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  #11   Report Post  
Doug Dotson
 
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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



  #12   Report Post  
Glenn Ashmore
 
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I would not keep it completely full of melt and by making it relatively
narrow fore and aft the level can still be fairly high without spilling.

auerbach wrote:

Glenn,

You say "It will need foot rests to keep braced in the seats on a heel."
Won't melt-water in your cooler spill out on when your boat heels?

Alex


--
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

  #13   Report Post  
Glenn Ashmore
 
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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

  #14   Report Post  
Jim Conlin
 
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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?


  #15   Report Post  
Doug Dotson
 
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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





  #16   Report Post  
surfnturf
 
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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?




  #17   Report Post  
Ron White
 
Posts: n/a
Default

Another option would be the kiss aproach.
Maybe build a nice combing that is sized to contain an ice chest. You can
buy a big cheap one like the 120 igloo that sells at sam's for under $40 or
you could go for a really nice expensive ice chest, like the Icey-Tek,
www.icey-tek.com . Friends tell me these are great.( I like the big and
cheap). If you really hate using ice, you could put a 12V power plug in the
combing and use a thermoelectric cooler, Igoo , Coleman ect .


--
Ron White
Boat building web address is
www.concentric.net/~knotreel


  #18   Report Post  
Richard Kollmann
 
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Glen, there are three proven way to build the system you are looking
for:

1. Install a full length stainless steel holding plate in an insulated
box, it can be used as a dry box or a wet box. See picture on front
page of my web site, this box's holding plate is connected to a
Danfoss BD2.5 compressor. The purpose of the plate in this cooler is
to act as a flywheel affect of energy when warm product is put in the
box.
2. The same insulated box can be cooled by a plain copper tube coil
attached to interior wall. When I did fish hold box designs I used
stainless tubing with tubing above and below the water.
3. Either one of the above concepts can be used with an existing large
refrigeration system by splitting the refrigerant flow.

I have system #1 in one of my boats and system #3 in the other.

Glen here is a concept using a Danfoss BD50 air cooled condensing
unit, and 50 ft. of ¼ inch tubing as an evaporator coil, A receiver
and expansion valve instead of a capillary tube.

This combination in a drink cooler with a 30 degree evaporator
temperature might deliver 790 btu. Per hour. ( Danfoss ASHRAE
Capacity chart with compressor running at 3500 rpm ). I would also
install a manual speed selector switch to adjust compressor speed for
current box demand.

From the author of books on boat refrigeration
http://www.kollmann-marine.com


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.

  #19   Report Post  
Glenn Ashmore
 
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#2 is the idea I am leaning towards. I have room to mount an air cooled
BD50 directly below the box with plenty of ventilation.

Couple of things still have me stalled. I would like to use .192" ID
stainless tube which should stand up better to bumps with cans and
corrosion but the thermal conductivity is a lot lower than copper. I
could compensate by going to .335" ID but that might slow down the
refrigerant to much to push the oil through. Think I will stick with
..192" and adjust the expansion valve and compressor speed.

The other thing is probably that I am not reading the charts right but I
can't figure out which orifice to use in the Danfoss expansion valve.
They all look to large for the BD50.

BTW, have you revised the DIY book? I have about worn my copy and the
Calder book out. :-)

Richard Kollmann wrote:
Glen, there are three proven way to build the system you are looking
for:

1. Install a full length stainless steel holding plate in an insulated
box, it can be used as a dry box or a wet box. See picture on front
page of my web site, this box's holding plate is connected to a
Danfoss BD2.5 compressor. The purpose of the plate in this cooler is
to act as a flywheel affect of energy when warm product is put in the
box.
2. The same insulated box can be cooled by a plain copper tube coil
attached to interior wall. When I did fish hold box designs I used
stainless tubing with tubing above and below the water.
3. Either one of the above concepts can be used with an existing large
refrigeration system by splitting the refrigerant flow.

I have system #1 in one of my boats and system #3 in the other.

