Solar
 

On Thu, 24 Nov 2005 14:37:41 +0000 someone who may be Peter Parry
wrote this:-

So I have measured over many years. On a cloudy, rainy summer day
the output was very low and inadequate by itself to provide hot
water. Those conditions sometimes prevailed for several days on the
run between late spring and early autumn.

Perhaps you should explain yourself a bit more.

Do you have a solar water heating system installed? If so then:

When was it installed?

What type of collector does it use, what size, facing which
direction?

How does it heat the domestic hot water; pre-heat cylinder, double
coil cylinder,...?

How is it controlled?

I may be wrong, but it sounds to me like you had one installed some
time ago and were disappointed.

Perhaps you are claiming that the comments at
http://www.solartwin.com/comments.htm are all made up?

It isn't that uncommon for such comments to be entirely made up - a
glance at any national double glazing or kitchen fitting companies
web site will provide you with examples.

If you wish to assert that about Solartwin then feel free to contact
the Trading Standards department.

However, assuming they are real, do you really think they represent
the full range of responses

No.

or do you think there is just a slight
possibility the company selling the gizmos and also publishing the
letters would only select the favourable comments to publish?

Yes.

However, unless they have been made up, the favourable ones
indicate that your absolute assertions are incorrect. Now it may be
that your assertions are correct for a particular system, but
generalising from that to absolute comments about all solar water
heating systems is not a good idea.

For a warts and all view of various forms of house size generation
http://www.sd-commission.org.uk/news...GMDMHZ-KSA3R0Z
is a good place to start.


--
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

Solar
 

On Thu, 24 Nov 2005 14:16:37 +0000 someone who may be Edgar Iredale
wrote this:-

So it's sensible to watch and wait about solar hot water until either a rise
in fuel prices or lowering costs of solar or both make the idea viable.

If you are looking at it in purely a financial way then there are
better ways to spend the money, like many other things. However,
purely looking at it in a financial way is not the only reason
people make decisions.



--
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

Solar
 

On Thu, 24 Nov 2005 13:57:23 +0000 someone who may be Peter Parry
wrote this:-

If you switch off the boiler for the summer

Who said anything about doing this?

You did

Incorrect. What I said was not running the boiler. Provided the
programming is correct the boiler will not run in the evening,
unless the solar system has not provided enough hot water during the
day. One might also run the boiler during the day sometimes, but
rather less than without solar water heating. This depends on usage
patterns, how well the collector is matched to the size of the
cylinder, how well the cylinder is matched to the household and how
well the cylinder is insulated. When the boiler is not running it is
not using gas, but remains available.

Now there are ways to design a bad solar water installation.
Cylinder too small for daily usage, cylinder not properly insulated
and a whole host of other things. In that case the boiler will run
rather a lot.



--
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

Solar
 

On Thu, 24 Nov 2005 11:28:16 +0000, Peter Parry
wrote:

On Thu, 24 Nov 2005 09:07:39 -0000, "Doctor Dribble"
wrote:



I don't believe it.

I'm sure you don't. Elementary understanding of physics and maths
has always been rather beyond your meager abilities.

If you spent £500 20 years ago and you haven't recouped
the cost? Do some sums.

I did, and it was monitored for much of its life. It saved an
average of GBP 18 per year. If the money had been put in a savings
account it would have earned far more than that.

What's the cost of energy (per kWh) that the £18/yr saving is based
upon? If based upon natural gas that could help explain why the
returns from the solar system are quite low.

Also how many people in your parents household? If only 2 it's
possible the system is oversized for their needs and they can't use
the majority of the water heated by the system.

For a four person household heating with LPG or oil where the system
can be DIY installed I'd expect the economics are quite different.

I'd be interested in a good formula for comparing money in the bank to
money spent on energy saving over a given time.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

cheers,
Pete.

Solar
 

David Hansen wrote:

On Thu, 24 Nov 2005 14:16:37 +0000 someone who may be Edgar Iredale
wrote this:-

So it's sensible to watch and wait about solar hot water until either a
rise in fuel prices or lowering costs of solar or both make the idea
viable.

If you are looking at it in purely a financial way then there are
better ways to spend the money, like many other things. However,
purely looking at it in a financial way is not the only reason
people make decisions.



Yes. But instead of saying things like "it's great fun" or "I'm doing my bit
for the Globe" or "it was that or a holiday in Spain and this seemed a
better way to spend the money" ..... the proponents seem to be claiming it
has financial advantages.

