On Sun, 09 Dec 2007 17:31:33 GMT, Tony Bryer
wrote:

On Sun, 9 Dec 2007 11:56:49 -0000 Mary Fisher wrote :
Why on Earth are people so antagonistic towards something
of which they have no personal experience?

Because lots of us know that in a significant number of cases
solar water heating is a mechanism for transferring money from
well meaning but gullible householders to smooth talking
salesmen. And if they spend their commission on big cars the
environmental benefit is nil.

It may make economic sense if you use a lot of hot water,

If you need a lot of hot water in the UK you'd need an enormous
installation and it would still let you down on days like yesterday
(Saturday), temp here 3C & dark at 3-00pm.

can DIY,

You couldn't DIY if you use a lot of hot water. Think tonnes of hot
water storage.

and use a fuel other than mains gas, otherwise probably not.

I might have a DIY play with it, but unfortunately the area I have
avaialble for Sloar Panels (where it gets the sun) is at the other
end of the plot from the Kitchen/Bathroom. I'm not happy to compromise
the structure of my house with panels on the roof (It's a modern
trussed roof designed only to support it's own weight and the ceiling
below) and pipes taken through the roof and through 40 feet of
building, then to interface somehow with a 37kW Siemens combi boiler.

DG

geoff wrote:
In message , Alan
writes
Data logger is the Resol DL1, which cost about £150. It's just a data
connecton to the solar controller, and has 2mb memory on board. Enough
for
about 3 months of readings, taken every 5 minutes, of 18 variables
such as
temperatures, pump speeds, heat transferred etc.


all that in 1/500th of a byte ?

cunning

If you take that as 2M Bytes, then that allows about 80 bytes per record...

--
Cheers,

John.

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

Mary Fisher wrote:
"Derek Geldard" wrote in message
...
On Sat, 8 Dec 2007 20:14:07 -0000, "Mary Fisher"
wrote:

How many kWh worth of energy in total did you gain from your solar
heating installation today Mary?

Not measured.
It was less than 3C (Got a constant frost warning in the car) and
gloomier than The Wreck of the Hesperus at 1-00 pm in Leeds, and dark
by soon after 3-00 pm.

It wasn't dark until after 4 in our part of Leeds and it wasn't cold enough
for the CH to come on

I assume you had the heating on in your car ... :-).

We haven't bothered measuring since the first few days after connection.
That day it was 4C in the shade and at the end of the day we ended up with a
large tank full of water at over 30C.

OTOH The temperature of the water in our rising main was 7C, it would
be very easy to make a net heat loss from a solar water heating system
under these circumstances.

It hasn't happened to us.
How many were you washing up for?

Three - why?
What kind of boiler/system and how big?

Irrelevant. The sun provides the majority of our domestic hot water, the
boiler provides the heating for the radiators - which are hardly ever been
on.

Why on Earth are people so antagonistic towards something of which they have
no personal experience?

Why do you assume questions are antagonistic? Some people may genuinely
want to know if a similar system would be worthwhile for them. Hence
they ask someone who does have personal experience in the hope they have
some actual data that can he assessed.

Some of the detail questions are relevant... like how big is your
cylinder? What temperature is your ground water at the moment? etc.
These things allow one to give a quantitative feel for the rate of
capture from the solar system.


--
Cheers,

John.

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

Andy Hall wrote:

It's like those wineboxes. It says on the box that once open they last
for 3 months, but they don't.....

I noticed that Makro have started carrying the 10L versions now. Might
have more of a fighting chance of them going the duration... in fact on
second thoughts, no probably not ;-)

--
Cheers,

John.

