In uk.d-i-y raden wrote:
In message , Eric Sears
writes
Of course, if the panels were for space heating, you might want the
greatest input in the morning, in which case the east facing roof
might be better. There are a number of factors to consider.

Like ...

what time the sun rises in winter, how big a thermal store you would
need to store sufficient heat overnight

it's just not very realistic for heating

Well...

I think the usual assumption is that the building will have significant
thermal mass internally, in the form of an insulated concrete slab, or
something.

On Sat, OldNick wrote:

Well, having done a few quick calcs, I tend to agree, unless you had a
HUGE heating panel to get it active the next morning.

If solar heat is wanted at 0700 in a certain room,
an east facing window wall might be better than any
panels. There is nothing lower cost than ordinary
window glass.
My only kitchen outside wall faces SSW, and
in the afternoon the window makes almost heat as
a 1000 watt baseboard heater, and the window is
a little over a square meter.

With fuel prices apparently retaining the
high prices, there could be a huge market for
things like solar air heaters for inside windows,
just a decorative black pattern or simple venetian
blinds black on one side and white on the other.

Many heating panels and heaters are hyped
as radiant heat feels warmer even if the air is not
as warm, and the same goes for sunshine, except
sunshine is free (when it shines), and it can heat
the air just as well as the electric panels.

A window can provide about 5 times the
energy as PV panels of the same area, and that
is a lot, and it also makes PV seem not all that
expensive considering what electricity can do,
it is cheap grid power that makes PV seem
expensive.

Joe Fischer

On Sat, 18 Nov 2006 08:09:03 +0800, OldNick
wrote:

Actually I am not sure I _do_ agree. Still interested in your basis.

On Fri, 17 Nov 2006 22:12:22 GMT, raden wrote:

Well, having done a few quick calcs, I tend to agree, unless you had a
HUGE heating panel to get it active the next morning.

However, I would be interested in your calcs and figures, as you seem
to feel strongly about this G

Like ...

what time the sun rises in winter, how big a thermal store you would
need to store sufficient heat overnight

it's just not very realistic for heating

In message , OldNick
writes
On Fri, 17 Nov 2006 22:12:22 GMT, raden wrote:

Well, having done a few quick calcs, I tend to agree, unless you had a
HUGE heating panel to get it active the next morning.

However, I would be interested in your calcs and figures, as you seem
to feel strongly about this G

(Look ... a contextual reply - the post has a chance to flow)

I have just had a run in with a company who ripped off my parents.
Having just done a "fag packet" response, they freely admitted that
solar central heating is a non starter for the reasons I stated below
(which, if you hadn't top posted would have been in the correct place to
quote)

I haven't done any detailed calcs, but they obviously have


Like ...

what time the sun rises in winter, how big a thermal store you would
need to store sufficient heat overnight

it's just not very realistic for heating


--
geoff

In message , Ian
Stirling writes
In uk.d-i-y raden wrote:
In message , Eric Sears
writes
Of course, if the panels were for space heating, you might want the
greatest input in the morning, in which case the east facing roof
might be better. There are a number of factors to consider.

Like ...

what time the sun rises in winter, how big a thermal store you would
need to store sufficient heat overnight

it's just not very realistic for heating

Well...

I think the usual assumption is that the building will have significant
thermal mass internally, in the form of an insulated concrete slab, or
something.

Possibly not very comforting at 7 am in the morning in december

--
geoff

In message Esr7h.750$J5.99@trnddc04, SJC writes
You seem to be so sure of yourself, but you are so wrong.
Look up fluid source heat pumps with solar...get a clue.

Sorry top posting dork with a clue (so you reckon)

fluid source heat pumps are not part of your average solar heating
system here

I presume you're a septic




"raden" wrote in message
...
In message ppk7h.30$JQ.26@trnddc06, SJC writes
Solar thermal panels for space heating is one of the ways we can
save lots of fossil fuels in the future.

Sorry, this is UK.d-i-y, not alt.bad jokes
as practical, as they say, as a chocolate teapot
where are you going to get meaningful heat from at 7am ?
the best source, I would suggest, would be the hot air emanating
from the sales rep
-- geoff

--
geoff

In message , raden
writes
In message , Curious
writes

"Will" wrote:
We moved into our two storey, reconstituted stone-built, pitched-roof
house in April.

We decided early on to get as much of our energy as possible from
renewables.

A couple of weeks ago we signed up for a solar heating system. I've
looked at a few and this seems like a very good system.

Watchdog 'did' the solar energy industry on BBC 1 last Tuesday evening.
Their conclusions were that there a lot of rogue companies, the estimates
for equipment and installation are very inflated (£12,000 in one case for a
non-working system), the claimed energy benefits are often very exaggerated,
the salesmen talk a lot of dishonest rubbish, and a lot of properties are
not suitable. My understanding is that the panels need to be mounted on a
south-facing aspect. Got a long bargepole?


