Siting of panels for solar water heating

In message , Peter Parry writes

On Mon, 20 Nov 2006 14:24:06 GMT, Tony Bryer <tonyb@delme.sda.co.uk wrote: On Mon, 20 Nov 2006 13:23:55 +0000 Peter Parry wrote :
Three of the eight systems on test had failures of some sort at some point during the one years testing.
What sort of failures?
In total there were 6 failures, 3 on delivery and three in use.
The three on delivery were -
A defective controller PCB. (Zen)

Think they generally supply Resol controllers. It does happen, but I don't recall us ever having a duff one. Well - maybe one.

Tube in vacuum array mounted upside down (Riomay)

ROFL ! We've never seen that either, but it would be a sod to fix as the tubes are brazed or silver soldered into the manifold, and might go bang, (big bang with those !), if you go mad with a torch !

Blocked non return valve (Filsol)

Interesting. Filsol don't normally use NRVs - these days at least.
Sometimes the problem with NRVs is not so much that they are stuck, as that a pump won't develop enough pressure to open them. Got to choose them with some care.

in service the three faults were:-
1. System boiled after power cut - melted manifold to supply plastic pipe, during rectification non return valve found to have no internal components. (Riomay)

ROFL !!!
(You might think that - I couldn't possibly comment !)

2. System pump failed (Fieldway)

Never heard of them.

3. System boiled after power cut, afterwards overpressure release valve leaked. (Thermomax).

Unlucky - I guess these days people do tent to fit high temperature ABVs and 'blow offs' which they didn't always in the early days. What's more, if the expansion vessels had been sized correctly, it shouldn't have blown off, another mistake that used to be pretty common.
But 'Shine 21' and 'Clear Skies' requirements have got the industry out of many bad habits !
Cheers, J/. -- John Beardmore

In message , Mary Fisher writes

"John Beardmore" wrote in message In message , Mary Fisher mary.fisher@zetnet.co.uk> writes
Given that the only realistic saving is in hot water (an optimistic 70%), not house heating (when it's REALLY required)
I wonder what is thought of as REALLY required.
Our thermostat is set at 10C - that is, the thermostat is wound to its lowest setting. When it comes on in the night, as it did last night when we had a frost, it's too hot for us.
Turn down the boiler then ?
I've turned off the bedroom RTV.
But that doesn't answer what is REALLY required in terms of house heating. Most houses I go into seem to have the thermostat at 25C, the inhabitants wear minimal clothing.

Hmm... I can't get our family under 18...
Cheers, J/. -- John Beardmore

"John Beardmore" wrote in message

But that doesn't answer what is REALLY required in terms of house heating. Most houses I go into seem to have the thermostat at 25C, the inhabitants wear minimal clothing.
Hmm... I can't get our family under 18...

You're very young! you didn't live through coal rationing ... not that I'd wish that on you.
Mary

On Mon, 20 Nov Matt wrote:

On Sun, 19 Nov 2006 13:54:56 -0500, Joe Fischer joe@westpointracing.com> wrote: In the immediate future, global warming is not the scary thing, volcanic activity on the continent of Antarctica should be the most feared thing by property owners in low lying coastal areas.
I hate to break the news to you but there is volcanic activity in Antarctica. In fact Mount Erebus is classified as a stratovolcano, the same as Krakatoa and Mount St Helens and we all know what a bang they made.
Do SUV's float?

For a little while, if you don't open a door or window.
It is difficult to imagine how just the ice sheet on Greenland could raise sea level so much if it melts, but somebody did the math. And there is something that skews the data on sea level rising, over the last 300 years, dams have been built that reduced or delayed runoff into the ocean, and about all the dams that can be built, have been built.
Joe Fischer

John Beardmore wrote:

In message , cynic icelandic@talktalk.net> writes
How does your horizontal tube set up an internal convection to transfer collected heat to the header at the top? I simply cannot visualise your layout unless it has an entirely different arrangement/principal to mine
You mean you have an ET system with an unpumped primary ?
Cheers, J/. -- John Beardmore

The first stage in the collection is twenty vertical tubes with partial pressure fluid inside. These "plug-in" to a series of copper sockets sealed into a top horizontal manifold tube thus can be changed without depressurising if so needed. The manifold has a pt1000 temperature sensor which monitors the temperature and if the differential between manifold and cylinder is sufficient the controller runs the circulation pump. If the top region of the cylinder is above a set point the pump is inhibited. Among other points I am awaiting the right weather to study is the effect of long periods of sunshine with the cylindewr up to temperature. There is no heat dump facility but if needed I could provide one relatively simply.