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

"Michael Shergold" wrote in message
...
Does anyone have good or bad experiences with any UK Solar Heating
suppliers/installers.. This is not really a DIY project but the total
house energy project is really DIY with, and often without, the help of
professionals. Any recommendations or people I should avoid?.
--
Michael in sunny Sussex
Many thanks for all the replies. Not exactly what I was hoping for but
quite a lot to think about and probably after this discussion I'll drop the
idea for now.. A persistent salesman has been trying to organise a survey
visit of my property but I have held him off until the new year now and
will probably find him far too expensive anyway. This house has limited
space where the cylinder is on the ground floor and access through to the
roof is far from easy.. What sits on the roof has also got to be wind and
salt resistant as I am about 50 metres from the sea, A neighbour's west
facing solar connector looks a wreck but it has been there for about 20
years, his east facing collector is not so bad. I wonder how efficient they
are now and would ask except he died last summer leaving an elderly widow.
Thanks anyway, for all the interest
Michael

On Sun, 9 Dec 2007 09:48:09 +0000 someone who may be Kostas
Kavoussanakis wrote this:-

What they call winter in Crete is an overcast June day in Scotland. I
agree, we are talking 15-20 years when the technology may have
matured, but Scotland has not moved any more south in the period :-)

That's good. If it were to be moved south it would not have the long
summer days which are ideal for solar water heating.

Obviously this comes at a price in that the winter days are short,
but that is still enough for a solar panel to provide some useful
heat.


--
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 Sun, 9 Dec 2007 12:02:01 -0000 someone who may be "Mary Fisher"
wrote this:-

Oh don't be silly. Who are you trying to convince, yourself?

It often sounds like it.


--
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 Sat, 8 Dec 2007 22:17:13 +0000 someone who may be Si
$3o&m wrote this:-

But there are other reasons than 'looking green' or recouping capital outlay
for wanting to use solar power.

? ...

They should be fairly easy to work out. One might be reducing one's
carbon footprint.


--
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, 10 Dec 2007 07:38:56 -0000 someone who may be "Michael
Shergold" wrote this:-

What sits on the roof has also got to be wind and
salt resistant as I am about 50 metres from the sea

A good reason for using vacuum tubes. Salt doesn't affect the glass
of the tube. As has been said, Navitron are the people to look at to
DIY.


--
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 2007-12-10 08:09:49 +0000, David Hansen
said:

On Sat, 8 Dec 2007 22:17:13 +0000 someone who may be Si
$3o&m wrote this:-

But there are other reasons than 'looking green' or recouping capital outlay
for wanting to use solar power.

? ...

They should be fairly easy to work out. One might be reducing one's
carbon footprint.

It might be, but that would be even more naive.

I wonder how many of the components are manufactured in China and how
many more coal fired power stations they opened to do the manufacturing.

On Mon, 10 Dec 2007 08:12:55 +0000, David Hansen wrote:

A good reason for using vacuum tubes. Salt doesn't affect the glass
of the tube.

Not like it attacks steel or ali but I bet you'll still get a hefty build
up of salt crystals but then you'll get that on any collector.

--
Cheers
Dave. pam is missing e-mail

On Sun, 09 Dec 2007 01:13:36 +0000 someone who may be Derek Geldard
wrote this:-

It was less than 3C (Got a constant frost warning in the car) and
gloomier than The Wreck of the Hesperus at 1-00 pm in Leeds, and dark
by soon after 3-00 pm.

What does the external air temperature have to do with a properly
designed solar heating system?

As it says at http://www.navitron.org.uk/solar_collector_panel.htm

"The vacuum tube solar panel has been around for over 10years, and
has proved to be reliable and dependable. The vacuum tubes consist
of a double wall glass tube (made from strong borosilicate glass ie
pyrex) with a space in the centre which contains the heat pipe. The
sun's radiation is absorbed by the selective coating on the inner
glass surface, but prevented from re-radiating by the silvered
innermost lining. This is in effect like a one-way mirror which has
been optimised for infra-red radiation. In fact it is very
efficient, of the sun light's energy hitting the tube's surface, 93%
is absorbed, whereas only 7% is lost through reflection and
re-emission. The presence of the vacuum wall prevents any losses by
conduction or convection - just like a thermos flask. Because of
this, the system will work even in very low temperatures, unlike
traditional flat plate collectors. This is why our system can be
used to heat up water at the South Pole Antarctic Science Base -
where ambient air temperatures can drop below -40°C"

Or, as it says at http://www.solartwin.com/technical_faq.php

"Q: During the winter months when most of the hot water will be
generated by the boiler, what happens if there is enough sun to set
the pump in action. At which time there is not enough thermal energy
to heat up the water sufficiently so that when it is returned to the
hot water tank it reduces the temperature there?

