Shady Posted February 20, 2012 Report Posted February 20, 2012 Germany is cutting solar-power subsidies because they are expensive and inefficientGermany once prided itself on being the “photovoltaic world champion”, doling out generous subsidies—totaling more than $130 billion, according to research from Germany’s Ruhr University—to citizens to invest in solar energy. But now the German government is vowing to cut the subsidies sooner than planned and to phase out support over the next five years. What went wrong? ... Using the government’s generous subsidies, Germans installed 7.5 gigawatts of photovoltaic capacity last year, more than double what the government had deemed “acceptable.” It is estimated that this increase alone will lead to a $260 hike in the average consumer’s annual power bill. ... According to Der Spiegel, even members of Chancellor Angela Merkel’s staff are now describing the policy as a massive money pit. Philipp Rösler, Germany’s minister of economics and technology, has called the spiraling solar subsidies a “threat to the economy.” ... Using solar, Germany is paying about $1,000 per ton of CO2 reduced. The current CO2 price in Europe is $8. Germany could have cut 131 times as much CO2 for the same price. Instead, the Germans are wasting more than 99 cents of every euro that they plow into solar panels. ... In the words of the German Association of Physicists, “solar energy cannot replace any additional power plants. Slate Another example of the environmentalist industrial complex. This policy, and these projects are a complete waste of time and tax money. And in every country they're implemented, they go bust. As soon as the subsidy runs dry, so do the jobs that they so-called create. It has to be obvious to most people by now, that this is not the way to tackle the issues of the world's energy concerns. REAL research and development, not crony capitalism and feel good money spending will address the issue. Quote
bush_cheney2004 Posted February 20, 2012 Report Posted February 20, 2012 Another example of the environmentalist industrial complex.... Hey, I like that...very catchy. That's why Rush calls them EnvironMentalists! Quote Economics trumps Virtue.
capricorn Posted February 20, 2012 Report Posted February 20, 2012 REAL research and development, not crony capitalism and feel good money spending will address the issue. The Chinese have steadily taken over Germany's solar panel market share and the quality of their products is said to be just as good. Green energy used to be Germany's great hope for its economic future. But now the German solar industry is in trouble amid huge losses, job cuts and the threat of bankruptcies. Chinese firms are gaining an ever greater share of the German market -- and are benefiting from German subsidies for renewable energy.--- Many German manufacturers can hardly keep up, now that Chinese suppliers are flooding the world market with solar panels. The Chinese have set their sights on Germany, in particular, which has become the most important market for companies like Suntech and Yingli. --- The marketing offensive has already had an impact, as the number of Chinese-made solar panels on German rooftops continues to grow. Even the competition admits that the Chinese products are just as good as German-made cells -- and cost about a third less, on average. --- The Chinese already generate close to half of global sales and almost 60 percent of profits in the industry, according to a study by the management consulting firm PRTM. This places the Chinese among the "biggest winners" of the last year, the study concludes. Eight companies from China and Taiwan are on the top-10 list of the fastest-growing players in the industry. There are no longer any German companies on the list, however. This means that the Chinese competition is now more likely to benefit from the billions in feed-in tariffs in Germany than domestic producers. To a substantial degree, German electricity consumers are helping to fund the rise of Chinese solar producers. According to the Rhenish-Westphalian Institute for Economic Research, the average German household pays about €123 a year to subsidize green electricity. http://www.spiegel.de/international/business/0,1518,784653,00.html And doesn't it seem whenever public funds are poured into the green energy black hole corruption rears its ugly head. From my link. A number of German companies are also facing legal problems. The former supervisory board chairman of Conergy, Dieter Ammer, faces charges of accounting fraud and insider trading in a Hamburg court, although he disputes the allegations. The public prosecutor's office in the Bavarian twin cities of Nuremberg-Fürth is looking into allegations of wrongdoing by Utz Claassen, a former top executive at Solar Millennium. The article goes on to chronicle similar problems in Germany's wind turbines fiasco. This scenario is being played out in other countries, and right under our noses here in Ontario, where politicians blindly jumped into the unknown simply because they felt it was the right thing to do. Quote "We always want the best man to win an election. Unfortunately, he never runs." Will Rogers
