Refridgeration - Keel coolers.

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Onaway Plymouth

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Hi,
I am having a mod done to my Waeco Cool Machine fridge where a Frigonautica keel cooling device is replacing the current air cooled version. Advice seems sound, price is right but then I saw the device that I will need to fit to the bottom of the boat ?

Frigonautica seem to be at the higher end of the boating fridge market, based on the details in their web site so I'm confident that this will be effective but has anyone have experience of this system ?
 
It looks a bit vulnerable, doesn't it?

This alternative may sound a little unlikely but I assure you it works and is used. You could install the heat exchanger in your fresh water tank, where it will be totally protected and will function just as well. My fridge has a pumped water system, normally using seawater. When ashore I circulate water from a bucket through it. The capacity is around 2 gallons and it runs for weeks on end without getting hot. I have heard of several boats who simply circulate their drinking water through the heat exchanger, which I would do also if it wasn't so difficult to arrange on my boat.
 
I had this system installed from new in a Vancouver 34C built in 2003, it has been excellent and works very well. I have never dealt with Frigonautica, my system was supplied by "PenguinFrigo" UK, they are the UK dealer and based in Havant.

http://www.penguinfrigo.co.uk/index.php?p=home

My only small complaint is that the keel cooler plate has two zinc anodes and I get only one season out of them before they need replacing and considering the size of these anodes they are expensive. But if I were to get another new yacht, I would certainly have a frigo hull cooler plate system again.

Ken
 
I had a keel cooler fitted before leaving for the med last year (Penguin Frigomatic). It works great and has slashed the energy consumption of the fridge and keeps the heat out of the boat. It hasn't been on long enough to judge how fast the anodes go, and I haven't ever worried about its strength - I'd be in deep trouble if it ever got hit.
 
Keel cooler

I have a keel cooler also from Penquin. Works fine. Last time out of the water in Volos despite warning the yard about the keel cooler plus showing them photos, they managed to land the keel cooler on the trailer skids. However it was no problem, no damage and still working well. I have access to a lathe so knocked up a dozen anodes but as stated a season is all they seem to last on our boat.
 
Have heard great things of keel coolers, but just to give the other side. I have two fridges, (one on 24v) an icemaker and a freezer, (on mains) all running on air cooling, been in the med/portugal for 6 years, never had a problem with them, or even noticed excessive power consumption or heat in the areas they are in. When it gets to 40 deg/C outside does anybody notice? I wonder how well keel cooling works when the water temp is 28 deg/C? Anyway, never felt the need for keel cooling. Lots of folk dont. Plus, more holes in the hull and things to get damaged. The water tank system sounds a good idea, as long as the tank is full?
 
dinwood said:
Water temp was high 20s for the last months of the summer in S Spain (max 29deg), keel cooled fridge worked just fine.
Click to expand...

Then you have answered my question, but will not be fitting this system to my boat, too difficult anyway, with multiple fridges etc.
Now if I had a central system, as I have seen, then maybe worth while.
My AC is water cooled.
 
dinwood said:
I had a keel cooler fitted before leaving for the med last year (Penguin Frigomatic). It works great and has slashed the energy consumption of the fridge and keeps the heat out of the boat. It hasn't been on long enough to judge how fast the anodes go, and I haven't ever worried about its strength - I'd be in deep trouble if it ever got hit.
Click to expand...

I have this keel kooler. I don't think it is at all vunerable. Its done one season, but still in the water. I will check on the anodes, and make sure I have some spares.

As a matter of interest, why does it need its own anodes? The main hull anode is within one foot of it. I have not bonded it is to the hull anode, but it would take 5 minutes.
 
Penguin have an alternative cooler that combines as a keel plate for the SSB and is much strudier that the tube type I think you are referring to. Worked well on my Prout cat with the occasional problem that it worked much better when the boat was moving, to the point where we froze the tonic for my wife's gin.
 
Bosun Higgs said:
Penguin have an alternative cooler that combines as a keel plate for the SSB and is much strudier that the tube type I think you are referring to. Worked well on my Prout cat with the occasional problem that it worked much better when the boat was moving, to the point where we froze the tonic for my wife's gin.
Click to expand...