Glen here is a concept using a Danfoss BD50 air cooled condensing
unit, and 50 ft. of ¼ inch tubing as an evaporator coil, A receiver
and expansion valve instead of a capillary tube.

This combination in a drink cooler with a 30 degree evaporator
temperature might deliver 790 btu. Per hour. ( Danfoss ASHRAE
Capacity chart with compressor running at 3500 rpm ). I would also
install a manual speed selector switch to adjust compressor speed for
current box demand.

From the author of books on boat refrigeration
http://www.kollmann-marine.com


--
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

  #20   Report Post  
Richard Kollmann
 
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Refrigeration tubing is measured in OD and ¼ OD is .192 in. ID. Many
home built systems make the mistake of using tubing that is too large
in their systems. All refrigeration compressors require a return
suction gas temperature of from 60 to 90 degrees F. for compressor
cooling. Compressors also rely on a reasonable gas velocity through
the system to return the oil. You could get by with 5/16 OD tubing,
but I would not run the system set to a very low temperatures.

You are correct about tube damage in the box, there must be some type
of a guard to protect it.
I ounce did a system for a crab fisherman in Alaska and he put a live
fish inside that punch a hole in the refrigerant tubing.

When you want variable capacity with the BD50 in the case of your
purposed system I would use a OX Danfoss orifice. Yes, I know the OX
is a 1500 btu orifice but as soon as it sees the cool return gas it
will adjust down.

You should have my latest Do It Yourself Book revised in 2000. And the
book you just ordered 12/24 volt Refrigeration Manual covers changes
in DC refrigeration up to 2004. I believed that revising the original
book every five years was good enough. Today with the changes in the
industry and the high cost of service I felt I should find another way
to communicate more often than five years. Book revisions, service
bulletins and typical repairs would cost too much so I elected to use
my web site as a way that book owners and others can keep up to date
with what is new in boat refrigeration. Glen if you don't find all
you need in the design section of the new book please use the new
refrigeration forum on my web site to ask your questions.
http://www.kollmann-marine.com.





Glenn Ashmore wrote in message news:vW5Uc.29891$Jo1.23863@lakeread01...
#2 is the idea I am leaning towards. I have room to mount an air cooled
BD50 directly below the box with plenty of ventilation.

Couple of things still have me stalled. I would like to use .192" ID
stainless tube which should stand up better to bumps with cans and
corrosion but the thermal conductivity is a lot lower than copper. I
could compensate by going to .335" ID but that might slow down the
refrigerant to much to push the oil through. Think I will stick with
.192" and adjust the expansion valve and compressor speed.

The other thing is probably that I am not reading the charts right but I
can't figure out which orifice to use in the Danfoss expansion valve.
They all look to large for the BD50.

BTW, have you revised the DIY book? I have about worn my copy and the
Calder book out. :-)

Richard Kollmann wrote:
Glen, there are three proven way to build the system you are looking
for:

1. Install a full length stainless steel holding plate in an insulated
box, it can be used as a dry box or a wet box. See picture on front
page of my web site, this box's holding plate is connected to a
Danfoss BD2.5 compressor. The purpose of the plate in this cooler is
to act as a flywheel affect of energy when warm product is put in the
box.
2. The same insulated box can be cooled by a plain copper tube coil
attached to interior wall. When I did fish hold box designs I used
stainless tubing with tubing above and below the water.
3. Either one of the above concepts can be used with an existing large
refrigeration system by splitting the refrigerant flow.

I have system #1 in one of my boats and system #3 in the other.

Glen here is a concept using a Danfoss BD50 air cooled condensing
unit, and 50 ft. of ¼ inch tubing as an evaporator coil, A receiver
and expansion valve instead of a capillary tube.

This combination in a drink cooler with a 30 degree evaporator
temperature might deliver 790 btu. Per hour. ( Danfoss ASHRAE
Capacity chart with compressor running at 3500 rpm ). I would also
install a manual speed selector switch to adjust compressor speed for
current box demand.

From the author of books on boat refrigeration
http://www.kollmann-marine.com

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