Wild Bill Posted February 20, 2012 Report Posted February 20, 2012 The Chinese have steadily taken over Germany's solar panel market share and the quality of their products is said to be just as good. http://www.spiegel.de/international/business/0,1518,784653,00.html And doesn't it seem whenever public funds are poured into the green energy black hole corruption rears its ugly head. From my link. The article goes on to chronicle similar problems in Germany's wind turbines fiasco. This scenario is being played out in other countries, and right under our noses here in Ontario, where politicians blindly jumped into the unknown simply because they felt it was the right thing to do. Cap, it doesn't matter who makes the panels! Neither does the price! They could be free and they still would be a financial loss. The installation, maintenance and the necessity for making backup power available for when the sun isn't shining are what makes photovoltaics a "money pit". That being said, the Germans have built traditional, large central generating stations. That is much of the problem. If the money had been put into smaller scale, individual solutions things might have worked better. Any tech would know this. Unfortunately, techs are rarely involved in the decisions about these things, except as salespeople to make a great deal of money by selling the products and services to the governments. The politicians make the decisions and they are as qualified as an autoshop teacher to fix your car cheaply and quickly, that is to say, not very! Quote "A government which robs Peter to pay Paul can always depend on the support of Paul." -- George Bernard Shaw "There is no point in being difficult when, with a little extra effort, you can be completely impossible."
capricorn Posted February 20, 2012 Report Posted February 20, 2012 Any tech would know this. Unfortunately, techs are rarely involved in the decisions about these things, except as salespeople to make a great deal of money by selling the products and services to the governments. The politicians make the decisions and they are as qualified as an autoshop teacher to fix your car cheaply and quickly, that is to say, not very! I hear you. Quote "We always want the best man to win an election. Unfortunately, he never runs." Will Rogers
Guest Manny Posted February 21, 2012 Report Posted February 21, 2012 (edited) There is more to this than meets the eye, and Wild Bill is right, most techies already knew that solar panel technology is not up to snuff, won't solve the problem unless some kind of dramatic technological breakthrough were to take place. I am a "techie", although not in the energy industry but I can read. I know what problems they are having. Fact is, solar panels are grossly inefficient. They can only convert about 10% of solar energy into electrical power. And solar energy is pretty feeble to begin with. I know people who have invested $60,000 dollars to put an array of panels on their roof, with the promise that they can sell surplus power back to the hydro grid and recoup their investment. But it will take ten years for them to break even! And for that they've got to hope for a lot of sunny days. What they don't realize is, those panels don't have a good life expectancy, they could fail during that ten year period. In fact the panels that produce more electricity per square meter are more expensive, and more prone to failure. Your investment might not break even at all. Second thing, and frequently overlooked- these panels contain toxic materials. They have rare earth metals like gallium arsenide, necessary to convert light into electricity. If every rooftop in the country gets covered in panels like these, and they need to be replaced every ten years, you'd have a serious problem dealing with the waste. A program needs to be put into effect to recycle them, reclaim the metals and dispose of the toxic materials. But it's not just the disposal that's a problem, toxic waste is created in the manufacture process. Example: Cleaning Up After Clean Energy: Hazardous Waste in the Solar Industry That's why the chinese product is only 1/3 the cost. Because, guess what? They don't have the environmental regulations that the German government demands, to reduce emission of toxic waste during production, so the price of their panels is proportionally cheaper. Edited February 21, 2012 by Manny Quote
dre Posted February 21, 2012 Report Posted February 21, 2012 There is more to this than meets the eye, and Wild Bill is right, most techies already knew that solar panel technology is not up to snuff, won't solve the problem unless some kind of dramatic technological breakthrough were to take place. I am a "techie", although not in the energy industry but I can read. I know what problems they are having. Fact is, solar panels are grossly inefficient. They can only convert about 10% of solar energy into electrical power. And solar energy is pretty feeble to begin with. I know people who have invested $60,000 dollars to put an array of panels on their roof, with the promise that they can sell surplus power back to the hydro grid and recoup their investment. But it will take ten years for them to break even! And for that they've got to hope for a lot of sunny days. What they don't realize is, those panels don't have a good life expectancy, they could fail during that ten year period. In fact the panels that produce more electricity per square meter are more expensive, and more prone to failure. Your investment might not break even at all. Second thing, and frequently overlooked- these panels contain toxic materials. They have rare earth metals like gallium arsenide, necessary to convert light into electricity. If every rooftop in the country gets covered in panels like these, and they need to be replaced every ten years, you'd have a serious problem dealing with the waste. A program needs to be put into effect to recycle them, reclaim the metals and dispose of the toxic materials. But it's not just the disposal that's a problem, toxic waste is created