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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I did some research on the Thermocouples. You can PWM them quite nicely if your PWM frequency is high. The problem is that slow PWM frequencies allow slow temperature changes which tends to degrade the Thermocouple.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Most switchers operate at high frequencies at 50 kHz and higher which eliminates the temperature fluctuations.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Good luck with whatever you do,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Ken Martindale<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'><p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Personal_Submersibles [mailto:personal_submersibles-bounces@psubs.org] <b>On Behalf Of </b>Alan<br><b>Sent:</b> Thursday, March 06, 2014 2:59 PM<br><b>To:</b> Personal Submersibles General Discussion<br><b>Subject:</b> Re: [PSUBS-MAILIST] Thermoelectric air conditioning<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal>Hi Keith,<o:p></o:p></p></div><div><p class=MsoNormal>someone else suggested PWM but I read that they don't like being<o:p></o:p></p></div><div><p class=MsoNormal>switched on & off frequently. There will need to be a thermostat in the<o:p></o:p></p></div><div><p class=MsoNormal>loop with I imagine long dwell times between on & off once the temperature<o:p></o:p></p></div><div><p class=MsoNormal>gets close to target temperature. Most modules I've seen work well off 12V,<o:p></o:p></p></div><div><p class=MsoNormal>so that will make things easy.<o:p></o:p></p></div><div><p class=MsoNormal>Yes I intend using the lower part of the hull as a heat sink.<o:p></o:p></p></div><div><p class=MsoNormal>Have you recently joined the Psub email blog or have you been out there for<o:p></o:p></p></div><div><p class=MsoNormal>a while. <o:p></o:p></p></div><div><p class=MsoNormal>Regards Alan<o:p></o:p></p></div><div><p class=MsoNormal><o:p> </o:p></p></div><div><p class=MsoNormal><br>Sent from my iPad<o:p></o:p></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt'><br>On 7/03/2014, at 7:50 am, keith tollett <<a href="mailto:k6fee@yahoo.com">k6fee@yahoo.com</a>> wrote:<o:p></o:p></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><p class=MsoNormal style='background:white'><span style='font-family:"Helvetica","sans-serif";color:black'>Alan,<br><br>Forgot to mention that those thermoelectric modules can be pulse width modulated to make their current drain much more manageable and still accomplish climate and humidity control. There would be a fan needed on the air side, and the other could be directly attached to the steel hull with thermal grease. That would make a very efficent heat/cold sink, and eliminate another fan. There are comercial pic controlers on Evil-Bay for under $50, or if your handy with a soldering iron, you can make your own.<br><br>Keith<o:p></o:p></span></p><div><p class=MsoNormal style='background:white'><span style='font-family:"Helvetica","sans-serif";color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt;background:white'><span style='font-family:"Helvetica","sans-serif";color:black'><o:p> </o:p></span></p><div><div><div><p class=MsoNormal style='background:white'><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>On Wednesday, March 5, 2014 8:05 PM, Joe Perkel <<a href="mailto:josephperkel@yahoo.com">josephperkel@yahoo.com</a>> wrote:</span><span style='font-family:"Helvetica","sans-serif";color:black'><o:p></o:p></span></p></div><div><div id=yiv2628794219><div><div><p class=MsoNormal style='background:white'><span style='font-family:"Helvetica","sans-serif";color:black'>Yes, very interesting. I also have a more than passing interest in climate control.<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Helvetica","sans-serif";color:black'><o:p> </o:p></span></p></div><div><p class=MsoNormal style='margin-bottom:12.0pt;background:white'><span style='font-family:"Helvetica","sans-serif";color:black'>Joe<o:p></o:p></span></p></div><div id=yiv2628794219yqt01943><div><p class=MsoNormal style='margin-bottom:12.0pt;background:white'><span style='font-family:"Helvetica","sans-serif";color:black'><br>On Mar 5, 2014, at 10:50 PM, Alan James <<a href="mailto:alanlindsayjames@yahoo.com" target="_blank">alanlindsayjames@yahoo.com</a>> wrote:<o:p></o:p></span></p></div><blockquote style='margin-top:5.0pt;margin-bottom:5.0pt'><div><div><div><p class=MsoNormal style='background:white'><span style='font-size:10.0pt;font-family:"Helvetica","sans-serif";color:black'>Thanks Keith,<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:12.5pt;font-family:"Helvetica","sans-serif";color:black'>that's an encouragement to know that they operate them on a large scale<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:12.5pt;font-family:"Helvetica","sans-serif";color:black'>like that.