Ice Box

[Danno]

I've been using a Coleman cooler & block ice since last August to
refridgerate my food, and it has worked fairly well so far. Now that
winter's over, and I am back to purchasing ice blocks again, I am looking
to extend the time in which the ice stays solid. Obviously, I would prefer
to extend this time significantly, but even a 25% extension would be good.
My first notion was to build a new chest, put maybe 15 or 20 cm (more?) of
styrofoam insulation for the walls & base, line it with plastic/fibreglass
metal, and seal it with perhaps 10 cm of foam for the lid. There are
several informative online articles, primarily by boat builders, it does
not seem like an endeavour beyond my ablities & means. It has occured to
me, though, that I might be able to simply build an insulated case large
enough to encompass my current cooler. I like this idea, because the notion
of lining a custom made box seems like the most difficult part of the task.
I am wondering if, using this approach, I would still reap the benefits of
thick insulation, or would the presence of the other material (plastic etc)
comprising the cooler, then interacting with the air caught inside the
insulated case, render the thermal benefits meaningless? Wouldn't the
temperature inside the case have to equal the temperature inside the cooler
in order to stop the transfer of heat? I think that removing the amount of
air between the liner and the insulation would increase the box's
efficiency (like a thermos)?
Does this sound right? Thanks for any insight/opinions.

 

[ptaylor]

I've been using a Coleman cooler & block ice since last August to
refridgerate my food, and it has worked fairly well so far. Now that
winter's over, and I am back to purchasing ice blocks again, I am looking
to extend the time in which the ice stays solid. Obviously, I would prefer
to extend this time significantly, but even a 25% extension would be good.
My first notion was to build a new chest, put maybe 15 or 20 cm (more?) of
styrofoam insulation for the walls & base, line it with plastic/fibreglass
metal, and seal it with perhaps 10 cm of foam for the lid. There are
several informative online articles, primarily by boat builders, it does
not seem like an endeavour beyond my ablities & means. It has occured to
me, though, that I might be able to simply build an insulated case large
enough to encompass my current cooler. I like this idea, because the notion
of lining a custom made box seems like the most difficult part of the task.
I am wondering if, using this approach, I would still reap the benefits of
thick insulation, or would the presence of the other material (plastic etc)
comprising the cooler, then interacting with the air caught inside the
insulated case, render the thermal benefits meaningless? Wouldn't the
temperature inside the case have to equal the temperature inside the cooler
in order to stop the transfer of heat? I think that removing the amount of
air between the liner and the insulation would increase the box's
efficiency (like a thermos)?
Does this sound right? Thanks for any insight/opinions.

You could try throwing in some dry ice,if you can get it where you
are.In most big citys you can get it at larger grogery stores,if you ask
nicely..(There's a place here that sells it most of the summer.)
A better insulated box would probably help as well.Maybe wrapping the
Coleman with extra insulation would help?
Keeping it somewhere cool,like a basement or something should help a bit
also.
With regular refridgerators,it's better to keep them well stocked,as the
thermal mass of everything in there will "hold" the cold inside,rather
than just having a bunch of "deadspace" full of cold air that will fall
out on the floor everytime you open it,thus kicking on the
compressor,each time you open the door.
Keeping your icebox full will help,maybe get some bags of ice cubes to
throw over the top to fill in the air pockets,and whatnot..

 

[[email protected]]

I've been using a Coleman cooler & block ice since last August to
refridgerate my food, and it has worked fairly well so far. Now that
winter's over, and I am back to purchasing ice blocks again, I am looking
to extend the time in which the ice stays solid...
My first notion was to build a new chest, put maybe 15 or 20 cm (more?) of
styrofoam insulation for the walls & base, line it with plastic/fibreglass
metal, and seal it with perhaps 10 cm of foam for the lid... It has occured
to me, though, that I might be able to simply build an insulated case large
enough to encompass my current cooler.

Sounds easier...

I am wondering if, using this approach, I would still reap the benefits of
thick insulation...

Sure. If your cooler were 1'x2'x1' tall, with R4 insulation (1" of white
foamboard) and you put it into a 4" thick box made with 3 layers of Atlas
Energy Shield 1" double-foil "R7.2" insulation with 1/4" plywood spacers,
the bottom 4 air spaces would have an R-value of about 6, so the bottom
would have a thermal conductance of 2 ft^2/(4+3x7.2+6) = 0.0633 Btu/h-F.
The top and side air spaces would have an R-value of about 10, making
the top and side conductance 8 ft^2/(4+3x7.2+10) = 0.2247, for a total
of 0.288 Btu/h-F.

