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BigWallop
 
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Default Solar space heating idea


"NickW" wrote in message
om...
"BigWallop" wrote in message

...
Hi Nick,

Have a good read through this:

http://tinyurl.com/fvfj

it will give you a better idea of what is needed.


---
BigWallop


Actually, my inspiration was this:

http://www.humboldt1.com/~michael.we...hotairhp72.pdf

I thought why pay through the nose for something which can be made on
a much larger scale with existing garage roofspace and ordinary
building materials. I might not achieve the same efficiency / sqm they
do but I'd more than make up for it with quantity. As a bonus, the
'collector' would not be as obtrusive.

(I have a grade 2 listed cottage so nothing can go on it's roof BTW)

Nick


Ah Ha !! Very Interesting Nick. The only thing with this is, will it work
in a British winter ? This system would be great for hot air heating during
the winter months, but do we get enough sunny days to make it viable ?

Me thinks me needs more research into this subject.

I may be back.


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NickW
 
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Ah Ha !! Very Interesting Nick. The only thing with this is, will it work
in a British winter ? This system would be great for hot air heating during
the winter months, but do we get enough sunny days to make it viable ?

Me thinks me needs more research into this subject.

I may be back.


---
BigWallop

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Well, in the link I posted the guy's system produces an average of
0.25 kw from a collector of size 2.8 sqm on an "overcast winters day".
I don't know where he lives but it's snowing there!

I guess the main benefit will be in spring and autumn where the
central heating will hopefully not come on much at all. Come the
middle of winter, I'm sure it will be on a lot.

However, I was looking at my site this morning and realised that the
garage roof might get shaded in the winter when the sun is low. It
gets sun all day in the summer...

Here is a photo of the site (looking east so the garage is north of
the house):
http://home.no.net/enaasen/back_garden_from_gate.JPG

So I might have to rethink :-(

If it's a non starter, I'll see if I can persuade the wife to have
removable panels on the ground at the front of the house...

Nick
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BigWallop
 
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Default Solar space heating idea


"NickW" wrote in message
om...
Ah Ha !! Very Interesting Nick. The only thing with this is, will it

work
in a British winter ? This system would be great for hot air heating

during
the winter months, but do we get enough sunny days to make it viable ?

Me thinks me needs more research into this subject.

I may be back.


---
BigWallop

http://basecuritysystems.no-ip.com

Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.495 / Virus Database: 294 - Release Date: 30/06/03


Well, in the link I posted the guy's system produces an average of
0.25 kw from a collector of size 2.8 sqm on an "overcast winters day".
I don't know where he lives but it's snowing there!

I guess the main benefit will be in spring and autumn where the
central heating will hopefully not come on much at all. Come the
middle of winter, I'm sure it will be on a lot.

However, I was looking at my site this morning and realised that the
garage roof might get shaded in the winter when the sun is low. It
gets sun all day in the summer...

Here is a photo of the site (looking east so the garage is north of
the house):
http://home.no.net/enaasen/back_garden_from_gate.JPG

So I might have to rethink :-(

If it's a non starter, I'll see if I can persuade the wife to have
removable panels on the ground at the front of the house...

Nick


It looks loverly Sir, and I am now jealous. I live in an Edinburgh
Tenement, but have to say that these houses are very cosy all year round.
Not to hot in the summer and well insulated for the winter months.

I see what you mean about the garage being in the shade, and the picture was
taken on quite a clear day which is ideal for your idea. So it may have to
be portable panels out the back door.

What the neighbours and I have done here, is put a small wind generator on
the roof, shhh, don't tell anyone 'cause it needs planning permission, which
runs the door entry system and a light at the bottom of the stairs, from a
rechargeable car battery system, that's how small it is. If we'd gone down
the, so called, correct route, we'd have had a big electric meter and fuse
blocks right at the bottom of the stairs or someone running cables through
the common stair to one of the houses, and no one here wanted that. So the
pyro' runs down the outside of the building and up to the front door, and it
only cost me a day a year to check that it's all OK. Which it has been now
since 19 dot and a bit.

Have you thought about going with a wind turbine ? Nothing to huge, just
something that would give enough power to run your hot water tank and maybe
a few outside lights at night from a battery storage system. It would help
cut at least something off the bills a bit. In the picture it looks like
the perfect spot for a small turbine not to far away from the back of the
house, and disguised by the trees in the background.


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Grunff
 
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Default Solar space heating idea

BigWallop wrote:

Have you thought about going with a wind turbine ? Nothing to huge, just
something that would give enough power to run your hot water tank and maybe
a few outside lights at night from a battery storage system. It would help
cut at least something off the bills a bit. In the picture it looks like
the perfect spot for a small turbine not to far away from the back of the
house, and disguised by the trees in the background.


Current prices mean that small wind turbines are not
economically viable. I'm not taling about a tiny thing that
generates a few W, I'm talking about a big one which produces
enough power to power a hot water tank.

--
Grunff

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N. Thornton
 
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Default Solar space heating idea

(NickW) wrote in message . com...

Hi

Good one.

Regards, NT


  #6   Report Post  
NickW
 
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Default Solar space heating idea

I have considered a wind turbine... there are plans for DIY ones which
don't cost too much. I have also been thinking about direct drive heat
producing ones, ie: convert the kinetic energy into heat using a heat
pump or stirling engine rather than into electricity first. This would
remove the efficiency loss of converting to electricity and also
produce something like 2-3 times more heat that the kinetic energy
taken to drive it.

Solar thermal however, I think should be exploited first as it seems
to yield the big numbers for something as simple as heating air. I
worked out at the weekend that I have enough space for an 8 square
meter freestanding collector on the south side of my house. Hopefully
enough to average 1.6kw during daylight hours during the winter.

BTW: you can get sizeable grants for solar/wind/hydro projects (yes,
even on a domestic scale). The only downside is that you must have an
approved system (not homemade!) and it must be installed by an
approved installer who will cheerfully jack up his labour cost to eat
up your grant. I know this because I got a quote to have solar matting
installed for my pool and the guy wanted to charge me 1000 quid for a
10 hour job. :-(

Regards

Nick.
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IMM
 
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Default Solar space heating idea


"NickW" wrote in message
om...

Solar thermal however, I think should be exploited first as it seems
to yield the big numbers for something as simple as heating air.


Air heaters are very efficient. have one on the back wall of a conservatory
with the heat rising into the house, or loft and ducted down.

What is very efficient and economical, is a sun tracker focusing the sun via
lenses onto a heat exchanger and producing very hot water. These can also
produce steam and run a small steam or Stirling engine/generator. Even in
cloudy weather very hot useful water can be produced. Steam or Stirling
engines can be very small for high large torque. There is research in the
USA on sun trackers/heat generators for CHP applications, or cogen as the
Yanks say, and it appears more cost effective and efficient than most other
methods: PV cells, flat plate collectors, etc.



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Martin Angove
 
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Default Solar space heating idea

In message ,
"IMM" wrote:


"NickW" wrote in message
om...

Solar thermal however, I think should be exploited first as it seems
to yield the big numbers for something as simple as heating air.


Air heaters are very efficient. have one on the back wall of a conservatory
with the heat rising into the house, or loft and ducted down.

