Frigoboat Keel Cooler in the tropics

[robert sailor]

Personal experience in the South Pacific and also discussion with others. I ran the sea water conversion on for a few months and it improved things for sure but the pump failed and I went back to air cooling. I was using about 50-60 amp hours a day in Mexico but it went way up in the tropics.
Current box is insulated with Aerogel and it's really good, with keel cooler here in the Med its only using about 25-30 amp hours. Summer temps are high 30's and low 40's and warm water but still can't compare with the tropics.

[robert sailor]

Forgot to mention my box is 5.8 cu ft.

[Celestialsailor]

I'm in Mexico now and using 30 amps a day. It has only been around 80F though. When the boat was in the Delta in Ca. Temps often spiked well over 100F and still 30 amps a day. I have 1" of aerogel around the bax and then 3"-4"s of styro and pour foam around it. My box is much smaller than yours though. I would think any gain in cooling with water would be lost in amps using a water pump.
My friend on his Peterson 44 reported that he had expected a better performance with the water cooling but with the warmer water did not produce the desired results he was hoping for. He has had the Frigo unit leak and required a $200 fix.
When I am in much warmer climates, I will report on my electrical consumption then.

[robert sailor]

If you have 4" of Styrofoam plus an inch of Aerogel plus a smaller box I'd say you are well set up and might very well stay well under 50 amp hrs in the tropics. Your set up is better than most out there and my figures were based on a typical poorly built fridge that you would get in a near new boat these days.

[skipmac]

Originally Posted by robert sailor

Fact is in the tropics air cooled units use lots of power even in a good box. You can figure on about 70-90 amp hours a day.

Originally Posted by Celestialsailor

thanks for that but would you like to show me the stats on that one?

Doesn't match my test in summertime Florida and I sure felt tropical last August. Do not think most cruisers will see temps higher than the mid nineties I saw during my one week test.

Also I think I have a larger than average box at approaching 10 cu ft which includes a small freezer compartment, plus the larger BD50 compressor and will all these the most I pulled on the first 24 hours cooling down the box was less than 80 amp hours and a lot less after the temperature had stabilized.

I don't think my box insulation is extraordinary. Most of it is 4-5" blue foam but due to space constraints there are places with only 3".

[Frigoboat Info]

Skipmac: The most consistant power consumption report we receive for Keel Cooled systems is for an average 6 cu ft box, on a cruising boat in The Caribbean, using 20-25 amp/hrs a day. Those are pretty good numbers you report with your air cooled system, and if that fits in to your power budget then you are in good shape, but you could reduce that considerably with the addition of a Keel Cooler later on if needed. That would be especially true if you headed south at any time.

[Frigoboat Info]

Originally Posted by mikereed100

My keel cooled frigoboat did very well in the tropics in water up to 90 degrees, with similar air temperatures.

We spent a couple of weeks on the hard with it and found it not too difficult to rig up a drip system to keep the refer running. Basicly a tupperware braced over the keel cooler with rags stuffed along the edges, then a tube siphoning water from bins in the cockpit. We had to refill the bins every couple days but not a big deal.

FYI Mike, Frigoboat now has an air cooled condenser available, the Air Add-On, that you can add to a Keel Cooled system with just simple tools and with no need to tinker with the refrigerant. Then you can use air cooled on the hard, and turn the fan off when the boat is in the water. We now sell many systems for serious cruisers comprising of an air cooled condensing unit with a Keel Cooler. Again, the fan is switched off with the boat afloat, but is always there to take over if you get hauled for any reason.

[skipmac]

Thanks FBI (did you ever think about the initials of your online handle?)

Originally Posted by Frigoboat Info

Skipmac: The most consistant power consumption report we receive for Keel Cooled systems is for an average 6 cu ft box, on a cruising boat in The Caribbean, using 20-25 amp/hrs a day. Those are pretty good numbers you report with your air cooled system, and if that fits in to your power budget then you are in good shape,

Well of course in the world of power budgets, less is always better. I think I can get my draw down a little more since I was actually freezing things in the bottom of the box. I think I need to insulate around the evaporator/freezer box a little and install the small fan to stir things up in the box.

Originally Posted by Frigoboat Info

but you could reduce that considerably with the addition of a Keel Cooler later on if needed.

If I recall and understand correctly, I can add the keel cooler as just a plug and play option? Just unscrew the appropriate connections in the system and connect the keel cooler in line?

Originally Posted by Frigoboat Info

That would be especially true if you headed south at any time.

Since I've been south my initial plans are to head north and east so maybe a keel cooler isn't needed, yet.

[Frigoboat Info]

Absolutely. You can add a Keel Cooler to a Frigoboat air cooled unit at any time, and now it is possible to the Air Add-On condenser to a Keel Cooled system at any time. These items are supplied charged with R134a refrigerant and with the Frigoboat couplings, and need only simple tools to connect into an existing system.
I fully agree that if you are heading north you may not need a Keel Cooled system, besides, the heat from the condenser discharge might be a bonus feature!

