A really odd refrigeration challange
 

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

A really odd refrigeration challange
 

Glenn Ashmore wrote:
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.

Stainless steel might work better. Many restaurants use a cooler to
pre-cool the carbonated water and the syrup for fountain pop. This uses
a bath of water as a "cold bank" and a set of coils for the product and
another set to keep everything cool. You could probably find a setup
like this in a used restaurant equipment store cheaply. They last forever.
--

If you don't go there, you will never know what is there.

I ain't looking for trouble,.....but you can find it here.

A really odd refrigeration challange
 

What would cause the Al to corrode? You have relatively pure fresh
water. Trying to think if I've seen any examples of Al in fresh water
part time, but nothing comes to mind.

Hmm. On second thought. Al siding and gutters seems to survive pretty
well, but that mostly has paint on it. Al is widely used as lightweight
flashing and although I would personally use something else, there have
been no code restrictions or other gross problems with it as far as I
know. That usually means that the product can give expected service
provided it's installed well, and that would means that 26gauge Al
provides at least 5 years of exterior service, probably much more since
roofing is usually guarranteed for 20 years or more.

Rufus


Glenn Ashmore wrote:
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.

A really odd refrigeration challange
 

A totally "off the wall" idea that has some basis in actual operation.

I forget but seem to think that you'll have a pretty good refrigeration
system on board.

If so, why not have a closed loop heat-exchange system, charged with
food grade glycol (my memory fails me, I can't recall if that is
Ethylene or Propylene Glycol) /water mixture, circulated by a small
pump, and running between your inside freezer section and this cockpit
mounted idea. Circulation rate does not need to be very great, just
sufficient to keep the liquid moving.

If you used heavy wall poly tubing between the two cold spaces you
wouldn't lose toooo much effect along the way. Use copper inside the
two boxes. Having the cockpit box initially filled with ice will greatly
lessen the induced load on the freezer.

We used to use a similar system on some fishing trawlers in NZ many
years ago. Worked well to keep a water slurry cold for long periods.

Brian Cleverly


Glenn Ashmore wrote:

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

Glen, Check this out http://www.marineair.com/marineair/pdfs/evap.pdf

From the author of four 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.

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

Richard Kollmann wrote:
Glen, Check this out http://www.marineair.com/marineair/pdfs/evap.pdf

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

Hey, Hey! I knew you would come up with something. Looking at the
specs for those plates though made me go back and figure the BTU loads.
Drink coolers are a real challange. Not only do they gain heat at the
same rate or faster than a frige but they are constantly opened and
closed and being loaded daily with more warm drinks. Also in the
cockpit they get a lot of radiation load. OTOH, being full of cold
water it will not gain as much heat every time it is opened.

Roughly figuring a 2.1 cu.ft. box (14Wx12Hx22L or about 10 sq ft of
surface) with 3" of foam (R=16) will gain about 600 BTU/day with a 40F
delta-T. Half again that at least for frequent openining and radiation
load so say a 900-1,000 BTU/day base. A case of beer weighs about 20
lbs and to get it from 75F to 42F will require an additional 660 BTUs.
Figuring a case and a half of drinks a day for a crew of 6 makes about
1,000 BTUs. All totaled that will be about 2,000 BTU/day or close to 80
BTU/Hr. If I stock it each evening the load should stay pretty steady
between 70 and 90 BTU/Hr. To maintain the box at about 40F the coil will
have to be running about 26F. That would make a BD35 at 2,500 RPM run
about 15-20 minutes an hour on average. That would be OK for the
compressor but I would be pushing the evaporator at a rate of about 270
BTU/Hr. I don't see how I can do that with those plates.

--
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

How about a compressor cooler like the ones Waeco sells? They take a bit of
power (30 Ah ?) but can be turned off and they will be a handy backup. They can
even be switched to freezer mode and used in a car.


http://www.waecoadlerbarbour.com/


"Glenn Ashmore" wrote in message
news:K_pTc.28301$Jo1.18335@lakeread01...


Richard Kollmann wrote:
Glen, Check this out http://www.marineair.com/marineair/pdfs/evap.pdf

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

Hey, Hey! I knew you would come up with something. Looking at the
specs for those plates though made me go back and figure the BTU loads.
Drink coolers are a real challange. Not only do they gain heat at the
same rate or faster than a frige but they are constantly opened and
closed and being loaded daily with more warm drinks. Also in the
cockpit they get a lot of radiation load. OTOH, being full of cold
water it will not gain as much heat every time it is opened.

Roughly figuring a 2.1 cu.ft. box (14Wx12Hx22L or about 10 sq ft of
surface) with 3" of foam (R=16) will gain about 600 BTU/day with a 40F
delta-T. Half again that at least for frequent openining and radiation
load so say a 900-1,000 BTU/day base. A case of beer weighs about 20
lbs and to get it from 75F to 42F will require an additional 660 BTUs.
Figuring a case and a half of drinks a day for a crew of 6 makes about
1,000 BTUs. All totaled that will be about 2,000 BTU/day or close to 80
BTU/Hr. If I stock it each evening the load should stay pretty steady
between 70 and 90 BTU/Hr. To maintain the box at about 40F the coil will
have to be running about 26F. That would make a BD35 at 2,500 RPM run
about 15-20 minutes an hour on average. That would be OK for the
compressor but I would be pushing the evaporator at a rate of about 270
BTU/Hr. I don't see how I can do that with those plates.

--
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,

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" 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