> ... I question the value of a heat pump H/W heater in winter. > If it's taking heat from your garage or basement, > that is ultimately taking some heat from your heated spaces...
Yes, one has to think about where it is. But my garage is not heated, nor is my basement. Therefore it is taking the heat from the environment which is taking it from outside (if it is your unheated garatge or fromteh ground if it is my basement. The temperature in my below ground basement never gets below 55F even during the winter no matter how much "heat" I pump out of it into the water heater. Nor the 10,000 BTu of heat I pump out of it via an old A/C unit serving as a heat pump by placing its cool side in the basement and its warm side into the follor of the room above. The surface area of the basement is about 2000 sqft includgint eh walls and crawlspace area. That is a huge source of latent heat, even in the winter. So I call them modest "ground source" heatpump systems since that is where the heat is actually coming from when I draw it from the basement. But I agree. If you put the heat pump water heater in a closet or in a heated portion of the house, one really needs to think it through. In the summer, it is great almost anywherer you put it, but if it is in a conditioned space, it should probably be exhaust vented outdoors in the winter. Bob, WB4APR which means you're simply using more energy elsewhere. If you could somehow duct the air intake from outside during winter, then it would be doing the best job it could. In summer, no doubt a true benefit. > > Before you argue that I'm wroing, consider this. If the air outside your > garage is colder than inside and the H/W tank is cooling the garage air in > exchange for heating the water, either the garage temp will drop to less > than the outside or warm air will be drawn from the home's heated spaces. > If you are truly insulated, then the former will happen and you will have > the equivalent of ducting intake from outside. I doubt that the normal > case. > > Peri > > > ------ Original Message ------ > From: "Mike Nickerson via EV" <ev@lists.evdl.org> > To: "Ben Goren" <b...@trumpetpower.com>; "Electric Vehicle Discussion > List" <ev@lists.evdl.org> > Sent: 15-Jan-15 9:04:35 PM > Subject: Re: [EVDL] EV Demand Response - (solar-thermal-NOT) > > I have one of the heat pump water heaters. It basically looks like a >> normal water heater with a small heat pump on top. They blow the cooler air >> out the top of the heat pump, so they can indeed be used to help with >> cooling in the summer. You need airflow around the area of the water heater >> to take advantage of the cooler air coming from the heat pump. >> >> Mike >> >> On January 14, 2015 9:39:18 AM MST, Ben Goren via EV <ev@lists.evdl.org> >> wrote: >> >>> On Jan 12, 2015, at 8:35 PM, Robert Bruninga <bruni...@usna.edu> 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) >>> >> >> _______________________________________________ >> 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/20150117/085dde36/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)
