Dry Ice Box?
 

Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


A couple pounds of dry ice seems like a good idea,
but how to use it?

Mix with wet ice?

Or keep separate?

Richard

Dry Ice Box?
 

Dry ice will keep it colder but not necessarily any longer. The latent heat
of sublimation of dry ice (246BTU/lb) is about 170% that of water ice
(144BTu/lb) (actually heat of fusion) but at the colder temperature the heat
movement through the sides of the cooler will be more than twice as fast.

For safety sake the cooler should not be stowed below deck which can also
add to the heat load.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"cavelamb" wrote in message
k.net...

Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


A couple pounds of dry ice seems like a good idea,
but how to use it?

Mix with wet ice?

Or keep separate?

Richard

Dry Ice Box?
 

Chris Newport wrote:
cavelamb wrote:


Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


Hmmmm - Carbon dioxide in a boat.
Darwin removes any idiots who try this from the gene pool, hopefully
before they breed and produce more idiots.

oh for Pete Sakes!

Stash an apple in the cooler, Chris.

Haven't you ever had a carbonated apple?

Richard

Dry Ice Box?
 

"cavelamb" wrote in message
nk.net...
Chris Newport wrote:
cavelamb wrote:


Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


Hmmmm - Carbon dioxide in a boat.
Darwin removes any idiots who try this from the gene pool, hopefully
before they breed and produce more idiots.

oh for Pete Sakes!

Stash an apple in the cooler, Chris.

Haven't you ever had a carbonated apple?

Richard

An apple is quite different from attempting to cool steaks, beers, etc.
Also, it'll probably be colder, but the dry ice may not last much longer.
Perhaps in an above-decks cooler would be better and safer. I sail on a boat
that has that arrangement. Perhaps a combination of dry ice and regular ice
above decks might be worth an experiment.

--
"j" ganz @@
www.sailnow.com

Dry Ice Box?
 

When we did some offshore racing, the owner of the boat had purchased dry
ice for the trip. It was a small amount of dry ice and was kept in a shoe
box with holes cut into it. Only trick was packing things in order of use.
Those items nearest the dry ice were frozen. Any bleed off drained into the
bilge.

Stu


"cavelamb" wrote in message
k.net...

Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


A couple pounds of dry ice seems like a good idea,
but how to use it?

Mix with wet ice?

Or keep separate?

Richard

Dry Ice Box?
 

Why going through all the cost and hassle with dry ice? Just pack extra
ice in a separate cooler that doesn't get opened every time someone
wants a drink. You will be surprised how long it lasts.
IF you want to go high tech and do have access to lab freezers (where
else would you get dry ice...:), you can also 'supercool' your normal
ice before the trip. Ice at -70 C will last a lot longer than at -3 C,
with no extra weight. Glen's caveat about heat conduction still
applies.




cavelamb wrote:
Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


A couple pounds of dry ice seems like a good idea,
but how to use it?

Mix with wet ice?

Or keep separate?

Richard

Dry Ice Box?
 

Two things I can recommend. The first is the 58 quart Coleman Ultra Xtreme
marine cooler. Both in practical sailor's and my tests it beat the
expensive high end marine coolers by a significant margin.

There is also a product called Technice. It comes as flat sheets that you
hydrate to form little gel packets and then freeze as low as you can get it.
It appears to spread out the hard 32F freezing point so that it absorbs heat
at a fairly even rate. Far better performance than Blue Ice or any of the
other reusable packs.

Last month, May 30 at 8PM to be exact, I packed 12 pounds of steaks, a
Honey Baked ham and 8 pounds of shrimp, all hard frozen in a 58 quart
Coleman Ultra Xtreme marine cooler with 4 sheets of Technice on top and a
beach towel on the bottom. The next morning it was checked on an airline to
St. Thomas where it was lost for 3 days somewhere between Atlanta and Ft.
Lauderdale. The cooler was delivered to West End, Tortola and unpacked on
June 3 about 1 PM and everything was still frozen solid.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"cavelamb" wrote in message
k.net...

Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


A couple pounds of dry ice seems like a good idea,
but how to use it?

Mix with wet ice?

Or keep separate?

Richard

Dry Ice Box?
 

Chris writes:

IF you want to go high tech and do have access to lab freezers (where
else would you get dry ice...:), you can also 'supercool' your normal
ice before the trip. Ice at -70 C will last a lot longer than at -3 C,
with no extra weight.

For water, the heat of fusion is about 80 times specific heat, so
supercooling ice is hardly effective. You're much better off just using a
little more ice.

Dry ice is no good for refrigeration because it is too cold and difficult
to regulate to a higher temperature. By the time you build a contraption
to regulate the chill, you've lost any weight advantage over ice, assuming
you don't need sub-freezing temperatures.

I remember as a child seeing another child severely injured at my dad's
company picnic. Someone brought popsicles in dry ice, the kid got into
them, and took a lick.

Liquid nitrogen is a more practical wasting refrigerant since the liquid is
easy to throttle. That's what some reefer trucks use.

Dry Ice Box?
 

For water, the heat of fusion is about 80 times specific heat...
So -70 C ice would have almost twice the cooling effect
as the same amount of barely frozen ice, right?
Hardly 'hadly effective'.

And yes, twice as much ice also works, but we knew that.
That's why I recommended to carry an extra cooler w/ ice,
not a lab freezer. :) But I am sure a liquid nitgrogen cooler
would be practical fo use on a boat, too.


Richard J Kinch wrote:
Chris writes:

IF you want to go high tech and do have access to lab freezers (where
else would you get dry ice...:), you can also 'supercool' your normal
ice before the trip. Ice at -70 C will last a lot longer than at -3 C,
with no extra weight.

