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Integrated solar roofs

Discussion in 'Tesla Energy' started by T B, Jul 22, 2016.

  1. T B

    T B President, Tesla Club Sweden

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    What if we should read the master plan literally?
    "Create stunning solar roofs with seamlessly integrated battery storage"

    [​IMG]
    Imagine this: a solar panel with batteries attached to the back of it. Thus it can "provide power" even after sunset!
    Between the solar panel and the batteries coolant fluid is circulated cooling both the panel and the batteries.
    As a "byproduct" you also get warm water. To be used in the house.

    Both solar panels and batteries loose efficiency when they become hot. One thing Tesla is really-really good at is cooling batteries.

    By having the roof actively cooled the house beneath it doesn't get as hot any more. Less power is needed to cool it down with AC. In the winter you can now and then circulate hot water in the pipes melting the snow on the panels (just the bottom layer so the rest slides down in an avalanche).

    Perhaps this is why Elon Musk wants to combine both companies? Everyone is talking about packaging solar panels and battery storage in one combined package people will buy - but what if they really want to create "solar roofs with seamlessly integrated battery storage"? That product would be hard(er) to make by two separate companies.
     
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  2. Electric Dream

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    Nice bit of lateral thinking there.

    One of the aspects of solar panels installed on houses in the UK which has always put me off the idea is that they look so out of place and retro-fitted.

    I'm expecting/hoping some thought is being given to how they integrate better. That might up their appeal over here. Maybe not so much of an issue in the U.S.?
     
  3. andrewket

    andrewket 2014 S P85DL, 2016 X P90DL (soon 100)

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    I think the idea has merit. Batteries take up space. Finding room for a few powerwalls is difficult. Hiding it behind the solar panels on the roof fixes that problem, and scales linerarly.
     
  4. Ryan MF

    Ryan MF Member

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    Batteries are very heavy and pre-existing homes are not designed for that kind of load.
     
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  5. T B

    T B President, Tesla Club Sweden

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    Batteries are not especially heavy. 1 kWh of batteries is enough to store a day's production of electricity from one m2 of solar panel.
    That is about 5 kg of added weight to a solar panel typically weighting about 15 kg/m2 already.
    Plus about 5 kg for the cooling.
    Results in 25 kg/m2 instead of today's 15.
    Roof tiles weigh about 50 kg/m2.
    If you remove the roof tiles and cover with solar panels you actually reduce weight.

    You can read more at Soltak - Tesla Club Sweden , especially the comments section. (Google translate is your friend)
     
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  6. WarpedOne

    WarpedOne Supreme Premier

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    Batteries on the roof are a bad idea because they do not solve any real problem, but they do create real problems.
    Not enough space for batteries inside the house is not even wrong. There is plenty of room. Mount them to the roof of your basement or smth.

    Putting batteries on the roof is exposing them to elements, heat AND cold. Batteries prefer room temperature, when you are comfortable, they are also. When you are not, they are also 'suffering'.
    They would also add considerable weight to the roof structure. Roofs are not built to support anything beyond plain old "roof material". Even solar panels alone are often to heavy already.

    Adding water colling to solar panels on the other hand is not bad idea. Solar panels get hot and loose efficiency. With active cooling you increase actual electricity production and also get some warm water.
     
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    • Informative x 2
  7. Alketi

    Alketi Member

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    Interesting lateral thinking, as someone mentioned, but I think you're probably being too literal.

    For the life of me, I can't figure out what's so "stunning" about Silevo's technology that would make it look better than a shingled roof, as Elon once put it. SunPower already has absolutely pitch black panels and though they don't look offensive, I wouldn't say they look better than a normal roof.

    I'm almost thinking that Silevo has made a black solar shingle that might snap together and cover the entire roof.

    Or, I'm thinking I'm not going to agree with Elon's assessment of how a roof looks. :)
     
  8. Silenus136

    Silenus136 Member

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    Would it be better to house batteries in a unit that can be buried adjacent to or under the home? Temperature largely controlled by the nature of underground insulation, contained fire risk, no need to find a place to hang a powerwall, and reduces the issue fire departments have with solar roofs (difficulty punching holes in roof to fight house fires).
     
  9. anthony

    anthony Member

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    I would buy panels that gave me solar hot water and pV all in one package for sure.
    Putting the batteries on the roof doesn't seem to have much if any advantage, except that you may be able to harvest some energy from the batteries giving off heat as well, though that would likely be negated by winter month heating of batteries for me.
     
  10. AB4EJ

    AB4EJ Member

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    Remember also that in large portions of the country, anything on the roof (i.e., batteries) will be exposed to extended periods of subfreezing temperatures (in some cases, below zero F, for like 8 hours at night), which has to be hard on them; to maintain temperature, perhaps heat has to be supplied, which is an energy drain. Can they be insulated well enough so that this is not a problem? Maybe integrated batteries are not ideal for all locations.
     
