If cooling the drinks fast is your goal thaen this approach will work.
But once the ice has melted, then the refrigeration will be working
much harder than usual to keep both the drinks and the large volume
of water cold. Better to turn on the fridge, add the drinks and ice
but let the water drain off as it melts.

Doug
s/v Callista

"Glenn Ashmore" wrote in message
news:07aTc.27910$Jo1.1742@lakeread01...
On our recent BVI cruise I started thinking about cockpit drink coolers.
The beneteau 505 has a very poorly insulated cooler in the cockpit
table that is a total waste of ice. RUTU, being derived from a modern
high performance design, has a very wide fairly shallow cockpit. It
will need foot rests to keep braced in the seats on a heel. I am
thinking about building a perminent heavily insulated box down the
center. It could also be used as a seat at anchor when the table is
folded up and the cushion would serve as additional insulation.

Now the question is how to keep it cold. I am thinking that a small
evaporator type system would work. Drinks cool fastest in water so
stocking originally with drinks and ice would provide the water. Once
the ice melts the evaporator would maintain the temperature and the
water would serve as a heat sink.

What I am worried about is that the aluminum evaporator would corrode
rather quickly constantly submerged in water. I am wondering if several
loops of copper tube might make a better evaporator.

--
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

I used to think that but the Coleman cooler people did a lot of research
on this controversy. The new Xtreme coole I bought for the trip came
with a little booklet about how to stock a cooler. They are saying that
as long as there is a little ice remaining before restocking to leave
the water in the box. The other thing is that water does not escape
when the lid is opened the way cold air will so the total heat gain will
be less.

BTW, the new Coleman Ultra Xtreme coolers do work. We used about 2/3rds
the ice this year over 10 days in the BVI as we did last year in a week.
As to whether they keep ice for 7 days as advertised, maybe in
Minnesota but not in the Virgin Islands. :-)

Doug Dotson wrote:

If cooling the drinks fast is your goal thaen this approach will work.
But once the ice has melted, then the refrigeration will be working
much harder than usual to keep both the drinks and the large volume
of water cold. Better to turn on the fridge, add the drinks and ice
but let the water drain off as it melts.

Doug
s/v Callista

--
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

I guess that depends upon the lid configuration and how often it
is opened. I have a Coleman Extreme and find the ice lasts alot
longer if you drain off the excess water. Perhaps leaving a little in bottom
is a good idea. I tend to rely on the laws of physics rather than
ad hype from vendors.

Doug
s/v Callista

"Glenn Ashmore" wrote in message
news:ZvqTc.28303$Jo1.5448@lakeread01...
I used to think that but the Coleman cooler people did a lot of research
on this controversy. The new Xtreme coole I bought for the trip came
with a little booklet about how to stock a cooler. They are saying that
as long as there is a little ice remaining before restocking to leave
the water in the box. The other thing is that water does not escape
when the lid is opened the way cold air will so the total heat gain will
be less.

BTW, the new Coleman Ultra Xtreme coolers do work. We used about 2/3rds
the ice this year over 10 days in the BVI as we did last year in a week.
As to whether they keep ice for 7 days as advertised, maybe in
Minnesota but not in the Virgin Islands. :-)

Doug Dotson wrote:

If cooling the drinks fast is your goal thaen this approach will work.
But once the ice has melted, then the refrigeration will be working
much harder than usual to keep both the drinks and the large volume
of water cold. Better to turn on the fridge, add the drinks and ice
but let the water drain off as it melts.

Doug
s/v Callista

--
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

Doug Dotson wrote:

I guess that depends upon the lid configuration and how often it
is opened. I have a Coleman Extreme and find the ice lasts alot
longer if you drain off the excess water. Perhaps leaving a little in bottom
is a good idea. I tend to rely on the laws of physics rather than
ad hype from vendors.

Doug
s/v Callista

Coleman isn't the only source of that information. Hormel provides a
camping tips booklet that says the same thing as did an article last
year in Trailer Sailor. There is definitely some good physics behind
the principle.