For water, the heat of fusion is about 80 times specific heat, so
supercooling ice is hardly effective. You're much better off just using a
little more ice.

Dry ice is no good for refrigeration because it is too cold and difficult
to regulate to a higher temperature. By the time you build a contraption
to regulate the chill, you've lost any weight advantage over ice, assuming
you don't need sub-freezing temperatures.

I remember as a child seeing another child severely injured at my dad's
company picnic. Someone brought popsicles in dry ice, the kid got into
them, and took a lick.

Liquid nitrogen is a more practical wasting refrigerant since the liquid is
easy to throttle. That's what some reefer trucks use.

Dry Ice Box?
 

On Sat, 1 Jul 2006 22:11:56 -0400, "Glenn Ashmore"
wrote:

The next morning it was checked on an airline to
St. Thomas where it was lost for 3 days somewhere between Atlanta and Ft.
Lauderdale. The cooler was delivered to West End, Tortola and unpacked on
June 3 about 1 PM and everything was still frozen solid.

===========

That 's impressive.

Where do you get the Technice?

Dry Ice Box?
 

On Sat, 01 Jul 2006 10:09:07 +0100, Chris Newport
wrote:

Hmmmm - Carbon dioxide in a boat.
Darwin removes any idiots who try this from the gene pool, hopefully
before they breed and produce more idiots.

Boats on distance races have been using dry ice on frozen foods for a
long time and I have never heard of any problems. The quantities are
small and the evaporation rate low. We used two different approaches:
one was to put it in the bottom of the ice box under the blocks of
water ice to extend their life, and the second was to pack a prefrozen
meal in a styrofoam cooler packed with a block of dry ice.

Dry Ice Box?
 

Chris wrote:
For water, the heat of fusion is about 80 times specific heat...
So -70 C ice would have almost twice the cooling effect
as the same amount of barely frozen ice, right?

Wrong. You should look up the Heat Capacity of cold ice. Its only
0.5 BTU/lb-degree at freezing, but it goes down so that by -50 F its
only 0.4.

Since the Heat of Fusion is 144 BTU/lb, sub-cooling even 100 degrees
only adds a small amount of cooling capacity.

Hardly 'hadly effective'.

No, its hardly effective.


And yes, twice as much ice also works, but we knew that.
That's why I recommended to carry an extra cooler w/ ice,
not a lab freezer. :) But I am sure a liquid nitgrogen cooler
would be practical fo use on a boat, too.


Richard J Kinch wrote:
Chris writes:

IF you want to go high tech and do have access to lab freezers (where
else would you get dry ice...:), you can also 'supercool' your normal
ice before the trip. Ice at -70 C will last a lot longer than at -3 C,
with no extra weight.
For water, the heat of fusion is about 80 times specific heat, so
supercooling ice is hardly effective. You're much better off just using a
little more ice.

Dry ice is no good for refrigeration because it is too cold and difficult
to regulate to a higher temperature. By the time you build a contraption
to regulate the chill, you've lost any weight advantage over ice, assuming
you don't need sub-freezing temperatures.

I remember as a child seeing another child severely injured at my dad's
company picnic. Someone brought popsicles in dry ice, the kid got into
them, and took a lick.

Liquid nitrogen is a more practical wasting refrigerant since the liquid is
easy to throttle. That's what some reefer trucks use.

Dry Ice Box?
 

I found the best price on ebay. There is a guy on there that sells it.
Apparently pretty reliable because I have suggested him to several people,
all of whom have been very happy with his shipping. The proper term is
"Techni Ice" . In my testing the Techni ice only lasted about 30% longer
than water ice but the temperature averaged about 15F lower. Frozen to 0F
it absorbs about 152 BTU's per pound compared to 176 BTU per pound of water
ice but water ice only absorbs 1 BTU per pound until it gets to 32F and
starts to melt. The gel in Techni Ice starts melting at a lot lower
temperature and is pretty well all melted by the time it reaches 32F.
Apparently it also will absorb more than 1BTU/pound when it is frozen to
very low temperatures although I don't fully understand the physics yet.

The other part of the performance is the Coleman Ultimate Extreme cooler.
It is exactly 1" under the maximum size you can check on an airline and is
about the best insulated mass produced cooler on the market. The "marine"
version cost about $10 more than the regular model but the only real
difference is that it is all white and has an extra set of rope handles
which can handle the rough treatment of baggage handlers. The 50 quart
wheeled model that Wal-Mart carries is nothing like as good.


I keep 5 or 6 sheets in the freezer and just turn the freezer side down to
the lowest setting about 4 days before a trip. All the food goes in Ziploc
bags in the freezer for 3 or 4 days to get it as cold as possible and I pack
the cooler completely full. A towel on the bottom adds a little insulation
to the coldest area and any voids are filled with towels, extra bathing
suits, etc.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Wayne.B" wrote in message
...
On Sat, 1 Jul 2006 22:11:56 -0400, "Glenn Ashmore"
wrote:

The next morning it was checked on an airline to
St. Thomas where it was lost for 3 days somewhere between Atlanta and Ft.
Lauderdale. The cooler was delivered to West End, Tortola and unpacked on
June 3 about 1 PM and everything was still frozen solid.

===========

That 's impressive.

Where do you get the Technice?

Dry Ice Box?
 

Glenn - Water ice only holds .5 (or less) BTU/lb-degree, so cooling it
down to zero is only adding another 15 BTU per pound for a total of
159 BTU.