I'm pleased to discover we agree that it does not.

Edgar

Solar
 

On Thu, 24 Nov 2005 16:40:09 +0000 someone who may be Edgar Iredale
wrote this:-

Yes. But instead of saying things like "it's great fun" or "I'm doing my bit
for the Globe" or "it was that or a holiday in Spain and this seemed a
better way to spend the money" ..... the proponents seem to be claiming it
has financial advantages.

Feel free to use a search engine to call up such posts from me, or
anyone else, in this thread that make such claims.

What you will find is that people say that solar water heating is
not a short term financial investment, at least at the moment. They
may be a long term financial investment and there are other reasons
for investing in this way.

Such systems will, if designed and used properly, save money on fuel
bills. Whether such investment is worthwhile is a matter of how one
judges the capital cost against the savings over the life of the
system. Simple payback tends not to be a good measure of long term
investments, but some people like it as a measure.


--
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

Solar
 

Doctor Drivel wrote:
wrote in message

Tell us something. Why install an array of highly priced commercial
panels/tubes, plus plumbing system, plus UFH, when you could just as
well install panels that are nothing more than glazed frames with black
cloth, add holes in the wall and dampers, and harvest stacks of heat
directly without all that nonsense in the way. You'd get twice the
output for half the money.

You are on about an air heater in a conservatory. Good choice and v good.
But you need a conservatory.

a conservatory has nothing whatsoeevr to do with it. What a twit.


NT

Solar
 

Andy Dingley wrote:
On 23 Nov 2005 17:32:26 -0800, wrote:

Why install an array of highly priced commercial
panels/tubes, [...]

Because a passive system really needs to be designed into the building
when it's built (or extended).

Because a flat panel system works well in wam weather but very badly in
cold sunny weather. It may still capture plenty of solar heat, but it
also has losses too high for effective use in our climate, year-round.

then youre using the wrong type of panels. The use of multiple layers
of open weave black cloth as an absorber makes them dramatically more
efficient.

NT

Solar
 

Andy Dingley wrote:
On 23 Nov 2005 17:32:26 -0800, wrote:

Why install an array of highly priced commercial
panels/tubes, [...]

Because a passive system really needs to be designed into the building
when it's built (or extended).

not at all.

Solar
 

wrote in message
oups.com...
Doctor Drivel wrote:
wrote in message

Tell us something. Why install an array of highly priced commercial
panels/tubes, plus plumbing system, plus UFH, when you could just as
well install panels that are nothing more than glazed frames with
black
cloth, add holes in the wall and dampers, and harvest stacks of heat
directly without all that nonsense in the way. You'd get twice the
output for half the money.

You are on about an air heater in a conservatory. Good choice and v
good.
But you need a conservatory.

a conservatory has nothing whatsoeevr to do with it. What a twit.

Air heaters work best inside conservatories. What a pillock.

Solar
 

On Thu, 24 Nov 2005 16:08:15 +0000, David Hansen
wrote:

On Thu, 24 Nov 2005 14:37:41 +0000 someone who may be Peter Parry
wrote this:-

So I have measured over many years. On a cloudy, rainy summer day
the output was very low and inadequate by itself to provide hot
water. Those conditions sometimes prevailed for several days on the
run between late spring and early autumn.

Perhaps you should explain yourself a bit more.

I have, earlier in this thread, you should read it.

Do you have a solar water heating system installed? If so then:

When was it installed?

What type of collector does it use, what size, facing which
direction?

Read what I have written before when I explained all this.

How does it heat the domestic hot water; pre-heat cylinder, double
coil cylinder,...?

Double coil cylinder.

How is it controlled?

Differential thermal switching with temporal and optical feed
forward.

I may be wrong,

You are, again.

but it sounds to me like you had one installed some
time ago and were disappointed.

It was installed some time ago but using components which were very
advanced for the time (and are still on sale such as vacuum wall
collectors). Its measured performance over a decade was consistent
with that of systems researched in DTI/Pub URN 01/1202 (2001). The
control system was somewhat more complex than those on offer today
with most systems. It incorporated a unique monitoring system.

If you wish to assert that about Solartwin then feel free to contact
the Trading Standards department.

Thank you for giving permission to do that.

However, unless they have been made up, the favourable ones
indicate that your absolute assertions are incorrect.