What is very efficient and economical, is a sun tracker focusing the sun via
lenses onto a heat exchanger and producing very hot water. These can also
produce steam and run a small steam or Stirling engine/generator. Even in
cloudy weather very hot useful water can be produced. Steam or Stirling
engines can be very small for high large torque. There is research in the
USA on sun trackers/heat generators for CHP applications, or cogen as the
Yanks say, and it appears more cost effective and efficient than most other
methods: PV cells, flat plate collectors, etc.




Can I ask a couple of questions?

1: If suntrackers are so efficient, why is it that the only one at the
Centre for Alternative Technology is about 25 years old? Why haven't
they installed more? Is it perhaps that the reflectors are a waste of
time?

2: Are you *sure* Stirling engines have high torque? The ones I've seen
certainly don't - they are very efficient, but only when operating high
speed/low torque.

Just interested :-)

Hwyl!

M.

--
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
.... To hell with the prime directive, let's kill something.
  #10   Report Post  
N. Thornton
 
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Default Solar space heating idea

"IMM" wrote in message ...
"NickW" wrote in message
om...

Solar thermal however, I think should be exploited first as it seems
to yield the big numbers for something as simple as heating air.


Air heaters are very efficient. have one on the back wall of a conservatory
with the heat rising into the house, or loft and ducted down.

What is very efficient and economical, is a sun tracker focusing the sun via
lenses onto a heat exchanger and producing very hot water.


I like that approach too, tho its not problem free. I would go flat
plates /air first.

These can also
produce steam and run a small steam or Stirling engine/generator.


They can but its very impractical and very inefficient.

Even in
cloudy weather very hot useful water can be produced.


Partly cloudy yes, but qith full cloud youve got no way to concentrate
the diffuse sunlight.

Steam or Stirling
engines can be very small for high large torque.


Steam is the true master of inefficiency and bulk.

There is research in the
USA on sun trackers/heat generators for CHP applications, or cogen as the
Yanks say, and it appears more cost effective and efficient than most other
methods: PV cells, flat plate collectors, etc.


I'd be interested to see your refs then, as figures I've always seen
or calculated would suggest its a real no-no.

There are also additional problems with any steam setup due to legal
issues with the high pressure boiler. Plus PV and hot air are far more
reliable.

Regards, NT


  #11   Report Post  
IMM
 
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Default Solar space heating idea


"Martin Angove" wrote in message
...
In message ,
"IMM" wrote:


"NickW" wrote in message
om...

Solar thermal however, I think should be exploited first as it seems
to yield the big numbers for something as simple as heating air.


Air heaters are very efficient. have one on the back wall of a

conservatory
with the heat rising into the house, or loft and ducted down.

What is very efficient and economical, is a sun tracker focusing the sun

via
lenses onto a heat exchanger and producing very hot water. These can

also
produce steam and run a small steam or Stirling engine/generator. Even

in
cloudy weather very hot useful water can be produced. Steam or Stirling
engines can be very small for high large torque. There is research in

the
USA on sun trackers/heat generators for CHP applications, or cogen as

the
Yanks say, and it appears more cost effective and efficient than most

other
methods: PV cells, flat plate collectors, etc.




Can I ask a couple of questions?

1: If suntrackers are so efficient, why is it that the only one at the
Centre for Alternative Technology is about 25 years old? Why haven't
they installed more? Is it perhaps that the reflectors are a waste of
time?


Lots have happened in 25 years. Do a Goggle on sun trackers. There are
some off the shelf versions from the USA.

2: Are you *sure* Stirling engines have high torque? The ones I've seen
certainly don't - they are very efficient, but only when operating high
speed/low torque.


Specifically steam engines have high torque at low speeds. Steam trucks,
which were built up to WW2, never had gear boxes the torque was so high.
The highest torque is at stall speed. A team engines does not idle; the old
steam trucks just opened up the steam and off she went at an amazing speed
for the time. The problem with steam engines is condensing the steam back
to water, otherwise the steam has to be released and water used at high
rates. Stirling's do not have that problem. So using steam and having a
guaranteed cool condenser, such as a large thermal store, may be feasible.
Seam engines are used in ships still with a guaranteed endless supply of
cool sea water to guarantee the steam turns back to water. The most
efficient steam engines are the marine variety , which have been made far
more efficient over the past 15 years or so. The cooling problem applies
also to Stirling's, which are used in French and Swedish submarines also
using cold seas water to cool. The engines are super quiet and virtually
vibration free.

R&D using sun trackers using Stirling's and steam engines, and focusing on a
metal water filled sphere to produce steam/hot water is going on. many keen
armatures using their own home built equipment have reported excellent
results.



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  #12   Report Post  
IMM
 
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Default Solar space heating idea


"N. Thornton" wrote in message
om...
"IMM" wrote in message

...
"NickW" wrote in message
om...

Solar thermal however, I think should be exploited first as it seems
to yield the big numbers for something as simple as heating air.


Air heaters are very efficient. have one on the back wall of a

conservatory
with the heat rising into the house, or loft and ducted down.

What is very efficient and economical, is a sun tracker focusing the sun

via
lenses onto a heat exchanger and producing very hot water.


I like that approach too, tho its not problem free. I would go flat
plates /air first.

These can also
produce steam and run a small steam

or Stirling engine/generator.

They can but its very impractical and very inefficient.


The more sun in a brighter climate the better of course, but lenses have
been used that produce enough heat to make them more than feasible.

Even in
cloudy weather very hot useful water can be produced.


Partly cloudy yes, but qith full cloud youve got no way to concentrate
the diffuse sunlight.


That is so, but useful heat in part cloud conditions.

Steam or Stirling

engines can be very small for high large torque.


Steam is the true master of inefficiency and bulk.


Not these days. One double acting piston, the equivalent of a one stroke,
which is the equivalent of a V8 is very efficient, and small. Highly
efficient flash boilers containing no water, just water turned to steam
rather like a powerful instantaneous gas water heater, and burners have come
a along way too to improve efficiency.

There is research in the
USA on sun trackers/heat generators for
CHP applications, or cogen as the
Yanks say, and it appears more cost effective
and efficient than most other
methods: PV cells, flat plate collectors, etc.


I'd be interested to see your refs then,
as figures I've always seen
or calculated would suggest its a real no-no.

There are also additional problems with any steam setup due to legal
issues with the high pressure boiler.


No boiler with stored water required. Instant flash boilers don't have very
high pressures. The technology has been around for 300 years. An internal
combustion engines has a series of explosions ignited by highly volatile
fuel (petrol), which is far more dangerous than a steam engine. As in the
internal combustion engines, electronics can make a steamer far more
efficient too.

Plus PV and hot air are far more
reliable.


PV? With all those inverters and batteries. You are joking of course? Hot
air is more reliable. A sun tracker focusing to make hot water is also very
reliable.


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  #13   Report Post  
Martin Angove
 
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Default Solar space heating idea

In message ,
"IMM" wrote:


"Martin Angove" wrote in message
...

[...]

1: If suntrackers are so efficient, why is it that the only one at the
Centre for Alternative Technology is about 25 years old? Why haven't
they installed more? Is it perhaps that the reflectors are a waste of
time?


Lots have happened in 25 years. Do a Goggle on sun trackers. There are
some off the shelf versions from the USA.


The point I think I was making was that they tend to get the best/most
efficient stuff at CAT eventually, and will try (almost) anything in the
meantime. Unless something's happened since I was last there, the only
sun tracker is this 25 year old thing. If they were so good (in this
climate perhaps) then *surely* CAT would have installed a couple more
up to date versions? I can understand how they might fractionally
increase the efficiency of a system where direct sunlight is the norm,
but where diffuse light is the norm (i.e. here) where do you aim your
device? On top of that you've the extra mechanicals to maintain, and the
extra energy required to cause the thing to track.