It takes 144 Btu to melt a pound of ice, so 25 pounds could cool for h hours
in a 70 F room, where 25x144 = h(70-32)0.288, so h = 329 hours, or 13.7 days,
if it's seldom opened.

Nick

 

[Dale Farmer]

I've been using a Coleman cooler & block ice since last August to
refridgerate my food, and it has worked fairly well so far. Now that
winter's over, and I am back to purchasing ice blocks again, I am looking
to extend the time in which the ice stays solid. Obviously, I would prefer
to extend this time significantly, but even a 25% extension would be good.
My first notion was to build a new chest, put maybe 15 or 20 cm (more?) of
styrofoam insulation for the walls & base, line it with plastic/fibreglass
metal, and seal it with perhaps 10 cm of foam for the lid. There are
several informative online articles, primarily by boat builders, it does
not seem like an endeavour beyond my ablities & means. It has occured to
me, though, that I might be able to simply build an insulated case large
enough to encompass my current cooler. I like this idea, because the notion
of lining a custom made box seems like the most difficult part of the task.
I am wondering if, using this approach, I would still reap the benefits of
thick insulation, or would the presence of the other material (plastic etc)
comprising the cooler, then interacting with the air caught inside the
insulated case, render the thermal benefits meaningless? Wouldn't the
temperature inside the case have to equal the temperature inside the cooler
in order to stop the transfer of heat? I think that removing the amount of
air between the liner and the insulation would increase the box's
efficiency (like a thermos)?
Does this sound right? Thanks for any insight/opinions.

As a general rule, more insulation is better. But you also need to allow
the heat to escape from any active cooling elements. Other things to do
are to keep the fridge compartment as full as possible, giving you more
thermal mass. Put in things that have been pre-cooled. I.e.. a dish full of
leftover lasagna should be allowed to cool to room temperature before
being put into the fridge.
Things with top open lids rather than doors that open on the front are
more efficient, as the cold air will tend to stay in the cooler rather than
spill out. If you have enough stuff, a couple of smaller coolers that you
sort stuff into by frequency of use. Keep the milk, butter, and other
things you are constantly using in a smaller fridge, less frequently used
items go into the other fridge. Think ahead, don't go rummaging through
browsing, but decide what you are going to get, open, grab and close
quickly.
Dry ice is a lot more cold per pound, check with local sources for
pricing. It is dangerous, so take care you don't hurt yourself or your
fridge with it.

--Dale

 

[William P.N. Smith]

I've been using a Coleman cooler & block ice since last August to

You might look at the Igloo line, they have a series of models that
are a bit smaller on the inside, but "keep ice for 5 days" due to
thicker insulation.

[Yeah, any additional insulation will help. Anyone know if you should
drain the water or leave it in to keep drinks cooler longer?]

 

[Ecnerwal]

It has occured to
me, though, that I might be able to simply build an insulated case large
enough to encompass my current cooler. I like this idea, because the notion
of lining a custom made box seems like the most difficult part of the task.
I am wondering if, using this approach, I would still reap the benefits of
thick insulation,

Yes. Just seal the foam overbox well to reduce air leaks - spray-can
foam wourks well to make tight joints in rigid sheet foam. You can foam
the cooler into place if you like, though it will be easier to clean if
it can be removed, I'd think. Build carefully to get a nice snug joint
for the lid you need to open on top.

Wouldn't the
temperature inside the case have to equal the temperature inside the cooler
in order to stop the transfer of heat?

Heat transfer won't _stop_ as long a the inside of the cooler is warmer
than the room. With additonal insulation it _will_ slow down, by having
the outside of the cooler being an intermediate temperature lower than
the room air and higher than the inside of the cooler. If you use a lot
of insulation, it will be quite effective at greatly slowing down heat
transfer.

I think that removing the amount of
air between the liner and the insulation would increase the box's
efficiency (like a thermos)?

Not practical, don't go there. Fill it with spray can foam if it makes
you feel better.

Figuring the average cooler as an inch (2.5 cm) of rigid foam, a 1"
(2.5cm) overbox should get you twice as long on a block of ice (except
that it won't _actually_ be that much better, due to opening the thing
to use it). 5 cm should get you 3 times as long, 10 cm 5 times as long,
20 cm 9 times as long. If your cooler is thicker, adjust the estimates
(total thickness of foam including cooler/original thickness of cooler
foam).

 

[Ecnerwal]

[Yeah, any additional insulation will help. Anyone know if you should
drain the water or leave it in to keep drinks cooler longer?]