John Beardmore wrote:

In message , cynic writes John Beardmore wrote: In message , cynic writes
I installed a system a few weeks ago. My vacuum tube array collector is vertical on the gable end. I was faced with a cylinder replacement and decided to go solar rather than stay limited to fossil.
OK. Reflector below ?
No - behind
Yes - know what you mean...
The whole batch of kit and pipes came to �1100.
Does that include pump, controller, antifreeze etc ?
Everything except the 1.0mm t&E I used to extend the array pt1000 sensor down to the airing cupboard. I had a roll lying around.
OK. And cylinder ?
Yes the cylinder was included in the price. Its a slim tall unit with

solar coil flat to the bottom, a boiler fed coil about halfway up and an immersion boss at the top. Without going up and raking out the airing cupboard to measure i'd say about 400mm diameter and around 1700mm high with a thick foam insulation applied in manufacture.

In message , Mary Fisher writes

"John Beardmore" wrote in message
But that doesn't answer what is REALLY required in terms of house heating. Most houses I go into seem to have the thermostat at 25C, the inhabitants wear minimal clothing.
Hmm... I can't get our family under 18...
You're very young!

Thanks - I think !

you didn't live through coal rationing ... not that I'd wish that on you.

No - just the first 70s 'oil shock'.
Cheers, J/. -- John Beardmore

In message , cynic writes

John Beardmore wrote:
In message , cynic icelandic@talktalk.net> writes
How does your horizontal tube set up an internal convection to transfer collected heat to the header at the top? I simply cannot visualise your layout unless it has an entirely different arrangement/principal to mine
You mean you have an ET system with an unpumped primary ?
Cheers, J/. -- John Beardmore
The first stage in the collection is twenty vertical tubes with partial pressure fluid inside.

Heat pipes I guess ?

These "plug-in" to a series of copper sockets sealed into a top horizontal manifold tube thus can be changed without depressurising if so needed.

Sounds standard.

The manifold has a pt1000 temperature sensor which monitors the temperature and if the differential between manifold and cylinder is sufficient the controller runs the circulation pump. If the top region of the cylinder is above a set point the pump is inhibited. Among other points I am awaiting the right weather to study is the effect of long periods of sunshine with the cylindewr up to temperature. There is no heat dump facility but if needed I could provide one relatively simply.

Yes. Cylinder stat and solenoid valve, but maybe better just to let the pump stop and the water from the manifold displace to an expansion vessel ?
Cheers, J/. -- John Beardmore

In message , Matt writes

On Sun, 19 Nov 2006 13:54:56 -0500, Joe Fischer joe@westpointracing.com> wrote:
In the immediate future, global warming is not the scary thing, volcanic activity on the continent of Antarctica should be the most feared thing by property owners in low lying coastal areas.
I hate to break the news to you but there is volcanic activity in Antarctica. In fact Mount Erebus is classified as a stratovolcano, the same as Krakatoa and Mount St Helens and we all know what a bang they made.
Do SUV's float?
Volcanic activity seems to be generally on the rise ATM

I can think of at least three in Indonesia which are puffing away with increased enthusiasm - Merapi, Anak Krakatau and one in Papua
and then there's a few sliding plates
something 's gonna happen soon
-- geoff

In message , Joe Fischer writes

On Mon, 20 Nov Matt wrote:
On Sun, 19 Nov 2006 13:54:56 -0500, Joe Fischer joe@westpointracing.com> wrote: In the immediate future, global warming is not the scary thing, volcanic activity on the continent of Antarctica should be the most feared thing by property owners in low lying coastal areas.
I hate to break the news to you but there is volcanic activity in Antarctica. In fact Mount Erebus is classified as a stratovolcano, the same as Krakatoa and Mount St Helens and we all know what a bang they made.
Do SUV's float?
For a little while, if you don't open a door or window.
It is difficult to imagine how just the ice sheet on Greenland could raise sea level so much if it melts, but somebody did the math.

