On Jan 12, 2015, at 8:35 PM, Robert Bruninga <[email protected]> wrote:
> Compare the 60% efficiency of the PV/Heatpump water heater to the 50% losses > half the year of the 70% thermal panels and higher cost and the PV panels > with heatpump water heating win hands down. I hadn't heard of heat pump water heaters before this discussion. Something like that could, indeed, tip the balance. What happens to the cold side of the heat pump? Can that be used to reduce air conditioning load in summer? As of a few years ago, the return on investment, the payback time, for solar hot water was better than that of PV -- and that included maintenance every few years, electricity to heat the water on cloudy days (though much less electricity since you still get a substantial amount of warming), and so on. But it's obviously a rapidly-evolving field. If heat pumps really are coming to water heaters, that's huge not just for PV adopters but energy efficiency across the spectrum. If my own system lasts a few more years -- and there's no reason it shouldn't last a few times a few more years -- then it'll have paid for itself. Be nice to make a sizable profit off of it by getting it to last that "few times a few more years," but, if it dies prematurely, I suppose an all-electric replacement will have to be on the short list as well as a drop-in equivalent replacement. b& _______________________________________________ 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)