in the manufacture process. Example: Cleaning Up After Clean Energy: Hazardous Waste in the Solar Industry That's why the chinese product is only 1/3 the cost. Because, guess what? They don't have the environmental regulations that the German government demands, to reduce emission of toxic waste during production, so the price of their panels is proportionally cheaper. The problem with this analysis is that PV technology is changing pretty quickly both in terms of efficiency, cost per installed KW, and the types of materials used. Really the existing solar projects should be considered pilot projects, and just like with any other energy technology those early projects often dont go well, and usually need to be subsidized. That does not mean that PV does not have an important future. We wont know that for about 20 years. Storage technologies are progressing pretty rapidly as well. Having said that... its true. Countries should be carefull about putting too much emphasis on these relatively young technologies. We need to keep developing them, and we need some pilot projects... but its risky to rely to much on them at present. Quote I question things because I am human. And call no one my father who's no closer than a stranger
Bonam Posted February 21, 2012 Report Posted February 21, 2012 (edited) The problem with this analysis is that PV technology is changing pretty quickly both in terms of efficiency, cost per installed KW, and the types of materials used. This is only half true. The only PV technology that is economical enough for wide scale commercial deployment for general use is Silicon junction solar cells. These have had pretty much the exact same efficiency for decades. GaAs cells, multi-junction cells, nanomaterials, concentrator arrays, etc, all are prohibitively expensive and can only be used for special applications where such expense is justified, such as for spacecraft. Their costs are so high that even the ISS, a $250 billion project, didn't use them, opting for the cheaper and more conventional Silicon. While the costs of more advanced solar cells will of course come down in the future, the PV technologies that people are installing on their homes have not really been changing in terms of efficiency at all. Personally I think that in the near term, if people are hell bent on using solar energy, solar-thermal systems are a much more cost effective and efficient solution. Edited February 21, 2012 by Bonam Quote
dre Posted February 21, 2012 Report Posted February 21, 2012 This is only half true. The only PV technology that is economical enough for wide scale commercial deployment for general use is Silicon junction solar cells. These have had pretty much the exact same efficiency for decades. GaAs cells, multi-junction cells, nanomaterials, concentrator arrays, etc, all are prohibitively expensive and can only be used for special applications where such expense is justified, such as for spacecraft. Their costs are so high that even the ISS, a $250 billion project, didn't use them, opting for the cheaper and more conventional Silicon. While the costs of more advanced solar cells will of course come down in the future, the PV technologies that people are installing on their homes have not really been changing in terms of efficiency at all. Personally I think that in the near term, if people are hell bent on using solar energy, solar-thermal systems are a much more cost effective and efficient solution. Funny you mentioned that, because Im building two of these systems as we speak to heat domestic water and large concrete slab full of pex. Its a closed loop glycol antifreeze system. The collector is the copper tubing/aluminum fin design, and Im using recycled propane tanks for storage. Its actually a pretty damn good DYI project and I expect it to completely pay for itself within 2-3 years. One is for my own house and will be backed up with my existing electric water heater, and other is for a friend that runs a wood gassification boiler. The only part of the project that im finding challenging is the collector itself... You need to get a really good thermal bond between the aluminum plates and the copper tubes... Professionally manufactured models weld the plates to the tubes, but DIY builders generally do something like this.. http://www.builditsolar.com/Experimental/CopperAlumCollector/OV5.jpg Problem is its tricky to be sure that you get a good bond. Quote I question things because I am human. And call no one my father who's no closer than a stranger
Bonam Posted February 21, 2012 Report Posted February 21, 2012 Funny you mentioned that, because Im building two of these systems as we speak to heat domestic water and large concrete slab full of pex. Its a closed loop glycol antifreeze system. The collector is the copper tubing/aluminum fin design, and Im using recycled propane tanks for storage. Its actually a pretty damn good DYI project and I expect it to completely pay for itself within 2-3 years. One is for my own house and will be backed up with my existing electric water heater, and other is for a friend that runs a wood gassification boiler. The only part of the project that im finding challenging is the collector itself... You need to get a really good thermal bond between the aluminum plates and the copper tubes... Professionally manufactured models weld the plates to the tubes, but DIY builders generally do something like this.. http://www.builditsolar.com/Experimental/CopperAlumCollector/OV5.jpg Problem is its tricky to be sure that you get a good bond. I made one too. I used copper sheet rather than aluminum sheet. I soldered the copper tubes (using a torch, an iron can't deliver an enough heat) directly to the sheet, providing about as ideal a bond as you can get. The system I made had automatically controlled valves that simply drained the system of water if the temperature ever approached freezing, thus avoiding the need for antifreeze and a heat exchanger. Avoiding the heat exchanger was a big boost to efficiency, since heat exchangers are often one of the least efficient components of such systems. The heated water could thus be used directly for showering, washing hands & dishes, etc. Quote
