Siting of panels for solar water heating

Will wrote:

We moved into our two storey, reconstituted stone-built, pitched-roof house in April.
We decided early on to get as much of our energy as possible from renewables.
A couple of weeks ago we signed up for a solar heating system. I've looked at a few and this seems like a very good system.
The marketing wonk who visited us (who had obviously been in the pub first) declared that our directly west-facing roof would be perfectly adequate to site the panels. It is a very clear prospect as it faces a flat field, and there are no trees in the line of sight.
However, when their surveyor came to measure up he said that the west-facing roof was inadequate and the panels would have to be sited on the gable-end wall (facing south).
I can't see how this would be an improvement. Even though the panels would be angled away from the wall (mimicing the roof's pitch) they would certainly be obscured by the angle of the roof for at least part of the morning and part of the evening.
Am I wrong? The alternative, according to the surveyor, would be double the number of panels with half on the east pitch and the other on the west.
Many thanks
Will.

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. The whole batch of kit and pipes came to �1100. I was dubious about the effectiveness of having the panel vertical so I have used 4 "L" brackets to mount it to the wall. If I find it lacks performance when the spring comes round I can simply extend the bottom brackets with mild steel bar. with the present dull weather we do notice an elevation of the temperature of the cylinder bottom by about 15 to 20 degree C on many days (the sensor is about 300mm above the base of the cylinder) It will be interesting to see what happens to our energy bill over the next twelve months. Obviously I would like a decent saving but its an experiment with a potential for economy
John

"cynic" wrote in message Will wrote:

We moved into our two storey, reconstituted stone-built, pitched-roof house in April.
We decided early on to get as much of our energy as possible from renewables.
A couple of weeks ago we signed up for a solar heating system. I've looked at a few and this seems like a very good system.
The marketing wonk who visited us (who had obviously been in the pub first) declared that our directly west-facing roof would be perfectly adequate to site the panels. It is a very clear prospect as it faces a flat field, and there are no trees in the line of sight.
However, when their surveyor came to measure up he said that the west-facing roof was inadequate and the panels would have to be sited on the gable-end wall (facing south).
I can't see how this would be an improvement. Even though the panels would be angled away from the wall (mimicing the roof's pitch) they would certainly be obscured by the angle of the roof for at least part of the morning and part of the evening.
Am I wrong? The alternative, according to the surveyor, would be double the number of panels with half on the east pitch and the other on the west.
Many thanks
Will.

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. The whole batch of kit and pipes came to �1100. I was dubious about the effectiveness of having the panel vertical so I have used 4 "L" brackets to mount it to the wall. If I find it lacks performance when the spring comes round I can simply extend the bottom brackets with mild steel bar. with the present dull weather we do notice an elevation of the temperature of the cylinder bottom by about 15 to 20 degree C on many days
Yes, so do we. 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.
Mary

In message , John Beardmore writes

I don't see what my folks signed for as being economically viable
No, but I think our clients divide into at least four categories.
People that want to save the world.

Well, they really aren't going to, are they
They've been taken in by the con
The reality is that the total energy demand of the UK is insignificant when compared to that of the USA and the potential consumption of China, India and other fast developing nations
One thing which I have not come across is anyone publishing the manufacturing footprint i.e. energy require and CO2 created in manufacturing the system, keeping the factory open, maintaining reps cars, etc

People that like interesting toys.

FSVO interesting

People that want to set an educational example.

probably

People that want to save money.

Given that the only realistic saving is in hot water (an optimistic 70%), not house heating (when it's REALLY required) or cooking
and seeing the cost of these systems (>�5k) I fail to see how most people would see a payback in less than 10 years

All three seem worthy in one respect or another.

Not really

Another category may also creep in.
People that follow fashion.
I remember hearing last week "Solar heating is the double glazing of the

21st century"
.... sounds about right to me
-- geoff

In message , Joe Fischer writes

On Sat, Andy Hall wrote:
All of this is focus in completely the wrong area. All the time that the U.S. continues not to make much of a federal effort in terms of emissions control
The federal government doesn't own many fossil fuel power plants. But both the coal industry and the power plants have been spending fortunes cleaning up coal to reduce pollution.

Reducing demand might help too

and China is opening a new coal fired power station weekly, all of this other stuff makes so little difference that it is a waste of time on environmental grounds.
There is a lot of USA bashing, but other than the French nuclear industry, I see very little about what other countries are doing to reduce CO2 emissions.