They indicate nothing of the sort. There are people who believe in
homeopathy and gods - neither have any objective evidence to prove
their claims. My statements are based upon measurements on a system
which was in many ways more advanced than many sold today and which
utilised collector technology still advertised as "state of the art"
20 years later.

Now it may be
that your assertions are correct for a particular system, but
generalising from that to absolute comments about all solar water
heating systems is not a good idea.

It is a perfectly good idea. As Tony Briar has said the saving
achieved by modern solar water heating over conventional heating in a
house constructed to modern standards is about GBP15 per year. In
energy terms it is trivial.

For a warts and all view of various forms of house size generation
http://www.sd-commission.org.uk/news...GMDMHZ-KSA3R0Z
is a good place to start.

You must be joking. A report with not a single figure in it and in
50 pages only one small graph concerning what happens when you turn a
towel rail off? It is however certainly instructive in illustrating
how you can fool people with propaganda whilst carefully avoiding any
of the nasty facts.

"SUSTAINABLE CONSUMPTION ROUNDTABLE
Minutes of the 7th Meeting Tuesday, 7th
September 2005"

"9.45am Micro- generation report
Judith Dobbyn & Gillian Thomas, The Hub Consultants, gave a
presentation of their findings on the impact of on-site
energy generation on attitudes to and use of energy.
The findings were supplemented by potent case studies.
The research endorsed the hypothesis that home energy
generation impacts on the way energy is used in the home,
indicating that users of micro-generation became engaged
with the process and were able to make the connection
between energy and warmth in the home...

Discussion of report findings and follow-up
Members discussed how best to present the findings of the
research/case studies which illustrate the link between
attitudes and behaviours as well as the role micro-
generation can play as a catalyst of behaviour change.
Some members suggested getting these personal stories into
the public through media as they are about personal change.
However, members agreed that often consumers do not follow
the language that is used and so there is a need to be
mindful of language...

Other members suggested that as RT is principally trying to
influence Government policy, RT should use this piece of
work to influence policy makers ..."

That makes the agenda fairly clear doesn't it? Seems to have worked
on you.

Written by

Judith Dobbyn "15 years specialist experience in qualitative
research. Previous agencies include: The Value Engineers,
Diagnostics, Whalley Associates and SW one research. "

and

Gillian Thomas, "a qualitative researcher engaged in the study of the
relationship between everyday lives and mass socio-economic change."

Not a single objective fact in the whole report, no engineers
involved, no scientists involved - nothing but wooly touchy feely
waffle.

"It seems that micro-generation provides a tangible hook to engage
householders emotionally with the issue of energy use… Householders
described the sheer pleasure of creation and of self-sufficiency..."

"A teenage couple, who moved into social housing fitted with solar
water heating in Shropshire, have actively chosen to buy A-rated
appliances and investigate the environmental credentials of washable
nappies."

"pupils and teachers in all three schools are proud of their solar
panels or wind turbines, and feel inspired to live up to their new
environmental identity,"

"Households with micro-generation installed had often attributed
living credentials to their homes, most notably in the case of the
elderly widow in Kirklees with her new air source heat pump. She
deemed the heat pump to be so independent and intelligent as to
warrant being given a name."

"It means we do not waste the power station’s electricity” Girl, 7"

Is this really the level of understanding we really want people to
have? The real horror is that the bunch of dimwits who want to
substitute this drivel for intelligent consideration of the problem
actually have influence amongst the chatterati.

--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

On Thu, 24 Nov 2005 16:20:36 +0000, David Hansen
wrote:

On Thu, 24 Nov 2005 13:57:23 +0000 someone who may be Peter Parry
wrote this:-

If you switch off the boiler for the summer

Who said anything about doing this?

You did

Incorrect. What I said was not running the boiler.

Ah, that was what "Not running a boiler all the year round is not an
advantage?Fascinating." meant. Thank you for explaining.


--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

Peter Parry wrote:
On Thu, 24 Nov 2005 13:50:41 +0000, David Hansen
wrote:
On Thu, 24 Nov 2005 12:13:59 +0000 someone who may be Peter Parry
wrote this:-

Over the whole years solar may produce substantial heat,

It may, however it doesn't, there are many summer days where the
output is negligible.

So you assert.

So I have measured over many years. On a cloudy, rainy summer day
the output was very low and inadequate by itself to provide hot
water. Those conditions sometimes prevailed for several days on the
run between late spring and early autumn.

the system design was therefore inadequate for the job.

