[PSUBS-MAILIST] Thermoelectric air conditioning

[Alan]

Hi Keith,
someone else suggested PWM but I read that they don't like being
switched on & off frequently. There will need to be a thermostat in the
loop with I imagine long dwell times between on & off once the temperature
gets close to target temperature. Most modules I've seen work well off 12V,
so that will make things easy.
Yes I intend using the lower part of the hull as a heat sink.
Have you recently joined the Psub email blog or have you been out there for
a while. 
Regards Alan


Sent from my iPad

> On 7/03/2014, at 7:50 am, keith tollett <k6fee at yahoo.com> wrote:
> 
> Alan,
> 
> 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.
> 
> Keith
> 
> 
> 
> On Wednesday, March 5, 2014 8:05 PM, Joe Perkel <josephperkel at yahoo.com> wrote:
> Yes, very interesting. I also have a more than passing interest in climate control.
> 
> Joe
> 
> 
>> On Mar 5, 2014, at 10:50 PM, Alan James <alanlindsayjames at yahoo.com> wrote:
>> 
>> Thanks Keith,
>> that's an encouragement to know that they operate them on a large scale
>> like that.
>> Alan
>> 
>> From: keith tollett <k6fee at yahoo.com>
>> To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
>> Sent: 
>> Subject: Re: [PSUBS-MAILIST] Thermoelectric air conditioning
>> 
>> Alan,
>> 
>> 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).
>> 
>> Keith
>> 
>> 
>> 
>> On Wednesday, March 5, 2014 6:22 PM, Marc de Piolenc <piolenc at archivale.com> wrote:
>> There's an active discussion of Peltier devices ongoing on the other 
>> personal submersibles mailing list 
>> (international_psubs_minisubs at yahoogroups.com). You might want to join it.
>> 
>> Quick points: you still need some way to dump heat outside the boat, 
>> otherwise you're just moving heat from one point you want to cool, to 
>> another that can't afford to get any hotter. And of course the Peltier 
>> device produces heat of its own.
>> Which leads to the second key point, namely that there is an optimum 
>> current for heat pumping, and for some reason the manufacturers 
>> routinely rate their modules for a voltage that gives a higher current, 
>> and thus poor heat pumping efficiency. You have to learn certain key 
>> characteristics of your unit and come up with your own rating. The unit 
>> I fooled with back in the States was rated at 12 volts, but worked much 
>> better with an 8-ohm resistor in series.
>> 
>> Marc de Piolenc
>> 
>> On 3/6/2014 9:08 AM, Alan James wrote:
>> > Hi Psubbers,
>> > Has anyone looked at thermoelectric coolers (peltier devices) for air
>> > conditioning / dehumidifying & heating.
>> > I'm hopeful someone might be able to save me a bit of research.
>> > http://en.wikipedia.org/wiki/Thermoelectric_cooling
>> > For those who aren't familiar, they are normally used to cool small
>> > units like computers, electrical cabinets & chili bins.
>> > They are about 1&1/2" square & 1/8"  thick with two wires coming off them.
>> > The unit I have is 60W & operates off 12-15V. When powered up, one side
>> > gets hot & the other cold.
>> > The cooling effectiveness is regulated by how well you can dissipate the
>> > heat from the hot side.
>> > In the submersible application the hull can act as the heat sink. By
>> > switching polarity you have a heater.
>> > The down side is that you use about 3 times more power for cooling than
>> > traditional refrigeration units,
>> > however an air conditioning unit is bulky, & it would be a trade off
>> > between the additional battery size & expense
>> > to run the peltier cooler as apposed to the bulk & expense of an air
>> > conditioning unit & it's associated through
>> > hull heat exchange unit .
>> > The heating faze is more economical.
>> > G.L. require air conditioning & humidity control in submersibles.
>> > Thanks
>> > Alan
>> >
>> >
>> > _______________________________________________
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>> >
>> 
>> -- 
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>> Polymath weblog: http://www.archivale.com/weblog
>> Translations (ProZ profile): http://www.proz.com/profile/639380
>> Translations (BeWords profile): http://www.bewords.com/Marc-dePiolenc
>> Ducted fans: http://massflow.archivale.com/
>> 
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