Glenn Ashmore wrote:
I found the best price on ebay. There is a guy on there that sells it.
Apparently pretty reliable because I have suggested him to several people,
all of whom have been very happy with his shipping. The proper term is
"Techni Ice" . In my testing the Techni ice only lasted about 30% longer
than water ice but the temperature averaged about 15F lower. Frozen to 0F
it absorbs about 152 BTU's per pound compared to 176 BTU per pound of water
ice but water ice only absorbs 1 BTU per pound until it gets to 32F and
starts to melt. The gel in Techni Ice starts melting at a lot lower
temperature and is pretty well all melted by the time it reaches 32F.
Apparently it also will absorb more than 1BTU/pound when it is frozen to
very low temperatures although I don't fully understand the physics yet.

The other part of the performance is the Coleman Ultimate Extreme cooler.
It is exactly 1" under the maximum size you can check on an airline and is
about the best insulated mass produced cooler on the market. The "marine"
version cost about $10 more than the regular model but the only real
difference is that it is all white and has an extra set of rope handles
which can handle the rough treatment of baggage handlers. The 50 quart
wheeled model that Wal-Mart carries is nothing like as good.


I keep 5 or 6 sheets in the freezer and just turn the freezer side down to
the lowest setting about 4 days before a trip. All the food goes in Ziploc
bags in the freezer for 3 or 4 days to get it as cold as possible and I pack
the cooler completely full. A towel on the bottom adds a little insulation
to the coldest area and any voids are filled with towels, extra bathing
suits, etc.

Dry Ice Box?
 

Lets look at the safety of both suggestions.

1) Nitrogen liquid will boil to gas. The gas is an asphyxiate. Many people
have died from nitrogen. Air contains 21.5% O2 mostly the rest is N2. If
you breath pure N2 the first breath you pass out and the second breath brain
damage and the third death. Think about passing out when reaching for
something in the ice chest. If you fall in your dead; if you fall out you
will probably be ok. The next day you will be ripping out your N2 system.
A closed boat can accumulate N2 which will displace air. Maybe get you in
your sleep or when you go down for a cold one.

2) CO2 is heaver then air and would accumulate in the low parts of the boat.
Same issue as with N2 but it would at least give you some warning signs.

Whats wrong with a little water from melting ice. You are on a boat
right???





"Jeff" wrote in message
. ..
Glenn - Water ice only holds .5 (or less) BTU/lb-degree, so cooling it
down to zero is only adding another 15 BTU per pound for a total of 159
BTU.

Glenn Ashmore wrote:
I found the best price on ebay. There is a guy on there that sells it.
Apparently pretty reliable because I have suggested him to several
people, all of whom have been very happy with his shipping. The proper
term is "Techni Ice" . In my testing the Techni ice only lasted about
30% longer than water ice but the temperature averaged about 15F lower.
Frozen to 0F it absorbs about 152 BTU's per pound compared to 176 BTU per
pound of water ice but water ice only absorbs 1 BTU per pound until it
gets to 32F and starts to melt. The gel in Techni Ice starts melting at
a lot lower temperature and is pretty well all melted by the time it
reaches 32F. Apparently it also will absorb more than 1BTU/pound when it
is frozen to very low temperatures although I don't fully understand the
physics yet.

The other part of the performance is the Coleman Ultimate Extreme cooler.
It is exactly 1" under the maximum size you can check on an airline and
is about the best insulated mass produced cooler on the market. The
"marine" version cost about $10 more than the regular model but the only
real difference is that it is all white and has an extra set of rope
handles which can handle the rough treatment of baggage handlers. The 50
quart wheeled model that Wal-Mart carries is nothing like as good.


I keep 5 or 6 sheets in the freezer and just turn the freezer side down
to the lowest setting about 4 days before a trip. All the food goes in
Ziploc bags in the freezer for 3 or 4 days to get it as cold as possible
and I pack the cooler completely full. A towel on the bottom adds a
little insulation to the coldest area and any voids are filled with
towels, extra bathing suits, etc.

Dry Ice Box?
 

OK, let's look at the fallacies of both your scenarios:

Rick wrote:
Lets look at the safety of both suggestions.

1) Nitrogen liquid will boil to gas. The gas is an asphyxiate. Many people
have died from nitrogen. Air contains 21.5% O2 mostly the rest is N2. If
you breath pure N2 the first breath you pass out and the second breath brain
damage and the third death.

GROSS exaggeration. This assumes you purge *all* the lung volume with
each breath (when it's typically only about 30% or less) and that there
are no O2 reserves in circulating hemoglobin or stored myoglobin.
Neither is the case. It also assumes (at 12-15 breaths per minute) that
brain damage occurs in 10-15 seconds. Right.

Think about passing out when reaching for
something in the ice chest. If you fall in your dead; if you fall out you
will probably be ok. The next day you will be ripping out your N2 system.
A closed boat can accumulate N2 which will displace air.

N2 evaporation does not *displace* air, it dilutes the O2 concentration.
For a sleeping individual, oxygen concentration does not become
dangerous until it reaches about 10%. That means you'd need to
evaporate sufficient N2 to equal the volume inside the boat, and you'd
have to do it without ventilation. Not very likely. My boat doesn't
hold 30 PSIA, does yours?

Maybe get you in
your sleep or when you go down for a cold one.

2) CO2 is heaver then air and would accumulate in the low parts of the boat.
Same issue as with N2 but it would at least give you some warning signs.

It gives exactly the same warning signs as N2. No more, no less. You'd
require the same volume of subliming CO2 as evaporating N2 to cause O2
deprivation issues.

Bottom line, you must have ventilation in any sleeping environment. You
exhale CO2, you'll recall, so you'll die in a sealed box or without
subliming CO2 or evaporating N2. That's just common sense.

Whats wrong with a little water from melting ice. You are on a boat
right???