We also had a discussion in here following my father having signed up
to such a system

This was £7000

Say a payback period of 10 years being reasonable, it has to save £700
/ year to pay itself back. Given that it's only saving (optimistically
) 70% of hot water, not central heating or gas for cooking, it's
patently impossible for it to be viable

Yes, though pay back time is not the only reason people invest in
things.

What's the pay back time on a new car or a new kitchen ?

A better question is probably 'could he have got a better deal ?'.

It's hard to know that without knowing the details of the site, the size
of the system etc, but the very cheapest systems we do are flat plat
2sqm collectors which under a local authority scheme are a bit over
£2,000. At the other end of the domestic scale, we did a 7.2sqm
evacuated tube system we did last week was £3,700 ex VAT, ex cylinder
change. Guess which was better value.

The main overhead is not buying the panels, it's getting people on site,
running the pipes and getting access to the roof with reasonable safety.


Cheers, J/.
--
John Beardmore

In message ppk7h.30$JQ.26@trnddc06, SJC writes

Solar thermal panels for space heating is one of the ways we can
save lots of fossil fuels in the future.

I really doubt it !


Cheers, J/.
--
John Beardmore

In message Esr7h.750$J5.99@trnddc04, SJC writes

You seem to be so sure of yourself, but you are so wrong.
Look up fluid source heat pumps with solar...get a clue.

OK, but solar is just one of the many things that you can plug onto the
front of a heat pump and heat store set, and not necessarily the most
appropriate in many circumstances.

Presumably if the collector is going to run cold there won't be any
advantage to putting it in a glazed insulated box, but if you run it
when the sun isn't shining it reduces to an air source heat pump, and
these tend to have crap coefficients of performance when its cold
outside compared to ground source and water source.

Or did you have some other arrangement in mind ?


Cheers, J/.
--
John Beardmore

In message , Ian
Stirling writes
In uk.d-i-y raden wrote:
In message , Eric Sears
writes

I think the usual assumption is that the building will have significant
thermal mass internally, in the form of an insulated concrete slab, or
something.



That's not a standard feature of the solar water heating systems we
install. You are getting into the realm of the Hockerton Housing
Project design strategy here, but this has been criticised because of
the environmental impact if making the concrete. Ultra low thermal
capacity buildings also have something to commend them as long as they
can dump heat when required.


Cheers, J/.
--
John Beardmore

In message , Joe Fischer
writes
On 16 Nov "Will" wrote:

If this is for space heating,

Optimising the orientation is similar for space heating and SDHW
presumably ?


then both the east and
west facing slopes are no good unless the panels are mounted
at a complex angle so that they face south and up at an angle
according to latitude (to get more heat in winter than summer,
plus 23 degrees, which at north 50 degrees, approaches
vertical).

The heat gathered by a panel also depends on the area. In the UK panels
are generally mounted flat to roof, partly because of aesthetics, partly
because it reduces the chance of the wind ripping a panel off, and
partly because adding is more area is cheaper than making a complex
mounting.


Am I wrong? The alternative, according to the surveyor, would be double
the number of panels with half on the east pitch and the other on the
west.
Will.

For a millionaire, sure.

As explained elsewhere in this thread it need not make things hugely
more expensive.


But the type of panels might make a difference,
air panels without storage might heat certain rooms,
like the kitchen and bath in the morning, and other
rooms later in the day.

Hmmm... Hard to get in the UK.


Drain-down water panels with thermal storage
really should be tracking panels to get the most heat, and
tracking is not implemented as much as it should be.

See above. Not sure why you restrict this comment to
drain-back/down though ?


In general, east and west facing roof slopes
are not good for solar water heating unless the pitch
is shallow, and the panels are angled to the south

Not sure that they are so bad if you do the sums.


The roof pitch should be ignored, and the
panels mounted so they get the most direct sun,



I started out thinking that, but clients and planners have slowly ground
me down.


Cheers, J/.
--
John Beardmore

In message , Steve Firth
writes
On Fri, 17 Nov 2006 12:58:52 -0000, Mary Fisher wrote:

Your observations about the appearance of the panels also refers really to
the style of low-efficiency flat panel that you favour.



Ow ! Pass the tin opener and that huge can of worms !!


Cheers, J/.
--
John Beardmore

In message , Joe Fischer
writes

On the west slope roof there would be zero efficiency
until nearly noon, even if the panels have the north edge
of each higher than the south edge with the panels spaced
wide apart so they don't shade each other.

Due west certainly isn't great, but they'll go on working into the
evening longer, and our measurements of panels 45 degrees west of south
show useful heat gain from 9 am on sunny summer days.


