5 ms·

Regarding the first point - they increased overall panel efficiency not cell efficiency. There are a lot more cells in these 3D panels than in a flat panel and

Regarding the first point - they increased overall panel efficiency not cell efficiency. There are a lot more cells in these 3D panels than in a flat panel and considering that in the accordion layout a lot of them don't see light unless sun is low (morning, evening, winter), the average output per cell is lower than in a conventional panel. But apparently it's the output per panel that counts.

jacquesm 15y ago
Panels are arrangements of cells. Panel efficiency is measured in $/Watt or as a percentage of incident light over the total area taken up by the array including shade, not in output per square unit of area under the array. If you want to do a really nice job in measuring panel efficiency you set up equal area arrays (equal areas of cells with the same packing density on the cells themselves) and measure them side-by-side over the course of a year. The 'control' should be a non-tracking array that you correct for elevation once every month and that points due South on the Northern hemisphere and vice versa.
- brudgers 15y ago
  >"not in output per square unit of area under the array" It can be measured that way, and for many practical applications it is. Solar tracking a small surface area is easier than tracking a larger one, water management of six solar panel mounting penetrations through a roof is more efficient than for sixty penetrations. Engineering efficiency shouldn't just be measured in a lab. However, based on the article one standard measure of efficiency does seem to be addressed, kw-hrs/panel/day because of the claims of better performance at low incident angles.
  - jacquesm 15y ago
    Tracking a small surface area is indeed easier but this is actually a larger area (the funnel effect will undo quite a bit of the effect of the reduced cross section), and it will nicely capture the wind because of its shape. On top of that you'll have to deal with force in more than one direction compared to panels mounted flush with a roof. Mounting solar panels using aluminum stand-offs is very easy and tried-and-true tech, setting up a tower like this up on your roof is not going to be nearly as easy as you think because there will be a lot of force trying to pull the whole assembly off the roof whereas conventional installations have to deal mostly with compressive forces (which is a whole lot easier). And that's with the wind directly on the panels. The arm of force from such an assembly will be proportional to the height of the total stack and will be quite impressive. You'll need - at a minimum - braces and guys behind the stack if you don't want it to take off in the first storm. Those sixty penetrations have a nice side effect of spreading the load evenly over the roof so that you don't need to design a structure behind it to deal with the force of the whole array.
    - bhousel 15y ago
      Heh, mount this "tower" on slip rings and an alternator and you can have both a solar array and a windmill in one.
      - jacquesm 15y ago
        Someone beat you to it (that's the HAT variety, I guess yours would be a VAT): http://www.freepatentsonline.com/7045702.html http://www.freepatentsonline.com/7045702.html The windmill scene is even more outlandish than the solar panel people, and the funny thing is all the weird ideas come full circle every decade or so.
        bhousel 15y ago
        Wow, that is outlandish.. The panels aren't pointed at the sun, and the blades would be so heavy that they'd need a gale to get moving. It's kinda the worst of both worlds. Though part of me is tempted to build it to see what it would do.
    - brudgers 15y ago
      Let us leave aside how much more readily a vertical stack lends itself to ground mounting compared to a flat array for now. Gravity loads are not typically the primary concern for conventional solar arrays, uplift is. Deadload is an effective means of counteracting uplift. Lateral force per unit area on a roof mounted object is significantly less than uplift (and lest we forget, the length of the lever is mid height for a uniformly distributed load. Roof design is like computer security, every penetration in the membrane is a potential site of infiltration. More holes = more probability of bulk water in the building. One of the worst places to direct bulk water is around electrical equipment. Flat layouts create additional problems in regards to maintenance. Access to penetrations and the the membrane will be more largely dependent on the ease with which panels can be demounted, in addition access to panels in the center of the array may also be dependent upon demounting panels - one probably does not want to walk across an energized electrical grid and solar panels tend to be energized when the sun is shining. Hail and wind borne debris are banes of roof mounted arrays and flat panels are generally at significantly greater risk to both. One ignores that solar panels are a part of a building's electrical system at their own peril, quite literally. A flat scheme not only requires significantly more conductors, it also increases the area over which the potential for a lethal shock is high quite significantly - talk to a fire fighter sometime about how one plans for operations around solar arrays during daylight hours. It may be reasonable to consider that a longer diurnal period in which significant power is generated will reduce the need for storage capacity - lead acid batteries, hydrogen tanks, and other standard storage methods all come with significant life safety concerns. Finally, packaged technical solutions tend to provide better quality, lower cost, and a higher degree of safety compared to custom site built solutions. One can assemble a tower in an enclosed factory using industrial Q.C. processes. Doing so on a pitched surface ten meters above grade as light fades at the end of a cold winter day is a bit more unlikely. This is not to say that the claims of the article are accurate. But from a building science standpoint, a vertical array is a significantly better option than a flat one.

