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#21
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Ways to save energy, carbon, or pollution - NOW!
"Mike Vandeman" wrote in message ... On Wed, 09 May 2007 22:23:46 GMT, "Jeff Strickland" wrote: "Mike Vandeman" wrote in message . .. My panels are not PV. They are black rubber/plastic. Black absorbs heat, watter passes through and absorbs the heat. The panels are raised about 4 inches above the roof tiles. Then they should keep the roof under them cooler than it would otherwise be. You would have to measure that underneath the roof. First, I'd have to care. Second, I'd have to know what the temp was before the panels went up. Third, the temp inside the attic is the only thing that is important, and it's very high -- as attics are in my part of the world. The purpose of the panels is to heat the water. If there is a side benefit, I can't tell and don't care. Any side benefit is so minute as to be utterly insignificant. My only point here is that one should buy solar panels for a swimming pool because they want to warm the pool. There is no other reason to consider solar panels, keeping the house cooler is not something that happens. I'm not dissing panels, I think they are great and well worth the money to buy and install them. I just dispute the supposed benefit that they will cool the house. I note that you have the ability to easily test that, but prefer to use your own unscientific judgment -- as usual. I haven't the ability to easily test anything. I have no benchmark from which to compare what I have currently with what I had before the panels went up onto the roof. |
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#22
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Ways to save energy, carbon, or pollution - NOW!
On Thu, 10 May 2007 02:05:27 GMT, "Jeff Strickland"
wrote: "Mike Vandeman" wrote in message .. . On Wed, 09 May 2007 22:23:46 GMT, "Jeff Strickland" wrote: "Mike Vandeman" wrote in message ... My panels are not PV. They are black rubber/plastic. Black absorbs heat, watter passes through and absorbs the heat. The panels are raised about 4 inches above the roof tiles. Then they should keep the roof under them cooler than it would otherwise be. You would have to measure that underneath the roof. First, I'd have to care. Second, I'd have to know what the temp was before the panels went up. Third, the temp inside the attic is the only thing that is important, and it's very high -- as attics are in my part of the world. The purpose of the panels is to heat the water. If there is a side benefit, I can't tell and don't care. Any side benefit is so minute as to be utterly insignificant. My only point here is that one should buy solar panels for a swimming pool because they want to warm the pool. There is no other reason to consider solar panels, keeping the house cooler is not something that happens. I'm not dissing panels, I think they are great and well worth the money to buy and install them. I just dispute the supposed benefit that they will cool the house. I note that you have the ability to easily test that, but prefer to use your own unscientific judgment -- as usual. I haven't the ability to easily test anything. I have no benchmark from which to compare what I have currently with what I had before the panels went up onto the roof. That's irrelevant. The temperature is different now. What you need to do is compare the temperature under the solar panels (UNDER the roof, in the attic) with the temperature elsewhere under the roof. -- I am working on creating wildlife habitat that is off-limits to humans ("pure habitat"). Want to help? (I spent the previous 8 years fighting auto dependence and road construction.) Please don't put a cell phone next to any part of your body that you are fond of! http://home.pacbell.net/mjvande |
#23
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Ways to save energy, carbon, or pollution - NOW!
On May 10, 7:28 am, Mike Vandeman wrote:
On Thu, 10 May 2007 02:05:27 GMT, "Jeff Strickland" I haven't the ability to easily test anything. I have no benchmark from which to compare what I have currently with what I had before the panels went up onto the roof. That's irrelevant. The temperature is different now. What you need to do is compare the temperature under the solar panels (UNDER the roof, in the attic) with the temperature elsewhere under the roof. In theory an OK idea, but real-world internal convection and conduction would make this test very difficult, unless the attic were compartmentalized so as to reflect the covered vs. uncovered area. BJ |
#24
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Ways to save energy, carbon, or pollution - NOW!
On 10 May 2007 07:40:54 -0700, Bruce Jensen
wrote: On May 10, 7:28 am, Mike Vandeman wrote: On Thu, 10 May 2007 02:05:27 GMT, "Jeff Strickland" I haven't the ability to easily test anything. I have no benchmark from which to compare what I have currently with what I had before the panels went up onto the roof. That's irrelevant. The temperature is different now. What you need to do is compare the temperature under the solar panels (UNDER the roof, in the attic) with the temperature elsewhere under the roof. In theory an OK idea, but real-world internal convection and conduction would make this test very difficult, unless the attic were compartmentalized so as to reflect the covered vs. uncovered area. They are called "rafters". Haven't you even been in an attic? The test is EASY. Just hold a thermometer in the cooler & hotter areas & compare. What's so hard about that? BJ -- I am working on creating wildlife habitat that is off-limits to humans ("pure habitat"). Want to help? (I spent the previous 8 years fighting auto dependence and road construction.) Please don't put a cell phone next to any part of your body that you are fond of! http://home.pacbell.net/mjvande |
#25
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Ways to save energy, carbon, or pollution - NOW!