I don't use CO2 in my boat, but I've been using it for years in my
Vanagons' Dometic NH3 "refrigerator", and it's posed no problems. I put
in about 2 lbs which lasts about 3 days. 2 lbs sublimes to about 510
liters, in a van with an interior volume of approx. 6800L. When you do
the math, that results in a total O2 dilution of 7.5%, or a final O2
concentration of 19.9% which is well above OSHA's TEEL limit of 19.5%
for a confined space entry. This again assumes that no ventilation
occurred over the 3 days.

When you do the math, it just isn't a problem when using any reasonable
amounts, and with only normal ventilation (which should *always* be
ensured under *any* use conditions).

Keith Hughes

Dry Ice Box?
 

Hey it sounds like we got a volunteer.

I personally know of 2 deaths due to folks breathing N2. Thats pure N2.

"Keith Hughes" wrote in message
...
OK, let's look at the fallacies of both your scenarios:

Rick wrote:
Lets look at the safety of both suggestions.

1) Nitrogen liquid will boil to gas. The gas is an asphyxiate. Many
people have died from nitrogen. Air contains 21.5% O2 mostly the rest is
N2. If you breath pure N2 the first breath you pass out and the second
breath brain damage and the third death.

GROSS exaggeration. This assumes you purge *all* the lung volume with
each breath (when it's typically only about 30% or less) and that there
are no O2 reserves in circulating hemoglobin or stored myoglobin. Neither
is the case. It also assumes (at 12-15 breaths per minute) that brain
damage occurs in 10-15 seconds. Right.

Think about passing out when reaching for something in the ice chest. If
you fall in your dead; if you fall out you will probably be ok. The next
day you will be ripping out your N2 system. A closed boat can accumulate
N2 which will displace air.

N2 evaporation does not *displace* air, it dilutes the O2 concentration.
For a sleeping individual, oxygen concentration does not become dangerous
until it reaches about 10%. That means you'd need to evaporate sufficient
N2 to equal the volume inside the boat, and you'd have to do it without
ventilation. Not very likely. My boat doesn't hold 30 PSIA, does yours?

Maybe get you in your sleep or when you go down for a cold one.

2) CO2 is heaver then air and would accumulate in the low parts of the
boat. Same issue as with N2 but it would at least give you some warning
signs.

It gives exactly the same warning signs as N2. No more, no less. You'd
require the same volume of subliming CO2 as evaporating N2 to cause O2
deprivation issues.

Bottom line, you must have ventilation in any sleeping environment. You
exhale CO2, you'll recall, so you'll die in a sealed box or without
subliming CO2 or evaporating N2. That's just common sense.

Whats wrong with a little water from melting ice. You are on a boat
right???

I don't use CO2 in my boat, but I've been using it for years in my
Vanagons' Dometic NH3 "refrigerator", and it's posed no problems. I put
in about 2 lbs which lasts about 3 days. 2 lbs sublimes to about 510
liters, in a van with an interior volume of approx. 6800L. When you do
the math, that results in a total O2 dilution of 7.5%, or a final O2
concentration of 19.9% which is well above OSHA's TEEL limit of 19.5% for
a confined space entry. This again assumes that no ventilation occurred
over the 3 days.

When you do the math, it just isn't a problem when using any reasonable
amounts, and with only normal ventilation (which should *always* be
ensured under *any* use conditions).

Keith Hughes

Dry Ice Box?
 

Would you mind doing the math for
10 lbs of -70 C ice,
10 lbs of 0 C Ice, and
10 lbs of 0 C water?
I don't have the temp dependent specific heat curves.

Thanks,

Chris

Jeff wrote:
Chris wrote:
For water, the heat of fusion is about 80 times specific heat...
So -70 C ice would have almost twice the cooling effect
as the same amount of barely frozen ice, right?

Wrong. You should look up the Heat Capacity of cold ice. Its only
0.5 BTU/lb-degree at freezing, but it goes down so that by -50 F its
only 0.4.

Since the Heat of Fusion is 144 BTU/lb, sub-cooling even 100 degrees
only adds a small amount of cooling capacity.

Hardly 'hadly effective'.

No, its hardly effective.


And yes, twice as much ice also works, but we knew that.
That's why I recommended to carry an extra cooler w/ ice,
not a lab freezer. :) But I am sure a liquid nitgrogen cooler
would be practical fo use on a boat, too.


Richard J Kinch wrote:
Chris writes:

IF you want to go high tech and do have access to lab freezers (where
else would you get dry ice...:), you can also 'supercool' your normal
ice before the trip. Ice at -70 C will last a lot longer than at -3 C,
with no extra weight.
For water, the heat of fusion is about 80 times specific heat, so
supercooling ice is hardly effective. You're much better off just using a
little more ice.

Dry ice is no good for refrigeration because it is too cold and difficult
to regulate to a higher temperature. By the time you build a contraption
to regulate the chill, you've lost any weight advantage over ice, assuming
you don't need sub-freezing temperatures.

I remember as a child seeing another child severely injured at my dad's
company picnic. Someone brought popsicles in dry ice, the kid got into
them, and took a lick.

Liquid nitrogen is a more practical wasting refrigerant since the liquid is
easy to throttle. That's what some reefer trucks use.

Dry Ice Box?
 

So where did these folks find that pure N2? Sure not
in the bilge of a boat, because it mixes into the air
readily. It does not 'displace air'.
And yes, any gas mix without oxygen will kill you
if breathed from a bottle for a few minutes. That
doesn't have to do anything with fridges.


Rick wrote:
Hey it sounds like we got a volunteer.

I personally know of 2 deaths due to folks breathing N2. Thats pure N2.

