Since the Water Heater is a storage tank type, it also leaks heat back to its environment and needs regular re-heating. Since that is essentially a closed system, your garage may both be cooled (de-humidified!) by the heat pump and subsequently warmed up by the heat leaking from the vessel back into its ambient. Of course there is a net flow of heat out of your garage/basement when you open a hot water tap somewhere in the home, but there is also the loss in the heatpump that is adding to the heating of your garage/basement. It is simple to look at your garage as a closed system and calculate the energy in and out. If the amount of energy as hot water that you pull out of the garage is larger than the energy going into the garage as electric power, then the garage is cooled by the heat pump WH. If not, the garage is heated up by the WH, because there must be a balance of energy.
Cor van de Water Chief Scientist Proxim Wireless Corporation http://www.proxim.com Email: [email protected] Private: http://www.cvandewater.com Skype: cor_van_de_water XoIP: +31877841130 Tel: +1 408 383 7626 Tel: +91 (040)23117400 x203 -----Original Message----- From: EV on behalf of Peri Hartman via EV Sent: Fri 1/16/2015 4:47 PM To: Electric Vehicle Discussion List Subject: Re: [EVDL] EV Demand Response - (solar-thermal-NOT) Not that it would make a huge difference, but 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, 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" <[email protected]> To: "Ben Goren" <[email protected]>; "Electric Vehicle Discussion List" <[email protected]> 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 ><[email protected]> wrote: >>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) > >_______________________________________________ >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 -------------- A non-text attachment was scrubbed... Name: not available Type: application/ms-tnef Size: 5152 bytes Desc: not available URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20150116/dfb08db1/attachment.bin> _______________________________________________ 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)