"A: The pump runs only on solar energy in the form of electricity.
It has no temperature sensor, only a high pressure bypass in case
the panel or its pipes are frozen. In response to your question:
First - best not to have the hot water system on all day since this
is wasteful anyway and does not allow for optimum solar performance.
Most boilers have separate timers for this, but not all. Ideally
time the boiler to add heat to the domestic hot water after 4pm.
Second, even in winter some hot water is made by Solartwin, not all
by the boiler as you say. Third - the panel is well insulated and so
will still raise the temperature of water going into it since it
collects heat from the sun and not the air. Fourth - at 100% sun and
a water input temperature of 50C and air temperature of freezing our
mathematical model (based on extensive tests at Napier University)
suggests that the water will still leave the panel at least 10C
hotter than when it went in. Fifth - if they really want to put cold
water in under these circumstances they can connect a second
cylinder behind the first and draw water off it! This will also
allow for more summer hot storage and is a neat solution for people
with AGAs and Rayburns."



--
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 Sun, 09 Dec 2007 22:57:02 +0000 someone who may be John Rumm
wrote this:-

Why on Earth are people so antagonistic towards something of which they have
no personal experience?

Why do you assume questions are antagonistic?

Some of the people concerned have given this impression many times
in the past.

Some people may genuinely
want to know if a similar system would be worthwhile for them.

The answer to that question has not changed since the last time it
was discussed. Although I'm not noted for spoon feeding I will make
an exception for once.

There is a question of how one measures things. Some people will
spend 10,000 pounds on a new kitchen, for which they will get a
financial return of nothing, for various reasons which they think
are important to them. Some people will install double glazing,
knowing that it has a number of advantages but saving lots of money
on heating bills is not one of these advantages.

In the case of solar water heating people install it for a variety
of reasons they find acceptable, reducing carbon footprint being an
example.

To generalise, in terms of just pound notes, at current fuel prices,
a "professionally" installed system is unlikely to pay for itself
over anything but the long term, possibly longer than it will last.
At current fuel prices a DIY system, using new components, is likely
to pay for itself over the medium term, say 10 years. As a result
one should always do simple energy saving measures, like insulation,
first and only progress to things like solar water heating after
that.



--
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, 10 Dec 2007 08:36:23 +0000 someone who may be Andy Hall
wrote this:-

They should be fairly easy to work out. One might be reducing one's
carbon footprint.

It might be, but that would be even more naive.

Excellent, more abuse. Do keep it up.

I wonder how many of the components are manufactured in China and how
many more coal fired power stations they opened to do the manufacturing.

The Chinese seem to be becoming the yellow peril again, at least as
far as some are concerned. All that shows is their lack of
knowledge.

The majority of vacuum tubes are built in China for many reasons,
one of which is that is where the vast majority are used.



--
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, 10 Dec 2007 09:17:33 +0000 (GMT) someone who may be "Dave
Liquorice" wrote this:-

A good reason for using vacuum tubes. Salt doesn't affect the glass
of the tube.

Not like it attacks steel or ali but I bet you'll still get a hefty build
up of salt crystals but then you'll get that on any collector.

One might do, but if the rain doesn't wash them off then all it
takes is a bucket and brush. I don't notice houses by the sea with
salt encrusted roofs, even if the roof has been there for centuries.


--
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 Fri, 7 Dec 2007 14:07:26 -0000 someone who may be "Michael
Shergold" wrote this:-

Does anyone have good or bad experiences with any UK Solar Heating
suppliers/installers.. This is not really a DIY project

You don't say why. It would help if you did.

A solar panel generating hot water is well within the capabilities
of many DIYers. It is mostly plumbing, with a little electrical work
and generally some roof work. The latter is no problem if one is
used to working at height and works methodically.



--
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 Sun, 09 Dec 2007 13:24:28 +0000 (GMT) someone who may be "Dave
Liquorice" wrote this:-

It's probably worth investigating if the total installed price is under
£1000, but I better the data logger option cost more than that.

Look at the (retail) price list on the Navitron site. DL1 data logger
£150... Though I don't know how many "extras" are required.

Right at the start of their price list are three kits
http://www.navitron.org.uk/pricelist.htm which are fairly complete.