Mainly because the USA is by far he most energy hungry country

I would suggest that efforts are turned towards dealing with the major issues, and that does not include getting GW Bush to sign up for silly politicised nonsense like Kyoto, but for serious efforts for change.
Actually, the only really viable change can only come from alcohol production from bio sources, there can be some CO2 sequestration but not on the scale that would be needed to make a difference.
Even if the case for CO2 induced global warming could be demonstrated clearly and proven beyond doubt, there is nothing much that can be done without people freezing

How did mankind survive 200 years ago ?

or giving up income.

Well that's the rub - when you're living beyond your (ecological) means, you have to cut back
The same as is happening to North Sea cod - over-fishing means that we're reaching the tipping point from which it seems unlikely that the stocks will recover. Factory farming will be useful in the future, but there's a chasm between then and now
similarly with energy consumption
.... which needs a cunning plan, not people turning off their TVs and disconnecting phone power supplies
-- geoff

On Sat, OldNick wrote:

On Sat, 18 Nov 2006 04:17:39 -0500, Joe Fischer joe@westpointracing.com> wrote: There is a lot of USA bashing, but other than the French nuclear industry, I see very little about what other countries are doing to reduce CO2 emissions.
Well, coming from Australia I certainly cannot talk. We are right up there for energy usage.
But a lot of countries might be saying "well we don't need to clean up so much because we simply use /produce less."

I wasn't aware of any world central government coming into power. :-)
And I am not convinced there is a problem, about the only pollution that may spread outside North America is from forest fires, and everything possible is being done to prevent them and put them out.
As far back as the early 1970s, I know that a lot of money was being spent on cleaning up metallurgical coal (used to make coke), and I am pretty sure the power plants have had a lot of equipment installed over the years. I know there is a huge mountain of flue ash at the closest power plant, and it is being sold to the cement plant right across the road, but I don't know for sure how much of it is calcium, and how much of it is carbon.
If anybody wants me to freeze to reduce energy use, I can only say, "kiss my grits". :-)
Joe Fischer

On Sat, 18 Nov 2006 09:39:44 GMT, Anthony Matonak wrote:

Joe Fischer wrote: A house built for solar heat, or any type of efficient heating, should have a triple wall construction, in contrast to present common designs, a well insulated outer wall, a thick masonry wall (concrete block), and either face brick on the inside, or furring strips and plaster (drywall). There are many concrete block houses, but almost all have the block on the outside.
Perhaps because the block is much more durable and resistant to the weather than insulation. Myself, I would have to run the numbers but I have a feeling that if you have a well (even super) insulated house then the typical contents of that house, drywall, furniture, collections of brick a brack, would have more than enough thermal mass to do the job.

Not even close to the mass of concrete blocks, in fact, a double row of blocks with concrete poured between them would pay for itself in 5 years in energy savings. When current construction design was made, energy was not much of a consideration. It is really hard to break bad habits.

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

South facing windows do not allow direct sunlight in summer if there is much overhang at all, this is something that needs to be taught in the first grade. And it would be easy and low cost to have a swinging overhang that could be set for seasons and unusually warm days in spring and fall.
Joe Fischer

On Sat, 18 Nov 2006 10:09:37 -0000, "Mary Fisher" wrote:

"Joe Fischer" wrote in message snip roofs don't usually last more than 15 or 20 years,
WHAT?
Our house was built in 1937 and has its original roof (plus solar water heating panel). Most of the others houses on this estate are the same, the few who have newer roofs have replaced them for reasons other than failure. Mary

What kind of roof, slate or terra cotta tile, or metal?
I guess there are places where a kind of concrete tiles are the most used.
Joe Fischer

On 18 Nov 2006 02:47:08 -0800, meow2222@care2.com wrote:

Joe Fischer wrote: On 17 Nov 2006 meow2222@care2.com wrote: A typical brick or block house should be big enough, assuming its decently insulated. Mine doesnt lose a whole lot of temp overnight. One simply sets the solar heating stat to above the temp of the gas CH, make use of that comfort zone. NT
A house built for solar heat, or any type of efficient heating, should have a triple wall construction, in contrast to present common designs, a well insulated outer wall, a thick masonry wall (concrete block), and either face brick on the inside, or furring strips and plaster (drywall). There are many concrete block houses, but almost all have the block on the outside.
This is as bad as all the industrial buildings having north facing windows. Joe Fischer
It would be a lot more material efficient to have 2 wall leafs than 3, with the inner being thicker than the outer, eg 2.5" outer leaf, 1" uninsulated cavity, 6" insulated cavity then 6" inner leaf. SS wall ties would give the 2.5" leaf good stability.
Triplewall construction only gives a 2nd cavity, and this can be achieved at far lower cost in other ways. NT

