
an option for a lot of people. But you'd have to hope that the climate
isn't going into a cooling period and we start getting less sunshine,
and that it pays itself back a bit quicker.
Surely if we have a cooling period there will still be the same amount
of sunshine.

That's right. The temperature isn't all that important. when we
connected ours up the air temperature was 4C and we got a large
cylinder full of water at over 30C in a few hours.


You can get a large cylinder full of 30C water in a few miniutes at a
couple of shillings of electricity cost.

I reckon about 12 minutes to get 225l 10C hotter with a 3kW heater.
My boiler will do it in less than three minutes at a cost of less than 1 pence.
If that is the standard by which solar water heating is a success I
won't bother.
I expect it to give me 70C water to be worthwhile.

I priced up a ground source heat pump the other day..
about £1000 for the heat pump.
about 2000-3000 to have a 75m borehole done in the local mud stone.
I want a DIY way of drilling a 75m borehole in mud stone if anyone has
any ideas?
If I used say four 25m boreholes how far apart would they need to be to
give a suitable heat store?


You can buy an awful lot of gas or even electrically heated hot water
for ten grand.

"Dave Liquorice" wrote:

It rasies the profile of what can be done but these days most people
aren't capable of changing a tap washer let alone designing and installing
a solar heating system. They have money though and may be willing to part
with that fopr someone to come and do it for them, the brighter ones want
impartial advice on the variations that are out there. CAT may well be
able to fullfill that need.


Correction, it should be able to fulfil that need. An independent,
unbiased consultancy service charging modest rates for impartial
advice would be of enormous help.

"dennis@home" wrote:

I want a DIY way of drilling a 75m borehole in mud stone if anyone has any
ideas?


An SDS drill with a 75m long bit?

RobertL wrote:
On Jul 29, 3:16 am, The Natural Philosopher wrote:
R D S wrote:
I have been thinking about getting a solar panel to keep a fridge runnning
and keep a battery charged while camping.
Has anyone any experience/opinions?
Also with energy prices being the way they are has anyone gone further than
this and installed solar in the home? Likewise with wind, a local electrical
supplier reckoned he could get me a 2kw turbine for approx £1500. At one
point I would have thought alternative power was prohibitively expensive but
now it looks as though it may sense.
Neither wind nor solar make any real economic sense in a domestic
situation in the UK..


...unless you live off-grid. When I lived on a boat with no access to
mains electricity, I found that solar PV panels were far more useful
than wind turbines. I had about 5 square metres of PV panel on the
roof and this did run the lights, TV,radio and the pumps (but not
heating of course).

Robert

Yes. You can get a few watts out of PV and normal solar hot water
panels. If that is enough, then they are sensible.

dennis@home wrote:


"The Natural Philosopher" wrote in message
...
Mary Fisher wrote:
"R D S" wrote in message
...
Maybe if energy prices go sky high a solar thermal system may become
an option for a lot of people. But you'd have to hope that the climate
isn't going into a cooling period and we start getting less sunshine,
and that it pays itself back a bit quicker.
Surely if we have a cooling period there will still be the same
amount of sunshine.

That's right. The temperature isn't all that important. when we
connected ours up the air temperature was 4C and we got a large
cylinder full of water at over 30C in a few hours.


You can get a large cylinder full of 30C water in a few miniutes at a
couple of shillings of electricity cost.

I reckon about 12 minutes to get 225l 10C hotter with a 3kW heater.
My boiler will do it in less than three minutes at a cost of less than 1
pence.
If that is the standard by which solar water heating is a success I
won't bother.
I expect it to give me 70C water to be worthwhile.

I priced up a ground source heat pump the other day..
about £1000 for the heat pump.
about 2000-3000 to have a 75m borehole done in the local mud stone.
I want a DIY way of drilling a 75m borehole in mud stone if anyone has
any ideas?
If I used say four 25m boreholes how far apart would they need to be to
give a suitable heat store?


http://www.lboro.ac.uk/well/resources/technical-briefs/43-simple-drilling-methods.pdf

The contact in Zimbabwe might not be ideal at the moment but the PDF
does have lots of techniques.

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

On Tue, 29 Jul 2008 10:10:36 +0100 someone who may be "dennis@home"
wrote this:-

Mary Fisher wrote:

That's right. The temperature isn't all that important. when we connected
ours up the air temperature was 4C and we got a large cylinder full of
water at over 30C in a few hours.


