Again, this may be true, but it might not be appropriate for all
systems. Adding a thru-hull and more components probably isn't worth
a few Amp-hours savings.

From Richard Kollman's site:

28. Question: Why would I want air cooling when water is more efficient?

Answer: Boat refrigeration systems smaller than ¼ HP are generally
air cooled for best performance and long term reliability. There are
few conditions where the seawater cooling can out perform air cooling
on these small units. To dispose of the heat in a boat from a small
Danfoss refrigeration system is about the same as disposing of the
heat generated from one person onboard, three hundred BTUs per hour.
It is true that heat from larger refrigeration systems must use
seawater because the heat can not be disposed adequately of onboard a
boat.

http://www.kollmann-marine.com/answers.html#28


And, what kind of pump is only a half Amp? Most of the circulating
pumps for DC belt driven systems seem to take an Amp or more. The
traditional March 809, for example, is rated at 1.5 Amps. Of course,
the pump for a Danfoss system could be much smaller.

Doug Dotson wrote:
The water pump on my system draws less than 1/2 amp. Using a water-cooled
system saves enough energy to more than offset the overhead of the pump.

Doug

"Jeff" wrote in message
...

It may be true that water cooled is usually more efficient, but for a
minimal system based on a BD35, the added efficiency may not be worth the
power use of a water pump. This is a small issue with a large holding
plate system because it only runs one or two hours a day, but the small
evaporator based system may run 8 hours a day, and the water pump would
then add a lot of overhead. And, it adds a through-hull, strainer and
plumbing, and can get clogged with silt. This may be worthwhile Downeast,
where the water is 52 degrees, but might not be in the tropics.

Doug Dotson wrote:

A water-cooled unit is always more efficient than an air-cooled unit.
Unless
somehow the air temp gets cool for a long period while the water temp
stays
high. Not very common. This is why all the larger units are water-cooled.

Doug
s/v Callista


"Jeff" wrote in message
...


A lot depends on the size of your fridge and how you use it. If you can
go into a bit of detail, such as the size of the box(es), freezer
requirements, and the nature of your cruising, you might get better
advice. For example, if you cruise in cold water, a water cooled system
would be more efficient. But if you power each day (or run a genset for
A/C) then the power issues might not be important to you.

I have larger Crosby (actually part of A/B) holding plate system for a
separate fridge and freezer system that I've had a love/hate relationship
with. When I pull a steak out of the freezer that's frozen down to zero
degrees, I'm happy. But when I don't need the freezer, its a real
annoyance to use 70 to 100 Amp-hours a day on the system. And of course,
one small leak and the whole system is down. (This happened twice in 7
seasons, and both times was detected in home port, not while traveling.)

If I were building my system now, I might consider having two systems
based on the new Danfoss compressors. While perhaps not the most
efficient in total, having two systems for the two boxes would give more
flexibility in case one is lost.

Danfoss is the "hermetic" sealed compressor your A/B is based on, and is
used in most of the smaller systems today. Of course, the units have
changed in the last 20 years, and each company has some "special
technology" that makes theirs the best. You might look over
www.rparts.com to get a free education about the components in use today.
They carry the latest Danfoss units and this will give you a baseline to
see if you're getting your money's worth from whichever system you decide
on.





Dick Behan wrote:


The 20-year-old Adler/Barbour unit on our Victory Tug has expired. Can't
complain about the service, but what do you cruisers out there think
about replacing it? Go with Adler/Barbour again, or is there a more
up-to-date technology (and product) you'd recommend as superior?
TIA.

Dick Behan
M/V ANNIE