<o:p></o:p></span></p></div><div><p class=MsoNormal><span style='font-size:12.5pt;font-family:"Helvetica","sans-serif";color:black'>Alan<o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-size:10.0pt;font-family:"Helvetica","sans-serif";color:black'><o:p> </o:p></span></p></div><div><div><div><div class=MsoNormal align=center style='text-align:center;background:white'><span style='font-family:"Helvetica","sans-serif";color:black'><hr size=1 width="100%" align=center></span></div><p class=MsoNormal style='background:white'><b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>From:</span></b><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'> keith tollett <<a href="mailto:k6fee@yahoo.com" target="_blank">k6fee@yahoo.com</a>><br><b>To:</b> Personal Submersibles General Discussion <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> <br><b>Sent:</b> <br><b>Subject:</b> Re: [PSUBS-MAILIST] Thermoelectric air conditioning</span><span style='font-family:"Helvetica","sans-serif";color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Helvetica","sans-serif";color:black'><o:p> </o:p></span></p><div id=yiv2628794219><div><div><p class=MsoNormal style='background:white'><span style='font-family:"Helvetica","sans-serif";color:black'>Alan,<br><br>U.S. Military subs use this for climate control. Don't want any noxious refrigerants loose in a closed environment. No moving parts, though they do eat a lot of power (not an issue on nuke boats).<br><br>Keith<o:p></o:p></span></p><div><p class=MsoNormal style='background:white'><span style='font-family:"Helvetica","sans-serif";color:black'><o:p> </o:p></span></p></div><div id=yiv2628794219yqt19033><div><p class=MsoNormal style='margin-bottom:12.0pt;background:white'><span style='font-family:"Helvetica","sans-serif";color:black'><o:p> </o:p></span></p><div><div><div><p class=MsoNormal style='background:white'><span style='font-size:10.0pt;font-family:"Arial","sans-serif";color:black'>On Wednesday, March 5, 2014 6:22 PM, Marc de Piolenc <<a href="mailto:piolenc@archivale.com" target="_blank">piolenc@archivale.com</a>> wrote:</span><span style='font-family:"Helvetica","sans-serif";color:black'><o:p></o:p></span></p></div><div><p class=MsoNormal style='background:white'><span style='font-family:"Helvetica","sans-serif";color:black'>There's an active discussion of Peltier devices ongoing on the other <br>personal submersibles mailing list <br>(<a href="mailto:international_psubs_minisubs@yahoogroups.com" target="_blank">international_psubs_minisubs@yahoogroups.com</a>). You might want to join it.<br><br>Quick points: you still need some way to dump heat outside the boat, <br>otherwise you're just moving heat from one point you want to cool, to <br>another that can't afford to get any hotter. And of course the Peltier <br>device produces heat of its own.<br>Which leads to the second key point, namely that there is an optimum <br>current for heat pumping, and for some reason the manufacturers <br>routinely rate their modules for a voltage that gives a higher current, <br>and thus poor heat pumping efficiency. You have to learn certain key <br>characteristics of your unit and come up with your own rating. The unit <br>I fooled with back in the States was rated at 12 volts, but worked much <br>better with an 8-ohm resistor in series.<br><br>Marc de Piolenc<br><br>On 3/6/2014 9:08 AM, Alan James wrote:<br>> Hi Psubbers,<br>> Has anyone looked at thermoelectric coolers (peltier devices) for air<br>> conditioning / dehumidifying & heating.<br>> I'm hopeful someone might be able to save me a bit of research.<br>> <a href="http://en.wikipedia.org/wiki/Thermoelectric_cooling" target="_blank">http://en.wikipedia.org/wiki/Thermoelectric_cooling</a><br>> For those who aren't familiar, they are normally used to cool small<br>> units like computers, electrical cabinets & chili bins.<br>> They are about 1&1/2" square & 1/8" thick with two wires coming off them.<br>> The unit I have is 60W & operates off 12-15V. When powered up, one side<br>> gets hot & the other cold.<br>> The cooling effectiveness is regulated by how well you can dissipate the<br>> heat from the hot side.<br>> In the submersible application the hull can act as the heat sink. By<br>> switching polarity you have a heater.<br>> The down side is that you use about 3 times more power for cooling than<br>> traditional refrigeration units,<br>> however an air conditioning unit is bulky, & it would be a trade off<br>> between the additional battery size & expense<br>> to run the peltier cooler as apposed to the bulk & expense of an air<br>> conditioning unit & it's associated through<br>> hull heat exchange unit .<br>> The heating faze is more economical.<br>> G.L. require air conditioning & humidity control in submersibles.<br>> Thanks<br>> Alan<br>><br>><br>> _______________________________________________<br>> Personal_Submersibles mailing list<br>> <a href="mailto:Personal_Submersibles@psubs.org" target="_blank">Personal_Submersibles@psubs.org</a><br>> <a href="http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles" target="_blank">http://www.psubs.org/mailman/listinfo.cgi/personal_submersibles</a><br>><br><br>-- <br>Archivale catalog: <a href="http://www.archivale.com/catalog" target="_blank">http://www.archivale.com/catalog</a><br>Polymath weblog: <a href="http://www.archivale.com/weblog" target="_blank">http://www.archivale.com/weblog</a><br>Translations (ProZ profile): <a href="http://www.proz.com/profile/639380" target="_blank">http://www.proz.com/profile/639380</a><br>Translations (BeWords profile): <a href="http://www.bewords.com/Marc-dePiolenc" target="_blank">http://www.bewords.com/Marc-dePiolenc</a><br>Ducted fans: <a href="http://massflow.archivale.com/" target="_blank">http://massflow.archivale.com/</a><o:p></o:p></span></p><div id=yiv2628794219yqtfd83832><p class=MsoNormal style='background:white'><span style='font-family:"Helvetica","sans-serif";color:black'><br>_______________________________________________<br>Personal_Submersibles mailing list<br><a href="mailto:Personal_Submersibles@psubs.org" target="_blank">Personal_Submersibles@psubs.org</a><br><a 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