dre Posted February 21, 2012 Report Posted February 21, 2012 I made one too. I used copper sheet rather than aluminum sheet. I soldered the copper tubes (using a torch, an iron can't deliver an enough heat) directly to the sheet, providing about as ideal a bond as you can get. The system I made had automatically controlled valves that simply drained the system of water if the temperature ever approached freezing, thus avoiding the need for antifreeze and a heat exchanger. Avoiding the heat exchanger was a big boost to efficiency, since heat exchangers are often one of the least efficient components of such systems. The heated water could thus be used directly for showering, washing hands & dishes, etc. Alumimum is supposed to be more efficient for the fins Iv read. Can you tell me a little bit more abouthow you sweated the plates snugly onto the tubes? Quote I question things because I am human. And call no one my father who's no closer than a stranger
Bonam Posted February 21, 2012 Report Posted February 21, 2012 Alumimum is supposed to be more efficient for the fins Iv read. Can you tell me a little bit more abouthow you sweated the plates snugly onto the tubes? Copper is a better thermal conductor. I don't see why aluminum would be more efficient. Not sure what you mean by fins though. My design was just a continuous rectangular copper sheet, with copper tubing soldered in a serpentine back and forth path along its back surface. Attaching the tubes to the sheet was pretty straightforward... I just would clamp each segment of tube down, heat it up with a propane gas torch, and feed in solder and let it melt into the region around the base of the copper tube where it was tangent to the sheet surface. Then I'd slowly move along the length of the tube. Because of the concentrated heat, this process did cause some thermal deformation of the copper sheet, which wasn't nice cosmetically but I don't think it impacted system efficiency substantially. Quote
dre Posted February 21, 2012 Report Posted February 21, 2012 Copper is a better thermal conductor. I don't see why aluminum would be more efficient. Not sure what you mean by fins though. My design was just a continuous rectangular copper sheet, with copper tubing soldered in a serpentine back and forth path along its back surface. Attaching the tubes to the sheet was pretty straightforward... I just would clamp each segment of tube down, heat it up with a propane gas torch, and feed in solder and let it melt into the region around the base of the copper tube where it was tangent to the sheet surface. Then I'd slowly move along the length of the tube. Because of the concentrated heat, this process did cause some thermal deformation of the copper sheet, which wasn't nice cosmetically but I don't think it impacted system efficiency substantially. That seems like a good design. You really rely on your solder though to get the heat into the tubes, so obviously it needs to have thermal conductivity approaching copper? Do you remember what you used? Most designs Iv seen use aluminum fins because its way cheaper, and you can wrap the fins right around the tubes as shown here. http://www.builditsolar.com/Projects/WaterHeating/Fins/Fins.h14.jpg. You could do the same thing with copper fins/strips as well. Not sure how it would compare in performance to your design but it seems cheaper. Quote I question things because I am human. And call no one my father who's no closer than a stranger
Wild Bill Posted February 21, 2012 Report Posted February 21, 2012 That seems like a good design. You really rely on your solder though to get the heat into the tubes, so obviously it needs to have thermal conductivity approaching copper? Do you remember what you used? Most designs Iv seen use aluminum fins because its way cheaper, and you can wrap the fins right around the tubes as shown here. http://www.builditsolar.com/Projects/WaterHeating/Fins/Fins.h14.jpg. You could do the same thing with copper fins/strips as well. Not sure how it would compare in performance to your design but it seems cheaper. Cheaper? That's always the most important factor for a DIY'r! Aluminum may be cheaper but of course, you can't solder it like copper. So that thermal conductivity to the fins will always be a problem unless you have access to an aluminum welder or something. Kudos to you for what you're doing, my good Dr. Dre! That's the sort of thing I respect and sadly, is getting more and more rare these days. Have you looked at car radiators? I have a small radiator I keep on my bench designed as an extra add-on for a car transmission. Surely they would be cheap from an auto wreckers! They may not be an optimum design but sometimes if something is cheaper you can just use an extra one or two. I've no direct experience to share with you - just passing on an idea. Quote "A government which robs Peter to pay Paul can always depend on the support of Paul." -- George Bernard Shaw "There is no point in being difficult when, with a little extra effort, you can be completely impossible."