I was thinking of getting more mass inside the insulation, masonry only has a specific heat about half that of water, but 100,000 pounds of concrete inside the insulation would mean that 50,000 BTU would have to be lost for the temperature to drop one degree.
The latest thing seems to be thick foam core walls, which gives excellent insulation if thick enough, but doesn't have the mass to buffer temperature changes.
Joe Fischer

On Sat, 18 Nov 2006 11:01:44 -0000, "Mary Fisher" wrote:

"Andrew Gabriel" wrote in message He's posting from the US.
And it's different there?

Most buildings, yes, roofs are asphalt shingles, with a little glass fiber in them now that asbestos is banned. Most houses here have been built since WWII, mostly to house all the people coming here from Europe. :-)

In the UK, roof life between significant maintenance events has normally been around 70 years (so you've got 1 year to go Mary;-).
Ours hasn't needed any maintenence and my father back-pointed the (rosemary) tiles when the house was new. Nothing has shifted - we keep an eye on it but apart from a bit of flaunching round the chimney (not really the roof) nothing needs doing.
If only the rest of the house were as good :-) Mary

There are very few rosemary roofs here, and with tile roofs, the construction would have to be much different, at least double the wood in rafters, and maybe a lot of shorter spans, plus better ties to keep the walls from spreading under the load.
I just put a new roof on, but the insurance company paid for it even though it was near it's life, the hail storm in 2002 made a couple of holes in each span and saved me $3000. Maybe you don't have hail storms, tornados, hurricanes or earthquakes? ;-)
Joe Fischer

"cynic" wrote:

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. The whole batch of kit and pipes came to £1100.

How many square feet did that 1100 pounds buy?

I was dubious about the effectiveness of having the panel vertical so I have used 4 "L" brackets to mount it to the wall. If I find it lacks performance when the spring comes round I can simply extend the bottom brackets with mild steel bar. with the present dull weather we do notice an elevation of the temperature of the cylinder bottom by about 15 to 20 degree C on many days (the sensor is about 300mm above the base of the cylinder) It will be interesting to see what happens to our energy bill over the next twelve months. Obviously I would like a decent saving but its an experiment with a potential for economy John

It sounds like excellent planning, you might even want to make the angle adjustable for each season.
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.
Joe Fischer

Joe Fischer wrote:

I was thinking of getting more mass inside the insulation, masonry only has a specific heat about half that of water, but 100,000 pounds of concrete inside the insulation would mean that 50,000 BTU would have to be lost for the temperature to drop one degree.

Are phase-change materials currently a cost-effective way of improving thermal mass?
Toby

On Fri, 17 Nov 2006 19:46:10 -0500 Joe Fischer wrote :

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

We already have this: it's called low-E glass - Kappafloat is one trade name. A microscopic coating on the inside of the outer pane of a DG unit reflects heat back into to room instead of letting it escape. Over the heating season, a high-spec window on a south elevation will let in more heat than it lets out.
www.bfrc.org has more for anyone interested.
-- Tony Bryer SDA UK 'Software to build on' http://www.sda.co.uk

On Sat, 18 Nov 2006 raden wrote:

In message x Joe Fischer joe@westpointracing.com> writes On Sat, Andy Hall wrote: All of this is focus in completely the wrong area. All the time that the U.S. continues not to make much of a federal effort in terms of emissions control
The federal government doesn't own many fossil fuel power plants. But both the coal industry and the power plants have been spending fortunes cleaning up coal to reduce pollution.
Reducing demand might help too

That's why we buy everything from China and Asia now, so we don't use so much energy in factories. :-)

and China is opening a new coal fired power station weekly, all of this other stuff makes so little difference that it is a waste of time on environmental grounds.
There is a lot of USA bashing, but other than the French nuclear industry, I see very little about what other countries are doing to reduce CO2 emissions.
Mainly because the USA is by far he most energy hungry country

And the biggest energy producing country.
But if the A-380 is ever used by airlines, fuel use all over the world will go up.