On May 10, 8:02 am, Mike Vandeman wrote:
In theory an OK idea, but real-world internal convection and conduction would make this test very difficult, unless the attic were compartmentalized so as to reflect the covered vs. uncovered area. They are called "rafters". Haven't you even been in an attic? The test is EASY. Just hold a thermometer in the cooler & hotter areas & compare. What's so hard about that? Nothing hard about it, but you won't get an accurate answer. I have never seen an attic rafter that would substantially prevent conduction or convection. The slightest breeze would almost immediately mix the air, and as you know, most attics are ventilated. On top of this, the slightest slant of the roof would encourage immediate internal convection and mixing loops, even without an external breeze source. The mixing of air and transfer of heat from warm to cool would be so constant and rapid, right from the moment the first solar rays hit the roof, that your temperature measurement deltas would be meaninglessly low. The only thing you could do would be to measure the temps of the roof material itself - and even that is not really accurate. I have no doubt that siphoning off the heat from solar radiation incident on a rooftop would result in substantial attic cooling, whether by hot water flow or absorption and reflection/insulation from solar cells (which would not only capture and convert some of the energy, but with the right system design also allow free airflow underneath the panels, allowing for further heat dissipation). One could design a good-quality experiment with specially insulated compartments in an attic - and I am sure this has been done by somebody - but as Jeff suggests, the insulating or off-conducting properties of solar systems on roofs may not be the first thing a customer would be thinking of, even if it is measurable and significant. BJ |
#26
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Ways to save energy, carbon, or pollution - NOW!
On 10 May 2007 08:49:36 -0700, Bruce Jensen
wrote: On May 10, 8:02 am, Mike Vandeman wrote: In theory an OK idea, but real-world internal convection and conduction would make this test very difficult, unless the attic were compartmentalized so as to reflect the covered vs. uncovered area. They are called "rafters". Haven't you even been in an attic? The test is EASY. Just hold a thermometer in the cooler & hotter areas & compare. What's so hard about that? Nothing hard about it, but you won't get an accurate answer. I have never seen an attic rafter that would substantially prevent conduction or convection. The slightest breeze would almost immediately mix the air, and as you know, most attics are ventilated. On top of this, the slightest slant of the roof would encourage immediate internal convection and mixing loops, even without an external breeze source. The mixing of air and transfer of heat from warm to cool would be so constant and rapid, right from the moment the first solar rays hit the roof, that your temperature measurement deltas would be meaninglessly low. The only thing you could do would be to measure the temps of the roof material itself - and even that is not really accurate. I have no doubt that siphoning off the heat from solar radiation incident on a rooftop would result in substantial attic cooling, whether by hot water flow or absorption and reflection/insulation from solar cells (which would not only capture and convert some of the energy, but with the right system design also allow free airflow underneath the panels, allowing for further heat dissipation). One could design a good-quality experiment with specially insulated compartments in an attic - and I am sure this has been done by somebody - but as Jeff suggests, the insulating or off-conducting properties of solar systems on roofs may not be the first thing a customer would be thinking of, even if it is measurable and significant. BJ One test is worth a thousand opinions. -- I am working on creating wildlife habitat that is off-limits to humans ("pure habitat"). Want to help? (I spent the previous 8 years fighting auto dependence and road construction.) Please don't put a cell phone next to any part of your body that you are fond of! http://home.pacbell.net/mjvande |
#27
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Ways to save energy, carbon, or pollution - NOW!
"Mike Vandeman" wrote in message ... I haven't the ability to easily test anything. I have no benchmark from which to compare what I have currently with what I had before the panels went up onto the roof. That's irrelevant. The temperature is different now. What you need to do is compare the temperature under the solar panels (UNDER the roof, in the attic) with the temperature elsewhere under the roof. Dude! I've been in the attic. It's the same everywhere. The question is, is it cooler now than it was before? I have no way of knowing because I don't know what it was before, but I do know that it is very hot up there now. The relevence is that I need a benchmark to know if it is cooler now. As a practical matter, it is no cooler. It is not cooler enough to warrant that as a reason to buy solar panels. |
#28
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Ways to save energy, carbon, or pollution - NOW!