Dry Ice Box?
 

On Sat, 01 Jul 2006 04:29:08 GMT, cavelamb
wrote:


Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


A couple pounds of dry ice seems like a good idea,
but how to use it?

Mix with wet ice?

Or keep separate?

Richard

The CO2 evolved from dry ice is too cold for chilling food and drinks
directly, but it can keep the water ice from melting so quickly.
This suggests a cooler within a cooler - the inner cooler giving
off CO2 gas which bubbles through a water ice mixture, which chills
the food container.

Dry ice provides a tidy explosion if its vapor has nowhere to go, and
it is not a good breathing gas - but at least it gives plenty of
warning - we are designed to pant if the CO2 proportion rises
(unlike low O2 which induces unconsciousness with no warning at all.)

You might take a look at the electric cooler boxes. Either way,
expanded polystyrene is an excellent insulation.

Brian Whatcott Altus OK

Dry Ice Box?
 

As I said, I do it in my Vanagon all the time and, last I checked, I'm
not dead. Anyone who will travel, sleep, or play bingo in a sealed
container is just a contaminant in the gene pool.

Rick wrote:
Hey it sounds like we got a volunteer.

I personally know of 2 deaths due to folks breathing N2. Thats pure N2.

And what, pray tell, were these geniuses doing breathing pure N2? I
personally know of 4 individuals who died breathing N2O. They
were...uhm...what was that word? Stupid. Pressurized gas, sealed
environment, stupid. You'll note that in none of the scenarios
presented was anyone exposed to any prolonged exposure to "pure N2". Do
the math, it's not rocket science.

Please, feel free to demonstrate how any reasonable amount of CO2 or N2
can sublime or evaporate into an average size boat, **in the typical
amount of time required**, to result in a dangerous environment. Note
we are *not* talking about something like CO, which preferentially binds
with hemoglobin relative to O2, and thus presents a very real hazard.

Keith Hughes

Dry Ice Box?
 

Chris writes:

For water, the heat of fusion is about 80 times specific heat...

So -70 C ice would have almost twice the cooling effect
as the same amount of barely frozen ice, right?

No, because heat load is proportional to temperature differential.

Now if you put that supercooled ice into watery payload that freezes, then
the supercooling heat sink will convert to new ice in the payload, and a
different process is involved that is more "efficient". However, this is
no better than just freezing your food to start with.

Hardly anybody appreciates that temperature and heat are two different
things.

Dry Ice Box?
 

Keith Hughes writes:

When you do the math, it just isn't a problem when using any reasonable
amounts, and with only normal ventilation (which should *always* be
ensured under *any* use conditions).

Quite so.

A restaurant soda fountain typically has multiple 20 lb CO2 tanks sitting
around. If these were to leak out rapidly from a burst hose, which happens
frequently, there is no hazard to personnel.

A 20 lb CO2 fire extinguisher discharged indoors does not present an
asphyxiation hazard.

Dry Ice Box?
 

On Sun, 02 Jul 2006 08:31:58 -0400, Jeff wrote:

Chris wrote:
For water, the heat of fusion is about 80 times specific heat...
So -70 C ice would have almost twice the cooling effect
as the same amount of barely frozen ice, right?

Wrong. You should look up the Heat Capacity of cold ice. Its only
0.5 BTU/lb-degree at freezing, but it goes down so that by -50 F its
only 0.4.

Since the Heat of Fusion is 144 BTU/lb, sub-cooling even 100 degrees
only adds a small amount of cooling capacity.

Hardly 'hadly effective'.

No, its hardly effective.

This is in error: using old CGS units
heat for fusion of ice is 80 cal/gm specific heat cap near 0degC is
1 cal/gm

Supercool to -40 deg C and its worth roughly another 40% of cooling
power cf. ice at freezing.

Brian Whatcott Altus OK

Dry Ice Box?
 

On Sun, 02 Jul 2006 23:50:59 -0500, Richard J Kinch
wrote:

Chris writes:

For water, the heat of fusion is about 80 times specific heat...

So -70 C ice would have almost twice the cooling effect
as the same amount of barely frozen ice, right?

No, because heat load is proportional to temperature differential.

Now if you put that supercooled ice into watery payload that freezes, then
the supercooling heat sink will convert to new ice in the payload, and a
different process is involved that is more "efficient". However, this is
no better than just freezing your food to start with.

Hardly anybody appreciates that temperature and heat are two different
things.

This note looks suspect - especially the "what everybody doesn't know"
bit.

Brian Whatcott Altus OK

Dry Ice Box?
 

On Sun, 2 Jul 2006 12:12:44 -0500, "Rick"
wrote:

Lets look at the safety of both suggestions.

1) Nitrogen liquid will boil to gas. The gas is an asphyxiate. Many people
have died from nitrogen. Air contains 21.5% O2 mostly the rest is N2. If
you breath pure N2 the first breath you pass out and the second breath brain
damage and the third death. Think about passing out when reaching for
something in the ice chest. If you fall in your dead; if you fall out you
will probably be ok. The next day you will be ripping out your N2 system.
A closed boat can accumulate N2 which will displace air. Maybe get you in
your sleep or when you go down for a cold one.

2) CO2 is heaver then air and would accumulate in the low parts of the boat.
Same issue as with N2 but it would at least give you some warning signs.

Whats wrong with a little water from melting ice. You are on a boat
right???


Nitrogen displaces oxygen, so you pass out without warning. It is not
otherwise toxic. So figure being underwater for a few seconds. That's
as much time as you have with N2. With CO2 you pant.
Both gases diffuse of course.

Brian Whatcott Altus OK

Dry Ice Box?
 