dre Posted February 22, 2012 Report Posted February 22, 2012 Cheaper? That's always the most important factor for a DIY'r! Aluminum may be cheaper but of course, you can't solder it like copper. So that thermal conductivity to the fins will always be a problem unless you have access to an aluminum welder or something. Kudos to you for what you're doing, my good Dr. Dre! That's the sort of thing I respect and sadly, is getting more and more rare these days. Have you looked at car radiators? I have a small radiator I keep on my bench designed as an extra add-on for a car transmission. Surely they would be cheap from an auto wreckers! They may not be an optimum design but sometimes if something is cheaper you can just use an extra one or two. I've no direct experience to share with you - just passing on an idea. Actually I think an array of radiators would work very well. I would need a few of them to build my collectors thoug. They are 10X10 and the boxes are already built. Thanks for the suggestion though Im pretty sure it would work well. Im damn tempted to go with Bonhams design but Iv already bought most of the materials, and bent the grooves in some of the fins. I AM worried about the thermal bonding but I think it should be ok, because once the grooves are made in the fins, I can torque them down over the pipes with screws on either side. A bead of silicon should help as well. http://www.builditsolar.com/Projects/WaterHeating/Fins/Fins.htm Ill post some pictures of whatever monstrosity I manage to create This is a great project IMO, and with hydro rates set to go up where I live its definately viable and will save money. Quote I question things because I am human. And call no one my father who's no closer than a stranger
Guest Manny Posted February 22, 2012 Report Posted February 22, 2012 (edited) There are also thermal compounds that help to transfer heat between thermal conductors. One such compound is "Heat-Sink grease". Edited to add: http://en.wikipedia.org/wiki/Thermal_grease Shows an interesting table comparing thermal conductivity of different metals. Edited February 22, 2012 by Manny Quote
Bonam Posted February 22, 2012 Report Posted February 22, 2012 (edited) Actually I think an array of radiators would work very well. I would need a few of them to build my collectors thoug. They are 10X10 and the boxes are already built. Thanks for the suggestion though Im pretty sure it would work well. Im damn tempted to go with Bonhams design but Iv already bought most of the materials, and bent the grooves in some of the fins. I AM worried about the thermal bonding but I think it should be ok, because once the grooves are made in the fins, I can torque them down over the pipes with screws on either side. A bead of silicon should help as well. http://www.builditsolar.com/Projects/WaterHeating/Fins/Fins.htm Ill post some pictures of whatever monstrosity I manage to create This is a great project IMO, and with hydro rates set to go up where I live its definately viable and will save money. Nice link, quite informative. I see why they get a better efficiency for aluminum: they use a thicker sheet of aluminum, so that the fin has a higher conductivity. If you used equal thicknesses of copper and aluminum, you'd definitely get more efficiency with the copper. Of course, copper is more expensive for the same amount of material. Regardless, small differences in efficiency in the 90%+ range are kind of irrelevant in most DIY system applications. Like the article says, you're likely to have a much bigger efficiency drop in the bond between the collector and the tubes than in the collector itself. And even worse will be the efficiency loss in the heat exchanger between your glycol-antifreeze loop and the potable water that it would be heating. By the way, what are you using for the absorption coating on the sun-facing surface of the collector? A lot of people assume black paint would be the best, but that is far from the best choice, actually. A generic black paint will increase the emission coefficient of your collector just as much as the absorption. Ideally, you want to find a coating that has a high absorption coefficient in the Sun's radiation spectrum (~500 nm), but a low coefficient at the peak of the blackbody spectrum generated by the array's temperature (~7000 nm). Google "solar absorption paint" and you'll get some links that talk about this a bit. As for your question about the solder, I just used standard off the shelf solder from radioshack. Solder kind of has to be a good thermal conductor by design. As far as I remember, the overall system efficiency was over 90% (I'd have to go back and look at the data to get the exact number) so I think the thermal bonds were pretty good. You're right that the design I described is not the most cost effective. We were trying to make a DIY solution that would maximize space efficiency as much as possible. Our sponsor had only a very small roof area to dedicate to the solar collector and wanted to maximize the power he could get, so cost was a secondary consideration after performance. Because our system did not use a heat exchanger but rather used the heated water directly, it was actually considerably more efficient than most commercially available solar water heating systems. Edited February 22, 2012 by Bonam Quote