"Mike Vandeman" wrote in message ... On 10 May 2007 07:40:54 -0700, Bruce Jensen wrote: On May 10, 7:28 am, Mike Vandeman wrote: On Thu, 10 May 2007 02:05:27 GMT, "Jeff Strickland" I haven't the ability to easily test anything. I have no benchmark from which to compare what I have currently with what I had before the panels went up onto the roof. That's irrelevant. The temperature is different now. What you need to do is compare the temperature under the solar panels (UNDER the roof, in the attic) with the temperature elsewhere under the roof. In theory an OK idea, but real-world internal convection and conduction would make this test very difficult, unless the attic were compartmentalized so as to reflect the covered vs. uncovered area. They are called "rafters". Haven't you even been in an attic? The test is EASY. Just hold a thermometer in the cooler & hotter areas & compare. What's so hard about that? My panels extend from the front edge of the roof all of the way to the rear. I cannot simply measure the heat under a set of rafters, then measure again under another set. I say again, solar panels to heat swimming pool water is a very good idea -- if a bit costly. Buy them because you want to extend the swimming season or have a hot pool that is not heated via natural gas. Do not buy solar panels because there is any evidence they cool the space underneath them. They are black, and they heat all of the way through, and radiate heat from the underside. Buy them to heat the pool, not to cool the house. |
#29
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Ways to save energy, carbon, or pollution - NOW!
"Mike Vandeman" wrote in message ... On 10 May 2007 08:49:36 -0700, Bruce Jensen wrote: On May 10, 8:02 am, Mike Vandeman wrote: In theory an OK idea, but real-world internal convection and conduction would make this test very difficult, unless the attic were compartmentalized so as to reflect the covered vs. uncovered area. They are called "rafters". Haven't you even been in an attic? The test is EASY. Just hold a thermometer in the cooler & hotter areas & compare. What's so hard about that? Nothing hard about it, but you won't get an accurate answer. I have never seen an attic rafter that would substantially prevent conduction or convection. The slightest breeze would almost immediately mix the air, and as you know, most attics are ventilated. On top of this, the slightest slant of the roof would encourage immediate internal convection and mixing loops, even without an external breeze source. The mixing of air and transfer of heat from warm to cool would be so constant and rapid, right from the moment the first solar rays hit the roof, that your temperature measurement deltas would be meaninglessly low. The only thing you could do would be to measure the temps of the roof material itself - and even that is not really accurate. I have no doubt that siphoning off the heat from solar radiation incident on a rooftop would result in substantial attic cooling, whether by hot water flow or absorption and reflection/insulation from solar cells (which would not only capture and convert some of the energy, but with the right system design also allow free airflow underneath the panels, allowing for further heat dissipation). One could design a good-quality experiment with specially insulated compartments in an attic - and I am sure this has been done by somebody - but as Jeff suggests, the insulating or off-conducting properties of solar systems on roofs may not be the first thing a customer would be thinking of, even if it is measurable and significant. BJ One test is worth a thousand opinions. All you have is an opinion. You have no test. You have no experience in this field. And, you have no practical exposure to that which you stand behind. I too only have an opinion, but my opinion is backed by practical experience -- 10 years of practical experience. My attic is one ****ing hot place to be, with or without the solar panels. You might be able to show some other kind of home construction where solar panels help to cool the house beneath them, but none of the homes in my community appear to be any different than mine in this respect. PS I was mildly pleased that you posted a list of stuff that is actually beneficial, and that I agreed with almost entirely. I point out a tiny, miniscule really, point of contention, and you completely turned it around. I used to think you were a complete idiot. Now I know. There is no hope for you as a human. We'll all be better off if you just went away. |
#30
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Ways to save energy, carbon, or pollution - NOW!
Mike Vandeman wrote: Ways to save energy, carbon, or pollution - NOW!: 1. Replace incandescent bulbs with compact fluorescent bulbs - especially those you leave on for an extended period. No, *Only* those you leave on for an extended period of time. Fluorescents have a much greater start-up energy requirement than do incadescents so if you have a light somewhere that is usually only on for brief periods (closet, some bathrooms, storeroom) an incadescent can be more energy efficient. |
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