NT

Solar
 

On Thu, 24 Nov 2005 16:23:27 +0000, Pete C
wrote:

On Thu, 24 Nov 2005 11:28:16 +0000, Peter Parry
wrote:

I did, and it was monitored for much of its life. It saved an
average of GBP 18 per year. If the money had been put in a savings
account it would have earned far more than that.

What's the cost of energy (per kWh) that the £18/yr saving is based
upon?

The actual cost of fuel each quarter over the decade or so the system
was monitored.

If based upon natural gas that could help explain why the
returns from the solar system are quite low.

It was natural gas, and an efficient and carefully sized boiler.

Also how many people in your parents household? If only 2 it's
possible the system is oversized for their needs and they can't use
the majority of the water heated by the system.

It varied between two and four over the period. There were certainly
a few times in the summer months with only two people that more hot
water was produced than could be used.

For a four person household heating with LPG or oil where the system
can be DIY installed I'd expect the economics are quite different.

I don't think many people could install a better system for lower
cost - remember the starting point was the purely serendipitous
discovery of a stack of apparently new vacuum tube solar collectors
in a scrap yard which avoided the major cost and the construction was
entirely DIY.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

The life of solar panels isn't infinite, nor are they a practical
energy saving measure in most situations.

--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

On 24 Nov 2005 13:40:51 -0800, wrote:

Peter Parry wrote:

So I have measured over many years. On a cloudy, rainy summer day
the output was very low and inadequate by itself to provide hot
water. Those conditions sometimes prevailed for several days on the
run between late spring and early autumn.

the system design was therefore inadequate for the job.

How do you collect something which isn't there in adequate amounts to
begin with? Or are you suggesting it should have a heat store with
several days reserve capacity?



--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

On Thu, 24 Nov 2005 21:38:49 +0000 someone who may be Peter Parry
wrote this:-

My statements are based upon measurements on a system
which was in many ways more advanced than many sold today and which
utilised collector technology still advertised as "state of the art"
20 years later.

Excellent, you are basing your assertions on a twenty year old
system. That tells us all we need to know.

You must be joking. A report with not a single figure in it and in
50 pages only one small graph concerning what happens when you turn a
towel rail off?

Of course, it is a report on how the installation of such things
affects attitudes.

It is however certainly instructive in illustrating
how you can fool people with propaganda whilst carefully avoiding any
of the nasty facts.

On the contrary, it is a very good report that describes attitudes
to such systems well.


--
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

Solar
 

"AJH" wrote in message
...
On Thu, 24 Nov 2005 01:09:50 +0000, Andy Dingley
wrote:

On Wed, 23 Nov 2005 18:29:53 -0000, "Doctor Drivel"
wrote:

Try the Thermomax panels from Navitron - I gave the link.

Oddly enough, I find myself almost agreeing with Drivel. I've no idea
who Navitron are, but Thermomax make a good product. If they can get
them to work cost-effectively in Northern Ireland, they ought to work in
Somerset!

Their site seems down atm but I think these look remarkably similar to
the Consol Baijing tubes.

They are made in China and rebadged. The Chinese invented the Thermomax
solar tubes. 75% of installed solar panels in the world are in China.

Navitron are importing and charging realistic prices for solar equipment.

Solar
 

On Fri, 25 Nov 2005 07:33:40 +0000, David Hansen
wrote:

On Thu, 24 Nov 2005 21:38:49 +0000 someone who may be Peter Parry
wrote this:-

My statements are based upon measurements on a system
which was in many ways more advanced than many sold today and which
utilised collector technology still advertised as "state of the art"
20 years later.

Excellent, you are basing your assertions on a twenty year old
system. That tells us all we need to know.

If you could put your irrational prejudice to one side for a moment
would you care to point out in what way it was deficient? Perhaps
you missed the bit about the performance I _measured_ over a decade
being consistent with that from systems tested in 2001 (and still on
sale today)? (the collector construction used is still being
represented as "new" by manufacturers).

You must be joking. A report with not a single figure in it and in
50 pages only one small graph concerning what happens when you turn a
towel rail off?

Of course, it is a report on how the installation of such things
affects attitudes.

How very useful when trying to determine how effective (or otherwise)
they are. You take an elderly lady from an old draughty, cold, damp
house and put her in a well insulated modern house and say its all
caused by a solar panel (which of course has nothing to do with it)
and wow - great surprise - she loves her solar panel.

It is a wholly worthless report from spinmeisters to spinmeisters to
support a political agenda.