dre Posted February 22, 2012 Report Posted February 22, 2012 (edited) Regardless, small differences in efficiency in the 90%+ range are kind of irrelevant in most DIY system applications. Like the article says, you're likely to have a much bigger efficiency drop in the bond between the collector and the tubes than in the collector itself. And even worse will be the efficiency loss in the heat exchanger between your glycol-antifreeze loop and the potable water that it would be heating. By the way, what are you using for the absorption coating on the sun-facing surface of the collector? A lot of people assume black paint would be the best, but that is far from the best choice, actually. A generic black paint will increase the emission coefficient of your collector just as much as the absorption. Ideally, you want to find a coating that has a high absorption coefficient in the Sun's radiation spectrum (~500 nm), but a low coefficient at the peak of the blackbody spectrum generated by the array's temperature (~7000 nm). Google "solar absorption paint" and you'll get some links that talk about this a bit. As for your question about the solder, I just used standard off the shelf solder from radioshack. Solder kind of has to be a good thermal conductor by design. As far as I remember, the overall system efficiency was over 90% (I'd have to go back and look at the data to get the exact number) so I think the thermal bonds were pretty good. You're right that the design I described is not the most cost effective. We were trying to make a DIY solution that would maximize space efficiency as much as possible. Our sponsor had only a very small roof area to dedicate to the solar collector and wanted to maximize the power he could get, so cost was a secondary consideration after performance. Because our system did not use a heat exchanger but rather used the heated water directly, it was actually considerably more efficient than most commercially available solar water heating systems. I was planning on using regular black stove paint but Ill definately look into your suggestion. As for the design I think that as long as theres lots of solder bonding the pipes to the copper your design is definately superior. One thing I really like about it, is that it would look tidier and more professional. You can see on that page the end results are kinda patchy looking. Also, theoretically your design would last longer... when you mechanically bond aluminum to copper you should get a bit of corrosion over time although from what Iv read it isnt much of a problem. I think the design Im using is popular simply because its cheap and they assume lots of DIYers cant weld or solder I think that if I dont feel Im getting the fins to wrap really snugly around the tubes, I will just put more vertical tubes and overlap the fins a bit. Manny had a good idea too as long as you can get something that doesnt cost a fortune. Most of the DIY tutorials recommend silicon because AT LEAST its ten times better than air. Id love to avoid having a heat exchanger, but I would need more info from you. This does not appear to be a common DIY technique. "Drainback" systems operate similar to what you described but still need a heat exchanger. Theres diagrams of the basic types here... http://homepower.com/basics/hotwater/ I assume you built an Open Loop Direct system, but for that to work it seems like you would need to be able to automatically isolate the entire collector loop right above the storage tank, and bleed the water out into the sewer? Is that what you did? That should work fine, but if that system ever fails while its freezing (power outage?) then your collector might get totally ruined. Not saying thats a bad thing... efficiency is worth some risk, and to be honest its only frozen about half a dozen times this year so far where I live. Edited February 22, 2012 by dre Quote I question things because I am human. And call no one my father who's no closer than a stranger
