<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
<div class="moz-cite-prefix">A couple of things - first, the
specific heat capacity of water is much greater than that of air,
so effective cooling can be effected even with small delta-T's.
Second, if you think about the latent and sensible sources of heat
generated by the submarine's systems and its occupants, if you
can't lose that heat to the seawater, where else is it going to
go? Even circulating the air to cool the motors will result in a
temperature rise of the air, which is subsequently transferred to
everything it touches. When surfaced, you have two ways of losing
that heat: to the air, or to the surrounding water. When
submerged, the water is your only option. Now, this can be done
passively, which necessitates relying on a delta-T between the sub
and the water, or actively, which requires energy input (i.e. air
conditioning) but permits you to expel water or air at a higher
temperature than the ambient medium. Either way, if you can't
lose heat to the environment, the only possible outcome is a rise
in temperature of your closed system.<br>
<br>
Sean<br>
<br>
<br>
On 2014-04-13 19:33, Joe Perkel wrote:<br>
</div>
<blockquote
cite="mid:7E6CF671-CC60-4FB2-9332-AA86968E710C@yahoo.com"
type="cite">
<meta http-equiv="content-type" content="text/html;
charset=ISO-8859-1">
<div>Sean,</div>
<div><br>
</div>
<div> Northern climates have nice cool seas, but I'm dealing with
tropical temps here averaging in the 80's in summer. With hot
seas, which scheme would be best? I simply am not certain, my
gut says relying on the ambient water may not do the job. I
could be wrong.</div>
<div><br>
</div>
<div>Joe</div>
<div><br>
Sent from my iPhone</div>
<div><br>
On Apr 13, 2014, at 9:16 PM, "Sean T. Stevenson" <<a
moz-do-not-send="true" href="mailto:cast55@telus.net">cast55@telus.net</a>>
wrote:<br>
<br>
</div>
<blockquote type="cite">
<div>
<p dir="ltr">Airflow in constrained spaces is often difficult
to model. Alternatives include water cooled motors, or
simply effectively heat sinking the motor housings to the
hull and using passive water cooling to the ambient
seawater. Ultimately, that's where the heat is going anyway.
Unless you can use it for some purpose (cabin heat, humidity
control etc.) you might as well sink it as directly as
possible.</p>
<p dir="ltr">Sean<br>
</p>
<br>
<br>
<div class="gmail_quote">On April 13, 2014 6:45:39 PM MDT, Joe
Perkel <<a moz-do-not-send="true"
href="mailto:josephperkel@yahoo.com">josephperkel@yahoo.com</a>>
wrote:
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;">
<div style="color:#000; background-color:#fff;
font-family:HelveticaNeue, Helvetica Neue, Helvetica,
Arial, Lucida Grande, sans-serif;font-size:14pt">
<div><font face="Times New Roman" size="3">
</font></div>
<div style="margin: 0in 0in 10pt;"><font face="Calibri"
size="3">I am considering a scheme for dealing with
electric motor
cooling and would like input on the viability of the
idea and any pros or cons
that I may be missing.</font></div>
<div><font face="Times New Roman" size="3">
</font></div>
<div style="margin: 0in 0in 10pt;"><font face="Calibri"
size="3">In looking at my SeeHund replica, note that
the
torpedo/pod(s) length exceed needed battery
capacity. <span style="mso-spacerun: yes;"> </span>So
the idea being that the aft ends of both
will house electric motors that are isolated from
the battery compartments.</font></div>
<div><font face="Times New Roman" size="3">
</font></div>
<div style="margin: 0in 0in 10pt;"><font face="Calibri"
size="3">I’m thinking to ventilate these aft motor
units into the aft
machinery space within the main hull. Incidentally,
the hull diameter will be
42” and the torpedoes #14 pipe. This will leave a
significant airspace around
these motor units allowing me to use fan cooled
motor cases.<span style="mso-spacerun: yes;"> </span>Each
motor pod could be connected with vent
pipes for intake and output airflow, then the
machinery space itself force
vented to the outside with <span
style="mso-spacerun: yes;"> </span>main
induction and exhaust vents. <span
style="mso-spacerun: yes;"> </span>All this
for continuous surface running of course. Submerged,
the motor units would be
intermittent duty.</font></div>
<div><font face="Times New Roman" size="3">
</font></div>
<div style="margin: 0in 0in 10pt;"><font face="Calibri"
size="3">The centerline unit would be fully enclosed
and not vented,
therefore not as attractive for continuous duty due
to thermal constraints.</font></div>
<div><font face="Times New Roman" size="3">
</font></div>
<div style="margin: 0in 0in 10pt;">
<p><font face="Calibri" size="3"> </font></p>
</div>
<div><font face="Times New Roman" size="3">
</font></div>
<div style="margin: 0in 0in 10pt;"><font face="Calibri"
size="3">Joe</font></div>
<br>
</div>
</blockquote>
</div>
</div>
</blockquote>
</blockquote>
<br>
</body>
</html>