2: Are you *sure* Stirling engines have high torque? The ones I've seen
certainly don't - they are very efficient, but only when operating high
speed/low torque.


Specifically steam engines have high torque at low speeds.


[snip the rest which interested parties have probably already read]

I understand that steam engines have high torque - but as far as I
understand it, a Stirling engine is *not* a steam engine, though I
suppose steam could be used as the heat source.

Unlike a steam engine, the cylinder is sealed.

Unlike a steam engine, the "working piston" isn't actually *in* the
cylinder, it is merely attached to it. In models it is often a sheet of
rubber, though I see no reason why a piston shouldn't be used.

Unlike a (modern) steam engine, the working fluid in the cylinder (air)
must be heated *and* cooled in order to complete one full cycle.

Can you post me some web references to the Stirling steam engine? I'm
very interested in the technology since coming across that boiler which
uses a Stirling engine on the exhaust to generate electricity. One thing
I don't quite understand about that thing though is whether it'd
actually get much use in a modern highly insulated house :-)

Hwyl!

M.

--
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
.... Pop Tarts. Perhaps the most disgusting thing you can put in a toaster.
  #14   Report Post  
IMM
 
Posts: n/a
Default Solar space heating idea


"Martin Angove" wrote in message
...

Lots have happened in 25 years. Do a Goggle on sun trackers. There are
some off the shelf versions from the USA.


The point I think I was making was that they tend to get the best/most
efficient stuff at CAT eventually, and will try (almost) anything in the
meantime. Unless something's happened since I was last there, the only
sun tracker is this 25 year old thing. If they were so good (in this
climate perhaps) then *surely* CAT would have installed a couple more
up to date versions? I can understand how they might fractionally
increase the efficiency of a system where direct sunlight is the norm,
but where diffuse light is the norm (i.e. here) where do you aim your
device? On top of that you've the extra mechanicals to maintain, and the
extra energy required to cause the thing to track.


Trackers have been fixed on sphere that contain the water. they swivel
around the ball while focusing the intense suns rays.

I understand that steam engines have high torque - but as far as I
understand it, a Stirling engine is *not* a steam engine, though I
suppose steam could be used as the heat source.


I never actually said a Stirling was steam engine. It is a "heat" engine.
There are many variations of the Stirling sing differeing gasses to expand.
It has in common with "piston" steam engine: eternal combustion (very eco)
and a heat and cooling source.

Unlike a steam engine, the cylinder is sealed.


I most yes. the early versions (1830ish) were not. There is also a rotary
(wankle type) of Stirling engine.

Unlike a steam engine, the "working piston" isn't actually *in* the
cylinder, it is merely attached to it. In models it is often a sheet of
rubber, though I see no reason why a piston shouldn't be used.


Virtually all usable Stirling's have a piston in cylinder arrangement.

Unlike a (modern) steam engine, the
working fluid in the cylinder (air)
must be heated *and* cooled in order
to complete one full cycle.


The working fluid can be air, but the more efficient versions uses various
more efficient gasses.

Can you post me some web references
to the Stirling steam engine?


http://www.stirlinginfo.com/

I'm very interested in the technology since
coming across that boiler which
uses a Stirling engine on the exhaust to
generate electricity.


Not available yet.

One thing
I don't quite understand about that
thing though is whether it'd
actually get much use in a modern
highly insulated house :-)


The unit actually has a burner playing on the Stirling, which has a free
wheeling piston with no crank, being the only moving part. The gasses pass
through a heat exchanger, Another supplementary burner is used to boost to
hot water output.

On existing poorly insulated homes the Stirling boiler is feasible. Any
excess electricity produced passes to the grid via a two-way meter.


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IMM
 
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Default Solar space heating idea


"IMM" wrote in message
...

One thing
I don't quite understand about that
thing though is whether it'd
actually get much use in a modern
highly insulated house :-)


The unit actually has a burner playing on the Stirling, which has a free
wheeling piston with no crank, being the only moving part. The gasses

pass
through a heat exchanger, Another supplementary burner is used to boost to
hot water output.

On existing poorly insulated homes the Stirling boiler is feasible. Any
excess electricity produced passes to the grid via a two-way meter.


More info....
British Gas to launch individual CHP boiler for homes


British Gas has announced that it is developing a household boiler that
generates both heat and electricity, which will increase energy efficiency
and cut costs for customers, allowing them to sell excess electricity back
to the Grid.

The new combined heat and power (CHP) boilers, developed by MicroGen Energy,
a subsidiary of BG Group plc, will result in increased energy efficiency,
says the company. Normally, only 37% of electricity that is generated at a
power station and transferred to customers via the grid is used. However,
the new boilers will have an efficiency of around 90% or more, cutting
fossil fuel use and reducing the need for gas imports, a British Gas
spokesperson told edie. One million of the boilers would be the equivalent
to Sizewell B.

The system uses a Stirling engine, invented by the Reverend Robert Sterling
in 1816. The pistons are the only moving parts of the engine, which uses gas
bearings to minimise wear. The engine is a sealed unit with no requirement
for regular servicing or maintenance, says MicroGen. The Stirling engine
generates both heat and electricity and additional heat needs are met by a
supplementary burner.

The boilers will produce a baseload of 1.1kW, which is sufficient to run
most domestic appliances during the day, and any excess is then sold back to
the Grid. At times of peak electricity use, the household will have to buy
extra electricity, and will receive a net electricity bill at the end of the
quarter.

It is also estimated that they will reduce an average household electricity
bill by around 25%, and will cut a home’s annual carbon dioxide emissions by
about 1.5 tonnes and nitrous oxides emissions by an average of 40%.

“This could herald the biggest change in British homes since the
introduction of gas central heating in the 1960s and 70s,” said John Shears,
Commercial Director of British Gas. According to Steven Evans, Chief
Executive Officer of MicrGen, the prospect of the new technology is already
arousing a great deal of interest in the market.

An added benefit, says British Gas, will be for homeowners subject to power
cuts, as they will guarantee continued heat and electricity.

The CHP boilers are currently undergoing tests by British Gas, and the first
boilers will be available commercially by late 2004/early 2005, said the
British Gas spokesperson.


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IMM
 
Posts: n/a
Default Solar space heating idea


"Martin Angove" wrote in message
...

1: If suntrackers are so efficient, why is it that the only one at the
Centre for Alternative Technology is about 25 years old? Why haven't
they installed more? Is it perhaps that the reflectors are a waste of
time?


Lots have happened in 25 years. Do a Goggle on sun trackers. There are
some off the shelf versions from the USA.


The point I think I was making was that they tend to get the best/most
efficient stuff at CAT eventually, and will try (almost) anything in the
meantime. Unless something's happened since I was last there, the only
sun tracker is this 25 year old thing. If they were so good (in this
climate perhaps) then *surely* CAT would have installed a couple more
up to date versions? I can understand how they might fractionally
increase the efficiency of a system where direct sunlight is the norm,
but where diffuse light is the norm (i.e. here) where do you aim your
device? On top of that you've the extra mechanicals to maintain, and the
extra energy required to cause the thing to track.


Some info:
Associated Press



1/13/2003 02:15 pm

A solar power demonstration program is making UNLV a hot spot for research
into tapping the sun in the southern Nevada desert as an alternative for the
nation's energy needs.