Bonam Posted February 22, 2012 Report Posted February 22, 2012 (edited) Id love to avoid having a heat exchanger, but I would need more info from you. This does not appear to be a common DIY technique. "Drainback" systems operate similar to what you described but still need a heat exchanger. Theres diagrams of the basic types here... http://homepower.com/basics/hotwater/ I assume you built an Open Loop Direct system, but for that to work it seems like you would need to be able to automatically isolate the entire collector loop right above the storage tank, and bleed the water out into the sewer? Is that what you did? That should work fine, but if that system ever fails while its freezing (power outage?) then your collector might get totally ruined. Not saying thats a bad thing... efficiency is worth some risk, and to be honest its only frozen about half a dozen times this year so far where I live. Yep ours was an open loop direct system with an automatic drain feature whenever the temperature reached a sufficiently low value. That was actually the main point of the project: demonstrating the automatic control. We got a microcontroller, developed our own algorithm, coded it, wired the cables to all of the valves, thermocouples, and photodetectors that needed to be interfaced with, and even built our own motorized valves (to save costs compared to buying commercial ones). Protection against power outages and other failures is accomplished through a fail-safe valve that automatically goes to a safe position if it loses power or its control signal. In our case, the drain valves would empty the system of water in the case of a power outage. The water actually drained to a drain reservoir rather than a sewer, and could then feed into the home's conventional water heater. This was just to avoid having to waste water. It's definitely a little beyond the scope of a typical DIY project, but fun if you have some spare time and knowledge of electronics, control, programming, etc. Edited February 22, 2012 by Bonam Quote
dre Posted February 23, 2012 Report Posted February 23, 2012 Yep ours was an open loop direct system with an automatic drain feature whenever the temperature reached a sufficiently low value. That was actually the main point of the project: demonstrating the automatic control. We got a microcontroller, developed our own algorithm, coded it, wired the cables to all of the valves, thermocouples, and photodetectors that needed to be interfaced with, and even built our own motorized valves (to save costs compared to buying commercial ones). Protection against power outages and other failures is accomplished through a fail-safe valve that automatically goes to a safe position if it loses power or its control signal. In our case, the drain valves would empty the system of water in the case of a power outage. The water actually drained to a drain reservoir rather than a sewer, and could then feed into the home's conventional water heater. This was just to avoid having to waste water. It's definitely a little beyond the scope of a typical DIY project, but fun if you have some spare time and knowledge of electronics, control, programming, etc. That seems like an excellent solution thanx for the info. Im definately waffling on the glycol now. Ill post more here as my project developes. Quote I question things because I am human. And call no one my father who's no closer than a stranger
Guest Manny Posted February 24, 2012 Report Posted February 24, 2012 (edited) Meanwhile in the UK they're considering a different form of alternative energy. Expect that the Germans will be looking at this one as well: Dead bodies used to heat UK swimming pool LONDON -- Dead bodies will be burned to heat a swimming pool in the U.K. -- and the British government is considering adopting the idea across the country. "The government is aware of this particular scheme," Young said. "The Department for Energy and Climate Change will shortly be publishing its heat strategy and this will explore the potential for better recovery and reuse of wasted heat in schemes such as this one." Carole Gandy, the leader of Redditch Borough Council, was quoted as saying she would rather the energy was used than “just see it going out of the chimney and heating the sky. It will make absolutely no difference to the people who are using the crematorium for services,” she told The Telegraph. Unison, a labor union representing public workers, has described the idea as "sick and an insult to local residents,” The Telegraph reported. It added that Durham Crematorium, in northern England, was thinking about fitting turbines to its burners in order to create electricity that could potentially power 1,500 televisions. Edited February 24, 2012 by Manny Quote
bush_cheney2004 Posted February 24, 2012 Report Posted February 24, 2012 Meanwhile in the UK they're considering a different form of alternative energy. Expect that the Germans will be looking at this one as well: Just a guess, but I suspect the Germans know more about this than the Brits! Quote Economics trumps Virtue.
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