The big advantage of the south facing wall mount
is the near optimum efficiency in winter, with the
possibility of extra reflections to exceed 100 percent
rating of the panels, and the reduction of thermal
energy in summer.

Hmmm... Little snow here, and only a few polished aluminium
driveways...


Cheers, J/.
--
John Beardmore

In message , Toby Kelsey
writes
Joe Fischer wrote:

Is overheating a big issue?

Not in the UK.


Could you automatically cover the panels?

Generally no need, and other ways to deal with overheating.


Or the circulation and heat transfer may be
faster in a vertical orientation.

Are you assuming a convection driven primary circuit.


It's better to do a direct comparison in the
field if possible.

See the SPF web site.


And the same for the east side after noon, and with the poor angle you would
probably get less than 1/4th the normal heating effect.

Depends on the roof pitch.


Cheers, J/.
--
John Beardmore

In message , Richard Bates
writes

1.Do not do anything until you have looked at Navitron's website.

Agreed, though I don't think their tubes are Clear Skies / LCBP
approved.


2. Solar panels do not have to be high up - I know at least one geezer who
has them at ground level and another who has one on his garage.

Yes.


3. Do not believe ignoramuses who suggest that you will not get much heat -
that did apply to the old flat panel stuff, still being sold by B&Q, but the
vacuum tubes now being used on the continent are vastly superior. I recently
went to a demo and noted a cylinder water temperature of 48 c being obtained
on a relatively cloudy and cool day.

Yes, though I've seen the same with good flat plat collectors, indeed
I've seen a Zen 28S collector with snow on the bottom third of it have a
temperature at the top of 116 centigrade in 3pm milky spring afternoon
sunlight with thin cloud.


I am reliably advised that on a warm
summers day, the tube manifold can reach well over 100 c and hence so much
heat is being soaked up that one can have 3 to 4 free baths

Yes.


and still have
to dump excess heat into a loft radiator - that's how good they are.

Not quite sure that you'd need a rad. Other ways to skin that cat.


4. If you have already signed up and paid a deposit for a flat panel system
do your best to get out of it.

Agreed.


5. I will probably be putting in a Navitron system myself soon with help
from plumber brother for around £900.

What area ?


The B & Q deal for £1500 is a total
rip off and the energy savings will take at least 15 years to recover.

Agreed ! And don't even get me started on their '10 year safe working
life' wind turbines. See for example

http://www.scoraigwind.com/citywinds/index.htm

and

http://www.warwickwindtrials.org.uk/


If anybody is curious about this I can also pass on copies of a report
from CREST looking at urban wind turbines.

It seems to me that B&Q risk a backlash from their consumers if the kit
doesn't recover its costs or make up for the environmental impact of the
manufacturing process.


Cheers, J/.
--
John Beardmore

In message . com,
writes
Richard Bates wrote:

First, flat panels give much better ROI than vac tubes

Quick nurse - the tin opener !


Second, British winters are mostly overcast, and flat panels work ok on
indirect sun, whereas silvered evacuated tubes work a lot less
efficiently under these conditions.

What do you mean by "silvered" ?


3rd, it is all more complex than that,

Quite so !


but suffice it to say that flat
panels are very much a going concern in Britain.

Yes.


An optimally designed system would have a mix of both flat panel and
vac tube, with each heating a separate part of the system.

Yes - been there, got the T-shirt.

Really they need to be on separate primary circuits.


Flat panel
is best for mid-temp water, as it gives much more output per £/$. Vac
tube is best for the final max temp water, as it gives high output
temps that flat panels cant consistently deliver. However, the ROI on
the flat tubes will be much poorer, so spending some of the money on
flat panels will much improve total annual output.

Hmmm... Have you seen the prices of the Chinese import ETs ?

To be honest, while what you say was true 10 years ago, the difference
in cost per area is now pretty small, and the prices we quote to end
users are much the same per area for FP and ET, because while ET is
slightly more expensive, installation is easier and safer in lifting and
handling terms, if not actually quicker.


Cheers, J/.
--
John Beardmore

In message , John Beardmore
writes
) 70% of hot water, not central heating or gas for cooking, it's
patently impossible for it to be viable

Yes, though pay back time is not the only reason people invest in
things.

What's the pay back time on a new car or a new kitchen ?

No idea in your circumstances, but it is less well defined than solar

Solar panels have a reasonably well spec'd return


I don't see what my folks signed for as being economically viable

--
geoff

In message .com, Todd
writes

Will,

I too have been experimenting and trying to get all my energy from
renewables. First was to have a structure that needed a minimum of
energy. I have a simple structure with 12" thick walls filled with
fiberglass insulation.

I use no power for heating or A/C.As long as there is light outside it
is enough to serve my needs inside ... the roof has clear sections
insulated with bubble wrap.

Nice ! I know somebody who lived in an 8' by 12' shed with poly
urethane wall insulation from an old container truck, and aluminium foil
wall paper. Excellent !