You can get a large cylinder full of 30C water in a few miniutes at a
couple of shillings of electricity cost.

If that is the standard by which solar water heating is a success I won't
bother.
I expect it to give me 70C water to be worthwhile.

Nice try. However, it is even easier than usual to see through that
distortions.

As anyone can see from the bit I have left in, Mary didn't say that
the maximum temperature solar heated water will reach is 30C.

The temperature solar heated water will reach obviously depends on
various factors. 70C is no great problem with reasonable sunlight.

Nice try.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Tue, 29 Jul 2008 10:37:01 UTC, Bruce wrote:

"Dave Liquorice" wrote:

It rasies the profile of what can be done but these days most people
aren't capable of changing a tap washer let alone designing and installing
a solar heating system. They have money though and may be willing to part
with that fopr someone to come and do it for them, the brighter ones want
impartial advice on the variations that are out there. CAT may well be
able to fullfill that need.


Correction, it should be able to fulfil that need. An independent,
unbiased consultancy service charging modest rates for impartial
advice would be of enormous help.

That lets out Mr. Hansen's masters, then.

--
The information contained in this post is copyright the
poster, and specifically may not be published in, or used by
http://www.diybanter.com

David Hansen wrote:
On Tue, 29 Jul 2008 10:10:36 +0100 someone who may be "dennis@home"
wrote this:-

Mary Fisher wrote:
That's right. The temperature isn't all that important. when we connected
ours up the air temperature was 4C and we got a large cylinder full of
water at over 30C in a few hours.

You can get a large cylinder full of 30C water in a few miniutes at a
couple of shillings of electricity cost.

If that is the standard by which solar water heating is a success I won't
bother.
I expect it to give me 70C water to be worthwhile.

Nice try. However, it is even easier than usual to see through that
distortions.

As anyone can see from the bit I have left in, Mary didn't say that
the maximum temperature solar heated water will reach is 30C.

The temperature solar heated water will reach obviously depends on
various factors. 70C is no great problem with reasonable sunlight.


In winter? harder..much harder...

Solar works well in a mediterranean climate when very little house
heating is needed and hot water is the primary energy use: here in the
UK its not cost effective at any prices I have been able to find.

At best, a 4 sq meter of panel represents less than a £200 a year energy
generation at current OIL prices..which are slightly above electricity
off peak prices. And above gas.

Do the sums yourself, on average insolation, and units of energy generated.

Oh. You dont do sums do you?


Nice try.

David Hansen wrote:
On Mon, 28 Jul 2008 17:17:36 +0100 someone who may be Andy Hall
wrote this:-

If the argument for buying this stuff is not an economic one, but a
feel good one,

It is I think revealing that the points which others have made
before on the reasons for installing such things remain unanswered.
Instead what is presented is the lie that the reason people install
these things is to feel good.

Could you suggest some other motivations then?


--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

The Natural Philosopher wrote:

Oh. You dont do sums do you?


No, but you got two "Nice try"s in one posting,
so you should be very grateful.

"Bob Eager" wrote:

On Tue, 29 Jul 2008 10:37:01 UTC, Bruce wrote:

"Dave Liquorice" wrote:

It rasies the profile of what can be done but these days most people
aren't capable of changing a tap washer let alone designing and installing
a solar heating system. They have money though and may be willing to part
with that fopr someone to come and do it for them, the brighter ones want
impartial advice on the variations that are out there. CAT may well be
able to fullfill that need.


Correction, it should be able to fulfil that need. An independent,
unbiased consultancy service charging modest rates for impartial
advice would be of enormous help.

That lets out Mr. Hansen's masters, then.


Nice try. ;-)

On 2008-07-29 15:45:23 +0100, Bruce said:

The Natural Philosopher wrote:

Oh. You dont do sums do you?


No, but you got two "Nice try"s in one posting,
so you should be very grateful.

That one's on Shift-F4

"David Hansen" wrote in message
...
On Tue, 29 Jul 2008 10:10:36 +0100 someone who may be "dennis@home"
wrote this:-

Mary Fisher wrote:

That's right. The temperature isn't all that important. when we
connected
ours up the air temperature was 4C and we got a large cylinder full of
water at over 30C in a few hours.


You can get a large cylinder full of 30C water in a few miniutes at a
couple of shillings of electricity cost.

