[PSUBS-MAILIST] Peltier Airconditioner

[Alan via Personal_Submersibles]

Thanks Hugh,
 Looked at a 7000 btu air conditioner that was 820 W, which is a bit better 
than the cars 3000 W.
You would still need 3,200 W to get the equivalent cooling with peltiers. 
However after scaling this down for a smaller sub, it may be reasonable.
I have ordered 1400 Watts worth of Peltiers, so could be on the money!
Those big acrylic spheres that Uboatworx uses are very insulative so it would 
be easy to maintain temperature under the water. I am not sure if they are a 
heat trap out of the water. I have seen large covers on them prior to diving!
Cheers Alan


Sent from my iPad

> On 15/08/2017, at 9:26 AM, Hugh Fulton via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> 7000 btu air conditioner is what Uboat Worx uses and they have stuck with that size for 2-3 people.  So find what models are around and what current they use and there is your answer.
> Regards,  Hugh
>  
> From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alan via Personal_Submersibles
> Sent: Tuesday, 15 August 2017 7:36 AM
> To: Personal Submersibles General Discussion
> Subject: Re: [PSUBS-MAILIST] Peltier Airconditioner
>  
> Tim,
> I was nearly going to mention this; but I was thinking just have
> the air flow directed on the occupants. 
> I have heard mention of clothing with Peltiers in them. 
> Alan
>  
> 
> Sent from my iPad
> 
> On 15/08/2017, at 5:40 AM, T Novak via Personal_Submersibles <personal_submersibles at psubs.org> wrote:
> 
> During the winter some people prefer infra-red heaters in their homes to directly warm the occupants. This is considered to be more efficient than heating up air and then forcing it into the living space.  Similarly, perhaps several peltiers could be placed on the sub pilots person to directly cool him in the otherwise warm air environment?  A set of cooling headband, wristbands, and leg/foot wraps to cool the blood where it is close to the surface of the body?  You only need cooling while the sub is on or close to the surface.
> Tim
>  
> From: Personal_Submersibles [mailto:personal_submersibles-bounces at psubs.org] On Behalf Of Alan via Personal_Submersibles; 
> Sent: Monday, August 14, 2017 12:08 AM
> To: personal_submersibles at psubs.org
> Subject: [PSUBS-MAILIST] Peltier Airconditioner
>  
> Have looked in to this a bit more.
> An average compression type car air conditioner takes about 3000W 
> of power to  run. Cooling with peltiers requires 4x this power to get the
> equivalent effect. So 12000W required to keep up with a car air conditioner!
> Peltiers have a typical maximum difference in temperature from one side
> to the other of 70C, but to run at maximum efficiency it is recommended 
> to keep the temperature difference at less than 30C. So this would mean
> a peltier rated 72W should be run at around 30W. 
> The efficiency also depends on how well you can remove the heat from
> the hot side, as if it gets too hot the heat build up can migrate across to the 
> cold side.
> A 1&1/2 x 1&1/2" peltier may be around 72W (12V & 6 A) & cost  US $3:61
> Deal Extreme with free shipping....
> http://m.dx.com/p/tec1-12706-semiconductor-thermoelectric-cooler-peltier-white-157283?stiff=99
> So to get the same cooling as your car air conditioner you need 166 of these 
> & that's running them at full power & not the more economical half power.
>     I have read that a peltier air conditioner can drop a cars temperature to 20C
> below ambient, but I don't have any specs on the unit they mention.
>    I am going to persevere with them as I am building a small one person sub
> & I like that I can make a dehumidifyer, airconditioner & heater all in one & take
> up little room.  As discussed, their heating efficiencies are great, so if you look
> at them as a descent heater with the spin off of some cooling benefit then they
> don't look so bad!  Battery technology is leaping forward, so I am anticipating that
> their power drain won't be such a big deal by the time I get around to buying
> batteries.
> Cheers Alan
>  
>  
> 
> Sent from my iPad
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