jacquesm 15y ago

Panels are arrangements of cells. Panel efficiency is measured in $/Watt or as a percentage of incident light over the total area taken up by the array including shade, not in output per square unit of area under the array. If you want to do a really nice job in measuring panel efficiency you set up equal area arrays (equal areas of cells with the same packing density on the cells themselves) and measure them side-by-side over the course of a year. The 'control' should be a non-tracking array that you correct for elevation once every month and that points due South on the Northern hemisphere and vice versa.

brudgers 15y ago
>"not in output per square unit of area under the array" It can be measured that way, and for many practical applications it is. Solar tracking a small surface area is easier than tracking a larger one, water management of six solar panel mounting penetrations through a roof is more efficient than for sixty penetrations. Engineering efficiency shouldn't just be measured in a lab. However, based on the article one standard measure of efficiency does seem to be addressed, kw-hrs/panel/day because of the claims of better performance at low incident angles.
- jacquesm 15y ago
  Tracking a small surface area is indeed easier but this is actually a larger area (the funnel effect will undo quite a bit of the effect of the reduced cross section), and it will nicely capture the wind because of its shape. On top of that you'll have to deal with force in more than one direction compared to panels mounted flush with a roof. Mounting solar panels using aluminum stand-offs is very easy and tried-and-true tech, setting up a tower like this up on your roof is not going to be nearly as easy as you think because there will be a lot of force trying to pull the whole assembly off the roof whereas conventional installations have to deal mostly with compressive forces (which is a whole lot easier). And that's with the wind directly on the panels. The arm of force from such an assembly will be proportional to the height of the total stack and will be quite impressive. You'll need - at a minimum - braces and guys behind the stack if you don't want it to take off in the first storm. Those sixty penetrations have a nice side effect of spreading the load evenly over the roof so that you don't need to design a structure behind it to deal with the force of the whole array.
  - bhousel 15y ago
    Heh, mount this "tower" on slip rings and an alternator and you can have both a solar array and a windmill in one.
    - jacquesm 15y ago
      Someone beat you to it (that's the HAT variety, I guess yours would be a VAT): http://www.freepatentsonline.com/7045702.html http://www.freepatentsonline.com/7045702.html The windmill scene is even more outlandish than the solar panel people, and the funny thing is all the weird ideas come full circle every decade or so.
      - bhousel 15y ago
        Wow, that is outlandish.. The panels aren't pointed at the sun, and the blades would be so heavy that they'd need a gale to get moving. It's kinda the worst of both worlds. Though part of me is tempted to build it to see what it would do.
  - brudgers 15y ago
    Let us leave aside how much more readily a vertical stack lends itself to ground mounting compared to a flat array for now. Gravity loads are not typically the primary concern for conventional solar arrays, uplift is. Deadload is an effective means of counteracting uplift. Lateral force per unit area on a roof mounted object is significantly less than uplift (and lest we forget, the length of the lever is mid height for a uniformly distributed load. Roof design is like computer security, every penetration in the membrane is a potential site of infiltration. More holes = more probability of bulk water in the building. One of the worst places to direct bulk water is around electrical equipment. Flat layouts create additional problems in regards to maintenance. Access to penetrations and the the membrane will be more largely dependent on the ease with which panels can be demounted, in addition access to panels in the center of the array may also be dependent upon demounting panels - one probably does not want to walk across an energized electrical grid and solar panels tend to be energized when the sun is shining. Hail and wind borne debris are banes of roof mounted arrays and flat panels are generally at significantly greater risk to both. One ignores that solar panels are a part of a building's electrical system at their own peril, quite literally. A flat scheme not only requires significantly more conductors, it also increases the area over which the potential for a lethal shock is high quite significantly - talk to a fire fighter sometime about how one plans for operations around solar arrays during daylight hours. It may be reasonable to consider that a longer diurnal period in which significant power is generated will reduce the need for storage capacity - lead acid batteries, hydrogen tanks, and other standard storage methods all come with significant life safety concerns. Finally, packaged technical solutions tend to provide better quality, lower cost, and a higher degree of safety compared to custom site built solutions. One can assemble a tower in an enclosed factory using industrial Q.C. processes. Doing so on a pitched surface ten meters above grade as light fades at the end of a cold winter day is a bit more unlikely. This is not to say that the claims of the article are accurate. But from a building science standpoint, a vertical array is a significantly better option than a flat one.