Maths ...
IIRC 76 metres

And there is something that skews the data on sea level rising, over the last 300 years, dams have been built that reduced or delayed runoff into the ocean, and about all the dams that can be built, have been built.
Joe Fischer

-- geoff

In message , Mary Fisher writes

"David Hansen" wrote in message On Sun, 19 Nov 2006 19:46:16 GMT someone who may be raden raden@kateda.org> wrote this:-
Today, with the outside temperature at 6C (and overcast sky) we had water at 25C. That's not hot enough for Spouse's washing up or my baths but it's fine for hand washing and it means that the boiler won't need to be on as long to raise the water temperature to his acceptable level.
So, considering it's not really cold and your system's struggling
Not really cold? You'd be happy to have your room temperature at that?

No, I am here lying on the sofa at 1 am (naked but for a T-shirt if you need that extra information) with no heating on at all.
But then, does yours heat the house ?

Solar water heating works on the sun, not the external temperature. The two do have some relationship, but the temperature from a solar system essentially depends on the length and intensity of the sunlight, the external temperature is largely irrelevant (except for frost protection in some systems).
not really very good then
It is very good. Even if the temperature in the cylinder needs to be boosted it will use far less gas and time than if the mains cold feed were being heated.

Just keep telling yourself that

I'm not trying to persuade anyone to have solar water heating, I do wonder why people try to prove that our system isn't good.

I think you have already proved it yourself
-- geoff

In message , David Hansen writes

On Sun, 19 Nov 2006 19:46:16 GMT someone who may be raden raden@kateda.org> wrote this:-
Today, with the outside temperature at 6C (and overcast sky) we had water at 25C. That's not hot enough for Spouse's washing up or my baths but it's fine for hand washing and it means that the boiler won't need to be on as long to raise the water temperature to his acceptable level.
So, considering it's not really cold and your system's struggling
Solar water heating works on the sun, not the external temperature. The two do have some relationship, but the temperature from a solar system essentially depends on the length and intensity of the sunlight, the external temperature is largely irrelevant (except for frost protection in some systems).

That's not what I meant - I meant that on a reasonable day when you need it, i.e. warmer than usual winter's day, it's marginally above useless

not really very good then
Look at the subject and note that the manufacturers say that solar water heating will provide nearly all the hot water in the summer, assuming a properly sized system, but need some boosting in autumn, winter and spring, depending on the amount of sunlight. The hot water requirement does not change much with the seasons.
See above

-- geoff

In message , John Beardmore writes

In message , Joe Fischer joe@westpointracing.com> writes "cynic" wrote:
Vacuum tube arrays could possibly be produced fairly cheap, just as 4 foot fluorescent tubes only cost 99 cents the last time I bought them, but I don't have much hope of seeing them sold to the DIY gang in small quantities at a good price.
It's getting better, mostly thanks to the Chinese !
I think I'd argue the exact opposite

.... but if you think so, and it keeps you happy ...
-- geoff

In message , John Beardmore writes

In message , raden <raden@kateda.org writes In message , Mary Fisher writes
Today, with the outside temperature at 6C (and overcast sky) we had water at 25C. That's not hot enough for Spouse's washing up or my baths but it's fine for hand washing and it means that the boiler won't need to be on as long to raise the water temperature to his acceptable level.
So, considering it's not really cold and your system's struggling
not really very good then
Considering it's one of the three months with the shortest day lengths and the amount of fossil fuel required for DHW is still being reduced,

Not really doing the biz when it's req'd though, is it
As long as she feels she is doing something, it's OK (whatever the reality of the situation is)
-- geoff

On uk.environment, in , "raden" wrote:
<snip>

As long as she feels she is doing something, it's OK (whatever the reality of the situation is)

That's garbage.
You must be an Environmentalist. They all feel like they are doing something to save the planet, although 35+ years of data clearly reveals that they aren't.
And they seem to think thats OK, because they aren't changing their strategy.
And their PR machine is still telling everyone that they are accomplishing something.
Which they obviously think is OK.
Neither of them are OK.
Far from it.
Alan
-- http://home.earthlink.net/~alanconnor/contact.html http://home.earthlink.net/~alanconnor/survival/index.html http://home.earthlink.net/~alanconnor/linux-unix/index.html