--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

"Peter Parry" wrote in message
...
On Fri, 25 Nov 2005 07:33:40 +0000, David Hansen
wrote:

On Thu, 24 Nov 2005 21:38:49 +0000 someone who may be Peter Parry
wrote this:-

My statements are based upon measurements on a system
which was in many ways more advanced than many sold today and which
utilised collector technology still advertised as "state of the art"
20 years later.

Excellent, you are basing your assertions on a twenty year old
system. That tells us all we need to know.

If you could put your irrational prejudice to one side for a moment

It is clear you are confused. It is painful to read what you write.

Solar
 

In article ews.net,
Doctor Drivel wrote:
If you could put your irrational prejudice to one side for a moment

It is clear you are confused.

You say that of one of the most logical people on here? Figures. You only
understand adverts, not the real world.

It is painful to read what you write.

Like I said, get your nurse to change your monitor to a lower resolution
setting. It will make the print much bigger for your failing eyesight.
Won't help your failing brain, though.

--
*When blondes have more fun, do they know it?

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

Solar
 

On Thu, 24 Nov 2005 21:51:25 +0000, Peter Parry
wrote:

On Thu, 24 Nov 2005 16:23:27 +0000, Pete C
wrote:

On Thu, 24 Nov 2005 11:28:16 +0000, Peter Parry
wrote:

I did, and it was monitored for much of its life. It saved an
average of GBP 18 per year. If the money had been put in a savings
account it would have earned far more than that.

What's the cost of energy (per kWh) that the £18/yr saving is based
upon?

The actual cost of fuel each quarter over the decade or so the system
was monitored.

OK so is that an _average_ of £18/yr or £18 _each_ year? Were you able
to work out the number of kWh of heating saved each year?

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

The life of solar panels isn't infinite, nor are they a practical
energy saving measure in most situations.

Was there any noticeable drop in the output of your parent's system
over 10 years?

The vacuum tubes should to last for 25-30 years at least, so after a
comparison over 10 years the system still has another 15-20 years life
in it. Even so, the tubes can be replaced quite easily if need be.

cheers,
Pete.

Solar
 

"Dave Plowman (News)" through haze of senile
flatulence wrote in message ...
In article ews.net,
Doctor Drivel wrote:

If you could put your irrational prejudice to one side for a moment

It is clear you are confused.

You say that

** sip confused senile ramblings **

Solar
 

Peter Parry wrote:
On 24 Nov 2005 13:40:51 -0800, wrote:
Peter Parry wrote:

So I have measured over many years. On a cloudy, rainy summer day
the output was very low and inadequate by itself to provide hot
water. Those conditions sometimes prevailed for several days on the
run between late spring and early autumn.

the system design was therefore inadequate for the job.

How do you collect something which isn't there in adequate amounts to
begin with? Or are you suggesting it should have a heat store with
several days reserve capacity?

You're effectively asking me what are the deficiencies of the system
you measured, when I havent seen it, have no figures etc. So its very
difficult to say where your particular system would be deficient.

All I can do with so little info is say a few rather general points,
without really knowing the details of your system.

Firstly, the question of whats there. NREL insolation figures answer
the question how much. There is also the question of direct vs diffuse.
We get infra red from above every day, some days direct from the sun,
some days diffuse. Vacuum tube collectors may have reflectors behind
the tubes to concentrate direct IR only, and the system design may well
rely on this concentration. In such cases, overcast days will not
produce the goods. Flat panels will perform better on such days. Bear
in mind that evacuated tubes only collect over a minority of the total
area they cover, whreas flat plates collect over nearly 100%.

Tubes are more energy efficient than flat plates in direct sun, but
when overcast their output falls heavily, whereas plate collectors dont
suffer from as much output reduction.

Plate collectors are a better choice for low temperature water, since
efficiency stays fairly high, cost per area is much lower, and
performance on overcast days stays fairly good. But of course what we
want is hot water, not warm to hot. A combination of the 2 collector
types can give some advantages over either type alone, with water
flowing through the plates first, then the vacuum tubes.


Then as you pointed out there is the question of storage. Storage
volume, temperature and insulation all effect cloudy day behaviour, as
well as collector type and design. There is also the question of how
the storage is set up to work with the panels. I cant be anything more
than vague on this, as I know almost nothing about your setup.


