<html><body><div style="color:#000; background-color:#fff; font-family:HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:10pt"><div><span>Thanks Marc,</span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>I am looking at maintaining 24C (75F) in the hull. As a starting point for heat dissipation experiments I </span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>came up with an average sea </span><span style="background-color: transparent;">surface temperature of 17C (62.6F). Although sea temperatures can get </span></div><div style="color: rgb(0, 0, 0);
font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span style="background-color: transparent;">up to 36 C in the Persian Gulf.</span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span style="background-color: transparent;">I will probably end up filling a bath with water at 24C & floating an aluminium enclosure with</span><br></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>the peltier cooler stuck to the bottom in it to see what temperature the cold side maintains.</span></div><div
style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>Also of importance is the peltier's ability to be used as a dehumidifier.</span></div><div style="color: rgb(0, 0, 0); font-size: 13.333333969116211px; font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; background-color: transparent; font-style: normal;"><span>Alan</span></div><div><br></div> <div style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 10pt;"> <div style="font-family: HelveticaNeue, 'Helvetica Neue', Helvetica, Arial, 'Lucida Grande', sans-serif; font-size: 12pt;"> <div dir="ltr"> <hr size="1"> <font size="2" face="Arial"> <b><span style="font-weight:bold;">From:</span></b> Marc de Piolenc <piolenc@archivale.com><br>
<b><span style="font-weight: bold;">To:</span></b> personal_submersibles@psubs.org <br> <b><span style="font-weight: bold;">Sent:</span></b> Thursday, March 6, 2014 3:13 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [PSUBS-MAILIST] Thermoelectric air conditioning<br> </font> </div> <div class="y_msg_container"><br>There's an active discussion of Peltier devices ongoing on the other <br clear="none">personal submersibles mailing list <br clear="none">(<a shape="rect" ymailto="mailto:international_psubs_minisubs@yahoogroups.com" href="mailto:international_psubs_minisubs@yahoogroups.com">international_psubs_minisubs@yahoogroups.com</a>). You might want to join it.<br clear="none"><br clear="none">Quick points: you still need some way to dump heat outside the boat, <br clear="none">otherwise you're just moving heat from one point you want to cool, to <br clear="none">another that can't afford to get any hotter. And of course the Peltier
<br clear="none">device produces heat of its own.<br clear="none">Which leads to the second key point, namely that there is an optimum <br clear="none">current for heat pumping, and for some reason the manufacturers <br clear="none">routinely rate their modules for a voltage that gives a higher current, <br clear="none">and thus poor heat pumping efficiency. You have to learn certain key <br clear="none">characteristics of your unit and come up with your own rating. The unit <br clear="none">I fooled with back in the States was rated at 12 volts, but worked much <br clear="none">better with an 8-ohm resistor in series.<br clear="none"><br clear="none">Marc de Piolenc<br clear="none"><br clear="none">On 3/6/2014 9:08 AM, Alan James wrote:<br clear="none">> Hi Psubbers,<br clear="none">> Has anyone looked at thermoelectric coolers (peltier devices) for air<br clear="none">> conditioning / dehumidifying & heating.<br clear="none">> I'm
hopeful someone might be able to save me a bit of research.<br clear="none">> <a shape="rect" href="http://en.wikipedia.org/wiki/Thermoelectric_cooling" target="_blank">http://en.wikipedia.org/wiki/Thermoelectric_cooling</a><br clear="none">> For those who aren't familiar, they are normally used to cool small<br clear="none">> units like computers, electrical cabinets & chili bins.<br clear="none">> They are about 1&1/2" square & 1/8" thick with two wires coming off them.<br clear="none">> The unit I have is 60W & operates off 12-15V. When powered up, one side<br clear="none">> gets hot & the other cold.<br clear="none">> The cooling effectiveness is regulated by how well you can dissipate the<br clear="none">> heat from the hot side.<br clear="none">> In the submersible application the hull can act as the heat sink. By<br clear="none">> switching polarity you have a heater.<br clear="none">>
The down side is that you use about 3 times more power for cooling than<br clear="none">> traditional refrigeration units,<br clear="none">> however an air conditioning unit is bulky, & it would be a trade off<br clear="none">> between the additional battery size & expense<br clear="none">> to run the peltier cooler as apposed to the bulk & expense of an air<br clear="none">> conditioning unit & it's associated through<br clear="none">> hull heat exchange unit .<br clear="none">> The heating faze is more economical.<br clear="none">> G.L. require air conditioning & humidity control in submersibles.<br clear="none">> Thanks<br clear="none">> Alan<br clear="none">><br clear="none">><br clear="none">> _______________________________________________<br clear="none">> Personal_Submersibles mailing list<br clear="none">> <a shape="rect" ymailto="mailto:Personal_Submersibles@psubs.org"
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