The only reason to drain it would be to make room for more ice, or to
keep your sandwiches from getting soaked (and a waterproof box will do
that). Otherwise it's thermal mass which is cold (it's not doing
anything to make the cooler cooler, but it does help to keep it from
getting warmer, especially when you open the top to get another
beverage).

 

[Roland Mösl]

I've been using a Coleman cooler & block ice since last August to

refridgerate my food, and it has worked fairly well so far. Now that
winter's over, and I am back to purchasing ice blocks again, I am looking
to extend the time in which the ice stays solid.

What are You talking about?

You seem to write this 2004, but describe something from 1904
or so.

Take a high efficient refrigerator with vakkuum insulation
and some solar panels.

Where are we, or better in what century to use ice blocks ?!?

 

[William P.N. Smith]

Where are we, or better in what century to use ice blocks ?!?

Many boaters still use ice as their primary refrigeration. It's a
very compact cooling source, and maintains the perfect temperature for
refrigeration...

 

[Danno]

Danno wrote:

Thanks for any insight/opinions.

Thanks for the responses, think I'll go with encapsulating the cooler for
now. Sounds like even just lining and sealing the base and three walls (so
I can keep the drain plug usable) will work reasonably well. Guess a bit of
experimentation is in order now <grin>.
I've tried using dry ice, but it freezes things like milk and meat, and
it sublimates too fast to make it useful/cost-effective for plain
refridgeration. I had often wondered about encasing, say a 3" cube of dry
ice inside a 10" cube of water ice, if that would keep the water ice solid
for longer, and control the subilmation at the same time?
Time to go looking at foam insulation, thanks again to everyone who
responded, appreciate it.

 

[Danno]

Sure. If your cooler were 1'x2'x1' tall, with R4 insulation (1" of white
foamboard) and you put it into a 4" thick box made with 3 layers of Atlas
Energy Shield 1" double-foil "R7.2" insulation with 1/4" plywood spacers,
the bottom 4 air spaces would have an R-value of about 6, so the bottom
would have a thermal conductance of 2 ft^2/(4+3x7.2+6) = 0.0633 Btu/h-F.
The top and side air spaces would have an R-value of about 10, making
the top and side conductance 8 ft^2/(4+3x7.2+10) = 0.2247, for a total
of 0.288 Btu/h-F.

It takes 144 Btu to melt a pound of ice, so 25 pounds could cool for h
hours in a 70 F room, where 25x144 = h(70-32)0.288, so h = 329 hours, or
13.7 days, if it's seldom opened.

Nick

Somehow, I get the impression you've done this before <grin>...
Thanks for the formula. Is it important to have an air space between each
layer of Atlas Energy Shield 1" double-foil. I had thought I would just
stack rigid foam sheets on top of each other, to increase the R-value.

 

[Danno]

What are You talking about?

Keeping perishable food cool.

You seem to write this 2004, but describe something from 1904
or so.

I admit, my "inspiration" was an old photograph from the city archives of
residents harvesting ice off the river. Worked then, works now, is
especially energy efficient in the winter. Kinda like my bicycle. Seems
most everyone has hooked into the automobile technology for their
transportation solution(s), even when a bike is a better answer.

Take a high efficient refrigerator with vakkuum insulation
and some solar panels.
Where are we, or better in what century to use ice blocks ?!?

Well, my power generating capability consists of precisely one 75 watt
panel mounted on a west-facing wall. While I would like to run an efficient
refridgerator off my 150Ah battery pack, it just isn't going to happen.
That energy is already consumed completely, refridgerating with it is too
great a tax on it.
I have a commercial ice vendor ~15 minutes' ride away, I can purchase two
4kg blocks of water ice for three bucks and get them in the cooler in under
1/2 hour. If I can stretch their usability out to, say, two weeks, that's 6
bucks a month for 6 or 7 months a year, maybe $50 a year and a bit of
cycling. Perhaps, over a decade or two, a solar-based refridgeration system
might yield savings for me, but it just doesn't fit my circumstance -
physically or financially.

 

[Danno]

You might look at the Igloo line, they have a series of models that
are a bit smaller on the inside, but "keep ice for 5 days" due to
thicker insulation.

My Coleman Xtreme (50-something litres) was advertised the same way (5
days), probably the same manunfacturer with a different branding. I have
been quite pleased with mine so far, it is sturdy and the drain plug is
convenient, although the 8kg of ice blocks melt in about 4 days when the
temperature breaks 30C+. I bet it keeps ice on average between 5 and 6
days, over summer/autumn autumn last year.

