<div dir="ltr"><div dir="ltr"><div><div dir="ltr" class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr">Stick with the thermo-electric coolers. IIRC the air conditioning on Triton's submersibles use a peltier based units for the reason Sean brings up. Having a refrigerant leak inside the sub is bad. Having to have more hull penetrations than necessary for an external heat rejection coil is bad. Needing some sort of high pressure overboard pump for coolant/condensation is bad. All of these problems are exacerbated when you have the surveyor/inspector/insurance agent breathing down your neck.</div><div dir="ltr"> </div><div dir="ltr">A half-foot thick acrylic sphere is a very good insulator, so requires almost constant use of the AC or else it can quickly become uninhabitable. The biggest heat management goals should be keeping the sun off of any domes, keeping the cabin circulated, and keeping humidity down to a reasonable level. </div><div dir="ltr"> </div><div dir="ltr">As for battery consumption, most Psubs shouldn't have to worry. The general usage trend is plenty of short dives in a day, instead of one or two long ones. In that case, the limiting factor for endurance will be HP air capacity.<br><div><br></div><div dir="ltr">-River J. Dolfi<div><div><br></div></div></div></div></div></div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Tue, Apr 2, 2019 at 2:34 PM via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org">personal_submersibles@psubs.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">Send Personal_Submersibles mailing list submissions to<br>
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Today's Topics:<br>
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1. Re: K350 motors and housings - available<br>
(Douglas Suhr via Personal_Submersibles)<br>
<br>
<br>
----------------------------------------------------------------------<br>
<br>
Message: 1<br>
Date: Tue, 2 Apr 2019 15:34:01 -0400<br>
From: Douglas Suhr via Personal_Submersibles<br>
<<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>><br>
To: Personal Submersibles General Discussion<br>
<<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>><br>
Subject: Re: [PSUBS-MAILIST] K350 motors and housings - available<br>
Message-ID:<br>
<<a href="mailto:CAOGJjnJKpT68VToQvCiBrZNOy9Cbaawd6oCandUPZmSzU3EFJg@mail.gmail.com" target="_blank">CAOGJjnJKpT68VToQvCiBrZNOy9Cbaawd6oCandUPZmSzU3EFJg@mail.gmail.com</a>><br>
Content-Type: text/plain; charset="utf-8"<br>
<br>
Cliff and Sean, how the heck did you learn all this stuff?!? All I know<br>
about A/C units is that the one in my car doesn't work anymore (maybe it<br>
needs some more poison stuff!). (Kinda kidding here).<br>
<br>
What I'm getting out of this conversation is that if I want A/C in Snoopy,<br>
I'm probably best off building an ice cooler like Brian and the like have<br>
done. ~ Doug<br>
<br>
On Tue, Apr 2, 2019 at 2:34 PM Sean T. Stevenson via Personal_Submersibles <<br>
<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br>
<br>
> The problem with refrigerants in confined spaces, and this is true both of<br>
> HFC-134a and the environmentally friendly(er) alternatives, such as<br>
> HFO-1234yf, is that they release extremely toxic decomposition products in<br>
> the event of fire. Of course, any fire is going to compromise your<br>
> atmosphere, so this may be a moot point, but it's something to consider.<br>
> HFC-134a has low acute toxicity, but is not strictly a simple inert<br>
> asphyxiant. A 1 hour EEGL exposure limit recommendation that I managed to<br>
> find for HFC-134a is 4,000 ppm.<br>
><br>
> In a 72 cu. ft. volume, assuming a starting FO2 of 20.9%, you could add a<br>
> full 7 cu. ft. of simple asphyxiant gas before the cabin FO2 dropped to<br>
> 19%. Death likely wouldn't occur due to hypoxia above 16% FO2, but you<br>