As long as the water is close to the target temperature of the box,
there are several advantages over a dry box, especially when the box is
refrigerated.

Basically the heat enters the box by adding warm drinks, allowing warm
air in when the box is opened or through the outer surfaces. There is
not much you can do about adding warm drinks except cut back on the beer
consumption but by reducing the amount of warm air that can get in heat
gained due to opening can be minimized.

The speed heat comes through the sides is directly related to the
difference between the inside surface of the box and the outside. It
does not matter if the box is full of water or air. As long as the
difference in temperature is the same. The evaporator coils are close
to the inside surface and will operate at a temperature about 10-15º
below the target temperature of the box. Water transfers the heat from
warm drinks to the coils faster than air so the temperature is more even
all over the box. If there is no water move the heat quickly the inside
surfaces next to the coils will get much colder which increases the rate
that the heat will come through the sides.

The compressor WILL run longer with the box full of water to cool the
box the same amount but it will run less often once it reaches the
target temperature. Net result is an overall energy savings.

Here is a pretty good explination using ice only but the effects
described are magnified with a refrigerated box:
http://www.madsci.org/posts/archives...3228.Ph.r.html

--
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

Glenn, here's a solution complicated enough to appeal to you ;-):

Let the cold box drain into another insulated tank/box whose function is to
pre-chill warm beers. You could get every last BTU out of that ice before it's
drained.
Don't some air heat exchangers work this way?

Jim,

Really like that solution for ice boxes. Have always hated to discard ice
cold water, and prechilling the beer will certainly help out ice life.
All those who stayed awake during high-school physics will recognize that
adding 4 cans of beer to an ice box will result in the melting of a beer can
sized block of ice - even without any heat transmission through the walls or
floor of the box. Cool your beer first, and you might be able to put a dozen
in for the same ice use. Thats energy conservation where it counts!

surfnturf

"Jim Conlin" wrote in message
...
Glenn, here's a solution complicated enough to appeal to you ;-):

Let the cold box drain into another insulated tank/box whose function is
to
pre-chill warm beers. You could get every last BTU out of that ice before
it's
drained.
Don't some air heat exchangers work this way?

Interesting. I'll have to read up on this some more. I suppose the same
principle won't work well in the freezer box

Doug
s/v Callista

"Glenn Ashmore" wrote in message
news:JVvTc.28578$Jo1.27533@lakeread01...


Doug Dotson wrote:

I guess that depends upon the lid configuration and how often it
is opened. I have a Coleman Extreme and find the ice lasts alot
longer if you drain off the excess water. Perhaps leaving a little in
bottom
is a good idea. I tend to rely on the laws of physics rather than
ad hype from vendors.

Doug
s/v Callista

Coleman isn't the only source of that information. Hormel provides a
camping tips booklet that says the same thing as did an article last
year in Trailer Sailor. There is definitely some good physics behind
the principle.

As long as the water is close to the target temperature of the box,
there are several advantages over a dry box, especially when the box is
refrigerated.

Basically the heat enters the box by adding warm drinks, allowing warm
air in when the box is opened or through the outer surfaces. There is
not much you can do about adding warm drinks except cut back on the beer
consumption but by reducing the amount of warm air that can get in heat
gained due to opening can be minimized.

The speed heat comes through the sides is directly related to the
difference between the inside surface of the box and the outside. It
does not matter if the box is full of water or air. As long as the
difference in temperature is the same. The evaporator coils are close
to the inside surface and will operate at a temperature about 10-15º
below the target temperature of the box. Water transfers the heat from
warm drinks to the coils faster than air so the temperature is more even
all over the box. If there is no water move the heat quickly the inside
surfaces next to the coils will get much colder which increases the rate
that the heat will come through the sides.

The compressor WILL run longer with the box full of water to cool the
box the same amount but it will run less often once it reaches the
target temperature. Net result is an overall energy savings.

Here is a pretty good explination using ice only but the effects
described are magnified with a refrigerated box:
http://www.madsci.org/posts/archives...3228.Ph.r.html

--
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