The big problem with solar energy generally is that although it is
possible to make systems that pay, 99% of them don't. The level of
design skill around doesnt seem to match the task at hand. This is to
be expected, since solar is still a fringe alternative field. Those
that do have the skills are thus far more likely to be employed in a
mainstream field.

With NREL insolation figures and sufficient skill, one can design
systems that will work, or design ones that sometimes do, or ones that
are not much use. There is nothing in principle that stops solar
heating working, it is all a question of getting payback good enough to
make it worthwhile. Few systems achieve that.


NT

Solar
 

On 25 Nov 2005 05:48:12 -0800, wrote:

Peter Parry wrote:

How do you collect something which isn't there in adequate amounts to
begin with? Or are you suggesting it should have a heat store with
several days reserve capacity?

You're effectively asking me what are the deficiencies of the system
you measured, when I havent seen it, have no figures etc. So its very
difficult to say where your particular system would be deficient.

You made the statement that it was inadequately for the job. Whilst
it was being monitored it achieved results which were broadly similar
to those achieved from the 7 commercial systems tested by the DTI in
their report DTI/Pub URN 01/1202 (available at
http://www.dti.gov.uk/renewables/pub...load=01%2F1292)

These are listed in Annex C to the report.

From the fact that the results I measured on my system and those
obtained by the DTI in their tests of commercial systems were similar
I conclude that my installation and design was quite adequate. I was
puzzled as to why you considered it to be inadequate - if it was then
it makes all the commercial systems tested by the DTI also
inadequate.

Thank you for your other comments, most useful.


--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

On Fri, 25 Nov 2005 10:52:13 +0000, Pete C
wrote:

On Thu, 24 Nov 2005 21:51:25 +0000, Peter Parry
wrote:

OK so is that an _average_ of £18/yr or £18 _each_ year?

It was an average of GBP18 per year. In a ten year period the total
saving was a shade over GBP180.

Were you able
to work out the number of kWh of heating saved each year?

I was able to measure the contribution from the solar panels and
calculated the cost of achieving the same contribution from the gas
boiler (taking into account boiler and transfer losses).

Was there any noticeable drop in the output of your parent's system
over 10 years?

There was no subjectively noticeable drop in nearly 20 years (it was
only monitored for about 10).

The vacuum tubes should to last for 25-30 years at least, so after a
comparison over 10 years the system still has another 15-20 years life
in it. Even so, the tubes can be replaced quite easily if need be.

Indeed, but the system do suffer from failures. Mine had a seal fail
on a collector tube and whilst a single collector tube is relatively
cheap and easy to DIY having one replaced commercially usually costs
GBP100-300. The neighbours had a leak in one of their commercially
installed panels after about 5 years as I recall which cost them over
GBP500 to have repaired. They removed the system just prior to
selling their house although I have no idea why they did so.

--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

That may be true from the amount a daylight that we have here in
Scotland in the summer but the heat collector does not track the sun so
the collection must only be effective during the major part of the day
which will be same for most of the UK.

Rob

Solar
 

On Fri, 25 Nov 2005 19:08:39 +0000, Peter Parry
wrote:

On Fri, 25 Nov 2005 10:52:13 +0000, Pete C
wrote:

Were you able
to work out the number of kWh of heating saved each year?

I was able to measure the contribution from the solar panels and
calculated the cost of achieving the same contribution from the gas
boiler (taking into account boiler and transfer losses).

I see, what was the contribution from the solar panels in kWh over a
year?

The vacuum tubes should to last for 25-30 years at least, so after a
comparison over 10 years the system still has another 15-20 years life
in it. Even so, the tubes can be replaced quite easily if need be.

Indeed, but the system do suffer from failures. Mine had a seal fail
on a collector tube and whilst a single collector tube is relatively
cheap and easy to DIY having one replaced commercially usually costs
GBP100-300.

At least with evacuated tube collectors there is some built in
redundancy. If a single tube failed I'd tend to leave it until the
roof needed other work, and get it replaced then.

The neighbours had a leak in one of their commercially
installed panels after about 5 years as I recall which cost them over
GBP500 to have repaired.

Sounds like an expensive system, as a whole 20 tube collector can be
had for £400 these days.

They removed the system just prior to
selling their house although I have no idea why they did so.

To put it on their new property I guess ;)

cheers,
Pete.

Solar
 

wrote in message
oups.com...

That may be true from the amount a daylight that we have here in
Scotland in the summer but the heat collector does not track the sun so
the collection must only be effective during the major part of the day
which will be same for most of the UK.

