Converting an air cooled Frigoboat Capri 50 to keel cooled

[fbchristo]

We currently have a Frigoboat Capri 50F Air Cooled compressor that is used in concert with the engine driven cold plate on our Leopard 47 chest freezer and the fridge that uses bleed off cold air to cool it. Spending our cruising time in the Caribbean the air cooled unit has a hard time maintaining temperatures much below 32f. We keep the fridge side mostly blocked off with just the minimal spillover of cold air. We have changed all he seals, reduced the volume of the box with foam cubes and are able to maintain just at freezing temps when not running the engine driven compressor. The entire unit is built into the cabinetry so adding additional insulation is not an option.

In my research and talking to other cruisers a keel cooled compressor seems the way to go for maximum efficiency in the tropics. As the title of the post indicates I need to know if it is possible to convert my current Air Cooled unit to a Keel Cooled unit? The compressor is only a few months old and am not crazy about replacing it again, however ice and occasionally ice cream would be nice.

Thanks in advance

Fred
s/v Caribbean Dream



Sent from my iPad using Cruisers Sailing Forum

[Richard Kollmann]

Yes you can add a Frigoboat Keel Cooler in liquid line leaving air cooled condensing unit. Be sure to add a new filter dryer between keel cooler and evaporator’s capillary tube.

No one can guarantee that adding a keel cooler will result in an improvement in tropical warm sea water. Frigoboat does recommend improving performance of there keel cooler systems in warm seawater by adding their fan cooled option using fan and seawater cooling at the same time.

Remember the Capri with its BD50 compressor has limited Btu output so if box is larger than four cubic ft the problem may be do to compressor speed or size. Check the temperature of high pressure line going towards evaporator it should be no warmer than 110 degrees F. The closer to ambient air temperature of 90 degrees F the more efficient the refrigeration unit will be. A simple fix sometimes is to replace fan with a higher CFM fan. An important measuring tool of performance on that type unit is to record a complete cycle of compressor from a normal stabilize system. Time compressor starts till the next time compressor starts again. A good performing variable speed compressor system should run less than 50% of the time.

[Anna Sail]

The Capri 50 can do a refrigerator box up to 18 cu ft or a freezer box up to 9 cu ft. This is on the Frigoboat literature and field proven on 1000s on installations world wide. It's all a matter of pairing it with the correct sized evaporator plate for the job. For a smaller box, of 4 cu ft, the Capri 50 is overkill; instead the smaller capacity Capri 35 will do the job better, with a smaller evaporator plate. Of course, this is all dependent on good insulation to keep the heat out of our box, as is true with any manufacturer's refrigeration equipment, as I'm sure you will agree Richard.

I have never heard Frigoboat recommend running the keel cooler and the fan cooler at the same time. Quite the opposite actually: I've heard them recommend running only the keel cooler when in the water and when the boat gets hauled for any reason and one still wants to run refrigeration, to switch on the fan cooler. Makes sense really, as the keel cooler (i.e. water) has a higher capacity of removing heat from refrigerant than air.

[a64pilot]

Originally Posted by Anna Sail

Quite the opposite actually: I've heard them recommend running only the keel cooler when in the water and when the boat gets hauled for any reason and one still wants to run refrigeration, to switch on the fan cooler. Makes sense really, as the keel cooler (i.e. water) has a higher capacity of removing heat from refrigerant than air.

Yes, but run them both, and you will remove the most heat

[Richard Kollmann]

Being satisfied with results from an ice box conversion unit means different expectable results to each boater. Believing in creative advertising and spreading that advice may misdirect a fellow boater. To believe a BD50 compressor can produce more than 500 Btu at +10 degrees F in a tropical climate and adequately handle a box larger than 4 cu ft is pushing its energy envelope. An 18 cu ft refrigerator or a 9 cu ft freezer powered by a Danfoss BD50 compressor in tropical climates is truly major creative salesmen ship regardless of how much insulation.

Yes, running a keel cooler out of the water or under heavy box heat loads has caused Frigoboat systems to self destruct to a point where complete system must be replaced. Frigoboat US has recommended installation of added fan cooled option when box heat loads are large and seawater is too warm for keel cooler only operation.

[Russ]

Have Keel Cooled and it is PRIMO. Works in Bahamas!!!!!!! Since it is new and since I was given the option of Keel,Air or water(pump) cooled, I believe they are interchangeable The folks at Coastal Climate Control in MD are VERY knowledgeable and helpful. Call them. Russ