"UNLV is quickly becoming one of the leading solar researchers in the
country,"said Mary Jane Hale, a senior engineer for the National Renewable
Energy Lab in Golden, Colo."And then you have this great solar resource
there in southern Nevada."

UNLV researchers are trying to find an affordable way to generate energy
using the sun's power, and a parabolic dish array at the edge of the campus
helps to spotlight the program.

Two mirrored dishes track the sun, focusing light energy on a tube filled
with hydrogen gas that heats and drives the pistons of a Stirling engine.

The unit has been in operation for about a year. It produces 25 kilowatts of
power, or enough power for 250 100-watt lightbulbs, every second.

If testing is successful, the technology might justify the cost of putting
solar collectors on Bureau of Land Management property in the desert.

Sen. Harry Reid, D-Nev., helped secure $1 million in federal funds in 2002
for the UNLV research program. The University of Nevada, Reno got $1 million
of research money for geothermal energy.

However, the technology is expensive, and the nation has resisted
alternatives to fossil fuels.

Other solar technologies also are being tested, including a Duke Energy
project in Boulder City that uses oil, not hydrogen, to power the engine.

"What we have is a (presidential) administration right now that's not really
high on this kind of stuff,"said Bob Boehm, director of UNLV's Center for
Energy Research."They are high on oil."

The dishes soak up 30 percent of the sun's rays _ three times as much as
conventional solar panels. It would cost the average user triple the price
of traditional power sources, according to NREL officials.

But with continued research and use of the technology, costs are expected to
go down, officials said.

UNLV's renewable energy program is also training experts in a field where
there aren't many experts to go around, Boehm said.

The hope is that UNLV's projects will help make the state a Mecca not only
for the collection of energy but also the manufacturing of energy
collectors, Boehm said.

"It's not unreasonable that this could lead to some sort of industry
here,"he said."We are in a prime location for using the sun and
manufacturing these types of things."


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  #17   Report Post  
NickW
 
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Default Solar space heating idea

Hi tech stuff is all very nice but have you checked on the price of a
suntracker lately? These types of system often don't pay you back for
maybe 20 years or so.

There's a lot that can be done with simple materials. You might
achieve a collector efficiency of only 60% compared to maybe 80% of a
vacuum tube collector or a suntracker but if it costs 1/10th the price
then it could be worth it.

This is a good link:

http://www.ece.vill.edu/~nick/

The solar closet is a simple and cheap 'heat battery' to buffer the
avialable solar energy so it last overnight and maybe even over
several overcast days.

Having said all this, I've done some checking and active solar space
heating is considered not to be viable in the UK since it is usually
overcast in winter time... ah well.

Nick.
  #18   Report Post  
BigWallop
 
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Default Solar space heating idea


"NickW" wrote in message
om...

snipped

Having said all this, I've done some checking and active solar space
heating is considered not to be viable in the UK since it is usually
overcast in winter time... ah well.

Nick.


Now that's why I'd stick to a wind power system. It's the only thing we can
sort of guarantee to get more of.

What I have noticed with the wind power suggestion, is people are working on
the assumption of just one turbine and blade system, yet there's nothing to
stop the use of three or four smaller turbines being used to power the
system.

And the price of DC to AC converters is reasonable for use of stored power.
A power store today can be much smaller as well, due to current battery
technology, so it can be put into the equation on any of the chosen systems.
I can even charge my car battery from a reasonably priced solar panel on the
dashboard of the car.

But, I'll stick to the wind power for now.


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  #19   Report Post  
IMM
 
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"NickW" wrote in message
om...
Hi tech stuff is all very nice but have you checked on the price of a
suntracker lately? These types of system often don't pay you back for
maybe 20 years or so.


R&D is still ongoing and the prices will drop accordingly when packaged
solutions are available.

There's a lot that can be done with
simple materials. You might
achieve a collector efficiency of only
60% compared to maybe 80% of a
vacuum tube collector


In this case use more collectors.

or a suntracker but if it costs 1/10th the price
then it could be worth it.


Sun trackers get 3 times the suns energy than flat plate collectors. So
much so they are powering Stirling engines.

This is a good link:

http://www.ece.vill.edu/~nick/

The solar closet is a simple and cheap 'heat battery' to buffer the
avialable solar energy so it last overnight and maybe even over
several overcast days.

Having said all this, I've done some checking and active solar space
heating is considered not to be viable in the UK since it is usually
overcast in winter time... ah well.


You will be surprised at the amount of winter sun the UK gets. It varies
from area to area too: Scotland is different to Cornwall.

Active solar in the UK is viable. The solar closet can be an air heater
inside a conservatory facing south.

The best setup in the UK is firstly superinsulation and elimination of cold
bridges. This is essential. Porches on all outside doors acting as air
locks should also be fitted. A whole south facing roof can be made into a
solar collector storing heat in a large thermal store. The large surface
area means it will efficient enough to gather enough hot water. Then use
"very low" temperature underfloor heating. The reason for low temp is that
in winter the store may not have water stored at a high temp, but hot enough
for low temp underfloor heating. Also have passive solar aspects of
windows, correctly sized roof overhangs for summer shading, deciduous trees,
etc.



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  #20   Report Post  
tony sayer
 
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Default Solar space heating idea

In article , IMM
writes

"NickW" wrote in message
. com...
Hi tech stuff is all very nice but have you checked on the price of a
suntracker lately? These types of system often don't pay you back for
maybe 20 years or so.


R&D is still ongoing and the prices will drop accordingly when packaged
solutions are available.


Correction...

The packaged solutions will come about when the price of fossil fuels
comes to a point when these systems will seem cheap...
--
Tony Sayer



  #21   Report Post  
N. Thornton
 
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Default Solar space heating idea

"IMM" wrote in
"N. Thornton" wrote


Re efficient steam engines:

Well, I'd be happier to trust your word on this if you could show us a
ref. What you say certainly sounds good, but I would like to see it
backed up.


Plus PV and hot air are far more
reliable.


PV? With all those inverters and batteries. You are joking of course?


Here you're comparing apples and oranges. Both PV and steam will
produce leccy when the sun shines, and both will need either grid tie
or batteries and invertor. The steamer is comparable to the PV panels
only, not the PV + batts + invertors. Comparing a steam engine with
PV panels, the PVs are clearly much more reliable. The externals will
be similar for both forms of generator.


Hot
air is more reliable.


I think its the most reliable of all, and about the best payer too.

A sun tracker focusing to make hot water is also very
reliable.


Fairly, but not as good as flat panel collectors. Mirror deterioration
and wind damage are the major bugbears.


It was mentioned that CAT are lacking in tracking, and that if it were
a good idea they'd have more of them. I'd say fixed mirrors are a good
addition to PV, specifically angled to increase the light away from
noon, ie when the light level falls, and specifically using greased
silver mylar mirrors, which are very cheap. But AFAIK CAT doesnt have
those either. CAT doesnt have everything.

Regards, NT
  #22   Report Post  
IMM
 
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Default Solar space heating idea


"N. Thornton" wrote in message
om...
"IMM" wrote in
"N. Thornton" wrote


Re efficient steam engines:

Well, I'd be happier to trust your word on this if you could show us a
ref. What you say certainly sounds good, but I would like to see it
backed up.