Brian Whatcott wrote:
Nitrogen displaces oxygen, so you pass out without warning. It is not
otherwise toxic. So figure being underwater for a few seconds. That's
as much time as you have with N2. With CO2 you pant.
Both gases diffuse of course.

"Carbon dioxide is a colourless gas which, when inhaled at high
concentrations produces a sour taste in the mouth and a stinging
sensation in the nose and throat. These effects result from the gas
dissolving in the mucous membranes and saliva, forming a weak solution
of carbonic acid."

Material Safety Data Sheet
Gaseous Nitrogen:

SIMPLE ASPHYXIANT
Section 3 : HAZARD IDENTIFICATION
Emergency Overview:
Nitrogen gas is colorless, odorless and non-flammable.

It is non-toxic. The primary health hazard is asphyxiation by
displacement of oxygen.
Route of entry:
Inhalation, skin and eye contact.
Effects of acute exposure
Eye contact:
Vapor may cause a stinging sensation.
Skin contact:
No adverse effects from gas.
Inhalation:
May cause dizziness.
Asphyxiant.
Can cause vomiting.
May result in unconsciousness.
May cause excitation, excess salivation, rapid breathing.
May cause headaches and drowsiness.
May cause stinging of the nose and throat.
Ingestion:
Not a likely route of exposure.
Effects of chronic exposu
None known. Chronic exposure to abnormal concentrations unlikely
Reproductive effects:
Oxygen deficiency during pregnancy has produced developmental
abnormalities in humans and experimental animals.

Dry Ice Box?
 

Brian Whatcott wrote:


Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2). Excess
Nitrogen will reduce the partial pressure of oxygen. Respiration is
controlled not only on CO2 concentration, but on blood pH and O2
saturation as well. N2 does not bind with hemoglobin, and does not
significantly affect blood pH. As a result, an excess of N2 will cause
further depletion of oxyhemoglobin in the red blood cells (less than 25%
is typically transferred, leaving a reserve factor which prevents your
sudden passing out scenario). This results in a higher respiratory rate
due to low O2 saturation, as well as causing a higher partial pressure
of CO2 (bicarbonate in solution), further lowering the pH of the blood,
and triggering the same reactions as does CO2. CO2 does it somewhat
more quickly is all.

It is not
otherwise toxic. So figure being underwater for a few seconds. That's
as much time as you have with N2.

I'm afraid I don't understand what this is trying to say.

With CO2 you pant.

As you will with N2. Increased CO2 will initiate higher respiratory
rates more quickly than decreased O2 saturation rates will, since the
homeostatic control sensors are more sensitive to CO2.

Both gases diffuse of course.

Which is why, with any reasonable implementation, neither N2 (although
the handling hazards of liquid N2 make it fairly useless IMO) nor CO2
are an issue.

Keith Hughes

Dry Ice Box?
 

Brian Whatcott wrote:
Nitrogen displaces oxygen, so you pass out without warning.

Keith Hughes wrote:
Nitrogen does not *displace* oxygen (O2 weighs more than N2). Excess
Nitrogen will reduce the partial pressure of oxygen.
Snip

Once again, this is copied directly from the MSDS (Emphasis added):

Material Safety Data Sheet
Gaseous Nitrogen:

SIMPLE ASPHYXIANT
Section 3 : HAZARD IDENTIFICATION
Emergency Overview:
Nitrogen gas is colorless, odorless and non-flammable.
It is non-toxic. The primary health hazard is asphyxiation by
displacement of oxygen.

Snip

Dry Ice Box?
 

Brian Whatcott wrote:
Nitrogen displaces oxygen, so you pass out without warning.


Material Safety Data Sheet
Gaseous Nitrogen:

SIMPLE ASPHYXIANT
Section 3 : HAZARD IDENTIFICATION
Emergency Overview:

Inhalation:
May cause dizziness.
Asphyxiant.
Can cause vomiting.
May result in unconsciousness.
May cause excitation, excess salivation, rapid breathing.
May cause headaches and drowsiness.
May cause stinging of the nose and throat.


So maybe lots of warning before passing out. But like others have said,
it only happens at extreme concentrations.

Dry Ice Box?
 

I have routinely taken a half gallon of ice cream on our Kayak
excursions. It is inside a smaller lunchbox size cooler with about 5
lbs of dryice on top, and that cooler placed inside another cooler.
Works great. The only problem has been that the ice cream was sometimes
still frozen (after 3 days) too rock hard to dispense. It hat to sit
out for thirty minutes to get a scoop in it.

I doubt it's advantageous to use dry ice for a longer cooler duration.
Three days seems to be the maximum. But if you want to keep things
frozen, it's perfect. It's available around here in any local grocery
store, from a special "Dry Ice" freezer by the entrance.

Dry Ice Box?
 

On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:

Brian Whatcott wrote:


Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).
//

Keith Hughes

This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)


OK?

Brian Whatcott Altus OK

Dry Ice Box?
 

On Mon, 03 Jul 2006 20:20:36 -0400, Sailaway
wrote:

Brian Whatcott wrote:
Nitrogen displaces oxygen, so you pass out without warning.


Material Safety Data Sheet
Gaseous Nitrogen:

SIMPLE ASPHYXIANT
Section 3 : HAZARD IDENTIFICATION
Emergency Overview:

Inhalation:
May cause dizziness.
Asphyxiant.
Can cause vomiting.
May result in unconsciousness.
May cause excitation, excess salivation, rapid breathing.
May cause headaches and drowsiness.
May cause stinging of the nose and throat.


So maybe lots of warning before passing out. But like others have said,
it only happens at extreme concentrations.