If that is the standard by which solar water heating is a success I won't
bother.
I expect it to give me 70C water to be worthwhile.

Nice try. However, it is even easier than usual to see through that
distortions.

As anyone can see from the bit I have left in, Mary didn't say that
the maximum temperature solar heated water will reach is 30C.

The temperature solar heated water will reach obviously depends on
various factors. 70C is no great problem with reasonable sunlight.

Nice try.

She did.
It doesn't matter as the 10C rise costs the same for the boiler if its from
60-70c.
It doesn't take the same time for solar, it gets longer and longer.. most
days you will be either be lucky to get *hot* water or have spent far too
much on big panels.
With gas prices as they are, solar water heating doesn't make sense, it
certainly didn't make sense last year.
Even if you save cash there is still the issue of using producing more
carbon than you save.
Some of us consider the environment and use the least polluting methods even
if it costs more than solar.

I certainly wouldn't use wind power, the environmental damage from wind
turbines is far too high whatever they save me in cash!

Bruce wrote:
"Bob Eager" wrote:

On Tue, 29 Jul 2008 10:37:01 UTC, Bruce wrote:

"Dave Liquorice" wrote:
It rasies the profile of what can be done but these days most people
aren't capable of changing a tap washer let alone designing and installing
a solar heating system. They have money though and may be willing to part
with that fopr someone to come and do it for them, the brighter ones want
impartial advice on the variations that are out there. CAT may well be
able to fullfill that need.

Correction, it should be able to fulfil that need. An independent,
unbiased consultancy service charging modest rates for impartial
advice would be of enormous help.
That lets out Mr. Hansen's masters, then.


Nice try. ;-)

With dynamo dave, nice try == 'I think you got me there, right on target'

"The Natural Philosopher" wrote in message
...

Anyway, it costs about 6 billion to construct AND decommsion a 3GW sized
nuclear reactor, so your number are a bit out.

I didn't say 'each', I said 'all'.

http://news.bbc.co.uk/1/hi/sci/tech/7421879.stm

The Natural Philosopher said...
R D S wrote:
I have been thinking about getting a solar panel to keep a fridge runnning
and keep a battery charged while camping.
Has anyone any experience/opinions?

Also with energy prices being the way they are has anyone gone further than
this and installed solar in the home? Likewise with wind, a local electrical
supplier reckoned he could get me a 2kw turbine for approx £1500. At one
point I would have thought alternative power was prohibitively expensive but
now it looks as though it may sense.


Neither wind nor solar make any real economic sense in a domestic
situation in the UK..

Solar panels to heat water make a lot of very real economic sense - but
it's a long term investment. I can't recall the exact figures now, but
I think the solar water heating system I had in Cardiff cost something
in the region of £3,000 to install around 10 years ago. By no stretch
of the imagination is that 'cheap'; however it will have paid for itself
within a few decades, even in the UK. Most people don't want to wait
that long to see a return on their investment (and who shall blame
them), so they don't see solar water heating as a viable choice. I have
a large family, and we use a lot of hot water. For us, it's viable; for
a single person or a couple with maybe one or two children it might not
be. Then again, they wouldn't need such a large system as we did, so
who knows. As I've said elsewhere, if I had the capital to have a
similar installation in the house I live in now, I wouldn't hesitate to
say yes. If I had the skills to install it myself it would have been
done as soon as we moved here.

--
Fran
To email me see 'from' in headers; use your net know-how to find the
domain, and put my real name in front thereof.

The Natural Philosopher said...
Fran wrote:
R D S said...
Also with energy prices being the way they are has anyone gone further than
this and installed solar in the home?

Yes. At our last house (SE Wales) we had solar panels in the roof for
heating water, and they were fabulous. It didn't need to be hot; it just
needed to be sunny for a couple of hours. The water was piping hot and
we rarely had to supplement the panels with the immersion heater.

Installation was expensive, and it would probably have taken us 5 to 10
years to recoup our outlay. We moved before that happened, and the solar
panels were a major selling point.

If I had the money now I'd do it again.

DHW probably accounts for maybe 60 quid a year fuel costs. If the panels
cost more than £600, they were a waste of money.

That depends on how much hot water you want though, doesn't it. I have
a large family and we spend considerably more than £60 a year heating
water for laundry and personal hygiene. Our expenses will reduce as the
children leave home, but that's not going to happen for a few years yet.