> won't be accomplishing much with oxygen that low. 19.0% to 19.5% are<br>
> typical occupational limits for oxygen deficient atmospheres.<br>
><br>
> That said, hypoxia is not the only risk as I pointed out. I would consider<br>
> the health effects from inhalation exposure and keep to recommended<br>
> exposure limits. For maximum safety, I might be inclined to separate<br>
> refrigerants from occupied spaces by means of a water / propylene glycol<br>
> heat exchanger circuit, but of course this will affect your energy budgets.<br>
><br>
> Sean<br>
><br>
><br>
> -------- Original Message --------<br>
> On Apr 2, 2019, 11:49, Cliff Redus via Personal_Submersibles <<br>
> <a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br>
><br>
><br>
> Keith, I like the idea of a DIY AC system for my boat but hate the idea of<br>
> dying because of a refrigerant leak. I looked up the MSDS sheet for<br>
> HFC-134a (common refrigant used in auto AC systems) ImageViewer<br>
> <<a href="https://3eonline.com/ImageServer/ImageViewer.aspx?id=3Q%2FfAR8ne%2FvPh6syVnSymkS%2BBDo8OjmbVocxRCMEgeG%2Fk%2B6G7BpCwxJIcm%2FtzFJTddB5zxzJXIW7nbmF5mKrdg%3D%3D" rel="noreferrer" target="_blank">https://3eonline.com/ImageServer/ImageViewer.aspx?id=3Q%2FfAR8ne%2FvPh6syVnSymkS%2BBDo8OjmbVocxRCMEgeG%2Fk%2B6G7BpCwxJIcm%2FtzFJTddB5zxzJXIW7nbmF5mKrdg%3D%3D</a>><br>
> Seems like it is classified as a Simple Asphyxian which according to<br>
> Wikipidia "An *asphyxiant gas* is a nontoxic or minimally toxic gas<br>
> <<a href="https://en.wikipedia.org/wiki/Gas" rel="noreferrer" target="_blank">https://en.wikipedia.org/wiki/Gas</a>> which reduces or displaces the normal<br>
> oxygen <<a href="https://en.wikipedia.org/wiki/Oxygen" rel="noreferrer" target="_blank">https://en.wikipedia.org/wiki/Oxygen</a>> concentration in breathing<br>
> air <<a href="https://en.wikipedia.org/wiki/Gas_composition" rel="noreferrer" target="_blank">https://en.wikipedia.org/wiki/Gas_composition</a>>. "<br>
><br>
> ImageViewer<br>
><br>
><br>
> <<a href="https://3eonline.com/ImageServer/ImageViewer.aspx?id=3Q%2FfAR8ne%2FvPh6syVnSymkS%2BBDo8OjmbVocxRCMEgeG%2Fk%2B6G7BpCwxJIcm%2FtzFJTddB5zxzJXIW7nbmF5mKrdg%3D%3D" rel="noreferrer" target="_blank">https://3eonline.com/ImageServer/ImageViewer.aspx?id=3Q%2FfAR8ne%2FvPh6syVnSymkS%2BBDo8OjmbVocxRCMEgeG%2Fk%2B6G7BpCwxJIcm%2FtzFJTddB5zxzJXIW7nbmF5mKrdg%3D%3D</a>><br>
><br>
><br>
><br>
> What this mean to me is that we would to do a calc to see what the oxygen<br>
> concentration in a 1-atm boat would go to if all the HFC-134a in the unit<br>
> was released at one time to see if the concentration would result in<br>
> hypoxia for the operator. In my boat I measure O2 concentration as I have<br>
> a PID controller tasked with keeping the O2 concentration at 21% So I<br>
> would get a low O2 alarm rather quickly.<br>
><br>
> Sean, you are a technical diver, do you think there would be an issue with<br>
> hypoxia if all the HFC-134a in a small AC unit were dumped into a one atm<br>
> cabin say 72 cuft?<br>
><br>
> Cliff<br>
><br>
><br>
> On Tuesday, April 2, 2019, 11:46:05 AM CDT, k6fee via<br>
> Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br>
><br>
><br>
> The DC compressor & water cooled condenser are the most expensive items.<br>
><br>
> If your a DIY'er, go to your nearest "Pick & Pull" get a car AC compressor<br>
> add a DC drive motor, condenser & evap coil and roll your own. It will<br>
> take 2 HP to full drive the compressor, however you can vary the speed and<br>
> control the cooling, while minimizing current drain. You'll need a<br>
> refrigerant detector as a leak will kill you in the confines of a PSUB. Or<br>
> go thermo electric.<br>
><br>
> Keith T.<br>
><br>
> -------- Original message --------<br>
> From: Cliff Redus via Personal_Submersibles <<br>
> <a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>><br>