I would suggest that efforts are turned towards dealing with the major issues, and that does not include getting GW Bush to sign up for silly politicised nonsense like Kyoto, but for serious efforts for change.
Actually, the only really viable change can only come from alcohol production from bio sources, there can be some CO2 sequestration but not on the scale that would be needed to make a difference.
Even if the case for CO2 induced global warming could be demonstrated clearly and proven beyond doubt, there is nothing much that can be done without people freezing
How did mankind survive 200 years ago ?

Depends on where, eskimos wore skins, and ate lots of blubber for energy. Rural Eastern Europe lived in shacks with dirt floors, and on real cold nights invited the cattle and pigs in, and cuddled with them. I guess maybe in the UK, coal was being burned for heat.

or giving up income.
Well that's the rub - when you're living beyond your (ecological) means, you have to cut back

Unless Saudia Arabia keeps selling oil.

The same as is happening to North Sea cod - over-fishing means that we're reaching the tipping point from which it seems unlikely that the stocks will recover. Factory farming will be useful in the future, but there's a chasm between then and now

I don't think the energy crisis is exactly analogous to over fishing, but I like the idea of fish farms. In 1958 I experimented with raising guppies in salt water until they were adults, they were sterile in ocean water, bur when slowly accustomed back to fresh water, they were extremely healthy and prolific. If the number of young I got from 15 pairs were to be extrapolated over 10 years, there would be enough to feed the world.

similarly with energy consumption

I am all for planting every square acre in sugar cane, potatoes, beets, water melon, and everything that can be used to make ethanol. But that may not work in every country.

... which needs a cunning plan, not people turning off their TVs and disconnecting phone power supplies

There is time, at least in the US, but I see Europe in a critical situation, with an urgent need to do something to assure that people don't freeze.
Even if there is a crisis, action will be fast, and a solution will be worked out (unless you are talking about sea level rise, which is going to happen anyway). My problems are just keeping warm in 2 rooms and bath (the rest of the house is not heated), and trying to keep from being bored.
Joe Fischer

On Sat, Toby Kelsey wrote:

Joe Fischer wrote: I was thinking of getting more mass inside the insulation, masonry only has a specific heat about half that of water, but 100,000 pounds of concrete inside the insulation would mean that 50,000 BTU would have to be lost for the temperature to drop one degree.
Are phase-change materials currently a cost-effective way of improving thermal mass? Toby

I haven't priced them, eutectic salts can be custom mixed to any temperature phase change and they are much better than passive mass like concrete because energy is transferred without a change in temperature of the salts (in the selected range).
But even so, the extra thick walls of a house is an advantage that works several ways as a buffer to temperature changes.
I lived in a permanent barracks near San Antonio in 1948 that had walls two feet thick, and outdoor temperature changes were hardly noticed without any heat or air conditioning, and temperatures could swing 60 degrees from 4 AM till 2 PM.
The problem with salts is where to put them, maybe a DIYer could put them in used 2 liter bottles and stack them in unused space, but most existing houses don't have a good place to put them. They need to be in fairly small containers or pipes so that room air can be circulated through them to get a rate of heat transfer high enough.
Joe Fischer

Joe Fischer wrote:

"cynic" wrote:
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. The whole batch of kit and pipes came to �1100.
How many square feet did that 1100 pounds buy?

The array is approximately five feet by five feet but this is interspaced by the gaps between the tubes so meaningless really. The tubes are about five feet long and 2.5 inches diameter

I was dubious about the effectiveness of having the panel vertical so I have used 4 "L" brackets to mount it to the wall. If I find it lacks performance when the spring comes round I can simply extend the bottom brackets with mild steel bar. with the present dull weather we do notice an elevation of the temperature of the cylinder bottom by about 15 to 20 degree C on many days (the sensor is about 300mm above the base of the cylinder) It will be interesting to see what happens to our energy bill over the next twelve months. Obviously I would like a decent saving but its an experiment with a potential for economy John
It sounds like excellent planning, you might even want to make the angle adjustable for each season.

I'm not so much concerned about the angle of incidence of the solar radiation since the net effect of having the tube angled or square on to the sun is minimal, its still illuminated. What I was concerned about was degradation of the convection currents within the reduced pressure fluid inside the fairly narrow copper collector core tubes. As I said I am treating this as an experiment and may alter things around to see how it responds

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.

e-bay is your friend!