--
Fran
To email me see 'from' in headers; use your net know-how to find the
domain, and put my real name in front thereof.

Fran wrote:

I think the solar water heating system I had in Cardiff cost something
in the region of £3,000 to install around 10 years ago. By no stretch
of the imagination is that 'cheap'; however it will have paid for itself
within a few decades, even in the UK. Most people don't want to wait

I expect if you include the interest lost you could have had form
leaving the money invested, or paying it off your mortgage for example,
then it takes on a different complexion. If you have to borrow the money
to install it then you are losing out from all directions.

who knows. As I've said elsewhere, if I had the capital to have a
similar installation in the house I live in now, I wouldn't hesitate to
say yes. If I had the skills to install it myself it would have been
done as soon as we moved here.

If you could DIY at a capital cost of a few hundred, then it starts to
look more attractive. (assuming you have a compatible hot water system
in the first place).

--
Cheers,

John.

/================================================== ===============\
| Internode Ltd - http://www.internode.co.uk |
|-----------------------------------------------------------------|
| John Rumm - john(at)internode(dot)co(dot)uk |
\================================================= ================/

"Fran" wrote in message
t...
The Natural Philosopher said...
Fran wrote:
R D S said...
Also with energy prices being the way they are has anyone gone further
than
this and installed solar in the home?

Yes. At our last house (SE Wales) we had solar panels in the roof for
heating water, and they were fabulous. It didn't need to be hot; it
just
needed to be sunny for a couple of hours. The water was piping hot and
we rarely had to supplement the panels with the immersion heater.

Installation was expensive, and it would probably have taken us 5 to 10
years to recoup our outlay. We moved before that happened, and the
solar
panels were a major selling point.

If I had the money now I'd do it again.

DHW probably accounts for maybe 60 quid a year fuel costs. If the panels
cost more than £600, they were a waste of money.

That depends on how much hot water you want though, doesn't it. I have
a large family and we spend considerably more than £60 a year heating
water for laundry and personal hygiene. Our expenses will reduce as the
children leave home, but that's not going to happen for a few years yet.

£60 will give you about 3 ton of water at 70C using electricity or about 10
ton with gas.
That will run a shower for about 350 hours.

Washing machines tend to use little hot water even if it has hot fill.

R D S wrote:
I have been thinking about getting a solar panel to keep a fridge runnning
and keep a battery charged while camping.
Has anyone any experience/opinions?

Also with energy prices being the way they are has anyone gone further than
this and installed solar in the home? Likewise with wind, a local electrical
supplier reckoned he could get me a 2kw turbine for approx £1500. At one
point I would have thought alternative power was prohibitively expensive but
now it looks as though it may sense.


Did anyone else notice the story that solar wind might have blown life
from Venus to Earth?

(What a difference a slash makes.)

--
Rod

Hypothyroidism is a seriously debilitating condition with an insidious
onset.
Although common it frequently goes undiagnosed.
www.thyromind.info www.thyroiduk.org www.altsupportthyroid.org

In article ,
John Rumm writes:
Bob Eager wrote:
On Sun, 27 Jul 2008 21:01:40 UTC, "Dave Liquorice"
wrote:

On 27 Jul 2008 18:14:10 GMT, Andrew Gabriel wrote:

I have a couple and have serviced several for other people. They all
contain the same peltier device, which is rated 5.5A at car battery
charging voltage. There maybe some larger cool boxes with two devices
in them.
Fairy Nuff, I was going from memory of reading the rating plates... Still
5.5A @ 14v is still the best part of 80W and bear in mind that 120W panel
will only do that in bright, full, sunshine... You'll probably still need
one that size to ensure that you have enough power when it's not full
bright sushine. And what about night time...

Not much extra, but there's usually a fan as well.

I have a small wine fridge that uses this type of cooler and fan. Rated
about 75W IIRC. The main limitation is it can only drop about 15 degrees
below ambient - which means it is only going down to 10 or 11 degrees at
the moment.

That's probably down to the insulation of the fridge.
Peltier devices can do more, although not having much
heat pump capacity compared to a compressor fridge, it
will take them quite a long time to cool down bottles.
Heat pump capacity tends to be just under than their
power consumption, but a lot of the cheaper circuits
just turn them on and off with no proportional control,
in which case they leak significant heat back in.
One of mine will carry on powering the fan for a couple
of minutes after you disconnect the supply, which it's
doing by using the temperature differential across it
to generate electricity as a thermocouple, but in
doing so is leaking heat into the fridge even faster
than it would just by conduction. Some don't have any
temperature control and just run the device continuously.

