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.

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

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