On Air cars... Too bad they can't be "charged" in the winter when the waste heat is 100% usable for heat in th ebuilding where the compressor is, and then driven in the summer when the expansion is free AC.. bob
On Sat, Oct 1, 2016 at 8:34 PM, Cor van de Water via EV <ev@lists.evdl.org> wrote: > I have reported before that almost 20 years ago I visited MDI in France, > who were supposed to release an air-powered car. I checked their physics > and came to the conclusion that without heat exchanger, their efficiency > would be horrible and the air engine would freeze up. That is exactly > what several news reporters have said once they took a slightly longer > test run than just a loop in the parking lot. Physics is quite clear > about the efficiency of compressing and expanding a gas like air. You > invest a *lot* of power in the compression and get a *lot* of heat out > at that moment. As Lee would say: heat is the indicator of > (in)efficiency. > Only if you are able to either store or feed that heat back in during > expansion, can you get a decent efficiency. Since MDI did not design > that in, their cars were doomed to be wasteful and since the compressed > air storage has so low energy density, their range was short. There > really was not a whole lot of difference compared to running batteries, > though in theory the weight could be less and the absence of lead or > acid or other dangerous materials was a benefit, but the lower > efficiency made it a non-starter. > There are niches where air powered vehicles were used, think mine > corridors where no dangerous goods, sparks or combustion was a big > benefit for the operation underground. Today we would use an AC > (brushless) drive to avoid the sparks and achieve better efficiency. > > Cor van de Water > Chief Scientist > Proxim Wireless > > office +1 408 383 7626 Skype: cor_van_de_water > XoIP +31 87 784 1130 private: cvandewater.info > > http://www.proxim.com > > This email message (including any attachments) contains confidential and > proprietary information of Proxim Wireless Corporation. If you received > this message in error, please delete it and notify the sender. Any > unauthorized use, disclosure, distribution, or copying of any part of > this message is prohibited. > > > -----Original Message----- > From: EV [mailto:ev-boun...@lists.evdl.org] On Behalf Of EVDL > Administrator via EV > Sent: Saturday, October 01, 2016 4:51 PM > To: ev@lists.evdl.org > Subject: Re: [EVDL] Compressed Air > > On 30 Sep 2016 at 19:44, Michael Ross via EV wrote: > > > Can we discuss compressed air a a storage medium that can spin > > electric motors in autos and trucks? > > Maybe, but I don't see how air can power a motor. > > We've had posts on compressed air cars before - check the archive - but > those aren't EVs. > > See Wikipedia for a decent article on compressed air cars that explains > why > they've never made the big time despite nearly a century of tinkering > witih > the concept. The problems are low efficiency and an energy density by > volume that's worse than lead batteries. > > > Certain elements can be reformatted to higher energy states and then > > reacted to power EV's. > > Isn't this how batteries work? > > > There is a particular reaction that could be used to store energy from > > sustainable, but temporally irregular energy sources. It is a very > > simple reaction, readily available ingredients are found everywhere > for > > little cost. > > And that is ... ??? > > > Technology exists to store the energy and release it, that is > > sufficiently efficient (since there is no alternative other than to > > waste solar and wind energy when it is inconveniently timed efficiency > > becomes less concerning) > > As I understand it, batteries are the gold standard for efficiency in > this. > Between 20% and 80% SOC, lead batteries are close to 100% efficient. > > I'd guess that other types have similar ranges with similar efficiency. > > Air compressed in undergound mines has been used for utility load > leveling. > The programs so far have required natural gas input to warm the cold > released air. Their efficiency looks decent if you ignore the gas > input. > However, one source I read put the actual efficiency for air storage at > 25- > 45%. > > Pumped hydro is much more common and supposedly runs 60-85% efficiency, > though I admit I find that hard to believe too. > > The island of El Hierro is now generating almost all of their > electricity > with wind, and storing it with pumped hydro. > > > compressed air could do this, but I would really prefer it was a > > compressed reactive gas not just nitrogen and some other lesser > > components. > > Can you explain why? > > > If this particular gas was used, an additional use is possible, we > > could use to power EVs. > > What gas are you talking about? It almost seems as if you're avoiding > naming it. Why all the mystery? > > David Roden - Akron, Ohio, USA > EVDL Administrator > > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > EVDL Information: http://www.evdl.org/help/ > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > Note: mail sent to "evpost" and "etpost" addresses will not > reach me. To send a private message, please obtain my > email address from the webpage http://www.evdl.org/help/ . > = = = = = = = = = = = = = = = = = = = = = = = = = = = = = > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at 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 > Read EVAngel's EV News at http://evdl.org/evln/ > Please discuss EV drag racing at 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/20161002/879a3bee/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org Read EVAngel's EV News at http://evdl.org/evln/ Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