The only thing missing from these kits is pipework (10mm microbore
is ideal) which depends on location, a few fittings for this pipe
and a few bits of electrical equipment (possibly extra cable and an
isolator). One may also need some more insulation for longer pipe
runs.


--
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 Sat, 8 Dec 2007 17:43:12 -0000 someone who may be "Donwill"
popple @diddle .dot wrote this:-

Can you recommend a DIY solar water heater site for information?

People have been pointed to www.navitron.org.uk more than once in
this thread. What is missing from their site?


--
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 2007-12-10 12:34:01 +0000, David Hansen
said:

On Mon, 10 Dec 2007 08:36:23 +0000 someone who may be Andy Hall
wrote this:-

They should be fairly easy to work out. One might be reducing one's
carbon footprint.

It might be, but that would be even more naive.

Excellent, more abuse. Do keep it up.

No abuse at all.

I simply said that reducing one's carbon footprint (a nonsense term to
begin with) via this method is naive.

That is simply a comment on a position not about any particular
individual or individuals.

It's something of a stretch to turn such a comment into an accusation
of abuse. Do you feel vulenerable about your position or something?



I wonder how many of the components are manufactured in China and how
many more coal fired power stations they opened to do the manufacturing.

The Chinese seem to be becoming the yellow peril again, at least as
far as some are concerned. All that shows is their lack of
knowledge.

I think that the Chinese are quite knowledgable. Certainly in using
the avarice of the West in terms of their trade arrangements while
ignoring issues that are of concern to some in the West is very clever
indeed. Alternatively, perhaps some in the West who like to speak
about green-ness out of one side of their mouth while buying cheap
goods from China out of the other are not as bright as it would appear.


The majority of vacuum tubes are built in China for many reasons,
one of which is that is where the vast majority are used.

Not very convincing.

The problem is sorted.....

http://www.guardian.co.uk/environmen...ec/10/politics

On Mon, 10 Dec 2007 18:37:40 +0000 someone who may be Andy Hall
wrote this:-

Do you feel vulenerable about your position or something?

Nice try. However, completely incorrect.

Do keep it up though.

The majority of vacuum tubes are built in China for many reasons,
one of which is that is where the vast majority are used.

Not very convincing.

It may not be very convincing to some. However, it remains a fact.


--
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 2007-12-10 19:56:44 +0000, David Hansen
said:

On Mon, 10 Dec 2007 18:37:40 +0000 someone who may be Andy Hall
wrote this:-

Do you feel vulenerable about your position or something?

Nice try. However, completely incorrect.

Do keep it up though.

There's really no need. As soon as something is said for which you
have no answer, you suggest that it's some form of abuse.



The majority of vacuum tubes are built in China for many reasons,
one of which is that is where the vast majority are used.

Not very convincing.

It may not be very convincing to some. However, it remains a fact.

That it may be. Whether it is in the least bit important is something
else entirely.

On Mon, 10 Dec 2007 21:35:16 +0000 someone who may be Andy Hall
wrote this:-

There's really no need. As soon as something is said for which you
have no answer, you suggest that it's some form of abuse.

Nice try, but just as incorrect as many of your other assertions.


--
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 Sun, 9 Dec 2007 11:59:42 -0000 someone who may be "Mary Fisher"
wrote this:-

If you are heating your water by mains gas a single panel will save
you about £40 per year.

Ours has saved us far more than that. Far more.

The post at http://navitron.org.uk/forum/index.php?topic=1387.0
gives some figures from another system, which included a few extras.

A 23% saving in gas. Most interesting.


--
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

David Hansen wrote:
On Sun, 09 Dec 2007 22:57:02 +0000 someone who may be John Rumm
wrote this:-

Why on Earth are people so antagonistic towards something of which they have
no personal experience?
Why do you assume questions are antagonistic?

Some of the people concerned have given this impression many times
in the past.

Some people may genuinely
want to know if a similar system would be worthwhile for them.

The answer to that question has not changed since the last time it
was discussed. Although I'm not noted for spoon feeding I will make
an exception for once.

There is a question of how one measures things. Some people will
spend 10,000 pounds on a new kitchen, for which they will get a
financial return of nothing, for various reasons which they think
are important to them. Some people will install double glazing,
knowing that it has a number of advantages but saving lots of money
on heating bills is not one of these advantages.