But it gains heat when you would be purchasing that heat. In the US many
experimenters have used devices to track the sun and gained brilliant
results. In more dim UK this must make a hell of a difference.

Solar
 

On Fri, 25 Nov 2005 21:12:31 +0000, Pete C
wrote:

On Fri, 25 Nov 2005 19:08:39 +0000, Peter Parry
wrote:

I see, what was the contribution from the solar panels in kWh over a
year?

It was just over 1000kWh per year over the period measured.

At least with evacuated tube collectors there is some built in
redundancy. If a single tube failed I'd tend to leave it until the
roof needed other work, and get it replaced then.

As I had several spares it was easy enough to replace. However the
cost of a DIY repair with available spares is not really applicable
to most people and the commercial cost is more appropriate.

The neighbours had a leak in one of their commercially
installed panels after about 5 years as I recall which cost them over
GBP500 to have repaired.

Sounds like an expensive system, as a whole 20 tube collector can be
had for £400 these days.

It can't be replaced for GBP400 though.

In any case it was a flat panel collector so replacing the whole
panel was the only option available.

I was quite surprised to read in the DTI report of the number of
faults they had upon delivery of new units.

They removed the system just prior to
selling their house although I have no idea why they did so.

To put it on their new property I guess ;)

As I purloined some bits of it from their skip I somehow doubt that
was the case :-).


--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

Pete C wrote:
I'd be interested in a good formula for comparing money in the bank to
money spent on energy saving over a given time.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

Using a simple formula of:

Money_This_Year = (Money_Last_Year * Interest_Rate) - Money_Taken_Out

And assuming that the amount that would have been saved by the heating
system were to be taken out each year immediately after the year's
interest was paid gives the following results:

With an interest rate of 3% and taking out £18 per year, after 20
years £425 remains in the bank.

If it were possible to get 3.6% interest the whole £500 would be left
in the bank after taking out £18 per year.

Today it is easy to get 4.5% or over, and over the last 20 years that
should not have been difficult to find most of the time, which would
have given £630 in the bank today - £130 profit on top of the £18
per year that the system saved in heating costs!

Solar
 

Pete C wrote:
I'd be interested in a good formula for comparing money in the bank to
money spent on energy saving over a given time.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

Using a simple formula of:

Money_This_Year = (Money_Last_Year * Interest_Rate) - Money_Taken_Out

And assuming that the amount that would have been saved by the heating
system were to be taken out each year immediately after the year's
interest was paid gives the following results:

With an interest rate of 3% and taking out £18 per year, after 20
years £425 remains in the bank.

If it were possible to get 3.6% interest the whole £500 would be left
in the bank after taking out £18 per year.

Today it is easy to get 4.5% or over, and over the last 20 years that
should not have been difficult to find most of the time, which would
have given £630 in the bank today - £130 profit on top of the £18
per year that the system saved in heating costs!

Solar
 

"Matt Beard" wrote in message
oups.com...
Pete C wrote:
I'd be interested in a good formula for comparing money in the bank to
money spent on energy saving over a given time.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

Using a simple formula of:

Money_This_Year = (Money_Last_Year * Interest_Rate) - Money_Taken_Out

And assuming that the amount that would have been saved by the heating
system were to be taken out each year immediately after the year's
interest was paid gives the following results:

With an interest rate of 3% and taking out £18 per year, after 20
years £425 remains in the bank.

If it were possible to get 3.6% interest the whole £500 would be left
in the bank after taking out £18 per year.

Today it is easy to get 4.5% or over, and over the last 20 years that
should not have been difficult to find most of the time, which would
have given £630 in the bank today - £130 profit on top of the £18
per year that the system saved in heating costs!


All assuming you left the money in the bank which many, or most, do not.
When it is there they spend it on garbage like plasma TVs. So, the solar
panels make better sense.

I just don't believe he only saved £18 a year. Most home for 4 months of
the year can get 95% of their DHW from solar, and the rest of the time it
supplements. This thread is based on his £18 year saving, which I think is
balls, so a waste of a thread. And, an new system DIYed would save a hell
of a lot more, especially as fuel rises in price. (13% increase in gas
alone this year)

Solar
 

On 26 Nov 2005 09:28:39 -0800, "Matt Beard" wrote:

Using a simple formula of:

Money_This_Year = (Money_Last_Year * Interest_Rate) - Money_Taken_Out

And assuming that the amount that would have been saved by the heating
system were to be taken out each year immediately after the year's
interest was paid gives the following results:

With an interest rate of 3% and taking out £18 per year, after 20
years £425 remains in the bank.