A few years back some car makers were looking at steam engines in view of
proposed increased emissions; no doubt their lawyers and lobbying prevented
the increase. The Stirling engine link I gave mentions the vast
improvements in the burners (from CH boilers mainly) giving very low
emissions. As a steam engine is external combustion also, the same applies.

There is no reason not to use Stirling or steam engines in slow moving town
and city utility vehicles like: buses, delivery trucks used by utility
companies, etc.

A Google will bring up lots on Stirling and steam engines. Lots of work is
being done on Stirling engines, with many models readily for sale.

Stirling and steam engines cannot give instant power, giving quick
acceleration, as the internal combustion engines can. This can be overcome
by having a Stirling/electric or air motor hybrid. The electric or air motor
is only used to assist in acceleration above a certain rate. Hybrid
technology is here with Honda, Toyota and now Ford.

The Stirling is imminent to use in vehicles and Combined Heat and Power
(CHP). Many points keep it from vehicle use: the industry is geared up for
the internal combustion engines, no energy crisis driving up fuel costs (AMC
made a Stirling engine car in the 1970s and were about to produce it when
the fuel crisis waned) and exhaust emissions have not yet been lowered
enough to preclude the internal combustion engine.

It was mentioned that CAT are lacking in tracking, and that if it were
a good idea they'd have more of them. I'd say fixed mirrors are a good
addition to PV, specifically angled to increase the light away from
noon, ie when the light level falls, and specifically using greased
silver mylar mirrors, which are very cheap. But AFAIK CAT doesnt have
those either. CAT doesnt have everything.


Some people want energy autonomous homes demanding little from the
environment. The Vales attempted this with partial success. The problem is
generating enough electricity and storing it. It would be simpler to:

1. Construct a house that requires minimum energy demands. Superinsulate
it with no thermal bridges, triple glazing and make it air tight, then
concentrate on producing and storing solar hot water for DHW and CH
(hopefully heating needs will be zero to minimal).

2. Have minimal electrical use by using electrical appliances that consume
as little power as possible, they are available, and use cheaper, and
cleaner, to run gas appliances where possible (gas ovens and tumble dryers
instead of electric, washing machines that take in hot water rather than
heat it itself, and the likes).

This is a far more cost effective approach for a new build, or full
renovation than trying to generate electricity.

The solar closets et al, are good retrofits to existing homes with some
added insulation points, as: triple glazing or double with low "e" glass,
make the house as air tight as possible, draught proof the windows and
doors, put over 1 foot insulation in the loft, install porches on outside
doors, etc.

The more a house is insulated and air-tight the less you need to generate
heat.



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  #23   Report Post  
NickW
 
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Default Solar space heating idea

R&D is still ongoing and the prices will drop accordingly when packaged
solutions are available.


There's a limit to how much cheaper it can get, it'll always be a
complex motorised thing.

There's a lot that can be done with
simple materials. You might
achieve a collector efficiency of only
60% compared to maybe 80% of a
vacuum tube collector


In this case use more collectors.


Indeed. This is my preferred this idea.



Sun trackers get 3 times the suns energy than flat plate collectors. So
much so they are powering Stirling engines.

This doesn't add up. The amount of energy available per square meter
is the same for any collector. At the height of summer, this is about
800-1000W per square meter. A suntracker maintains alignment with sun
so it's exposed area does not diminish as the sun moves. It might also
be 10-20% more efficient than the cruder panels but this doesn't add
up to 3 x difference...


Active solar in the UK is viable. The solar closet can be an air heater
inside a conservatory facing south.

An air heater?

A solar closet has a high thermal mass and high insulation. It's
basically a cube shaped room. A 1 meter cube would have 10cm of (say)
rockwool insulation, the rest of the space would be occupied by water
filled containers which can hold a lot of heat energy. A conservatory
is filled with air and even good double glazing is not a great
insulator.

Nick
  #24   Report Post  
Martin Angove
 
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Default Solar space heating idea

IMM,
Just a quickie, because this is turning into one of your religious-type
arguments, but

a: the sun tracker you mention is in NEVADA, for Pete's sake, not
NEASDEN! We *started* by discussing domestic scale arrangements in this
country. It needs DIRECT sunlight to work, hence their suggestion of it
being useful in the desert. All large reflector-arrays I've seen to date
have been in similar situations. It is very hard to focus a completely
diffuse source, which is what the sun is throughout most of the year in
this country. Even on only partly cloudy days you begin to reduce
efficiency dramatically. There are other technologies which are much
more suited to Britain's climate.

b: it is on a very large scale (25kW), when compared with domestic use
(and what kind of journalistic rubbish is "25kW per second"?)

c: it involves high pressure hot gasses and doesn't look like something
which could be scaled down any time soon.

d: I'm not convinced that an unsealed Stirling engine is really a
Stirling engine. It sounds more like a conventional high pressure steam
engine. Incidentally, are we actually talking about steam pressure
cylinders, or steam turbines when referring to "normal" steam engines?

e: when you say that "virtually all" Stirlings have a piston in cylinder
arrangement, I presume you are referring to an "expansion" cylinder
somehow attached to the main cylinder which contains the bulk of the
working fluid and the displacement piston? This is an interesting
compromise and the calculations as to dimensions of this extra cylinder
will have to be made very carefully in order to allow maximum heating
and cooling of the working fluid which is common to it and the main
cylinder.

f: are you aware that the fuel consumption and emmissions figures for
Renault's dCi Diesel High Pressure Common Rail engines actually *better*
those of Toyota's so-called "green" hybrid car? Ok, it was in a Renault
brochure I read this, but it's scary. (We have a large - 1.9l - Renault
dCi and it's fantastic. Last time I did the 400 mile round trip to see
the parents I averaged 61mpg, and I wasn't trying *very* hard to be
economical. The 1.9l dCi Scenic out-accellerates our 1.6l 16V Laguna
too).

Hwyl!

M.

--
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
.... If we don't succeed, we run the risk of failure
  #25   Report Post  
IMM
 
Posts: n/a
Default Solar space heating idea


"Martin Angove" wrote in message
...
IMM,
Just a quickie, because this is turning into one of your religious-type
arguments, but

a: the sun tracker you mention is in NEVADA, for Pete's sake, not
NEASDEN!


That was just one example, others are under R&D. The same sun actually
shines in England too.

We *started* by discussing domestic scale arrangements in this
country. It needs DIRECT sunlight to work, hence their suggestion of it
being useful in the desert.


There is direct sunlight in England too.

All large reflector-arrays I've seen to date
have been in similar situations. It is very hard to focus a completely
diffuse source, which is what the sun is throughout most of the year in
this country.


It will point "exactly to where it should be at that particular time and
date.

b: it is on a very large scale (25kW), when compared with domestic use
(and what kind of journalistic rubbish is "25kW per second"?)

c: it involves high pressure hot gasses and doesn't look like something
which could be scaled down any time soon.

d: I'm not convinced that an unsealed Stirling engine is really a
Stirling engine. It sounds more like a conventional high pressure steam
engine. Incidentally, are we actually talking about steam pressure
cylinders, or steam turbines when referring to "normal" steam engines?


Cylinders.

e: when you say that "virtually all" Stirlings have a piston in cylinder
arrangement, I presume you are referring to an "expansion" cylinder
somehow attached to the main cylinder which contains the bulk of the
working fluid and the displacement piston? This is an interesting
compromise and the calculations as to dimensions of this extra cylinder
will have to be made very carefully in order to allow maximum heating
and cooling of the working fluid which is common to it and the main
cylinder.

f: are you aware that the fuel consumption and emmissions figures for
Renault's dCi Diesel High Pressure Common Rail engines actually *better*
those of Toyota's so-called "green" hybrid car?