Indeed, although what I think we were looking for were hard data for a
change.

In the case of solar water heating people install it for a variety
of reasons they find acceptable, reducing carbon footprint being an
example.

The carbon footprint stuff is nice in concept but fairly meaningless in
reality. Unless you know the true energy consumption (and the carbon
released during its generation) during the extraction of raw materials,
the production, distribution, installation, and finally disposal of
the system, you can't make any realistic assessment as to whether you
are having a net positive or negative effect.


--
Cheers,

John.

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

On 2007-12-10 21:52:49 +0000, David Hansen
said:

On Sun, 9 Dec 2007 11:59:42 -0000 someone who may be "Mary Fisher"
wrote this:-

If you are heating your water by mains gas a single panel will save
you about £40 per year.

Ours has saved us far more than that. Far more.

The post at http://navitron.org.uk/forum/index.php?topic=1387.0
gives some figures from another system, which included a few extras.

A 23% saving in gas. Most interesting.

Very. Especially valuable from the vendor of the system.

On 2007-12-10 21:45:51 +0000, David Hansen
said:

On Mon, 10 Dec 2007 21:35:16 +0000 someone who may be Andy Hall
wrote this:-

There's really no need. As soon as something is said for which you
have no answer, you suggest that it's some form of abuse.

Nice try, but just as incorrect as many of your other assertions.

So why raise the subject?

On 2007-12-10 22:00:33 +0000, John Rumm said:

The carbon footprint stuff is nice in concept but fairly meaningless in
reality. Unless you know the true energy consumption (and the carbon
released during its generation) during the extraction of raw materials,
the production, distribution, installation, and finally disposal of
the system, you can't make any realistic assessment as to whether you
are having a net positive or negative effect.

Another cosy, fluffy thing where people can feel that they are "doing
their bit"

On Mon, 10 Dec 2007 22:00:33 +0000 someone who may be John Rumm
wrote this:-

The carbon footprint stuff is nice in concept but fairly meaningless in
reality. Unless you know the true energy consumption (and the carbon
released during its generation) during the extraction of raw materials,
the production, distribution, installation, and finally disposal of
the system, you can't make any realistic assessment as to whether you
are having a net positive or negative effect.

I think one can make a realistic assessment without having highly
accurate figures for a particular installation. That is what an
assessment is. One can benchmark that assessment by looking at
comparable figures. In the case of solar water heating such figures
are available from the usual sources.


--
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, 10 Dec 2007 22:00:48 +0000 someone who may be Andy Hall
wrote this:-

The post at http://navitron.org.uk/forum/index.php?topic=1387.0
gives some figures from another system, which included a few extras.

A 23% saving in gas. Most interesting.

Very. Especially valuable from the vendor of the system.

You appear to be claiming that the person who made the posting is
the vendor of the system, but that is not the case.

http://homepage.ntlworld.com/anthony...g%20Review.pdf
contains details of the system, which those genuinely interested in
the subject may like to read.


--
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, 10 Dec 2007 23:15:20 +0000 someone who may be Peter Parry
wrote this:-

Most interesting indeed. He has a single solar collector virtually
identical to the Thermomax one used in the DTI test (DTI/Pub URN
01/1292) tilted at a similar angle and with slightly less optimal
alignment yet managed to get 5,400kWh in a year wheras the Energy
Monitoring Company Ltd for the DTI could only manage 1,010 kWh from an
identical panel in one year.

The difference is that the DTI test did not involve systems fitted
in real houses connected to a real gas boiler undergoing real draw
offs. I don't recall the detail of what size of storage the DTI
panel was connected to and whether they observed it reaching the
maximum temperature and thus shutting down.

The author does not claim that all the reduction in gas consumption
was due to the solar panel, yet you imply this would have to be the
case.


--
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 10 Dec, 12:44, David Hansen
wrote:
On Sun, 09 Dec 2007 13:24:28 +0000 (GMT) someone who may be "Dave
Liquorice" wrote this:-

It's probably worth investigating if the total installed price is under
£1000, but I better the data logger option cost more than that.

Look at the (retail) price list on the Navitron site. DL1 data logger
£150... Though I don't know how many "extras" are required.

