(Rob) wrote in message . com...
Seen the seminar and also just been reading the tortuous thread in
2000 - "More on Refrigeration", but it would not let me add a post, so
here goes.

However, what are the views on using the Frigoboat keel coolers?? - as
shown here with either the 35F or 50F Danfoss for a 80 litre freezer
box - top entry and underneath the floor in the "bilge".
http://www.penguinfrigo.co.uk/pdfs/K35F.pdf
Penguin in the UK have been using them for 10 years without any
problems.

Also looking at insulation and achieving an R value of 30. A
Kooltherm duct insulation (phenolic foam) has a k value of 0.018W/m.k
- which seems to be be pretty good compared with other products
located on the WWW, but the formula R = thickness in m/k value only
comes out at 5.5 for a 100mm/4 inch thick layer of foam. Or are my
sums amiss???
Also looking at VIPs and their cost in UK.

TVMIA.

Keel coolers have been used on commercial fishing boats for years to
remove the process heat from oil, AC and refrigeration. The Frigoboat
Keel Cooler works well with the small Danfoss BD compressor systems
and I have recommended them for boats with limited onboard DC power
systems cruising in warm climates. For a freezer of 3.8 cu. ft. I
would use a BD 35 if the cruising climate water temperature are below
75 degrees F. If cursing in areas where the seawater is above 75
degrees F. I would install a BD50. In either case I would make sure
there was a quick way to shift compressor speed for the best
performance.
As to Keel coolers, their service life is questionable, they need to
be inspected and cleaned regularly. Always consider how salt water may
attack and corrode metal appendages on boats. Keel coolers have been
known to fail letting salt water into the refrigerant system, this
means the entire system is junk. I would ask you, why do you want a
keel cooler? Say when you size your refrigeration unit you are able to
use a compressor the size of a BD50.. For a savings of three amp-hrs
per day or even six a day in the tropics, do you really need a keel
cooler? A fan air-cool condensing unit, I believe to be the most
efficient, see FAQ #33 on my web site. Remember that fan cooling of
the Danfoss module and even the compressor may still be required in
warm climates.

As to your question about conversion of R value to K value I can't
find the formula and I have no experance with Phenolic Insulations.