In repairing these fridges, I would say the main issue
is they aren't designed for continuous operation, but
just occasional use, e.g. a couple of weeks a year,
in which case you might get 10 years out of them. With
continuous use, they seem to last around 6 months.
There are 3 common failures:
Peltier device corrodes because cold side is not well
enough protected against condensation. You can buy
sealed ones which aren't that much more expensive, but
these cheaply built fridges don't use those.
Fan motor dies (brushes give up). I've doctored a few
fridges to take a standard PC fan, which lasts much
longer.
12V power connector burns out -- they aren't of a
suitable quality to take 5A and keep contact resistance
low enough long term not to overheat.
A few other one-offs such as a signal transistor
shorting on the thermostat control board so the unit
ran continuously, and I had one quite new peltier
device which burned out on the last junction - I
managed to solder a thin wire across that one so all
the others would continue working.

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

On 2008-07-29 18:10:34 +0100, Fran said:

The Natural Philosopher said...
R D S wrote:
I have been thinking about getting a solar panel to keep a fridge runnning
and keep a battery charged while camping.
Has anyone any experience/opinions?

Also with energy prices being the way they are has anyone gone further than
this and installed solar in the home? Likewise with wind, a local electrical
supplier reckoned he could get me a 2kw turbine for approx £1500. At one
point I would have thought alternative power was prohibitively expensive but
now it looks as though it may sense.


Neither wind nor solar make any real economic sense in a domestic
situation in the UK..

Solar panels to heat water make a lot of very real economic sense - but
it's a long term investment.

How long of a long term investment?

Is there a full return before replacement is required?



I can't recall the exact figures now, but
I think the solar water heating system I had in Cardiff cost something
in the region of £3,000 to install around 10 years ago. By no stretch
of the imagination is that 'cheap'; however it will have paid for itself
within a few decades, even in the UK.

Will the system remain in a good state of repair and function without
additional costs for these several decades?



Most people don't want to wait
that long to see a return on their investment (and who shall blame
them), so they don't see solar water heating as a viable choice. I have
a large family, and we use a lot of hot water. For us, it's viable;

How do you know?


for
a single person or a couple with maybe one or two children it might not
be. Then again, they wouldn't need such a large system as we did, so
who knows.

Exactly. Who knows? Do you have figures?



As I've said elsewhere, if I had the capital to have a
similar installation in the house I live in now, I wouldn't hesitate to
say yes. If I had the skills to install it myself it would have been
done as soon as we moved here.

It's easy to spend capital if you have it. Anybody can do that because
it seems like a good idea at the time and especially if the salesman
thinks so too.

On 2008-07-29 22:14:34 +0100, Rod said:

R D S wrote:
I have been thinking about getting a solar panel to keep a fridge
runnning and keep a battery charged while camping.
Has anyone any experience/opinions?

Also with energy prices being the way they are has anyone gone further
than this and installed solar in the home? Likewise with wind, a local
electrical supplier reckoned he could get me a 2kw turbine for approx
£1500. At one point I would have thought alternative power was
prohibitively expensive but now it looks as though it may sense.

Did anyone else notice the story that solar wind might have blown life
from Venus to Earth?

(What a difference a slash makes.)

I tend to find that's the case after a few beers.....

The Natural Philosopher wrote:

With dynamo dave, nice try == 'I think you got me there, right on target'


Bang on!

On Tue, 29 Jul 2008 07:36:14 +0100, "Cerumen"
wrote:

On Sun, 27 Jul 2008 11:49:57 +0100, R D S wrote:

I have been thinking about getting a solar panel to keep a fridge
runnning and keep a battery charged while camping.
It'll have to be a *big* (expensive) photovoltaic panel to run a fridge
even under bright sunlight conditions.

Not a caravan fridge!

That depends if it's a peltier type which uses a lot of power or the more
expensive but lower consumption compressor type.

Other way round I would have thought? I would not have expected many
compressors to run on 75W or less...

I have a 12 volt compressor that runs on 3 amps and of course it has a
thermostat so is not continuously pulling power as peltier units do.
According to the manual to maintain 5C at ambient 20C it runs 10% of the
time

I also have a small compressor fridge/freezer, and can echo your
findings. It is a Waeco CF18 and my measurements showed that:

From 20C ambient temp, it got down to 5C in less than 5 minutes.