> Date: 4/2/19 8:40 AM (GMT-08:00)<br>
> To: k6fee via Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>><br>
> Subject: Re: [PSUBS-MAILIST] K350 motors and housings - available<br>
><br>
> Thanks for the links, The MES24S - 24V unit looks like it would work<br>
> great but at $3,895 , I am not going to be ordering in the near future. In<br>
> the spirit of Psub and DIY, I wonder how hard it would be to design and<br>
> build on of these units. Seems to be made up of readily available parts<br>
> like a compressor, blower, coil ....<br>
><br>
> Cliff<br>
><br>
> On Tuesday, April 2, 2019, 9:46:03 AM CDT, k6fee via Personal_Submersibles<br>
> <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br>
><br>
><br>
> Allen,<br>
><br>
> Check these out.<br>
><br>
><br>
> <a href="http://www.cruisencomfortusa.com/marineseries/?gclid=EAIaIQobChMIirDF5s6x4QIVcyCtBh3K8w2JEAMYASADEgIDqvD_BwE" rel="noreferrer" target="_blank">http://www.cruisencomfortusa.com/marineseries/?gclid=EAIaIQobChMIirDF5s6x4QIVcyCtBh3K8w2JEAMYASADEgIDqvD_BwE</a><br>
><br>
> <a href="http://www.comar-marine.com/product.php?id_product=20" rel="noreferrer" target="_blank">http://www.comar-marine.com/product.php?id_product=20</a><br>
><br>
> Keith T.<br>
><br>
> -------- Original message --------<br>
> From: Cliff Redus via Personal_Submersibles <<br>
> <a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>><br>
> Date: 4/2/19 7:06 AM (GMT-08:00)<br>
> To: Brian Hughes via Personal_Submersibles <<br>
> <a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>><br>
> Subject: Re: [PSUBS-MAILIST] K350 motors and housings - available<br>
><br>
> To me AC on personal subs is an interesting topic. As the Psub community<br>
> frequently dives off Islamorada Florida, it is a relative thread.<br>
> Below is a graph taken from flight recorder on the R300 during a Psub dive<br>
> off the coast of Islamorada in August of 2017.<br>
><br>
> [image: Inline image]<br>
><br>
> It got very hot and humid during the 4.5 hour dive. Note that the cabin<br>
> temperature reached 96 F, the relative humidly reached 85% and the heat<br>
> index reached 146 F. To say that I could have used small AC unit in the<br>
> boat is an understatement! One of the implications of this cabin<br>
> environment was that I could not keep the viewport clear. I soaked the<br>
> towels I had on board very quickly trying to clear the viewport. As a<br>
> consequence, is was hard to see.<br>
><br>
> There are challenges in designing a AC system for small subs. Ideally, it<br>
> would be self contained and easily removed for service. The unit is going<br>
> to have a reservoir for capturing quite a bit of condensed water extracted<br>
> over say a 6 hour design mission time. For my boat the unit would need to<br>
> be small and compact. Would be nice if we could find a OTS small compact<br>
> AC unit that was DC powered.<br>
><br>
> If any one knows of a small compact AC unit, send me the link. I would<br>
> like to test in my boat.<br>
><br>
> Cliff<br>
><br>
><br>
><br>
><br>
><br>
><br>
> On Monday, April 1, 2019, 3:26:25 PM CDT, Brian Hughes via<br>
> Personal_Submersibles <<a href="mailto:personal_submersibles@psubs.org" target="_blank">personal_submersibles@psubs.org</a>> wrote:<br>
><br>
><br>
> And it occurred to me, while we discussed air conditioning systems on our<br>
> personal subs, we were likely the only three people on the planet having<br>
> that conversation. 'Tis a small collection of fellow adventurers.<br>
><br>
> Brian<br>
> Owner of Harold, the wonder K350 and<br>
> Maude, the Porta Bote extraordinaire<br>
><br>
> Yes, Harold and Maude ....<br>
><br>
> Get Outlook for Android <<a href="https://aka.ms/ghei36" rel="noreferrer" target="_blank">https://aka.ms/ghei36</a>><br>
><br>
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