X-Message-Number: 1844.1
From: R. Ettinger
Subject: Further Thoughts on Storage Near -136 C

	    Cryonics Institute
	    24443 Roanoke, Oak Park, MI 48237
	    (313) 548-9549   (313) 547-2316

Feb. 21, 1993

To: CI Directors and a Few Individuals of Other Organizations

Subject: Further Thoughts on Storage Near -136 C

So far I have had only a few telephoned expressions of interest in this,
and no technical comments.  Andy Zawacki and I continue to discuss it.

In the previous note I neglected to point out that Alcor and Trans Time
could probably store heads or brains near -136 C in their MVE-type units,
using my suggestions of Feb. 12.  One or both of them could probably
experiment with this easily enough at no great expense.

If CI were to decide to offer such service, we could probably also
offer head-only storage in an HSSV-1 type cylindrical unit at only a
moderate increase over our basic price.  We will probably go ahead and
experiment with this as soon as time allows.  The HSSV-1 is available
now, since we have completed the transport unit, the RSSSVT.

There are also some other designs that appear feasible, using liquid
nitrogen, without pontoons or equivalent.  For example, perhaps one
could use a central reservoir of liquid nitrogen, surrounded laterally
by insulation; outside of this are vertical compartments for patients;
the patients in each compartment are surrounded by thermally conducting
material to tend to equalize temperatures at all points around the
patient; each compartment has insulation around it, and the whole
patient region is surrounded by insulation; by making the thickness
or thermal resistance in the reservoir side less than the outside,
it may be possible to attain the desired temperature, in the vicinity
of -136 C, in the patient compartments.  If this would work, it might
be better than the pontoon approach -- first, because no pontoons or
flotation would be needed; second, because less of the heat sink might
be wasted, although I don't have firm numbers on this; and third,
because it lends itself to large systems....  I haven't given this
much thought yet, and it may well prove impractical for various
reasons, but so far I don't see any obvious fundamental flaw.  The
sketch below is for a cylindrical configuration, which is not the
only one possible.

I understand that some Alcor people believe commercially available
mechanical refrigerators might be good enough for neuro storage,
and with redesign for whole body -- but I haven't seen enough
details or numbers to form an opinion.

Bob Ettinger

<<< Here is my square, ASCII rendition of Ettinger's drawing of a
    cylindrical configuration. - KQB >>>

		----------------------------------------
	       |               insulation               |
	       |       --------------------------       |
	       |  i   |         patients         |   i  |
	       |  n   |  p   --------------   p  |   n  |
	       |  s   |  a  |  insulation  |  a  |   s  |
	       |  u   |  t  |   --------   |  t  |   u  |
	       |  l   |  i  |  | liquid |  |  i  |   l  |
	       |  a   |  e  |   --------   |  e  |   a  |
	       |  t   |  n  |  insulation  |  n  |   t  |
	       |  i   |  t   --------------   t  |   i  |
	       |  o   |  s      patients      s  |   o  |
	       |  n   |                          |   n  |
	       |       --------------------------       |
	       |               insulation               |
		----------------------------------------

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