We use chrome oxide collectors exclusively.
What I'm getting at is that the system will satisfactorily self regulate. Just from all the combined parasitic losses, a typical flat plate system will top out around 180F max.tank temp. in an average summer climate even without nighttime heat dumping. Night time heat dumping is nice way to bring that number down more in a case of limited occupancy / overproduction. Here in the Northeast, more often than not, residences have basement dehumidifiers running all summer. If that is the case and there isn't significant AC being used, we tend to use a basement heat loop for the excess heat. Again, no numbers, but any thermal load that can help against a giant electrical dehumidification one is a gain. An evacuated tube system needs more sophisticated top heat regulation. Conrad Cotuit Solar _____ From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of m...@hurshtown.com Sent: Friday, December 18, 2009 10:26 PM To: RE-wrenches Subject: Re: [RE-wrenches] solar hot water nighttime recirc I was once told that the best collector used black chrome plated on bright nickel. This combination absorbs heat well, with the advantage of not letting the heat back out. Sort of a thermal "diode" of sorts. I have no data, but I believe "good" collectors radiate less than they collect. Mark -------- Original Message -------- Subject: Re: [RE-wrenches] solar hot water nighttime recirc From: "Carl Emerson" <freepo...@freepower.co.nz> Date: Fri, December 18, 2009 10:04 pm To: "'RE-wrenches'" <re-wrenches@lists.re-wrenches.org> Hi there gang, Just to say that IMHO solar thermal panels will radiate quite a bit less than they collect, someone must have some data on this ?? Have a great Christmas. Carl Emerson Free Power Ltd. Web www.freepower.co.nz _____ From:re-wrenches-boun...@lists.re-wrenches.org [ <mailto:re-wrenches-boun...@lists.re-wrenches.org> mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Conrad Geyser Sent: 18 December 2009 5:42 p.m. To: npon...@buildingenergyus.com; 'RE-wrenches' Subject: Re: [RE-wrenches] solar hot water nighttime recirc Nicholas, You can certainly do that. Most newer controllers have a "vacation" function that will provide this. Another method is to put in a bypass to the check valve that you can open and the system will naturally reverse thermo siphon at night. Not much in the way of calculations other than the collectors reradiate as effectively as they collect. Conrad Cotuit Solar _____ From:re-wrenches-boun...@lists.re-wrenches.org [ <mailto:re-wrenches-boun...@lists.re-wrenches.org> mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Nicholas Ponzio Sent: Wednesday, December 16, 2009 10:54 PM To: RE-wrenches Subject: [RE-wrenches] solar hot water nighttime recirc Apologies if this has already been discussed here. One heat diversion method I hear suggested often is recirculating through the collectors (flatplate) at night. Are there any data, calculations or anecdotal evidence on the effectiveness of this approach? That is, can I really radiate as much energy back to a dark sky as I collect during the day? Thanks for any feedback. __________ NOD32 4697 (20091217) Information __________ This message was checked by NOD32 antivirus system. <http://www.eset.com/> http://www.eset.com _____ _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: <http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: <http://www.re-wrenches.org/etiquette.htm> www.re-wrenches.org/etiquette.htm Check out participant bios: <http://www.members.re-wrenches.org/> www.members.re-wrenches.org
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