But my experience with solar panels show them to be an abject failure.

1. Cost is high. My 165W high voltage panel cost over $700

Think you were robbed !


2. My 165W panel has never delivered more than 90W

Hmmm... We generally get pretty near peak output for a few hours a year
even without OPT regulators.


3. The panel can only supply current about 5 hrs per day

About right.


4. The panel only supply useful power on sunny days



Depends how much you need, but yes, what did you expect ?


5. The panel loses lots of efficiency on hot days

Yes - though it doesn't seem to be much of a problem on open frames in
the UK.


6. Any shadow on the panel is the same as complete panel in shade

Pretty much.


7. Can lose 30% or more if panel is not perpendicular to sun's rays

Yes. Do the sums.


8. Charge controller must be very efficient or more is lost

Not hard.


9. For anything practical a huge number of panels and batteries is
necessary

Or grid connection where appropriate.


The solution I have arrived at is hybrid. I use my one panel to charge
batteries when I'm away. When away, my refrigerator is my only load
(about 120W with 30% duty cycle). My battery bank is 10 70AH car
batteries. All together they cost about as much as my 1 PV panel. I
don't use deep discharge because they are much more expensive

Look for 'leisure batteries'.


and I
haven't seen an inverter that works below 10V. Most shut down at 11.5V.

Would trash the batteries if they went lower.


My real power source is a 3hp diesel engine driving a car alternator
capable of delivering 40A. I run it on waste vegatable oil (WVO) at low
RPM (~1,000).

Good one !


I route it through the same high voltage (up to 53VDC)
charge controller that I use with the PV panel. It does a splendid job
of keeping the batteries charged and only runs 4 to 5 hours per day. It
uses hopper cooling so I get my hot water from it as well.

Interesting ! What's hopper cooling ?


Cheers, J/.
--
John Beardmore

In message , raden
writes
In message , John
Beardmore writes
) 70% of hot water, not central heating or gas for cooking, it's
patently impossible for it to be viable

Yes, though pay back time is not the only reason people invest in
things.

What's the pay back time on a new car or a new kitchen ?

No idea in your circumstances, but it is less well defined than solar

Yes - but my point is that for people to make a purchase, it need not
be defined at all !


Solar panels have a reasonably well spec'd return

Agreed, but some people buy them for other reasons.


I don't see what my folks signed for as being economically viable

No, but I think our clients divide into at least four categories.

People that want to save the world.

People that like interesting toys.

People that want to set an educational example.

People that want to save money.


All three seem worthy in one respect or another. Another category may
also creep in.

People that follow fashion.


Still - I suppose their CO2 is as bad as anybody elses, and every
little helps !


Cheers, J/.
--
John Beardmore

In uk.d-i-y John Beardmore wrote:
In message , Ian
Stirling writes
In uk.d-i-y raden wrote:
In message , Eric Sears
writes

I think the usual assumption is that the building will have significant
thermal mass internally, in the form of an insulated concrete slab, or
something.



That's not a standard feature of the solar water heating systems we
install. You are getting into the realm of the Hockerton Housing
Project design strategy here, but this has been criticised because of
the environmental impact if making the concrete. Ultra low thermal
capacity buildings also have something to commend them as long as they
can dump heat when required.

I'm not convinced it has no place - you would admittedly need a very
large additional thermal mass - a ton or two of water probably, to keep
the heating on overnight, with a 10-20C drop.

This is not of itself very expensive, though the places it can be easily
installed are of course going to be very limited.

On Sat, 18 Nov 2006 01:12:45 GMT, raden wrote:

So stop arguing about this **** and stay with your topic. I post as I
see fit, and try to make it reasonable.

Bottom posting when someone leaves the whole bloody thread on top is
in my mind the worst crime. If I have done it I don't remember.

Otherwise, unless I get sniped at I live and let live.

OK?
(which, if you hadn't top posted would have been in the correct place to
quote)

Which is very little water. A couple of cubic metres. Storage of that
water would not be difficult. Obvuously a cube or sphere and all one
lump is best for losses. That can be a nuisance.

I'm not convinced it has no place - you would admittedly need a very
large additional thermal mass - a ton or two of water probably, to keep
the heating on overnight, with a 10-20C drop.

This is not of itself very expensive, though the places it can be easily
installed are of course going to be very limited.

John Beardmore wrote:
In message , raden
writes
In message , John
Beardmore writes

What's the pay back time on a new car or a new kitchen ?

No idea in your circumstances, but it is less well defined than solar

Yes - but my point is that for people to make a purchase, it need not
be defined at all !


Solar panels have a reasonably well spec'd return

Agreed, but some people buy them for other reasons.


I don't see what my folks signed for as being economically viable

No, but I think our clients divide into at least four categories.

People that want to save the world.