From that point, to maintain 5C, the compressor was operating for an
average of 1.5 minutes ON, followed by an average of 15 minutes OFF.
Which is very close to(slightly better than) your own 10% running time
figure!

The current draw while running was measured at approx 4 amps from a
small 12v lead acid battery.

I make that 48 watts for 2.25 hours per 24, or 108 watt hours per day.
Compared with 1440 watt hours per day for Peltier, or 2304 watt hours
per day for an absorption fridge on 12v. Unless my maths are wildly
out!

So I reckon that's doable with a reasonable PV panel and a small
lead/acid battery to carry it through the night and overcast days.

Obviously if I turn up the thermostat until the box becomes a freezer
at -20C(which it will do) then the watt hours goes up. But I didn't
carry out a test for that use, as it would not be the main function of
the CF18 in a camping role. As a freezer it's great for shopping for
frozen food and not having to rush home before the ice cream melts (

HTH

Neil

(Reply via NG please)

On 29 Jul, 18:16, Fran wrote:

That depends on how much hot water you want though, doesn't it. *I have
a large family and we spend considerably more than £60 a year heating
water for laundry and personal hygiene. *

How do you know? How are you measuring this? With gas in particular,
it's hard to split DHW costs from space heating.

Fran wrote:
The Natural Philosopher said...
Fran wrote:
R D S said...
Also with energy prices being the way they are has anyone gone further than
this and installed solar in the home?

Yes. At our last house (SE Wales) we had solar panels in the roof for
heating water, and they were fabulous. It didn't need to be hot; it just
needed to be sunny for a couple of hours. The water was piping hot and
we rarely had to supplement the panels with the immersion heater.

Installation was expensive, and it would probably have taken us 5 to 10
years to recoup our outlay. We moved before that happened, and the solar
panels were a major selling point.

If I had the money now I'd do it again.

DHW probably accounts for maybe 60 quid a year fuel costs. If the panels
cost more than £600, they were a waste of money.

That depends on how much hot water you want though, doesn't it. I have
a large family and we spend considerably more than £60 a year heating
water for laundry and personal hygiene. Our expenses will reduce as the
children leave home, but that's not going to happen for a few years yet.


Well, in the UK you can get about 200 quid return annually on 4 sq
meters of panel, used absolutely optimally. Mostly in the summer.

That was the calc I did based on the manufacturers own figures for
average insolation.

Its up to you as to whether thats worth 4 grand of installation. It
represents 5% ROI. you can get more han that leaving the money in the bank..

Andy Dingley said...
On 29 Jul, 18:16, Fran wrote:

That depends on how much hot water you want though, doesn't it. =A0I have
a large family and we spend considerably more than =A360 a year heating
water for laundry and personal hygiene. =A0

How do you know? How are you measuring this? With gas in particular,
it's hard to split DHW costs from space heating.

My central heating and water are heated by different systems.

--
Fran
To email me see 'from' in headers; use your net know-how to find the
domain, and put my real name in front thereof.

"Neil" wrote in message
...
On Tue, 29 Jul 2008 07:36:14 +0100, "Cerumen"
wrote:

Somebody said
Other way round I would have thought? I would not have expected many
compressors to run on 75W or less...
I said
I have a 12 volt compressor that runs on 3 amps and of course it has a
thermostat so is not continuously pulling power as peltier units do.
According to the manual to maintain 5C at ambient 20C it runs 10% of the
time

I also have a small compressor fridge/freezer, and can echo your
findings. It is a Waeco CF18 and my measurements showed that:

From 20C ambient temp, it got down to 5C in less than 5 minutes.

From that point, to maintain 5C, the compressor was operating for an
average of 1.5 minutes ON, followed by an average of 15 minutes OFF.
Which is very close to(slightly better than) your own 10% running time
figure!

I have the same model and was quoting the manufacturers figures and am glad
to hear they are confirmed by your tests, I have a very large leisure
battery and a 60 watt solar panel and am indeed hoping that the combination
will suffice for almost continual running of the unit.

--
Chris, (on tour)
Intellect is invisible to the man who has none.
Schopenhauer

"AJH" wrote in message
...


What ~20kW(t) combis can take a warm inlet? Can a thermostatic blender
valve reduce temperatures to 50C, before or after the combi?

Yes.