Froze the tonic!!!??? An unmitigated disaster! Skipper should have been flogged, damn negligence!
 
Bosun Higgs said:
Penguin have an alternative cooler that combines as a keel plate for the SSB and is much strudier that the tube type I think you are referring to. Worked well on my Prout cat with the occasional problem that it worked much better when the boat was moving, to the point where we froze the tonic for my wife's gin.
Click to expand...

Thats the model I have - it looks like a solid lump of bronze. I didn't know that they did anything else. I have seen on some boats a flimsy set of tubes and plates - they really do look a bit vunerable.
 
ccscott49 said:
Have heard great things of keel coolers, but just to give the other side. I have two fridges, (one on 24v) an icemaker and a freezer, (on mains) all running on air cooling, been in the med/portugal for 6 years, never had a problem with them, or even noticed excessive power consumption or heat in the areas they are in. When it gets to 40 deg/C outside does anybody notice? I wonder how well keel cooling works when the water temp is 28 deg/C? Anyway, never felt the need for keel cooling. Lots of folk dont. Plus, more holes in the hull and things to get damaged. The water tank system sounds a good idea, as long as the tank is full?
Click to expand...

It seems to be totally dependent upon how well air circulates over the condenser. If air is coming from the bilges and passes freely over the tubes to exit into the exterior through reasonable sized grilles then air cooled seems to work well. If it is like it was on mine, where the air was asked to go through a small grille and exit into a locker with no connection to the outside, then efficiency will be poor.

We have been in water temperatures around 28C many times and don't notice any excessive cycling of the fridge. Interesting that when water first exits as the compressor starts its temperature is probably about 35C. Within about 15 seconds the temperature is down to not much higher than sea temperature, but the fridge typically continues to run for about 6 - 8 minutes. It then remains off for around 15 minutes.
 
Onaway Plymouth said:
Hi,
I am having a mod done to my Waeco Cool Machine fridge where a Frigonautica keel cooling device is replacing the current air cooled version. Advice seems sound, price is right but then I saw the device that I will need to fit to the bottom of the boat ?

Frigonautica seem to be at the higher end of the boating fridge market, based on the details in their web site so I'm confident that this will be effective but has anyone have experience of this system ?
Click to expand...

Dont worry - they work had one for 6 years.

The anodes are I was informed by the makers an Oyster Marine requirement, the "standard" item does not have them.

IF you want to cool the fridge very quickly put a switch on the fan so you can have fan and keel cooling for short periods or when the boat is ashore and you need the fridge on.
 
The big advantage keel coolers have over air coolers is that water has 20 times the conductivity of air and hence is going to be far more efficient at dispersing the heat.

Nigel Calder reckoned that the changeover ambient temperature where water cooling was more energy efficient than air cooling was 38 C but that was because the calcs included the energy cost of pumping water over a heat exchangers - which of course the keel coolers do not require!

I have an air cooler which is in operation more than 50% of the cycle time in July and August in Tunisia when the ambient temperatures are around 40 C. The rest of the year it copes admirably, so for the time being I have no plans to change it.

I had the same problems as Vyv but wiring up a couple of computer cooling fans soon got the air circulating through the locker and improved the duty cycle noticeably - one of those £5 solutions that really works.

When the current system does fail I shall go for keel cooler and also upgrade the insulation; not because a modern air cooler couldn't cope but simply to preserve precious amps. Like most people, I suspect, the fridge is the biggest single user of electricity on the boat by far.
 
We have a keel cooler and it works superbly. I would not want to have that heat inside, a fridge/freezer MUST put out significant heat.

Question. When we are dried out and the keel cooler is exposed, we often leave the fridge running. The cooler gets hot, does anyone reckon we might do any damage ? I don't notice the compressor working harder but I suppose it must be.
 
Thanks for the feedback.

It was the Frigoboat version that caught my eye at the Boatshow, interestingly many of you rate this set up.

What I am being offered is Frigonautica CF30.............

http://pdf.nauticexpo.com/pdf/frigonautica/general-catalogue/24843-4542-_43.html

This sounds like one of the units mentioned in the thread by "Bosun Higgs". It does look vulnerable attached to the underside of the boat but the product is highly rated.

Anyone have experience of this type of unit ?
 
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