Find the 2013 or so article "Thermal water heating is dead, dead, dead. Solar PV (grid tied) and a heat-pump water heater won out in about 2008, (also see first article "thermal water heating is dead". By 2013 it was a loser hands down.
Thermal water heating is only 70% efficient if you use EVERY DROP of heated water EVERY day. Otherwise you are capturing photons for heat that is not needed in an already hot tank. And you get nothing when you are on vacation or travel. Since the 90's and 2000's solar PV has dropped more than 10 to 1 in cost and heatpump water heaters can deliver three times the heated water than resistance electric. That makes PV/Heatpump systems 30 times more cost effective than in the early 2000's. PLUS, you get FULL retail credit for every photon that falls on your roof whether you use the hot water or not. It's a no-brainer. Bob Author: http://aprs.org/Energy-Choices.html -----Original Message----- From: EV <[email protected]> On Behalf Of Michael Ross via EV Sent: Friday, January 24, 2020 3:32 AM To: Electric Vehicle Discussion List <[email protected]> Cc: Michael Ross <[email protected]> Subject: Re: [EVDL] Cheapest off grid storage but can it be used to make electricity. It is an inspired and compulsive goal to be off grid. He is not accounting for labor and the enormous complication to his home. He is not accounting for the far greater value of his time. What he is doing to his house will never be appreciated when he tries to sell it and move, so he is anchored to his home. Good or bad? I can't say. I put in 5.6kW of PV that will out live me by decades, so we all have a personal choices that don't make sense to many other people. While solar thermal (he never addressed the actual collector system or accounted for ist cost) is 70% efficient, it is lower quality energy (from an entropic POV) than solar PV and harder to actually apply in the home. Pumps, piping, wiring, mixing valves. Is he on a municipal water supply, or a self powered well system? Anyway, solar thermal is very troublesome to build and maintain versus a grid tied PV system. You could buy PV and use resistance heaters and it might be a good trade off compared to thermal, provided you can actually site the PV well. This is why the solar thermal business is all but dead these days. You can DIY it, but that is about the only way. He is paying $10/kwh (if you accept his very hazy estimates for a number of things) where he can probably buy power for $0.20 / kwh. It is hard to see what the money side of this really looks like. If he actually has a grid, then this is extravagant. On Fri, Jan 24, 2020 at 2:58 AM Lawrence Rhodes via EV <[email protected]> wrote: > Very interesting project with the math explained. Lawrence Rhodes > https://www.youtube.com/watch?v=ryJmtItfaXQ > > > > -------------- next part -------------- An HTML attachment was > scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20200124/9e2 > 10451/attachment.html > > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/index.html > INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Michael E. Ross (919) 585-6737 Land (919) 901-2805 Cell and Text (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Tablet, Google Phone and Text -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20200124/b30e55 06/attachment.html> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