If it were possible to get 3.6% interest the whole £500 would be left
in the bank after taking out £18 per year.

Today it is easy to get 4.5% or over, and over the last 20 years that
should not have been difficult to find most of the time, which would
have given £630 in the bank today - £130 profit on top of the £18
per year that the system saved in heating costs!

Hi,

Sounds good. (Though it assumes flat energy prices and zero
inflation!)

cheers,
Pete.

Solar
 

In article ews.net,
Doctor Drivel wrote:
I just don't believe he only saved £18 a year.

You - the biggest liar on newsgroups - 'don't believe'?

--
*A person who smiles in the face of adversity probably has a scapegoat *

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

Solar
 

"Dave Plowman (News)" through a haze of senile
flatulence wrote in message ...
In article ews.net,
Doctor Drivel the most homest man in the world
wrote:

I just don't believe he only saved £18 a year.

You

** snip senile drivel and babble **

Solar
 

Matt Beard wrote:
Pete C wrote:
I'd be interested in a good formula for comparing money in the bank to
money spent on energy saving over a given time.

However towards the end of the period the money in the bank will be
eroded to zero, leaving the householder facing high energy prices and
perhaps at that stage they can't afford to spend on energy saving
measures.

Using a simple formula of:

Money_This_Year = (Money_Last_Year * Interest_Rate) - Money_Taken_Out

And assuming that the amount that would have been saved by the heating
system were to be taken out each year immediately after the year's
interest was paid gives the following results:

With an interest rate of 3% and taking out £18 per year, after 20
years £425 remains in the bank.

If it were possible to get 3.6% interest the whole £500 would be left
in the bank after taking out £18 per year.

Today it is easy to get 4.5% or over, and over the last 20 years that
should not have been difficult to find most of the time, which would
have given £630 in the bank today - £130 profit on top of the £18
per year that the system saved in heating costs!

Ignore this copy - Google Groups had a bit of a fit yesterday!

Solar
 

On Thu, 24 Nov 2005 12:25:54 -0000, "Doctor Drivel"
wrote:


to go with the hot air heating you
worship (but don't have)?

I wish I had it.

If it is easy to retrofit as you keep claiming, what is stopping you?

--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

"Peter Parry" wrote in message
...
On Thu, 24 Nov 2005 12:25:54 -0000, "Doctor Drivel"
wrote:

to go with the hot air heating you
worship (but don't have)?

I wish I had it.

If it is easy to retrofit as you keep
claiming, what is stopping you?

I can do the upstairs and feed all, inc hall, from the loft. Nice fresh air
coming in and in summer keep it nice and cool. I may install a air hander
up there and heat this from the boiler via copper coil battery. I can
actually make my own air handler using marine ply varnished.

Solar
 

On Sun, 27 Nov 2005 20:04:51 -0000, "Doctor Drivel"
wrote:


"Peter Parry" wrote

If it is easy to retrofit as you keep
claiming, what is stopping you?

I can do the upstairs and feed all, inc hall, from the loft. Nice fresh air
coming in and in summer keep it nice and cool. I may install a air hander
up there and heat this from the boiler via copper coil battery. I can
actually make my own air handler using marine ply varnished.

I know what you claim to be able to do - however it hasn't happened
has it? You claim hot air is good - but don't use it; you claim
enormous savings for solar hot water yet can't do simple maths and
have never designed, built or used one. You claim to know better
than my decade of measurements when you have no experience
whatsoever. Your competence goes as far as "trust me- I'm a plumber"
and no further. It's all hot air and no action isn't it?


--
Peter Parry.
http://www.wpp.ltd.uk/

Solar
 

"Peter Parry" wrote in message
...
On Sun, 27 Nov 2005 20:04:51 -0000, "Doctor Drivel"
wrote:


"Peter Parry" wrote

If it is easy to retrofit as you keep
claiming, what is stopping you?

I can do the upstairs and feed all, inc hall, from the loft. Nice fresh
air
coming in and in summer keep it nice and cool. I may install a air
hander
up there and heat this from the boiler via copper coil battery. I can
actually make my own air handler using marine ply varnished.

I know what you claim to be able to do - however it hasn't happened
has it? You claim hot air is good - but don't use it;

But have and designed many systems. You just guess. And a bad guesser at
that.

** snip babble **