People that like interesting toys.

People that want to set an educational example.

People that want to save money.


All three seem worthy in one respect or another.


The world savers will achieve nothing by fitting solar dhw, as its
counterproductive. To understand that they'd need to see the connection
between supply & fit cost and the energy input in supplying and fitting
it. Very briefly, money is a form of measure of energy. Without
financial payback It just wont pay back in energy terms either.

Same is true for those seeking money payback. There are some systems
that do pay, but still too many dont.

As for education, I doubt theres a single person on the planet -
counting only those in any position to pay for a solar system - who
will be educated to any significant extent by seeing 1 more solar
system in the world.

There are well desgined systems that pay back, but most purchases still
come down to those that fail to properly understand the reasons for
purchase.


NT

raden wrote:
In message ppk7h.30$JQ.26@trnddc06, SJC writes

Solar thermal panels for space heating is one of the ways we can
save lots of fossil fuels in the future.

Sorry, this is UK.d-i-y, not alt.bad jokes

as practical, as they say, as a chocolate teapot

where are you going to get meaningful heat from at 7am ?

from the gas CH system. Why do you think a solar system would have to
output heat 24 hrs a day to save fuel?


NT

John Beardmore wrote:
In message ppk7h.30$JQ.26@trnddc06, SJC writes

Solar thermal panels for space heating is one of the ways we can
save lots of fossil fuels in the future.

I really doubt it !


Cheers, J/.

Whys that?

http://www.builditsolar.com/
&
http://www.builditsolar.com/Projects...ce_Heating.htm


NT

raden wrote:
In message , Eric Sears
writes

Of course, if the panels were for space heating, you might want the
greatest input in the morning, in which case the east facing roof
might be better. There are a number of factors to consider.

Like ...

what time the sun rises in winter, how big a thermal store you would
need to store sufficient heat overnight

it's just not very realistic for heating

A typical brick or block house should be big enough, assuming its
decently insulated. Mine doesnt lose a whole lot of temp overnight. One
simply sets the solar heating stat to above the temp of the gas CH,
make use of that comfort zone.


NT

raden wrote:

(Look ... a contextual reply - the post has a chance to flow)

I have just had a run in with a company who ripped off my parents.
Having just done a "fag packet" response, they freely admitted that
solar central heating is a non starter for the reasons I stated below
(which, if you hadn't top posted would have been in the correct place to
quote)

I haven't done any detailed calcs, but they obviously have

Correction, they admitted that their completely unsuitable designed
system was a nonstarter for CH - that I would 100% agree with.


NT

Ian Stirling wrote:
In uk.d-i-y John Beardmore wrote:
In message , Ian
Stirling writes

I think the usual assumption is that the building will have significant
thermal mass internally, in the form of an insulated concrete slab, or
something.



That's not a standard feature of the solar water heating systems we
install. You are getting into the realm of the Hockerton Housing
Project design strategy here, but this has been criticised because of
the environmental impact if making the concrete. Ultra low thermal
capacity buildings also have something to commend them as long as they
can dump heat when required.

I'm not convinced it has no place - you would admittedly need a very
large additional thermal mass - a ton or two of water probably, to keep
the heating on overnight, with a 10-20C drop.

This is not of itself very expensive, though the places it can be easily
installed are of course going to be very limited.

This looks very like an assumption trap to me.

A decently designed solar space heating system would not be using water
in the first place. Picking hydronic for space heating is pretty much a
design death blow.

Secondly, an entirely different method would be used to maintain temp
after dark. There is a comfort zone, not just one fixed temp at which
people are cosy. Heat to as high in that zone as solar power provides,
and you have n hours after sundown of sufficient warmth. N depends on
design details.


NT

On 2006-11-18 02:51:00 +0000, John Beardmore said:

In message , raden
writes


Solar panels have a reasonably well spec'd return

Agreed, but some people buy them for other reasons.


I don't see what my folks signed for as being economically viable

No, but I think our clients divide into at least four categories.

People that want to save the world.

People that like interesting toys.

People that want to set an educational example.

People that want to save money.


All three seem worthy in one respect or another. Another category may
also creep in.

People that follow fashion.

I think that that is probably a fair assessment of reasons to purchase.

I wonder how much the sales people focus on any of the others than the
possibility that the customer might save money. Maybe.

In terms of worthiness, I suppose it depends on what one means by worthiness.
Incrementalism is a poor argument at the best of times and one might have
hoped that people would be smart enough to realise that they won't save
the world
through installing a solar panel.





Still - I suppose their CO2 is as bad as anybody elses, and every
little helps !


Well, hmmm... isn't that Tesco's tag line as they report their latest
set of profits?

