From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: refrigerators
Message-ID: <i2akdusiljgjesk9pr1786a17vplghilg6@4ax.com>
Date: Thu, 09 May 2002 04:08:03 -0400

On 7 May 2002 04:21:19 -0700, paul@hepalmer.com (Paul Fredricks) wrote:

>Thanks for the responses. I've done more looking and it may make more
>sense to buy two 12v refrigertors. The dry ice sounds like a good idea
>also, but wouldn't that freeze everything in the fridge?. I can easily
>do the electrical work my self, but it may not make sense from a cost
>standpoint.

Before I learned better, early in my catering career, I used dry ice in
coolers to transport food (after I learned better, I used electric upright
freezers operated from either inverters or generators, depending on the
application.)  Dry ice is a bitch you probably don't want to court.

Dry ice evaporates at -109 deg F at sea level.  Its rate of evaporation is
determined by the heat transferred into it.  Inside a closed and insulated
container, it will continue to evaporate until the container is reduced to
near that temperature.  This will a) freeze everything beyond solid, b) will
likely crack the plastic walls, and c) will use a ton of dry ice.  Item a) is
much more of a problem than you might realize because it adds hours to thaw
time.

The only way to regulate the internal temperature is to insulate the dry ice.
Wrapping it in several layers of cloth is one method.  This is unregulated.
That is, you have to manually balance how much heat you allow to get to the
dry ice against the inleakage.  It is very difficult to impossible to regulate
the temperature to avoid freezing things.  Commercial dry ice refrigerators
put the dry ice in a highly insulated box with a damper connecting it to the
refrigerated space.  A thermal element varies the damper to control the
refrigerated space temperature.  Not practical for your application.  The only
place I've ever seen this was on reefer trucks.

You gave me far too little info to be able to recommend anything for your
existing setup.  What kind of refrigerators, etc.

What you might want to consider is one of the fairly new tri-mode portable
absorption refrigerator/freezers.  Here's $CW$'s page on 'em:

http://www.campingworld.com/browse/categories/index.cfm?deptID=4&catID=40&subOf=25

The first item, the Artic Cool and the last item the very similar Norcold
unit, are the best and most expensive options.  This same unit is widely used
in the concession and catering world.  12 volt or 120 volt operation using a
compressor and conventional refrigeration.  This unit will move the most heat
and therefore will perform the most satisfactorily in the hottest weather.
These are fairly large (about the size of a large Igloo ice cooler) but that
might not matter much if you're setting it in and out of a popup.  It has the
advantage of being able to operate in a sealed environment.

An alternative is this:

http://www.campingworld.com/browse/skus/index.cfm?deptID=4&subOf=40,25&skunum=17919

This is a smaller absorption type unit (like regular RV units) that will
operate on 12 volts, 120 volts or propane.  It has the advantages of size and
multi-fuel, being able to run from weeks on a 20 lb propane cylinder.  The
primary disadvantages include lower refrigeration capacity, the loss of
capacity with ambient heat and the internal flame.  Operated inside your
popup, you might have to provide some bit of ventilation.

I've seen both types listed with other vendors for less money so don't take
the references as a recommendation to buy from CW.

We're about to buy one of the later units to carry with us when we go shopping
or to places where we'd want to buy local food and haul home.  Seafood from
the coast, things like that.  The ability to run the thing on a propane torch
tank, from a portable tank or via a flex hose to the RV propane system is a
major plus for our camping style.

John

>
>    We are going to Nova Scotia for a week this summer. The idea was
>to load the fridges thursday evening and close up the camper. Leave
>Friday morning. Staying in a hotel on Friday night to facilitate
>catching the 8AM Bar Harbor ferry. We wouldn't reopen the camper until
>Saturday evening. Then campground hop for the week. Long days in
>between campgrounds would make it better to have the fridges running.
>
>    My wife wants to limit the number of coolers we carry. That's the
>reason for loading the refrigerators.

