X-Message-Number: 1773.1
From: R. Ettinger
Subject: Storage Near -136 C
Cryonics Institute
24443 Roanoke, Oak Park, MI 48237
(313) 548-9549 or (313) 547-2316
Feb. 12, 1993
To: Cryonics Institute Directors & Individuals of Other Organizations
Subject: Storage Near -136 C
I think I have essentially solved the problem of storage near -136 C,
in terms of reliability and available technology, and estimate the
cost at CI would be around three times our minimum for liquid nitrogen
storage.
Most of you understand the potential importance of this -- much less
cracking, according to some indications. Therefore I feel it is
appropriate to avoid delay in disclosure. On the other hand, because
of the possibility of some serious oversight or error, I don't want
to publicize it widely until there has been an opportunity for
feedback. In addition, it is not yet entirely clear to me how much
this approach might improve a patient's chances, given the other
kinds of damage that occur.
If the approach proves sound, and if the best opinion is that it will
indeed substantially improve a patient's chances, there will be obvious
serious repercussions. Many members of all organizations will just not
be able to afford it. Some members and potential members will feel
that, if they cannot afford this, they will not settle for liquid
nitrogen storage. All this will require careful handling.
If the best opinion is that the approach has potential merit, the next
step is to verify it by experiment, construction of a test unit.
Cryonics Institute, in its present facility, does not have room to
do this, and our new building is not likely to be ready for some
months at best. I think Trans Time has room; I don't know about Alcor,
but have the impression that they are already crowded also. We might
want to cooperate on funding the trial, in whichever facility would
work out best. (Cryonics Institute could, of course, rent additional
Detroit space for this purpose.)
Now the specifics:
We will still use liquid nitrogen, but instead of being immersed in
it the patient will be above the liquid level in the stratum of gas
around -136 C, or a few degrees on the conservative side of it.
This was always an obvious possibility, but what was not clear
earlier was how we could sufficiently limit variation of temperature
over time and over the patient. I believe this can be done using two
simple stratagems:
1. The patient is in a cocoon of thick insulation, perhaps polystyrene.
This wil tend to greatly retard any transmission of temperature
changes. (Remember that the patient's body is a relatively good
thermal conductor, tending to equalize temperature through and
over the patient, if heat flux at the surface is small.) If
necessary, there could also be an inner cocoon, between the
patient and the insulating cocoon, made of a highly thermally
conducting material, which would also tend to equalize temperatures
all around the patient.
2. The patient is on a framework which is attached to pontoons which
float on the liquid nitrogen. Hence, as the liquid level very
gradually falls and rises with boiloff and refill, the patient's
distance above the liquid is unchanged, and he remains in the
correct stratum. (Many obvious variations of this are possible.)
The two stratagems above, I believe, solve the problem of reliability
with relatively low expense and low technology. Using mechanical
refrigeration with thermostats, for example, would be much more
difficult and less reliable; using organic gases would be expensive
and dangerous.
Relatively minor problems remain, of course -- for example, we must
refill the nitrogen in a way that does not unduly roil the gas and
change the stratum. This might be done using an insulated filler
tube in one corner, reaching not quite to the bottom. The roiling
liquid/gas being added will be confined to the filler tube until the
bottom; the height of liquid in the main container and in the filler
tube will automatically remain equal.
The increased cost arises from the fact that we will get only one
(whole-body) patient per rectangular cryostat. (We could have
several patients under the liquid and one above, but for various
reasons this would not usually work out.) This increases the boiloff
per patient per year (although not proportionately) and also increases
the floor space per patient as well as the capital cost per patient
for the cryostat.
If the response indicates some serious mistake, I'll go back to the
drawing board. If not, I think we are obligated to press ahead with
trials and share results.
Long life--
Bob Ettinger
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