All of this is focus in completely the wrong area. All the time that
the U.S. continues
not to make much of a federal effort in terms of emissions control and
China is opening
a new coal fired power station weekly, all of this other stuff makes so
little difference
that it is a waste of time on environmental grounds. I would
suggest that efforts are turned
towards dealing with the major issues, and that does not include
getting GW Bush to sign up
for silly politicised nonsense like Kyoto, but for serious efforts for change.

John Beardmore wrote:
In message . com,
writes
Richard Bates wrote:

First, flat panels give much better ROI than vac tubes

Quick nurse - the tin opener !

heh, yes


Second, British winters are mostly overcast, and flat panels work ok on
indirect sun, whereas silvered evacuated tubes work a lot less
efficiently under these conditions.

What do you mean by "silvered" ?

outer envelope part silvered to concentrate sun onto the inner tube.


3rd, it is all more complex than that,

Quite so !


but suffice it to say that flat
panels are very much a going concern in Britain.

Yes.


An optimally designed system would have a mix of both flat panel and
vac tube, with each heating a separate part of the system.

Yes - been there, got the T-shirt.

Really they need to be on separate primary circuits.

Yes, thats what I mean. The FP makes warm water, then this goes to the
final high temp circuit with ETs.


Flat panel
is best for mid-temp water, as it gives much more output per £/$. Vac
tube is best for the final max temp water, as it gives high output
temps that flat panels cant consistently deliver. However, the ROI on
the flat tubes will be much poorer, so spending some of the money on
flat panels will much improve total annual output.

Hmmm... Have you seen the prices of the Chinese import ETs ?

To be honest, while what you say was true 10 years ago, the difference
in cost per area is now pretty small, and the prices we quote to end
users are much the same per area for FP and ET, because while ET is
slightly more expensive, installation is easier and safer in lifting and
handling terms, if not actually quicker.


Cheers, J/.

I suppose thats true of professional installs on rooftops, I'm thinking
more of diy installs, where the cost for a decent area of tubes is way
above that of flat panels, and makes a real difference to ROI figures.

Flat panels can give much better performance at ground level or on a
flat roof, as 1 or 2 reflectors are easily added to give anything from
1-2 suns. Equipment on a flat roof ditto, mounting the panel either at
an angle from roof to wall or else flat on the wall, reflector below.

I guess the ultimate is a 3 zone system, with a drain heat exchanger
providing the 1st stage of heat input, flat panels the 2nd (with
reflectors for best performance), and vac tubes the last. Perhaps one
day the equipment will be cheap enough for this to be the done thing.


NT

On 17 Nov 2006 wrote:

A typical brick or block house should be big enough, assuming its
decently insulated. Mine doesnt lose a whole lot of temp overnight. One
simply sets the solar heating stat to above the temp of the gas CH,
make use of that comfort zone.
NT

A house built for solar heat, or any type of efficient
heating, should have a triple wall construction, in contrast
to present common designs, a well insulated outer wall,
a thick masonry wall (concrete block), and either face brick
on the inside, or furring strips and plaster (drywall).
There are many concrete block houses, but almost
all have the block on the outside.

This is as bad as all the industrial buildings having
north facing windows.

Joe Fischer

On Sat, Andy Hall wrote:

All of this is focus in completely the wrong area. All the time that
the U.S. continues
not to make much of a federal effort in terms of emissions control

The federal government doesn't own many fossil
fuel power plants. But both the coal industry and the
power plants have been spending fortunes cleaning up
coal to reduce pollution.

and
China is opening
a new coal fired power station weekly, all of this other stuff makes so
little difference
that it is a waste of time on environmental grounds.

There is a lot of USA bashing, but other than the
French nuclear industry, I see very little about what other
countries are doing to reduce CO2 emissions.

I would
suggest that efforts are turned
towards dealing with the major issues, and that does not include
getting GW Bush to sign up
for silly politicised nonsense like Kyoto, but for serious efforts for change.

Actually, the only really viable change can only come
from alcohol production from bio sources, there can be some
CO2 sequestration but not on the scale that would be needed
to make a difference.

Even if the case for CO2 induced global warming could
be demonstrated clearly and proven beyond doubt, there is
nothing much that can be done without people freezing or
giving up income.

There are ways to reduce energy use, like having
people move close to where they work, but there isn't
a power that can accomplish that.

Retired people could move closer to the equator,
and many do, but most can't afford to.

Solar energy is primarily a sub-tropic region
energy source, and is not being guided in the right
direction. Solar panels on the roof, especially
retrofitted, is not a good idea, on walls facing the
equator is a much better idea.
Just one leak caused by installing panels
on the roof, and all the savings for 10 years is lost,
roofs don't usually last more than 15 or 20 years,
so installing panels on a 10 year old roof is not
a good idea.