Yes and that is why the hybrids have never caught on in Europe. But of
course there is a catch. Diesel produces particulates (soot) which is
cacogenic and blackens building. Horrible stuff, and diesel engines pollute
the environment in the excessive noise they produce. Nasty engines. Best
avoided, and I have had two turbo diesels.

Ok, it was in a Renault
brochure I read this, but it's scary. (We have a large - 1.9l - Renault
dCi and it's fantastic. Last time I did the 400 mile round trip to see
the parents I averaged 61mpg, and I wasn't trying *very* hard to be
economical. The 1.9l dCi Scenic out-accellerates our 1.6l 16V Laguna
too).


I have had one Renault in my life and hated it. Poorly made and rattly.


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  #26   Report Post  
IMM
 
Posts: n/a
Default Solar space heating idea


"NickW" wrote in message
om...
R&D is still ongoing and the prices will drop accordingly when packaged
solutions are available.


There's a limit to how much cheaper it can get, it'll always be a
complex motorised thing.

There's a lot that can be done with
simple materials. You might
achieve a collector efficiency of only
60% compared to maybe 80% of a
vacuum tube collector


In this case use more collectors.


Indeed. This is my preferred this idea.



Sun trackers get 3 times the suns energy than flat plate collectors. So
much so they are powering Stirling engines.

This doesn't add up. The amount of energy available per square meter
is the same for any collector. At the height of summer, this is about
800-1000W per square meter. A suntracker maintains alignment with sun
so it's exposed area does not diminish as the sun moves. It might also
be 10-20% more efficient than the cruder panels but this doesn't add
up to 3 x difference...


It does. It magnifies the suns rays.

Active solar in the UK is viable. The solar closet can be an air heater
inside a conservatory facing south.


An air heater?

A solar closet has a high thermal mass and high insulation. It's
basically a cube shaped room. A 1 meter cube would have 10cm of (say)
rockwool insulation, the rest of the space would be occupied by water
filled containers which can hold a lot of heat energy. A conservatory
is filled with air and even good double glazing is not a great
insulator.


The solar closet uses an air heater to circulate hot air through the closet,
which in turn heat the water (thermal mass) stored in large glass jars.
When the house requires heat a fan runs cool air from the house through the
closet and over the hot glass jars and back into the house heated.


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  #27   Report Post  
IMM
 
Posts: n/a
Default Solar space heating idea


"tony sayer" wrote in message
...
snipped a tad

The solar closets et al, are good retrofits to existing homes with some
added insulation points, as: triple glazing or double with low "e" glass,
make the house as air tight as possible, draught proof the windows and
doors, put over 1 foot insulation in the loft, install porches on outside
doors, etc.

The more a house is insulated and air-tight the less you need to generate
heat.



Humm. What do you do with the breeze in the hours after a curry
consumption?..


open the windows, or rely on the heat recovery system, which is virtually
mandatory in a air tight house.


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  #28   Report Post  
NickW
 
Posts: n/a
Default Solar space heating idea

Sun trackers get 3 times the suns energy than flat plate collectors. So
much so they are powering Stirling engines.

This doesn't add up. The amount of energy available per square meter
is the same for any collector. At the height of summer, this is about
800-1000W per square meter. A suntracker maintains alignment with sun
so it's exposed area does not diminish as the sun moves. It might also
be 10-20% more efficient than the cruder panels but this doesn't add
up to 3 x difference...


It does. It magnifies the suns rays.


What is your air heater you mentioned by the way? A commercially
produced one or a DIY one? I may yet look into an air heater because I
reckon I can make an 8 square meter one for under 200 pounds (not
including the fan - I have a spare extractor fan about 20cm diam)...

Nick
  #29   Report Post  
IMM
 
Posts: n/a
Default Solar space heating idea


"NickW" wrote in message
om...
Sun trackers get 3 times the suns energy than flat plate collectors.

So
much so they are powering Stirling engines.

This doesn't add up. The amount of energy available per square meter
is the same for any collector. At the height of summer, this is about
800-1000W per square meter. A suntracker maintains alignment with sun
so it's exposed area does not diminish as the sun moves. It might also
be 10-20% more efficient than the cruder panels but this doesn't add
up to 3 x difference...


It does. It magnifies the suns rays.


What is your air heater you mentioned by the way? A commercially
produced one or a DIY one? I may yet look into an air heater because I
reckon I can make an 8 square meter one for under 200 pounds (not
including the fan - I have a spare extractor fan about 20cm diam)...


Look at the solar closet web page. The heat generator is an air heater. It
heats air.


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  #30   Report Post  
IMM
 
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Default Solar space heating idea


"Martin Angove" wrote in message
...
In message ,
"IMM" wrote:


"Martin Angove" wrote in message
...
IMM,
Just a quickie, because this is turning into one of your

religious-type
arguments, but

a: the sun tracker you mention is in NEVADA, for Pete's sake, not
NEASDEN!


That was just one example, others are under R&D. The same sun actually
shines in England too.


Mmm... lower down, and behind a *lot* more cloud:


We *started* by discussing domestic scale arrangements in this
country. It needs DIRECT sunlight to work, hence their suggestion of

it
being useful in the desert.


There is direct sunlight in England too.

but not day-in day-out as you get in Nevada. If you want to create
"warmth" then fine, but if you want a reliable steam generator?


All large reflector-arrays I've seen to date
have been in similar situations. It is very hard to focus a completely
diffuse source, which is what the sun is throughout most of the year

in
this country.


It will point "exactly to where it should be at that particular time and
date.

Not much help if there's 5,000 feet of Cumulo Nimbus between the
collector and the Sun though, is there?

[...]


f: are you aware that the fuel consumption and emmissions figures for
Renault's dCi Diesel High Pressure Common Rail engines actually

*better*
those of Toyota's so-called "green" hybrid car?


Yes and that is why the hybrids have never caught on in Europe. But of
course there is a catch. Diesel produces particulates (soot) which is
cacogenic and blackens building. Horrible stuff, and diesel engines

pollute
the environment in the excessive noise they produce. Nasty engines.

Best
avoided, and I have had two turbo diesels.


(Cacogenic in Welsh might translate as "**** generating" :-)

A properly tuned Diesel produces far fewer particulates than some people
would have you believe. Modern engines are even better, and there are,
supposedly, some "clean exhaust" technologies on the drawing board,
though how they affect efficiency is anyone's guess. And our dCi engine
is *gorgeous* to drive and hardly any louder than our petrol cars
except for the first minute or so on a cold morning. We have previously
owned Citroen and Peugeot "bog standard" Diesels and loved them, but
this unit is much better.

If you think about it (Diesel being more efficient than hybrid), it
makes sense. A 1.5l dCi is quite a powerful engine really, and quite
capable of powering even medium-sized cars with good efficiency. The
hybrids tend to be based around similar sized units, but they introduce
a extra stages in the power use; conversion to electricity and back
again. This *must* be inefficient, so they are starting from a lower
point. They first have to close this gap before they can make the thing
more efficient than a standard setup.