FBI

[colemj]

Originally Posted by robert sailor

Fact is in the tropics air cooled units use lots of power even in a good box. You can figure on about 70-90 amp hours a day.

We have a 4cf freezer spillover cooling a 6cf reefer and an air-cooled BD50 compressor and thin plate evaporator. We use 45-55Ahr/day (depends on usage) throughout the tropics (Panama, Honduras, Guatamala, etc) where the air temps are 90+F.

That isn't a guess - we have a monitor on it.

Mark

[ColdEH]

Originally Posted by Celestialsailor

Maybe Kollman will chime in but I have heard when the water temp. goes up, efficiency goes down. Like others, my AB air cooled system works great. I think if you focus on 4" plus insulation, you'll do well.

Wow lots of great info , thanks guys.

Really helps when you hear other peoples experiences. Sounds like either way I go, air or water, they both have some trade offs . Such is life. The holes are already there for the keel coolers , the seafrost's are both water cooled .

I was actually going to use Vacuum Panels for insulation, not much room for anything else if I want an efficient box. I have a separate freezer and fridge on my Bristol . They have Seafrost engine driven systems now but I would like the constant temperature of a 12 volt system . Power is not a problem I am using 600 ah of LiFePO4 batteries charged from my Eco-tec 280 amp alternator attached to a dedicated yanmar diesel.

Regards

[Richard Kollmann]

Assuming water is a more efficient cooling medium design for small Danfoss 12 volt compressors is not always true. There are a number of problems with water cooling one of these is excessive compressor temperatures that will at some point cause total system to be replaced. Most boaters with keel cooler systems have small ice box conversion systems of less than five cubic feet and spend little time in tropical waters. Lower compressor temperatures on non tropical cruising with less demanding conditions will reduce O ring leaks and extends life of oil and system itself.

I understand that future Frigoboat keel cooler systems sold in the US will incorporate a liquid line Filter to conform to common refrigeration design standards. This filter should eliminate a need to tap on line to get unit to operate when contaminates plug cap tube inlet.

[ColdEH]

Originally Posted by Richard Kollmann

Assuming water is a more efficient cooling medium design for small Danfoss 12 volt compressors is not always true. There are a number of problems with water cooling one of these is excessive compressor temperatures that will at some point cause total system to be replaced. Most boaters with keel cooler systems have small ice box conversion systems of less than five cubic feet and spend little time in tropical waters. Lower compressor temperatures on non tropical cruising with less demanding conditions will reduce O ring leaks and extends life of oil and system itself.

I understand that future Frigoboat keel cooler systems sold in the US will incorporate a liquid line Filter to conform to common refrigeration design standards. This filter should eliminate a need to tap on line to get unit to operate when contaminates plug cap tube inlet.

Hi Richard, what causes the compressors to get so hot ? Is it lack of ventilation that you would get from an air cooled system?

Regards

[tomfl]

Originally Posted by Richard Kollmann

Assuming water is a more efficient cooling medium design for small Danfoss 12 volt compressors is not always true. There are a number of problems with water cooling one of these is excessive compressor temperatures that will at some point cause total system to be replaced. Most boaters with keel cooler systems have small ice box conversion systems of less than five cubic feet and spend little time in tropical waters. Lower compressor temperatures on non tropical cruising with less demanding conditions will reduce O ring leaks and extends life of oil and system itself.

I understand that future Frigoboat keel cooler systems sold in the US will incorporate a liquid line Filter to conform to common refrigeration design standards. This filter should eliminate a need to tap on line to get unit to operate when contaminates plug cap tube inlet.

Worth reposting this.

It is what I was told when I installed my air cooled Frigoboat system. Before I installed they system I added insulation reducing the size to around 7.5CF with the big Frigoboat freezer. I also moved the compressor so it was maybe 18 inches from the wall of the box, and put in a nice vent/air circulation system. Also installed the expensive digital control unit and the Merlin card. Worked fine this summer in the Keys. Conventional wisdom is the system requires around 50-60 amps a day and my experience matches this.

I also have the big plastic Engel in the salon. I keep stuff like sodas and yogurt in it and open it several times a day. I try to limit opening the big system in the galley to once a day.

Some folks would say the biggest consideration in any system is insulation. Sealing with double strips around the door/top is also very important. Keeping the run of the copper lines is also important.

But all of this pales when compared to how one uses the frig. Notice how the temp jumps when you open it. Also notice the difference between the draw when there is lots of ice on the tubes and freezer plate and when you have just defrosted the unit.

Bottom line is the biggest issue with any system is how often it is opened, and next is how low you set the temp.

[BambooSailor]

There is one aspect of keel cooler that I am not sure how to get around: keel coolers must be either bonded or have zincs. If your boat is not bonded, you have to use zinc version of keel cooler. I did not catch this mentioned anywhere, but I would like to understand how owners are dealing with this requirement and their experience.