Disturbingly enough (from a thermodynamic perspective), in northern climates, the cost of PV heated hot water via an electric element, and solar thermal heated hot water, are very close. PV costs have plummeted so far that it's about the same cost per BTU of heat as a solar thermal system now. Now, if you are in a nonfreezing climate, the cost of the solar thermal system is quite a bit lower, and still outcompetes.
Now, for efficiency, solar thermal is still way higher -- more like 50 to 60% average, vs 10 to 15% for PV, so you need a lot less roof area for it. Z On Thu, Jan 2, 2014 at 9:58 PM, Jamie K <[email protected]> wrote: > On 1/2/14 5:44 PM, Michael Ross wrote: > >> It makes a lot more sense to have a solar generating system on your home >> and plug in to the home or grid, than to put the array on the car roof. >> Soon enough solar thermal collection of hot water will not worth the >> trouble... when PV efficiencies are good enough you will be better off >> running the power through a heating element, rather than having fluids >> pumped around, holes in the roof, plumbing, electrical and control >> infrastructure. >> > > Maybe so. > > Right now solar thermal is more efficient in gathering energy, from what I > gather. But as people keep trying crazy ideas, the technology moves forward > and your prediction might eventually hold water (without needing to hold > water). :^) > > BTW, the University of Colorado Solar Decathlon team designed an > interesting rooftop PV system with liquid cooling - a solar PV/thermal > combination approach that was quite clever in getting the most out of a > small roof area - providing solar thermal heat to the home while keeping > the PV cool. > > > Same with this goofy carport idea. Just build a proper PV system for >> God's >> sake. >> > > Maybe so, and that's what practical people are doing now for solar power. > > But when it comes to R&D for future products, maybe it's a good idea for > university students to have Ford's backing in pushing the boundaries and > experimenting with new ideas, whether they pan out or not. > > Cheers, > -Jamie > > > >> On Thu, Jan 2, 2014 at 7:30 PM, Jamie K <[email protected]> wrote: >> >> >>> For those who haven't yet RTA, it says that the solar concentrator is >>> mounted on a carport, not on the car. The idea is to project more >>> sunlight >>> from a larger area down onto the car's roof-mounted solar panels. >>> >>> here's the relevant excerpt: >>> >>> "The concept car's roof is covered with a solar cells provided by >>> SunPower >>> Corp (SPWR). But because it takes awhile to charge, Ford has also teamed >>> with Georgia Tech to offer a special car port for charging. >>> >>> Ford calls it an "off-vehicle solar concentrator" -- essentially, a >>> magnifying glass that can track the sun as it moves across the sky. The >>> car >>> port boosts the power that can be collected from sunlight by a factor of >>> eight, according to Ford, allowing a full 8 kilowatt charge over the >>> course >>> of a day. The glass was originally designed for a lighthouse. >>> >>> Ford said its internal data show that the sun could power up to 75% of >>> all >>> trips made by an average driver. And it estimates that the solar C-Max >>> could reduce the annual greenhouse gas emissions a typical owner would >>> produce by four metric tons." >>> >>> >>> I like the notion of getting some help from the sun when parked outside, >>> even if it's not the major source of power. The tiny solar panel on the >>> Leaf SL doesn't do much, but it can help with keeping the 12 volt battery >>> charged under the right conditions. The Ford concept has a much larger >>> solar panel so it would be that much better, even if it doesn't create a >>> truly solar car by itself. Future solar panels could become more >>> efficient >>> but this is a start. >>> >>> The Carport idea is an interesting idea for leveraging the larger roof >>> area of a carport for those times when a vehicle can be parked under a >>> carport during the day, although I wonder about how that might heat up >>> the >>> paint and interior of the vehicle over time. Right now it might be more >>> efficient to just put more panels directly on the carport roof (even >>> though >>> that loses the advantage of having a small extra charging source with the >>> car itself), but I'm glad to see Ford playing around with ideas. At some >>> point, ideas and economics mesh and things become practical. >>> >>> Cheers, >>> -Jamie >>> >>> >>> >>> On 1/2/14 5:11 PM, Michael Ross wrote: >>> >>> Bill is right about concentrating solar, there is no magic gift doing >>>> it. >>>> >>>> I test solar thermal collectors in my professional capacity. I recently >>>> tested a concentrating system that made 400F temperatures in the heat >>>> transfer medium. >>>> >>>> Do you really want a concentrating system? If you put 3000W into one >>>> meter >>>> on the roof of a car that is what you will get (a 1 meter collector, >>>> with >>>> two meters of reflectors around it). There are a number of other >>>> contrary >>>> details beyond this show stopper. Much more practical to fold out a >>>> bunch >>>> more PV. >>>> >>>> >>>> On Thu, Jan 2, 2014 at 6:37 PM, Bill Woodcock <[email protected]> wrote: >>>> >>>> The roof of the car is the roof of the car. It has a fixed area. >>>> >>>>> >>>>>>> >>>>>> >>>>> What you are saying makes no sense. >>>>> >>>>>> By using a collector as a type of solar funnel you can certainly >>>>>> >>>>>> concentrate the energy that was going to be disbursed over a larger >>>>> area >>>>> onto a smaller one. >>>>> >>>>> How are you planning to explain to your wife why she should drive a car >>>>> with a big-ass funnel strapped to the roof? >>>>> >>>>> It’s not the _bottom_ of the funnel that’s roof-sized, it’s the _top_. >>>>> The bottom of the funnel is the PV receptors. Using a concentrator >>>>> doesn’t increase the amount of energy collected, because it doesn’t >>>>> increase the area of the roof. It decreases the size of the PV >>>>> receptor >>>>> needed, which allows for different economies of production of the lens >>>>> versus PV receptor. It doesn’t make magic extra energy. >>>>> >>>>> -Bill >>>>> >>>>> >>>>> >>>>> _______________________________________________ >>> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >>> http://lists.evdl.org/listinfo.cgi/ev-evdl.org >>> For EV drag racing discussion, please use NEDRA ( >>> http://groups.yahoo.com/ >>> group/NEDRA) >>> >>> >>> >> >> > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/ > group/NEDRA) > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140103/6137d4ee/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