As I see it there are two main areas they can do this: regenerative
braking and narrow powerband controls - i.e. decoupling the engine from
the drive system completely so that it can always run at its most
efficient. Neither is likely to make much difference to the overall
efficiency as far as I can see, certainly not for "normal" driving
styles, and the Toyota has the engine coupled to the drive system
anyway.

If you could charge batteries from the mains then localised emissions
*should* be better for a hybrid car, but total emissions may be worse
once you've taken electricity generation into account.

What about Diesel as a fuel? Is its environmental impact any different
to Petrol for its production? For use it *has* to be better with fewer
NO-types and CO and generally a much better miles-per-gallon. Even with
it being a couple of pennies more expensive per litre it still works out
*much* cheaper for us than running a petrol car.

Ok, it was in a Renault
brochure I read this, but it's scary. (We have a large - 1.9l -

Renault
dCi and it's fantastic. Last time I did the 400 mile round trip to see
the parents I averaged 61mpg, and I wasn't trying *very* hard to be
economical. The 1.9l dCi Scenic out-accellerates our 1.6l 16V Laguna
too).


I have had one Renault in my life and hated it. Poorly made and rattly.


Hardly a representative sample. I have now owned two. Both fine.
Especially the 2000 vintage Scenic with the dCi. My dad has many faults,
one of which is that he has owned nothing much *except* Renaults since
his first car; a second hand Renault 12 back in about 1974. In fact he
and mum between them have had

2 R12s
3 "original" R5s
1 "what's yours called" R5
1 R14
1 R21
3 R11s
1 R19
1 Megane hatchback
3 Scenics
2 Clios.

I agree about early Renaults (the 12s and the 5s) but since the "new" 5
and the 21, all dad's cars have had excellent build quality, and I've
driven a fair number of them.

But this is getting very OT so I'll stop there.

Hwyl!

M.

--
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
... Take care of the pence and the Inland Revenue will take care of the

rest.


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  #31   Report Post  
Martin Angove
 
Posts: n/a
Default Diesels and Renaults (Was: Solar space heating idea)

In message ,
"IMM" wrote:


"Martin Angove" wrote in message
...


Even with it being a couple of pennies
more expensive per litre it still works out
*much* cheaper for us than running a petrol car.


That is only taxation (accounting). Diesel is now more expensive than
petrol, which was not the case. The ploriferation of disels is disturbing,
and it is now being checked. They are "not" more economical overall at all.
The are only worth it if you do approx over 30,000 miles a year. The
service intervals are shorter, servicing is more expensive, the engines are
more complex, with turbos and the likes. When these go wrong you know about
it in your pocket.


Service intervals on our Diesel are *exactly* the same as on the petrol
versions of the car: 18,000 miles or two years. Free "safety check"
every year (so you don't miss MOT tests). The previous generation of
engines had 12,000 miles petrol, 10,000 miles Diesel. Hardly a
difference.

And, ok, nearly all Diesels these days have Turbos, but nearly all
petrols these days have highly complex 16-valve systems with variable
valve timing, engine management units and *spit* electrics to go wrong.



My sister has a Megane (Senic is a taller version) and it is a dog.

Scenic is rather more than a "taller" Megane. Define "dog". What don't
you like about it?

[rest snipped as unsubstantiated name-calling]

Hwyl!

M.

--
Martin Angove (it's Cornish for "Smith") - ARM/Digital SA110 RPC
See the Aber Valley -- http://www.tridwr.demon.co.uk/abervalley.html
.... Smile, but sharpen your knives.
  #32   Report Post  
N. Thornton
 
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Default Solar space heating idea

From: NickW )

Hi tech stuff is all very nice but have you checked on the price of a
suntracker lately? These types of system often don't pay you back for
maybe 20 years or so.


About £35. See redrok.com. Payback is quite practical with such a
tracker.


IMM replied:
R&D is still ongoing and the prices will drop accordingly when

packaged
solutions are available.


£35 not cheap enough then?


Nick wrote:
There's a lot that can be done with simple materials. You might
achieve a collector efficiency of only 60% compared to maybe 80% of a
vacuum tube collector or a suntracker but if it costs 1/10th the

price
then it could be worth it.


Exactly. You can't count on getting 60% off a flat plate, but then you
dont need to. Its more liekly to drop to half that when the water's
hot.


Having said all this, I've done some checking and active solar space
heating is considered not to be viable in the UK since it is usually
overcast in winter time... ah well.


There are a lot of different technologies, a lot of different designs
with each one, and a lot of differnet takes on them all. I definnitely
wouldn't assume active solar heat is no-go - tho most systems are.


Bigwallop wrote:
What I have noticed with the wind power suggestion, is people are

working on
the assumption of just one turbine and blade system, yet there's

nothing to
stop the use of three or four smaller turbines being used to power

the
system.

Planning permission. You'd have no chance.


From: IMM )
too many errors to reply to.


Regards, NT
  #33   Report Post  
IMM
 
Posts: n/a
Default Diesels and Renaults (Was: Solar space heating idea)


"Martin Angove" wrote in message
...

That is only taxation (accounting). Diesel is now more expensive than
petrol, which was not the case. The ploriferation of disels is

disturbing,
and it is now being checked. They are "not" more economical overall at

all.
The are only worth it if you do approx over 30,000 miles a year. The
service intervals are shorter, servicing is more expensive, the engines

are
more complex, with turbos and the likes. When these go wrong you know

about
it in your pocket.


Service intervals on our Diesel are *exactly*
the same as on the petrol versions of the
car: 18,000 miles or two years. Free "safety check"
every year (so you don't miss MOT tests). The
previous generation of engines had 12,000
miles petrol, 10,000 miles Diesel. Hardly a
difference.


Not so long ago all diesels had 6,000 mile services when petrol was 9,000
plus. Things have improved.

And, ok, nearly all Diesels these days
have Turbos, but nearly all
petrols these days have highly complex
16-valve systems with variable
valve timing, engine management units
and *spit* electrics to go wrong.


There are many petrol engines that are quite simple, with 2 valves per
cylinder and common fuel injection system. Diesel injection is now
electronic/mechanical. Diesel are more complicated with a heavy bill if a
turbo packs up.

My sister has a Megane (Senic is a taller version) and it is a dog.

Scenic is rather more than a "taller" Megane. Define "dog". What don't
you like about it?


Cheap nasty, breaks down a lot, lousy styling, lousy interior etc. Best
avoided. Renault used to have advanced styling, now they make blurb boxes
that looks the same as the next large auto makers blurb box.



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  #34   Report Post  
IMM
 
Posts: n/a
Default Solar space heating idea


"N. Thornton" wrote in message
om...
From: NickW )

Hi tech stuff is all very nice but have you checked on the price of a
suntracker lately? These types of system often don't pay you back for
maybe 20 years or so.


About £35. See redrok.com. Payback is quite practical with such a
tracker.


IMM replied:
R&D is still ongoing and the prices will drop accordingly when

packaged
solutions are available.


£35 not cheap enough then?


Nick wrote:
There's a lot that can be done with simple materials. You might
achieve a collector efficiency of only 60% compared to maybe 80% of a
vacuum tube collector or a suntracker but if it costs 1/10th the

price
then it could be worth it.


Exactly. You can't count on getting 60% off a flat plate, but then you
dont need to. Its more liekly to drop to half that when the water's
hot.


Having said all this, I've done some checking and active solar space
heating is considered not to be viable in the UK since it is usually
overcast in winter time... ah well.