Bee-hive apartments may be energy efficient
with less outside walls, but not everybody is willing
to live in an apartment.
Really old buildings may be the most difficult
to heat, and the trend in the US is larger homes,
so nothing is moving in the right direction to save
energy.
But it is not the US that is most at risk,
countries with no energy reserves are in a crisis
condition, and have few options but to continue
to import almost all their energy needs.

It seems evident that for solar energy to
be affordable by the masses, there has to be a
large Do-it-Yourself effort, with the right ideas,
and a modular approach that can be done a
little at a time is better both for time, and the
up front cost.

Joe Fischer

On Sat, 18 Nov 2006 04:17:39 -0500, Joe Fischer
wrote:

Well, coming from Australia I certainly cannot talk. We are right up
there for energy usage.

But a lot of countries might be saying "well we don't need to clean up
so much because we simply use /produce less."

There is a lot of USA bashing, but other than the
French nuclear industry, I see very little about what other
countries are doing to reduce CO2 emissions.

Joe Fischer wrote:
A house built for solar heat, or any type of efficient
heating, should have a triple wall construction, in contrast
to present common designs, a well insulated outer wall,
a thick masonry wall (concrete block), and either face brick
on the inside, or furring strips and plaster (drywall).
There are many concrete block houses, but almost
all have the block on the outside.

Perhaps because the block is much more durable and resistant to
the weather than insulation. Myself, I would have to run the numbers
but I have a feeling that if you have a well (even super) insulated
house then the typical contents of that house, drywall, furniture,
collections of brick a brack, would have more than enough thermal
mass to do the job.

This is as bad as all the industrial buildings having
north facing windows.

There is a good reason for this. South facing windows would have
direct sunlight shining in and this would be much too intense
and uneven for work. North facing windows, if there are enough
of them, provide more than enough diffuse light without 'hot spots'.

Anthony

"Joe Fischer" wrote in message
...


snip

roofs don't usually last more than 15 or 20 years,

WHAT?

Our house was built in 1937 and has its original roof (plus solar water
heating panel). Most of the others houses on this estate are the same, the
few who have newer roofs have replaced them for reasons other than failure.

Mary

Joe Fischer wrote:
On Sat, Andy Hall wrote:

All of this is focus in completely the wrong area. All the time that
the U.S. continues
not to make much of a federal effort in terms of emissions control

The federal government doesn't own many fossil
fuel power plants.

The US govt does control policy/law though.

But both the coal industry and the
power plants have been spending fortunes cleaning up
coal to reduce pollution.

Less toxins is nice, but wont have any effect on CO2 output tho.


and
China is opening
a new coal fired power station weekly, all of this other stuff makes so
little difference
that it is a waste of time on environmental grounds.

There is a lot of USA bashing, but other than the
French nuclear industry, I see very little about what other
countries are doing to reduce CO2 emissions.

This is because US uses a lot more energy per person than other
coutries. Where the european drive is more toward efficient use of more
limited resources, the US approach is still generally excess and waste.



Even if the case for CO2 induced global warming could
be demonstrated clearly and proven beyond doubt, there is
nothing much that can be done without people freezing or
giving up income.

Oh, there is.

First bear in mind convincing evidence would cause many more people to
make greener decisions.

1 National new build energy policies can switch from gas and coal to
nuke and wind.
2 New build houses can be required to have 6" insulation instead of 2".
Saves people money
3 New CH systems can be required to have a programmer for each room, so
time and temp can be set for each. Saves people money
4 A quality BS can be set up for cfls so the decent ones are recognised
by buyers, and marked properly instead of the nonsense equivalence
claims now common. People knowing they can buy quality cfls would mean
many more sales. Saves people money
5 filament bulbs can be taxed to prod people to move to cfl - the
amount of tax would be low enough not to have much real effect on
anyone's purse, and there is little need to buy filament bulbs anyway.
Moving to cfl saves money.
6 Legalise car engine conversion for greater mpg. The simplest way to
do this is to close off one or more cylinders by removing rocker arms.
Saves people money
7 Heavily tax hungry cars at point of sale. Moving people to leaner
vehicles reduces costs. Saves people money
8 Increase VED for low mpg cars (annual tax disc), while at the same
time offering a free VED bracket for the 5% highest mpg vehicles (this
would be a moving target, moved annually to keep it to the top 5%).
This could together not change total revenue, though we all know how
it'll go in practice. Saves people money by reducing total fuel
consumption.
10 Govt to offer a nice fat prize to the person who can design the best
of various categories of energy reduction equipment. Eg:
- solar space heating
- solar dhw
- any other enrgy saving tech
and so on. The requirements would include good ROI, little or minimal
maintnance, and practical diy fitting.

Theres plenty more. The main barriers are lack of genuine belief in the
need for it and general ignorance regarding energy saving options,
solar design and so on.


There are ways to reduce energy use, like having
people move close to where they work, but there isn't
a power that can accomplish that.