Though your MSDS cites supported a point of mine previously, I try to
recall that MSDS are heavily contaminated with lawyer inputs.
I have seen the baro chamber tests that I find more convincing.

Brian Whatcott Altus OK

Dry Ice Box?
 

Brian Whatcott wrote:
On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:


Brian Whatcott wrote:



Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).

//

Keith Hughes


This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)

No, it does not. In a "closed room", you would merely be pressurizing
the room, and reducing the partial pressures of whatever gases were
there to begin with. If the room is vented, then it would depend on the
relative densities of the N2 and the original gases, and the
configuration of the inlet and the exhaust vents. I do these types of
studies all the time in cleanrooms, autoclaves, EtO chambers, and
purging and overlaying containers with N2, and they are not simple
processes.

And let's put your scenario in the context of the discussion, 300
ft3/min of CO2 would require sublimation of 5400 lbs/minute.



OK?

My point was that, unlike say, propane, adding Nitrogen to air gradually
dilutes the O2 content. It doesn't displace it like a heavier gas would,
where, rather suddenly, you'd be submerged in a blanket layer. The
result is a gradual diminution of O2 that the body will detect, and
respond to. The response is increased respiration, which will work
until the O2 gets below about 10%.

And unlike your generator scenario, where you simply pressurize a
vessel, or flush a vessel designed for purging, the "generator" in real
life is very, very small, and boats are not sealed.

I'm not trying to win a ****ing contest, but let's remember that the
response to the OP was, to paraphrase 'do it and you'll die', which was
singularly unhelpful, and inaccurate relative to the question of using
reasonable quantities of dry ice in a cooler, in a typically vented
boat. I'm trying to point out that it can be done, and done safely, as
long as reasonable care is taken.

Keith Hughes

Dry Ice Box?
 

Brian Whatcott wrote:

snip

Though your MSDS cites supported a point of mine previously, I try to
recall that MSDS are heavily contaminated with lawyer inputs.
I have seen the baro chamber tests that I find more convincing.

Brian Whatcott Altus OK

I've been personally involved in some MSDS generation processes (needed
for cleaning validation of pharmaceutical processes), and I can tell you
from experience that lawyer inputs are probably one of the lesser
contaminants in the process. OSHA doesn't generate these things, the
folks making the chemicals do. Not suggesting anything nefarious, just
noting that some of these folks, IME, don't have all their dogs barking.

Keith Hughes

Dry Ice Box?
 

On Wed, 05 Jul 2006 09:19:03 -0700, Keith Hughes
wrote:

I'm trying to point out that it can be done, and done safely, as
long as reasonable care is taken.

And it *has* been done for many years by myself and others with no
problems whatsoever. The only real hazzard is touching the dry ice
with bare skin but that is easily avoided.

Dry Ice Box?
 

I am going to do an engineering guess and say that the density of CO2 gas at
room temperature is 0.11 #/ft. So for 300 ft/min it works out to 33# per
minute. Now that's a lot of dry ice subliming but something less then 5400
# per minute.


"Keith Hughes" wrote in message
...

Brian Whatcott wrote:
On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:


Brian Whatcott wrote:



Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).

//

Keith Hughes


This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)

No, it does not. In a "closed room", you would merely be pressurizing the
room, and reducing the partial pressures of whatever gases were there to
begin with. If the room is vented, then it would depend on the relative
densities of the N2 and the original gases, and the configuration of the
inlet and the exhaust vents. I do these types of studies all the time in
cleanrooms, autoclaves, EtO chambers, and purging and overlaying
containers with N2, and they are not simple processes.

And let's put your scenario in the context of the discussion, 300 ft3/min
of CO2 would require sublimation of 5400 lbs/minute.



OK?

My point was that, unlike say, propane, adding Nitrogen to air gradually
dilutes the O2 content. It doesn't displace it like a heavier gas would,
where, rather suddenly, you'd be submerged in a blanket layer. The result
is a gradual diminution of O2 that the body will detect, and respond to.
The response is increased respiration, which will work until the O2 gets
below about 10%.

And unlike your generator scenario, where you simply pressurize a vessel,
or flush a vessel designed for purging, the "generator" in real life is
very, very small, and boats are not sealed.

I'm not trying to win a ****ing contest, but let's remember that the
response to the OP was, to paraphrase 'do it and you'll die', which was
singularly unhelpful, and inaccurate relative to the question of using
reasonable quantities of dry ice in a cooler, in a typically vented boat.
I'm trying to point out that it can be done, and done safely, as long as
reasonable care is taken.

Keith Hughes

Dry Ice Box?
 

Hmmm....brainfart. 1 Lb of dry ice sublimes to 250L of CO2 gas, or
about 8.8 ft^3. So, 300 ft^3/min would requie about 34 Lbs/minute.
That's still a lot of dry ice :-)

Keith Hughes

Rick wrote:
I am going to do an engineering guess and say that the density of CO2 gas at
room temperature is 0.11 #/ft. So for 300 ft/min it works out to 33# per
minute. Now that's a lot of dry ice subliming but something less then 5400
# per minute.


"Keith Hughes" wrote in message
...

Brian Whatcott wrote:

On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:



Brian Whatcott wrote:




Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).

//


Keith Hughes


This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)

No, it does not. In a "closed room", you would merely be pressurizing the
room, and reducing the partial pressures of whatever gases were there to
begin with. If the room is vented, then it would depend on the relative
densities of the N2 and the original gases, and the configuration of the
inlet and the exhaust vents. I do these types of studies all the time in
cleanrooms, autoclaves, EtO chambers, and purging and overlaying
containers with N2, and they are not simple processes.

