Fridge
System-
A New Approach
This is the
first time we have not used a holding plate system in the fridge and freezer.
We took this approach as on paper it appeared more efficient. We are happy
to report that the Frigoboat system, with its Danfoss DB50 compressors,
evaporator plates, and keel cooler (inside a fresh water tank welded to
the hull) works very well.
We have a
separate system for each freezer (6 and 7 cubic feet/170L and 198L) and
fridge (12 cubic feet/339L). In the tropics, with ambient temperature
in the 84F (29C) range, we run on the slowest speed setting. This provides
plenty of capacity to offset the ambient heat load, plus the multiple
openings of the doors. When we loaded the freezers in New Zealand, at
full speed we could freeze substantial quantities of meat and bread overnight.
While it
is hard to make exact efficiency comparisons, our gut instinct is that
these are at least as good as the best of our old holding plate systems,
and possibly better.
A couple
of other comments are in order. First, an evaporator plate system can
be operated at almost any temperature (holding plates have to be run at
close to their eutectic point). This means a freezer can be used as a
fridge and visa-versa.
Right now
we've got two of the boxes used for freezing and the larger box as fridge.
But we will probably switch to two fridges and one freezer if we are closer
to good sources of fruit, veggies, and meat.
With our
metal boats we are in the habit of welding a fresh water tank to the hull,
which is used for cooling the compressors. This works well, given the
thermal efficiency of the aluminum hull. For fiberglass with the Frigoboat
system you can use their "keel cooler". Both of these approaches
gets rid of the cooling pump - one less thing to go wrong, and it is more
efficient electrically.
Here is a
shot of the fridge. There are doors into each side. The shelves are adjustable.
The evaporator plate can be seen at the top of the box. Note the spacing
3/4" (19mm) between the plate and the box wall. This is required
to allow air to circulate around the plate.
Here is a
shot of the saloon-level freezer. The evaporator is vertical, in a "C"
shape around the left of the photo perimeter. Same standoff between the
plate and box wall. Freezers have baskets for organizing the contents.
The freezers
have dual door gaskets, while the fridge has a single gasket.
Overall,
we have to say we are very pleased with the Frigoboat system, and will
use something similar in the future. We cannot see any shortcomings in
this approach.
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