  11. David99

    David99 Active Member

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    There is absolutely no reason to have the batteries on the roof. It's the one place where temperatures are the most extreme (hot and cold) and make servicing so much harder. You also don't gain anything compared to having them in the house. Space is really not an issue. Look at the 90 kWh of a Model S. Positioned upright, it would take away 15 cm of space from a wall, that's it.
     
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  12. Model 3

    Model 3 Active Member

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    You want something like this?
    (Sorry, link in Norwegian, but the images and the video has no language ;) )
    [​IMG]
     
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  13. tander

    tander Member

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    That does seem like it could make some sense at some point, why have a solar panel and a separate battery when they could just be one thing with one installation. Guessing that will be a while though considering they're still building the factories separately.
     
  14. Electric Dream

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    Well, it is better than this:

    [​IMG]

    But I'm thinking they should look more like this:
    [​IMG]
     
  15. pr0teu5

    pr0teu5 Member

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    #15 pr0teu5, Aug 1, 2016
    Last edited: Aug 1, 2016
    I think there are advantages and disadvantages to this idea, but I do think it might be something worth considering. I don't think anyone has mentioned this, but placing the storage directly on the panel could allow for one to match the output of cells that are suffering from uneven shading. This would increase the overall average efficiency of the panel for most users.

    As mentioned by other users the shared cooling of the batteries and the solar panels might also have the potential to increase the the efficiency of the panels by lowering the operating temperature.

    Also, one of the major costs of a solar system is installation. By combining the solar panels, inverter, and batteries in a single standard package could decrease the complexity of installation, and make solar + storage a more attractive proposition.

    Though solar+storage is necessary in the long run, I don't see it having an LCOE that is competitive with the grid until batteries reach around ~$100 per kWh.

    The powerroof might be coming, it just might take a few years.
     
  16. Garlan Garner

    Garlan Garner Active Member

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    Shouldn't put batteries on the roof in Chicago. It gets down to 30 below zero each winter. All liquid freezes. Cars don't start. Batteries die.
     
  17. AudubonB

    AudubonB Mild-mannered Moderator Lord Vetinari*

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    As someone who lives in an extreme climate, I will second the voice of those who would not place batteries on a roof. Furthermore, I believe firefighters everywhere would be in mass revolt at having to cope with the possibility of high-amperage units there - all sorts of unpleasant possibilities like (ugh!!) having to chop through them - fire departments are bad enough about shut-offs for just PV panels - and, far worse, having them and their associated cables falling through the house in a bad fire (ugh!! ugh!! ugh!!).

    That said, I do very much like the possibility of a combination PV panel / heat capture set-up. Current solar heat technology is about an order of magnitude more efficient than solar photon capture - I think about 94% efficient vs the 16% or so industry-wide mean for PV.

    AND, as noted by some above, such a system would naturally act as a heat sink for the PV panels, thus bringing them down to more efficient temperature levels.

    NEVERTHELESS, I fear much of the world at latitudes greater than about 40º N or S or altitudes higher than roughly 1000-1500meters would have to make use of some kind of antifreeze coolant at the roof level, as we do here, then running that through heat exchangers to transfer to domestic water systems. Very much a suboptimal situation and, as I extremely painfully can attest, fraught with engineering oopses and other headaches.
     
  18. bxr140

    bxr140 Member

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    I agree. Certainly with today's technology it doesn't make sense, but I think the idea considers an interesting design space for the reasons you and others have mentioned.

    Streamlining manufacturing and installation will be huge, and combining everything into one product line could really bring the cost down AND simplify the technology. We, or at least most of us, don't buy a power supply and a hard drive and a processor when we're buying a computer--we go out and buy a box that has all that 'unrelated' technology crammed inside because it's cheaper and easier, then all we do is plug the thing in and go. What if an integrated solar power unit was as plug and play as [figuratively] running an extension cord down off the roof to a household outlet?

    What if you could eliminate some of the system electronics by integrating the batteries into the solar panel assembly? Reduced recurring cost from materials all the way to installation and servicing.

    How about integrating a battery directly to the backside a CIC so it is its own little power unit--instead of a m2 pv array with a battery bolted to the back, you'd have a m2 array of fairly self contained mini power units.
     
  19. alseTrick

    alseTrick Member

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    That's fantastic. Making the panels the roofing is the way to go. And hasn't Musk even talked about having various colored panels to more closely match current roof colors? If they can do that while keeping efficiency close to that of black, that'd also be a good direction to go.

    What's up with that odd, flat portion of the roof, though? And are some of those "dummy" panels that are installed just to keep the roof uniform in look? Because there's no way every side of that roof is getting high levels of direct sunlight (especially in a latitude like Norway). And I wouldn't want to pay full price for cells that will only get a fraction of their possible energy.
     
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  20. alseTrick

    alseTrick Member

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    Is the latter really that much better than the former? Both have large black patches of roof on an otherwise orange roof.

    Truth be told, I don't have a problem with the first one. I'd be stoked if I had a house whose roof looked like that.
     

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