Right at the start of their price list are three kitshttp://www.navitron.org.uk/pricelist.htmwhich are fairly complete.

The only thing missing from these kits is pipework (10mm microbore
is ideal) which depends on location, a few fittings for this pipe
and a few bits of electrical equipment (possibly extra cable and an
isolator). One may also need some more insulation for longer pipe
runs.

--
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

I don't think they recommend microbore because of the heat losses.
Also, you have to get the right sort of insulation as the pipes can
get quite hot.

T

On Tue, 11 Dec 2007 07:08:08 +0000, David Hansen
wrote:

On Mon, 10 Dec 2007 23:15:20 +0000 someone who may be Peter Parry
wrote this:-

Most interesting indeed. He has a single solar collector virtually
identical to the Thermomax one used in the DTI test (DTI/Pub URN
01/1292) tilted at a similar angle and with slightly less optimal
alignment yet managed to get 5,400kWh in a year wheras the Energy
Monitoring Company Ltd for the DTI could only manage 1,010 kWh from an
identical panel in one year.

The difference is that the DTI test did not involve systems fitted
in real houses connected to a real gas boiler undergoing real draw
offs.

They involved systems fitted in a test rig with draw-off patterns
which were representative of normal usage. The storage tanks were
fitted in insulated equipment sheds maintained at a constant
temperature so they were representative of a normal house.

I don't recall the detail of what size of storage the DTI
panel was connected to and whether they observed it reaching the
maximum temperature and thus shutting down.

No high temperature shut-off was used and from the data it wasn't
necessary. The only overheating occured during a number of failures
that occured with the panel installations throughout the test.

The author does not claim that all the reduction in gas consumption
was due to the solar panel, yet you imply this would have to be the
case.

I may no more of an implication than you did when you said "A 23%
saving in gas. Most interesting.".

Assuming the panel performance is more or less in line with the DTI
test (which is reasonable as they are consistent with the amount of
collectable energy and the panel efficiency. They are also similar to
the results others have achieved in independent tests) then 80% of the
saving is not due to the solar panel but the other alterations he
made. From his description of them they wouldn't be expected to have
made this much difference so I'm interested in how it was achieved.

On Mon, 10 Dec 2007 15:26:15 -0800 (PST), Pete C
wrote:

You need to read on a little, quote:

"Actual cost saving works out to around £120 year-on-year. But, also
consider that as part of the package I spent a further £300 to improve
the exisiting CH/DHW controls to meet full Part-L specification so not
alll the saving can be attributable to the solar installation. However
this included dual cylinder stats on separately timed zones to
maximise the solar gain vs boiler operation."

Of the 5,400kWh saving no more than about 20% of that can be
attributed to the solar collector, there simply isn't enough energy
falling on the panel to produce significantly more. This is nothing
to do with how good or otherwise the solar panel may be - the energy
isn't there to collect.

If 80% of the saving came from the relatively modest (in cost)
alterations to the controls this obviously represents a far better way
of spending your money but is a lot more than most authorities would
estimate you would save. Its simply impossible for the panel to
produce more energy than it can possibly collect so I'm interested in
what did produce the observed effect.

On 8 Dec, 17:43, "Donwill" popple @diddle .dot wrote:
"Peter Parry" wrote in message

...

On Fri, 7 Dec 2007 14:07:26 -0000, "Michael Shergold"
snipped
Solar Water heating is one of the easiest DIY projects BTW and doing
it yourself is the only way of coming anywhere near breakeven.

Can you recommend a DIY solar water heater site for information?

I can envisage using a large single panel steel radiator painted black and
mounted in a well insulated double glazed frame. I think that the Max
incoming solar energy is about 3 quarters of a Kw per sq M, and reduced by,
say approx 50% efficiency, is that reasonable ball park figures to start
with.
I also think that winter solar gain is only approx 10% of Max.

Does any one have any info or figures to add to the debate?
Don

As far as I recall, average insolation in Birmingham is about 100W/m2.
The June average is about twice that, in December, less than a 1/5th.

T

Andy Hall wrote:
On 2007-12-10 22:00:33 +0000, John Rumm
said:

The carbon footprint stuff is nice in concept but fairly meaningless
in reality. Unless you know the true energy consumption (and the
carbon released during its generation) during the extraction of raw
materials, the production, distribution, installation, and finally
disposal of the system, you can't make any realistic assessment as to
whether you are having a net positive or negative effect.