Fuel taxation would, but I'm not sure this would be productive anyway.
More tax incentives for home workers, making up for it with tax on
non-homers would also skew the picture and reduce energy use.


Solar energy is primarily a sub-tropic region
energy source, and is not being guided in the right
direction. Solar panels on the roof, especially
retrofitted, is not a good idea, on walls facing the
equator is a much better idea.
Just one leak caused by installing panels
on the roof, and all the savings for 10 years is lost,

Kit mounted atop single storey flat roofs has significant advantages.

FWIW its quite possible to use a controller that detects leaks and
shuts off one section of a parallelled system. This would improve
reliability, reduce ongoing costs, and extend system lifetimes. But
this is only going to be cost effective when the equipment reaches mass
production.


roofs don't usually last more than 15 or 20 years,
so installing panels on a 10 year old roof is not
a good idea.

In Britain average roof lifetime is mesured in centuries.


Bee-hive apartments may be energy efficient
with less outside walls, but not everybody is willing
to live in an apartment.

Many are though. New build programs could become more apartment block
oriented. The British planning system makes extending existing
buildings difficult to impossible, and this could also be improved.
Larger buildings house more people more energy efficiently.


Really old buildings may be the most difficult
to heat, and the trend in the US is larger homes,
so nothing is moving in the right direction to save
energy.

Its not too hard to retroinsulate old houses.


It seems evident that for solar energy to
be affordable by the masses, there has to be a
large Do-it-Yourself effort, with the right ideas,
and a modular approach that can be done a
little at a time is better both for time, and the
up front cost.

Joe Fischer

Yes, and its doable. As the real cost of energy increases, and
knowledge spreads, courtesy of the www, we see more of it being done.


NT

In article ,
"Mary Fisher" writes:

"Joe Fischer" wrote in message
...

snip

roofs don't usually last more than 15 or 20 years,

WHAT?

Our house was built in 1937 and has its original roof (plus solar water
heating panel). Most of the others houses on this estate are the same, the
few who have newer roofs have replaced them for reasons other than failure.

He's posting from the US.
In the UK, roof life between significant maintenance events has
normally been around 70 years (so you've got 1 year to go Mary;-).

It is likely that with better materials used in recent years,
roofs which are less than 70 years old will extend this period,
but we don't have figures for them yet, obviously.

--
Andrew Gabriel

Joe Fischer wrote:
On 17 Nov 2006 wrote:

A typical brick or block house should be big enough, assuming its
decently insulated. Mine doesnt lose a whole lot of temp overnight. One
simply sets the solar heating stat to above the temp of the gas CH,
make use of that comfort zone.
NT

A house built for solar heat, or any type of efficient
heating, should have a triple wall construction, in contrast
to present common designs, a well insulated outer wall,
a thick masonry wall (concrete block), and either face brick
on the inside, or furring strips and plaster (drywall).
There are many concrete block houses, but almost
all have the block on the outside.

This is as bad as all the industrial buildings having
north facing windows.

Joe Fischer

It would be a lot more material efficient to have 2 wall leafs than 3,
with the inner being thicker than the outer, eg 2.5" outer leaf, 1"
uninsulated cavity, 6" insulated cavity then 6" inner leaf. SS wall
ties would give the 2.5" leaf good stability.

Triplewall construction only gives a 2nd cavity, and this can be
achieved at far lower cost in other ways.


NT

"Andrew Gabriel" wrote in message
...
In article ,
"Mary Fisher" writes:

"Joe Fischer" wrote in message
...

snip

roofs don't usually last more than 15 or 20 years,

WHAT?

Our house was built in 1937 and has its original roof (plus solar water
heating panel). Most of the others houses on this estate are the same,
the
few who have newer roofs have replaced them for reasons other than
failure.

He's posting from the US.

And it's different there?

In the UK, roof life between significant maintenance events has
normally been around 70 years (so you've got 1 year to go Mary;-).

Ours hasn't needed any maintenence and my father back-pointed the (rosemary)
tiles when the house was new. Nothing has shifted - we keep an eye on it but
apart from a bit of flaunching round the chimney (not really the roof)
nothing needs doing.

If only the rest of the house were as good :-)

Mary

On Sat, 18 Nov 2006 08:15:43 +0000 someone who may be Andy Hall
wrote this:-

I wonder how much the sales people focus on any of the others than the
possibility that the customer might save money. Maybe.

Are you expecting those of us in favour of such things to apologise
for the way some salespeople try and sell them?

In terms of worthiness, I suppose it depends on what one means by worthiness.
Incrementalism is a poor argument at the best of times and one might have
hoped that people would be smart enough to realise that they won't save
the world through installing a solar panel.

People said much the same sort of thing to a very great man when he
took on the largest empire in the world over the salt tax. As events
proved they were wrong and the largest empire the world has ever
seen was humbled.



--
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