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New solar energy developments

Home Forums Archive Infrastructure New solar energy developments

This topic contains 23 replies, has 8 voices, and was last updated by Avatar of J.L.-Frusha J.L.-Frusha 3 years, 2 months ago.

Viewing 9 posts - 16 through 24 (of 24 total)
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  • #9865
    Avatar of Melllvar
    Melllvar
    Participant

    Carl wrote:

    Mellvar, I am sure you and wikipedia are right about all the efficiency numbers. But has anyone ever built a floating concentrated solar energy plant? On land you clearly have an advantage with regards to alignment.

    I am not sure about what temperatures you can achieve with heat pumps, or what temperatures are required for Stirling engines. Maybe low-temp collectors aren’t feasible for electricity generation. I’m just suggesting it as an alternative that on the face of it seems to have some advantages over mirrors.

    On the reflective film, I really don’t have a clue what the going rate is. I just saw $32/m² and thought it sounded expensive for what seems like a simple product. Pot growers (I would presume) probably are limited by area though, so they can afford to use expensive stuff. And they don’t need a whole lot in comparison with a power plant.

    Well, I can’t disagree with any of that. $32/m^2 is expensive for my budget, but I believe they use that same stuff at the Kramer junction site, so it’s apparently cost effective for them, and those are just troughs, IIRC, not power towers. The flat set ups do have their advantages, like I was saying I think they would work better for low-temperature uses like water heaters and temp. control during winter. But we won’t be on land, so if a solar thermal station was going to be built, it would just have to deal with the sea conditions as best it could.

    Personally, I think solar thermal coupled w/ OTEC is the way to go for large scale energy production, w/ the exception of maybe nuclear. The energy island concept is still my favorite example of energy production at sea. Hopefully the cost of the fancier materials for any/all of these systems will go down with time due to manufacturing improvements, as opposed to up with inflation.

    #9869
    Avatar of i_is_j_smith
    i_is_j_smith
    Participant

    As much as I love the idea of OTEC…being a fan of Marshal Savage and all…I don’t think it can be counted on as a viable energy system. It looks great on paper, but nobody has been able to make it work well. While the theory is sound there is just no way to do it economically…you’ll end up spending far more than you would on any other off-the-shelf energy system. There are just too many unanswered issues with OTEC that don’t make it feasible in my opinion.

    Now if you have a ton of money for start-up then it would be nice to have an OTEC system. But that would be millions upon millions of dollars spent on an untested energy infrastructure that could be better spent on the seastead itself.

    #9880
    Avatar of admiral-doty
    admiral-doty
    Participant

    photovoltaic cells can be mounted to a thermal collector panel to capture most of the energy. this way, what doesn’t get turned into electricity is collected as heat. maybe the heat can be used for ammonia adsorption refrigeration as well as hot water. the nice thing about pv cells is they still produce power in cloudy weather, though with less current.

    #9883
    Avatar of Carl-Pålsson
    Carl-Pålsson
    Participant

    the nice thing about pv cells is they still produce power in cloudy weather, though with less current.

    I think this is true for low-temp solar thermal as well.

    Actually OTEC seems to prove that you can indeed produce electricity with low temperature differences. It uses just a 20 degrees Kelvin or so, if I understand things correctly. And without heat pumps as well, at least with an indirect cycle.

    Now, it obviously is not competitive with other mainstream energy sources. But it works. So it (or low-temp collectors) might be feasible if you are willing to pay a premium. The question is how much, of course.

    The big 1000 meter pipe transporting up the cold deep ocean water seems to be a weak spot with OTEC. I can think of problems both with storms and dynamic positioning (mobility).

    #9884
    Avatar of i_is_j_smith
    i_is_j_smith
    Participant

    You don’t want to mount PV cells where they are going to be hit by concentrated sunlight. While you can boost the amount of electricity they generate you can damage them very quickly. You want to keep PV cells far away from the furnace area of a solar thermal system or you are going to have a bunch of ruined PV cells.

    Yes, you can generate electricity from PV cells even on cloudy days…but at a fraction of their normally capacity. There are some new cutting-edge PV designs using new nano-scale materials that can collect even IR wavelengths…but they are all in the experimental stage. Do not count on an array of PV cells to power your seastead on a cloudy day. That’s why all solar systems (except for solar power satellite systems) require an energy storage mechanism. Whether that be batteries or flywheels or hydrogen you need a method to store energy so you can supply it when the sun goes down or the clouds roll in.

    That’s why I like two-tank molten salt solar thermal systems, because they have the energy storage mechanism built right in to the system. You are actually powering your seastead from the temperature differential of the molten salt…not from solar. The solar system is just the mechanism for heating the salt.

    As for OTEC, I wouldn’t actually say it “works”. Yes there have been a few small-scale experimental systems run in the past but nothing that really proves it can work on a seastead-sized scale. The ones in Hawaii were mostly for demo purposes, and I think only one ever generated any net power. I know the Japanese one made net power and sent it into the grid, but you are talking 40kW. There are many issues that are slowing down OTEC development such as biofouling, intake pipe design, heat exchanger designs and materials, and turbine design.

    There is really no place where you can go to get an OTEC system “off-the-shelf”. Every piece would need to be designed and built from scratch as a custom project. While I wouldn’t call solar thermal systems “off-the-shelf” there are several companies that are building them for commercial distribution so they are more readily available.

    OTEC is a great idea, and on paper it sounds perfect. But it still needs far more experimentation before it is ready to be rolled-out as a seasteads primary source of energy.

    #9887
    Avatar of i_is_j_smith
    i_is_j_smith
    Participant

    What a joke. The U.S. Department of Energy gives $1M in grants to explore OTEC:

    http://news.cnet.com/8301-11128_3-10469067-54.html

    Wow. A whole $1M. And that isn’t all going to be spent on OTEC research. My guess is they’ll sink most of it into seawater coolant research and drop a few hundred dollars on OTEC. And we wonder why these clean energy systems with huge potential aren’t going anywhere.

    #12046
    Avatar of makanbubur
    makanbubur
    Participant

    first of all, dont really believe mainstream media and talking about green energy, there are tons of cheap alternative the reason news and corporation dont promote it is because it is too efficient and theres no profit in the long term

    we can use fresnel lens either to boil water, as source of heat, and beam it to solar panel and YOU’LL GET 10 times of the typical sun efficiency. proof here : http://www.youtube.com/watch?v=C_yhi_fy-Q0

    #13361
    Avatar of Morganism
    Morganism
    Participant
    #13376
    Avatar of J.L.-Frusha
    J.L.-Frusha
    Participant

    I saw a proposal to heat water on the back side of solar panels. Collecting the heat, cooling the panels and increasing their efficiency. Using thermo-syphon water supply, the water is the only moving part…

    Later,

    J.L.F.

    Never be afraid to try something new…

    Remember, amateurs built the ark, professionals built the Titanic.

Viewing 9 posts - 16 through 24 (of 24 total)

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