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"Terry Spragg" wrote in message
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Jeff wrote:
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
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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
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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
My little electric frige has a warm plate at the rear, more or less
surrounded by cabinetry. My engine room vent inlet passes nearby. I
wonder if venting the warm plate to the vent pipe using a dryer air box
switch might provide some benefits during warm or even cold weather,
depending on the airbox switch?
First, would such a vent improve the efficiency of my frige?
As long as the air you are providing is cooler that what it would otherwise
see.
I am presuming that the engine would suck in the frige heat without any
complications, and that there is enough rise in the intake side for when
the engine is asleep. Hmmm.
Hmmmm is right 
Would I benefit from blowing a fan into the open frige on a hot night?
Maybe cooling down just for long enough to doze off in the saloon table
hammock?
You're kidding, right?
Terry K
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