Another cosy, fluffy thing where people can feel that they are "doing
their bit"


I have solar heating. In winterm,, the windows in the drawing room face
south. We open the curtains and gain about 2-3 degrees temp rise during
the day.

Thats probably at least a kilowatt of input.

On 10 Dec, 12:31, David Hansen
wrote:
On Sun, 09 Dec 2007 22:57:02 +0000 someone who may be John Rumm
wrote this:-

Why on Earth are people so antagonistic towards something of which they have
no personal experience?

Why do you assume questions are antagonistic?

Some of the people concerned have given this impression many times
in the past.

Some people may genuinely
want to know if a similar system would be worthwhile for them.

The answer to that question has not changed since the last time it
was discussed. Although I'm not noted for spoon feeding I will make
an exception for once.

There is a question of how one measures things. Some people will
spend 10,000 pounds on a new kitchen, for which they will get a
financial return of nothing, for various reasons which they think
are important to them. Some people will install double glazing,
knowing that it has a number of advantages but saving lots of money
on heating bills is not one of these advantages.

In the case of solar water heating people install it for a variety
of reasons they find acceptable, reducing carbon footprint being an
example.

To generalise, in terms of just pound notes, at current fuel prices,
a "professionally" installed system is unlikely to pay for itself
over anything but the long term, possibly longer than it will last.
At current fuel prices a DIY system, using new components, is likely
to pay for itself over the medium term, say 10 years. As a result
one should always do simple energy saving measures, like insulation,
first and only progress to things like solar water heating after
that.

--
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

I think you are being a bit generous with your payback times.
Insolation in middle England is about 0.1kW/m2 on average. A DIY solar
install is going to cost around 500 quid/m2, it's going to be at best
50% efficient. If you think 5p/kWh is a fair price, that means over 20
years to pay for itself. There's no way the system will last that
long, particularly if you use Navitron roof mounts.

T

wrote:
On 10 Dec, 12:31, David Hansen
wrote:

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

I think you are being a bit generous with your payback times.
Insolation in middle England is about 0.1kW/m2 on average. A DIY solar
install is going to cost around 500 quid/m2, it's going to be at best
50% efficient. If you think 5p/kWh is a fair price, that means over 20
years to pay for itself. There's no way the system will last that
long, particularly if you use Navitron roof mounts.



Dave is a Believer. Facts will not alter his opinion.

The reality is that given a clean sheet of paper it would be possible to
design a house that maximizes every possible energy factor. Such a house
would be very efficient, but would be utterly unlike a conventional house.


Essentially I have in mind a 'hobbit hole', with about 6-10 ft of earth
over it, south facing double glazing ONLY, light pipes for internal
illumination, and a full heat recovery ventilation system.

Insulated to the hilt, and built of massive amounts of masonry.

This would be its own heat store (or cool store)

I'd use a heat pump connected to pipes buried in the earth roof.

Possibly photovoltaics to charge batteries to drive the pump.

The key though for house heating is to have huge heat exchangers on the
ventilation. Ventilation is the dominant heat loss in a super insulated
house. If teh heat pump heated incoming air (or cooled it in summer)
that would be the final tuning of the internal temperatures.


In summer, reverse the heat pump and drive heating coil in an outside
swimming pool etc. And refrigerate the house..

Needless to say this would be a very ecpensive house, and would take a
lot of energy to make...

In the end you have to do the cost benefit analysis on whatever you make
and amortize it over the expected lifetime of the house.

For urban situations, the answer is to essentially roof over a city
block. And use photochromic glass..

On Dec 11, 8:40 am, Peter Parry wrote:

stuff snipped

Yes, you asked "It would be really useful to find out how he achieved
the fivefold
increase in performance"

and I answered, or at least pointed you to the answer.

cheers,
Pete.

On Mon, 10 Dec 2007 22:43:43 +0000, AJH wrote:

My infra red thermometer seems pretty effective at measuring bath
temperature.

That because it's measuring the IR given off by the ho****er...

--
Cheers
Dave. pam is missing e-mail