Is solar thermal water heating *still* more efficient? - Mark
Sent from my Fuel Cell powered iPhone > On Jul 17, 2019, at 11:28 AM, Robert Bruninga via EV <[email protected]> > wrote: > > Inefficent yes, but hooking up 2 wires is a lot easier than building one out > of copper, plywood, glass and paint. With solar panels costing only 25 > cents per watt (on a good deal) then the investment in 4 panels (800W) is > about $275 and totally maintenance free. Where as cobbling together one > will only work in the summer, or if you want to use antifreeze, then you > have to add pumps and heat exchangers, etc. And will it work 20 years > without any attention? > > But you are right. You can triple the efficiency with a modern heatpump > water heater, BUT then it wont run on DC, so then you have to have 4 times > more panels and then do the grid-tie-only-when-running trick, and it simply > is not worth it. Better to just bight the bullet and be grid tied. > > Oh, I assume you have seen the articles that thermal solar hot water heating > was dead in 2008 and now is considered dead-dead-dead. It is more efficient > and economical to do grid-tie solar and a heatpump water heater. Because > since 2005, price of PV panels has dropped ten to one and heatpump water > heater is 3 times more efficient. (combined, then is 30 times more cost > effective than it used to be. Plus, the biggie, is that for every drop of > hot water you do not use, then you still get full 100% retail value for your > solar energy. Whereas with thermal solar, unless you use 100% of your hot > water every single day, then your thermal panels are doing nothing once the > tank is hot. > > Bob > -----Original Message----- > From: EV <[email protected]> On Behalf Of Jan Steinman via EV > Subject: Re: [EVDL] Solar off grid with an EV? (DC AC/heatpumps and > waterheating) > >> From: Robert Bruninga <[email protected]> >> >> … using about 4 Solar panels >> for the bottom coil in a water heater are a good idea. You need hot >> water every day, and so this gives you 100% effectiveness of these 4 >> or so panels. > > Seems like a horribly inefficient way of heating water! > > Direct solar hot water is a much better use of resources and solar energy. > Someone who's handy can easily cobble one up out of copper tubing, plywood, > glass, and some flat-black spray paint. > > Jan > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > 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 > 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 http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
