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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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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. --- 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 |
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Solar space heating idea
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 |
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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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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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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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Solar space heating idea
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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. --- 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 |
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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. |
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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
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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. --- 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 |
#12
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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. --- 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 |
#13
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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
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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. --- 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 |
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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. --- 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: 06/06/2003 |
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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." --- 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: 06/06/2003 |
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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. |
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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. --- BigWallop http://basecuritysystems.no-ip.com Outgoing mail is certified Virus Free. Checked by AVG anti-virus system (http://www.grisoft.com). Version: 6.0.497 / Virus Database: 296 - Release Date: 04/07/03 |
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Solar space heating idea
"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. --- 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 |
#20
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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 |
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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 |
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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. --- 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 |
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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 |
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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 |
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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. --- 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 |
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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. --- 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 |
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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. --- 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 |
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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 |
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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. --- 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 |
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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. --- 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 |
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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. |
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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 |
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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. --- 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 |
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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 |
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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. |
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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. |
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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 |
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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 |
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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 |
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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 |