There are a lot of different technologies, a lot of different designs
with each one, and a lot of differnet takes on them all. I definnitely
wouldn't assume active solar heat is no-go - tho most systems are.


Bigwallop wrote:
What I have noticed with the wind power suggestion, is people are

working on
the assumption of just one turbine and blade system, yet there's

nothing to
stop the use of three or four smaller turbines being used to power

the
system.

Planning permission. You'd have no chance.


From: IMM )
too many errors to reply to.


What errors might these be?


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.488 / Virus Database: 287 - Release Date: 05/06/2003


  #35   Report Post  
Toby
 
Posts: n/a
Default Solar space heating idea

adjusting. It was awful. Best avoided and Japanese makes (although most
are made in the UK now).

....ah, the Lexus will just have to go now. Off to get a new Megane or 'bland
blurb box' as I shall now refer to it.




  #36   Report Post  
Andy Dingley
 
Posts: n/a
Default Diesels and Renaults (Was: Solar space heating idea)

On Thu, 10 Jul 2003 14:43:54 +0100, "IMM" wrote:

Diesel are more complicated with a heavy bill if a
turbo packs up.


So is a turbocharged petrol engine.

Except that many diesels don't need wastegates, which removes most of
the failure-prone components from the turbo.

  #37   Report Post  
NickW
 
Posts: n/a
Default Solar space heating idea

About £35. See redrok.com. Payback is quite practical with such a
tracker.


That's a good website. Although making it windproof would be fun.
Maybe a mylar lined parabolic mirror directing extra sun into the
house would be worthwhile. Directing extra light into the bathroom
which is on the north side of the hosue would be good.


There are a lot of different technologies, a lot of different designs
with each one, and a lot of differnet takes on them all. I definnitely
wouldn't assume active solar heat is no-go - tho most systems are.


Lets have a think. Oil heating costs about 1.4 pence / kwh.

If my 8sqm freestanding DIY collector cost me 200 quid, it would have
to produce a total of 14284 kw to pay me back. If it averages 1kw from
autumn through to spring, an average of 7 hours a day, call it 250
days... that's 1750 kwh a year. That's 8 years!! Oh well, I'd just
have to be thinking of the greenhouse gasses saved.

As an aside - remember my solar coil for the pool? I was forced to do
as you suggested and divide it into seperate circuits because the
bearings in my pump are starting to go, it sounds very noisy now. I
bought 6 T-pieces and made it into 4 seperate circuits and now the
water gushes out the other end instead of trickling. I shall replace
the pump with a less powerful one - a 1/4 horsepower one to save
leccy.

I've also bought some polythene, 36sqm for 15 quid, trouble is it's
not as clear as I hoped and I may not use it, hmmm.

Cheers

Nick
  #38   Report Post  
N. Thornton
 
Posts: n/a
Default Solar space heating idea

Hi

About £35. See redrok.com. Payback is quite practical with such a
tracker.


That's a good website. Although making it windproof would be fun.
Maybe a mylar lined parabolic mirror directing extra sun into the
house would be worthwhile. Directing extra light into the bathroom
which is on the north side of the hosue would be good.


Yup. You would have glare to deal with: you'd need to direct the light
up towards the ceiling. And I'd be a bit cautious about focussing the
sun into one small spot, a deliberately not-really-parabola might be
preferable. But I think this is basically a good way to go, you get
heat and light very cheaply.

I did something similar using a flat plate mirror, just mounted it apx
horizontal under the window on the outside. Doubled the light level in
the room. Direct sun mainly hits carpet and furnishings, whereas
reflected sun mainly hits the white ceiling, so such large light
increases are quite practical. Plus you get the birds landing on it,
and the cats sunbathing on it.


There are a lot of different technologies, a lot of different designs
with each one, and a lot of differnet takes on them all. I definnitely
wouldn't assume active solar heat is no-go - tho most systems are.


Lets have a think. Oil heating costs about 1.4 pence / kwh.


Are you sure? I dont know, its just that gas is more than that.

If my 8sqm freestanding DIY collector cost me 200 quid, it would have
to produce a total of 14284 kw to pay me back. If it averages 1kw from
autumn through to spring, an average of 7 hours a day, call it 250
days... that's 1750 kwh a year. That's 8 years!! Oh well, I'd just
have to be thinking of the greenhouse gasses saved.


I havent done the maths here, but ave of 1/8 kW per sqm sounds much
too low.
I dont know what kind of collector youre considering, all I can say is
big trackers can pay back according to previous calcs. But it does
depend how you design them. Somewhere I've got detailed figures on
this one: want me to mail them? Might be of interest.


As an aside - remember my solar coil for the pool? I was forced to do
as you suggested and divide it into seperate circuits because the
bearings in my pump are starting to go, it sounds very noisy now. I
bought 6 T-pieces and made it into 4 seperate circuits and now the
water gushes out the other end instead of trickling. I shall replace
the pump with a less powerful one - a 1/4 horsepower one to save
leccy.


Right. I'd be tempted to just run it slower, by using a series
impedance or transformer. Sounds pretty lousy tho if its crapping out
already.

Now if you turn your coil into 112 parallelled one foot long sections,
you'd only need 5w of pumping

I've also bought some polythene, 36sqm for 15 quid, trouble is it's
not as clear as I hoped and I may not use it, hmmm.


I reckon if you get more than 50% through it should gain you. Youre
really losing a lot with an open collector. It wont matter that theres
light scattering.

Wish I had the time to actually do what you are.


Regards, NT
  #39   Report Post  
N. Thornton
 
Posts: n/a
Default Solar space heating idea

geoff wrote in message news:bI$I+VDUFHE$Ew2W@
writes


I've also bought some polythene, 36sqm for 15 quid, trouble is it's
not as clear as I hoped and I may not use it, hmmm.


Having forgotten the details here, two points to bear in mind

1/ Polythene doesn't last forever in direct sunlight
2/ If you are talking about using the polythene to allow sunlight in to
heat the pipes, just because something is opaque to visible radiation,
doesn't mean it's not clear to I/R. You might have to ask someone or
look it up


Polytunnel greenhouses heat up same as glass ones, it works. Only lasts a few years.

Regards, NT
  #40   Report Post  
NickW
 
Posts: n/a
Default Solar space heating idea

Lets have a think. Oil heating costs about 1.4 pence / kwh.

Are you sure? I dont know, its just that gas is more than that.


Not certain but FWIW, this is my source:
http://www.chic-info.org.uk/electric.html

I havent done the maths here, but ave of 1/8 kW per sqm sounds much
too low.
I dont know what kind of collector youre considering, all I can say is
big trackers can pay back according to previous calcs. But it does
depend how you design them. Somewhere I've got detailed figures on
this one: want me to mail them? Might be of interest.

Yes please.


Right. I'd be tempted to just run it slower, by using a series
impedance or transformer. Sounds pretty lousy tho if its crapping out
already.

It was making a nasty whining noise, obviously too much back pressure,
I have a 1/4 hp one on order though.


I reckon if you get more than 50% through it should gain you. Youre
really losing a lot with an open collector. It wont matter that theres
light scattering.

I did another calc on the uncovered collector at the weekend. Now that
the coil is divided into 4 circuits, the flow rate is much higher but
the temp gain seems the same. Perhaps it's just better conditions now
(mid summer, high noon, no cloud at all). I got 10kw! If there is 800W
/sqm available then from my 25sqm collector, that's an efficiency of
50%. Given this, do you think the polythene will still benefit?

Nick
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