DaniFong

30 ms·

1. 301.▲
   by DaniFong 14y ago

   Consider a big Carnot cycle. It's 100% reversible -- as efficient as you can get. No losses. And it's 100% reversible no matter what temperature it operates at. The Carnot cycle is: 1. Isothermal compression (T_c) 2. Adiabatic compression (
2. 302.▲
   by DaniFong 14y ago

   1^m3 of 300 bar air = approx. 30 kwhr. Approximately 1/4th of that in water storage will hold the heat. We're aiming at a daily loss of 1%, but it caps out at 10% relative (~7% absolute) because the Energy Out/Energy In is proportional to
3. 303.▲
   by DaniFong 14y ago

   We get a higher energy density per m^3 of air at higher pressures. We were aiming at 4500 psi eventually. We aim for it not to be noisy -- any noise from high pressure air rushing out represents wasted energy. Sonic booms from exhaust have
4. 304.▲
   by DaniFong 14y ago

   Sorry! This is a very subtle process. If you analyze it superficially, it makes sense, dig deeper and it's confusing, and then dig still deeper and it makes sense again. When you cool the air by mixing it with water spray, a good portion
5. 305.▲
   by DaniFong 14y ago

   We want to use air because of the cheap, gravitational pressure vessel we have on this planet. :-)
6. 306.▲
   by DaniFong 14y ago

   Lead by Peter Thiel, an outside investor.
7. 307.▲
   by DaniFong 14y ago

   To tell the truth I'm not sure we ever spoke with Thiel about the DOE/ARPA-E rejection. That was back in 2010. We've come a long way since then.
8. 308.▲
   by DaniFong 14y ago

   Water actually has the highest volumetric sensible (no phase change!) heat capacity of any substance on earth. We don't rely on water vapor -- the problem is that at low temperatures there's very little vaporization that can even take place
9. 309.▲
   by DaniFong 14y ago

   The main thing is that the mist process is higher efficiency. If you compress the air, let it heat up, and THEN cool it by mixing the air with water, the pressure will be high during the compression process, which will take a lot of energy
10. 310.▲
    by DaniFong 14y ago

    Back at you tptacek!
11. 311.▲
    by DaniFong 14y ago

    Hopefully our website might be more enlightening... lightsail.com I give a 3 minute TR35 award talk on the concept at the emTech conference this year. Starts at 5:27 http://www.livestream.com/emtech2012/video?clipId=pla_cdd4c6...
12. 312.▲
    by DaniFong 14y ago

    :) Funding isn't the constraint now, it's time. But believe me there are more off the beaten path ideas where that came from ;-)
13. 313.▲
    by DaniFong 14y ago

    You have to store both. Also, you can't vaporize much air at low temperatures, which we aim for. You have to hold onto water for its sensible (no evaporation) heat capacity.
14. 314.▲
    by DaniFong 14y ago

    Well, the aim is to best peaking plants on a levelized energy cost basis. Not an easy challenge but momentous if possible.
15. 315.▲
    by DaniFong 14y ago

    Your calculations appear be within an order of magnitude of correct :-) One other way to think of the number of shipping containers needed: actually the average american home uses 30 kwh/day. At our target energy density and efficiency we'v
16. 316.▲
    by DaniFong 14y ago

    You might be overfitting the data. The initial series A, and B were essentially a seed round. I can tell you, this was certainly an upround!
17. 317.▲
    by DaniFong 14y ago

    My dad is visiting and we're playing bagpipe music on the stereo :-)
18. 318.▲
    by DaniFong 14y ago

    Thanks!
19. 319.▲
    by DaniFong 14y ago

    FWIW, Peter Thiel is totally awesome, and one of the most rational and brilliant and human people I know.
20. 320.▲
    by DaniFong 14y ago

    Shucks. I guess I just try to deal with the truths in front of and around me. And I found myself moving in important, but uncharted waters.
21. 321.▲
    by DaniFong 14y ago

    A knee-jerk reaction by poorly informed and motivated reviewers, which included a fear of: - Hydrolock (solved by default) - Corrosion (solved) - Inability to separate water and air (easy to solve and quickly solved) - a lack of understandi
22. 322.▲
    by DaniFong 14y ago

    Good luck with your company! Management of the systems is a seriously underappreciated and difficult problem, especially with batteries. To do it well, you have to really know the chemistry. I think the difference in fanfare is probably bec
23. 323.▲
    by DaniFong 14y ago

    ;)
24. 324.▲
    Peter Thiel, Bill Gates, Khosla fund LightSail Energy in $37M Deal(blogs.wsj.com)

    235 points by DaniFong 14y ago|123 comments
25. 325.▲
    Eulogy for Corwin Hardham(otherlab.com)

    1 points by DaniFong 14y ago|0 comments
26. 326.▲
    by DaniFong 14y ago

    Azealia Banks' 212 is absolutely killer -- and it is, in fact, exactly the track upon which I found out about Rap Genius. Kudos. They should think about alternative branding for the other types of content, though. Maybe "what's the rap?" or
27. 327.▲
    by DaniFong 14y ago

    Yup, and things stay around atmospheric pressure throughout. I intend to build it at some point. (There's a long list, obviously, but this is a keeper) so if you're ever interested in it, let's chat. :-)
28. 328.▲
    by DaniFong 14y ago

    Hi there, I read your IAmA where you had a reply to a message, now deleted, in which you must have been asked about aerial circumnavigation. You mentioned that you'd use a solar balloon, and that you merely would have to have a strategy for
29. 329.▲
    by DaniFong 14y ago

    Unless outsider membership confers other values, such as perspective or the capacity to make larger out of the box thinking judgements (according to Simonton's research, it does), and unless the degree to which stereotypes undervalue people
30. 330.▲
    by DaniFong 14y ago

    it was so unbelievably beautiful, how the rain caught the rocket's glow. what a beautiful way to leave the earth