From: vincewirth@earthlink.net (Vince Wirth)
Newsgroups: rec.outdoors.rv-travel
Subject: Re: refrigerators
Message-ID: <3cda94e9.6695513@news.earthlink.net>
Date: Thu, 09 May 2002 15:25:32 GMT

On Thu, 09 May 2002 04:08:03 -0400, Neon John <johngdDONTYOUDARE@bellsouth.net>
wrote:

>Before I learned better, early in my catering career, I used dry ice in
>coolers to transport food (after I learned better, I used electric upright
>freezers operated from either inverters or generators, depending on the
>application.)  Dry ice is a bitch you probably don't want to court.

John,
I agree 100%. Let me tell you how I learned Dry Ice is a bitch.

I was in Florida for a Launch in 1969 and had to return to
Pasadena for a meeting. My wife who stayed back here suggested
that I bring back some Florida sea food. Stuff like Rock shrimp,
regular shrimp and other - only in Florida stuff-.

I decided that I could borrow a buddies leather suitcase and load it
up and fly home with it. How to keep it cold? No problem.. Just
pack some Dry ice in with the stuff. I called the Dry ice dealer in
Cocoa and asked how much and all that. The price was two bucks
a pound but there was a five pound minimum so I had to buy five
pounds.

I borrowed the suitcase, bought the Sea food and purchased the
Dry Ice. Back at the Motel I lined the suitcase with crumpled
news paper and stacked in some of the food. I then added some
of the Dry ice. added more food and a bit more ice. I used up
about one pound of ice in the process. When I was done, I looked
at the remaining ice and could not bring myself to junking it. ($8).
SO, I added the remaining ice to the package.

All was well until the Los Angeles Airport. I was waiting for my
luggage at the baggage turnstile where the bags come down a
conveyer belt from above. As I was watching, This chunk of ice
with vapor trailing comes down. Yep, My Sea food. The
suit case was covered with ice and frozen solid. If this happened
in today's security environment, I would still be waiting to get out.

After paying the Ex- buddy $200 for his leather suit case, I came
out short on the deal. I could have gone to the local fish store
and came out ahead but then I would not have this memory. As they
say the only thing you take with you are your memories

Vince

From: John De Armond
Newsgroups: rec.outdoors.rv-travel
Subject: Re: dry ice or wet ice
Date: Sat, 29 May 2004 01:55:30 -0400
Message-ID: <t39gb01hgstl52ukpm34nbot6uk66apmtv@4ax.com>

On Sat, 29 May 2004 02:19:09 GMT, John <John@nospam.net> wrote:

>Brian Elfert wrote:
>
>> Dry ice will usually last longer.  It will certainly cool better.
>>
>> Dry ice is really only good for frozen stuff as dry ice will cool to well
>> below zero.  It will freeze everything.
>>
>>
>> Brian Elfert
>
>I'm guessing that reducing the amount of dry ice in a given space will
>limit its ability to reduce the temp too far below 32F.  I see some
>experimenting coming up!

Insulating the dry ice does the same thing.  On the occasion that my large
walk-in freezer goes down (always on a Friday night), I load up on a couple
hundred pounds of dry ice to carry me through til repairs are made.

My vendor supplies it in 5 lb blocks wrapped in kraft paper.  I stack the ice
on the top shelves of the freezer ("cold" goes down) and remove only enough
kraft paper to get the desired refrigeration effect.  The thermostat controls
the fans in the air handling unit.  I leave that active, as circulating the
air improves the heat transfer and thus the refrigeration.  Fan on == more
cooling.

This setup can carry the freezer for 3 days or more if the doors aren't opened
too often.

I personally would not fool with dry ice unless the refrigerated items need to
remain deeply frozen.  Too much hassle.  Like Vince reported, the stuff grows
a huge head of frost if exposed to the air.  That leaves everything water
logged.  The CO2 infiltration will alter the taste of unsealed, unfrozen
foodstuffs.  Finally, the dry ice will crack the liner of your ice chest if it
touches it.

John