 

[Roland Mösl]

Well, my power generating capability consists of precisely one 75 watt

panel mounted on a west-facing wall. While I would like to run an efficient
refridgerator off my 150Ah battery pack, it just isn't going to happen.
That energy is already consumed completely, refridgerating with it is too
great a tax on it.
I have a commercial ice vendor ~15 minutes' ride away, I can purchase two
4kg blocks of water ice for three bucks and get them in the cooler in under
1/2 hour. If I can stretch their usability out to, say, two weeks, that's 6
bucks a month for 6 or 7 months a year, maybe $50 a year and a bit of
cycling. Perhaps, over a decade or two, a solar-based refridgeration system
might yield savings for me, but it just doesn't fit my circumstance -
physically or financially.

With what sort of computer are You writing this?

 

[Danno]

Roland Mösl wrote:

With what sort of computer are You writing this?

A computer that is hooked into the grid. The sun is out high enough, long
enough, that I am once again almost able to start generating enough
electricity to fully unplug again. I have to plug in for the winter, so I
use the "good" PCs, but I am slowly working towards electrical
independence. I am hoping to have everything unplugged by the end of April.

 

[[email protected]]

Is it important to have an air space between each layer of Atlas Energy
Shield 1" double-foil.

Each airspace adds about R2 to the foil's R7.2, and the plywood strips
can make the enclosure stronger, with a few nuts and bolts...

Nick

 

[Roland Mösl]

With what sort of computer are You writing this?

A computer that is hooked into the grid. The sun is out high enough, long
enough, that I am once again almost able to start generating enough
electricity to fully unplug again. I have to plug in for the winter, so I
use the "good" PCs, but I am slowly working towards electrical
independence. I am hoping to have everything unplugged by the end of

April.

Change to a notebook.

This brings more than 100 W more solar cells.
A desktop wit CRT is a huge energy waster.

I make also studies for development countries with off grid villages.

The first items to establish a high living standard

High efficiency refrigerator with vakkuum insulation
Notebook as universal communication device
light
all powered by a 12V DC solar system

 

[Danno]

what a coincidence, I had been talking over a similar issue with a
friend, we do an annual desert trip for a couple of weeks a year,
there is a low-tech device engineered by a man named Mohammed Bah
Abba. You may google his name as an exact phrase to get the
pertinents... galeon dosen't like the Rolex site, maybe a poorly
scripted shockwave page
a synopsis can be found at
http://hinterlands.cc/index.php?showtopic=30
Could be worth a shot.

Wow, that is neat! I wonder what inside temperature (difference) it is
able to maintain? I'm told 7 degrees Celcius is the desired maximum
temperature I would want, 0 or 1 the minimum. Think perhaps I'll build a
smaller version, drop a thermometer in, see what it does. Wonder if I
really need to line it with sand, or if pure water would cool more
effectively... I had considered cooling with water, but my notion was to
put cold water, once or twice a day, into my (sealed) cooler. Wasn't sure
how effective that would be during mid-summer, as the "cold" water tap in
my apartment warmed up. The cooling properties of evaporation never occured
to me...
http://lehmans.com/shopping/product
detailmain.jsp?itemID=3167&itemType=PRODUCT&RS=1&keyword=water+cooler

http://www.teachers.ash.org.au/ceoteach/Federation/LearningAreas/science
coolgardie_safe/coolgardie_safe.htm

Thanks for the most excellent lead. (BTW Firefox under KDE is OK with the
main flash site).

 

[Dale Farmer]

I've tried using dry ice, but it freezes things like milk and meat, and
it sublimates too fast to make it useful/cost-effective for plain
refridgeration. I had often wondered about encasing, say a 3" cube of dry
ice inside a 10" cube of water ice, if that would keep the water ice solid
for longer, and control the subilmation at the same time?
Time to go looking at foam insulation, thanks again to everyone who
responded, appreciate it.

No! Bad idea. This is a recipe for a low power bomb. You could
add some dry ice to the top of the existing partially melted water ice block to

stretch out your water ice time. Or leave the drain plug in to the ice
compartment and toss in some dry ice to the meltwater to refreeze it. ( This
won't form a bomb as the escaping gas will keep venting keeping it safer. )


--Dale

 

[daestrom]

Each airspace adds about R2 to the foil's R7.2, and the plywood strips
can make the enclosure stronger, with a few nuts and bolts...

But be sure it is a 'dead' air space. If it allows air from the room to
circulate through the space between the cooler and extra insulation, it
negates the effectiveness of the extra insulation.

daestrom