And let's put your scenario in the context of the discussion, 300 ft3/min
of CO2 would require sublimation of 5400 lbs/minute.



OK?

My point was that, unlike say, propane, adding Nitrogen to air gradually
dilutes the O2 content. It doesn't displace it like a heavier gas would,
where, rather suddenly, you'd be submerged in a blanket layer. The result
is a gradual diminution of O2 that the body will detect, and respond to.
The response is increased respiration, which will work until the O2 gets
below about 10%.

And unlike your generator scenario, where you simply pressurize a vessel,
or flush a vessel designed for purging, the "generator" in real life is
very, very small, and boats are not sealed.

I'm not trying to win a ****ing contest, but let's remember that the
response to the OP was, to paraphrase 'do it and you'll die', which was
singularly unhelpful, and inaccurate relative to the question of using
reasonable quantities of dry ice in a cooler, in a typically vented boat.
I'm trying to point out that it can be done, and done safely, as long as
reasonable care is taken.

Keith Hughes

Dry Ice Box?
 

There in lays the futility of this debate. A 24x18X18 cooler with a typical
R value of 7 and an internal temperature of 0F in an 80F cabin will gain
about 190 BTUs per hour which will melt about 3/4 pound of dry ice to form
about 6 cu.ft of CO2.

Unless you are sleeping on the floor right next to the cooler in a sealed up
cabin there is not a lot of danger.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Keith Hughes" wrote in message
...
Hmmm....brainfart. 1 Lb of dry ice sublimes to 250L of CO2 gas, or about
8.8 ft^3. So, 300 ft^3/min would requie about 34 Lbs/minute. That's still
a lot of dry ice :-)

Keith Hughes

Rick wrote:
I am going to do an engineering guess and say that the density of CO2 gas
at room temperature is 0.11 #/ft. So for 300 ft/min it works out to 33#
per minute. Now that's a lot of dry ice subliming but something less
then 5400 # per minute.


"Keith Hughes" wrote in message
...

Brian Whatcott wrote:

On Mon, 03 Jul 2006 16:55:28 -0700, Keith Hughes
wrote:



Brian Whatcott wrote:




Nitrogen displaces oxygen, so you pass out without warning.

Nitrogen does not *displace* oxygen (O2 weighs more than N2).

//


Keith Hughes


This sort of technical thread too easily turns into a ****ing contest,
I realise.
So when I say nitrogen displaces oxygen, do tell me what happens when
I introduce a nitrogen generator of 300 cu ft /min into a closed room
of 1000 cu ft.
The nitrogen displaces the room atmosphere does it not?
(Whether the prior atmosphere in question is all oxygen, all hydrogen,
all helium, all whatever...)

No, it does not. In a "closed room", you would merely be pressurizing
the room, and reducing the partial pressures of whatever gases were there
to begin with. If the room is vented, then it would depend on the
relative densities of the N2 and the original gases, and the
configuration of the inlet and the exhaust vents. I do these types of
studies all the time in cleanrooms, autoclaves, EtO chambers, and purging
and overlaying containers with N2, and they are not simple processes.

And let's put your scenario in the context of the discussion, 300 ft3/min
of CO2 would require sublimation of 5400 lbs/minute.



OK?

My point was that, unlike say, propane, adding Nitrogen to air gradually
dilutes the O2 content. It doesn't displace it like a heavier gas would,
where, rather suddenly, you'd be submerged in a blanket layer. The
result is a gradual diminution of O2 that the body will detect, and
respond to. The response is increased respiration, which will work until
the O2 gets below about 10%.

And unlike your generator scenario, where you simply pressurize a vessel,
or flush a vessel designed for purging, the "generator" in real life is
very, very small, and boats are not sealed.

I'm not trying to win a ****ing contest, but let's remember that the
response to the OP was, to paraphrase 'do it and you'll die', which was
singularly unhelpful, and inaccurate relative to the question of using
reasonable quantities of dry ice in a cooler, in a typically vented boat.
I'm trying to point out that it can be done, and done safely, as long as
reasonable care is taken.

Keith Hughes

Dry Ice Box?
 

Brian Whatcott wrote:

On Sat, 01 Jul 2006 04:29:08 GMT, cavelamb
wrote:


Anyone out there use dry ice for refrigeration?

I want to keep the cooler cooler longer.


A couple pounds of dry ice seems like a good idea,
but how to use it?

Mix with wet ice?

Or keep separate?

Richard


The CO2 evolved from dry ice is too cold for chilling food and drinks
directly, but it can keep the water ice from melting so quickly.
This suggests a cooler within a cooler - the inner cooler giving
off CO2 gas which bubbles through a water ice mixture, which chills
the food container.

Dry ice provides a tidy explosion if its vapor has nowhere to go, and
it is not a good breathing gas - but at least it gives plenty of
warning - we are designed to pant if the CO2 proportion rises
(unlike low O2 which induces unconsciousness with no warning at all.)

You might take a look at the electric cooler boxes. Either way,
expanded polystyrene is an excellent insulation.

Brian Whatcott Altus OK

Well, I asked, didn't I.

Thanks to all for the information.

As it worked out a couple or three pounds of dry ice in one corner of the
ice chest kept the rest of the wet ice well frozen for three days. (!)

I think the wet ice is acting as insulation to protect the food stuff from
the dry ice - depending on how close stuff is to the dry stuff.

My boat is an 18 foot Capri (Catalina) so we don't have a lot of room to
play with. But with the companionway open at all there doesn't seem to be
much danger from CO2. There is just not enough dry ice in the box to make
much CO2 very rapidly (as was pointed out several times).

BUT! It really does keep the cooler cooler longer...

Thanks folks,

Richard