Keel cooled fridge

[gunnarsilins]

Has anybody any experience of the watercooled compressor Frigoboat uses together with an external keel cooler?
They say it´s more effecient then the air cooled ones and compared with normal water colled ones you don´t need a pump and associated hoses for circulating seawater through the compressor. The idea looks tempting!
www.frigoboat.com

 

[ccscott49]

It's an excellent system, but requires even more holes in the boat, and can easily be damaged, there is the system that fits in a through hull, say from the galley sink or any underwater outlet, which also works well.

 

[Guest]

Fitted as standard on my Moody, works well and far less damage to the batteries!!!!

Pete

 

[Sinbad1]

Yep, its excellent. I fitted one along with a 120litre box and it has performed well. There are two types of keel cooler. One is a sintered bronze ground plate which is porous and the cooling tubes run through it and the other is a stainless type heat exchanger.

The system is very efficient. It uses about 4.5 amps when operating. I have an evaporator plate which serves as a freezer by putting ice cubes in the centre of it.

I have heard reports that the models (isotherm) that fit the cooling tube inside your existing thru hulls are not so efficient as the water within the thru hull isn't actually moving unless the boat is underway.

I have been very pleased and understand that the new models are even more efficient. Have a look at the frigoboat website. They have English pages.

 

[gunnarsilins]

Concern about holes!

Yes, in theory I agree.
But as my boat, moored in Stockholm, stays in water all year around and some winters sits in more than 50 cms of ice I have got rid of all through-hulls under the waterline.
The only one left is a combined inlet for engine, heads etc. This one is regularly filled with anti-freeze and cannot be used for the fridge. All drains exits over the waterline.

By the way, as far as I have understood, the system you talk about cannot be shut off by an seacock. If that´s true it would rise some concern.
Is it really wise to have throgh-hulls which cannot be closed in an emergency?

Just drilling a hole and bolt this bronze keel cooler on seems a lot safer.

 

[ccscott49]

Re: Concern about holes!

Had a look at the site, bronze thing looks pretty good, I have a bronze earth plate, which hasn't been damaged, so I guess it's a good idea. The one thing I would be looking at now is the expense of the whole system, I haven't seen any prices yet, but I can bet they aren't cheap, but when it comes time to replace my fridges, maybe a twin cabinet system may be on the cards, we'll see. They of course may be cheaper when I'm in Italy, where they seem to come from. Actually once my fridges require replacement, I may go for mains ones again as they are a lot cheaper, I use computer cooling fans, four of them on each fridge, simply tied with tie wraps to the evaporators on the back of the fridges, that really helps the efficiency of the cooling. Butu theres many ways to skin a pussy! I have to look at the economics of all this, with two fridges and a freezer.

 

[bedouin]

Re: Concern about holes!

If it is the one I think he's refering to, then it doesn't need a sea-cock. It is in effect a mini heat-exchanger built into a skin fitting so the cooling water never actually leaves the fitting - hence no need for a sea-cock. It somehow uses wave action to circulate the water round the fitting - but I can't remember exactly how it works

 

[wpsalm]

Re: Concern about holes!

Anyone ever ask why yacht refrigeration systems cost so much.....?
on my little boat the compessor pumps through a coil in the fresh water tank...and no the water does,nt get warm .....

 

[ccscott49]

Re: Concern about holes!

NOw thats a bloody good idea, but what happens when the tank is empty?

 

[snowleopard]

Got to be better than my water-cooled system which sucks air in a seaway then stops working regularly

 

[gunnarsilins]

OK! Seems that....

..the best solution will be this "keel-cooler-thing"! This leaves me to check out how much it will cost....
Thank for all contribution!

 

[ccscott49]

Re: OK! Seems that....

:Let me know the pricing of the system, it has top be fitted to a new system, not retro-fitted, I guess.

 

[wpsalm]

Re: Concern about holes!

The tank does,nt get empty...have 2 tanks and use the one with the condenser coil last if I,m out of water or about to run out shut down the refrigeration...

 

[gunnarsilins]

I just talked...

...to the Swedish agent. Compressor and keel-cooler together will be £ 348 ex. VAT at todays exhange rate.
I can re-use the existing evaporator and thermostate.
This is not cheap....

A new aircooled compressor would be cheaper - but I´m quite sure my battery bank will appreciate a water cooled system.

I had a thought over your idea using a domestic fridge, I found it a bit tempting, but:
1. I have to rebuild the interior quite much.
2. I quite sure I´ll save a lot of energy having a box opening on top instead of a conventional door.

So in the end it all comes down to saving energy and the most efficent system must be a watercooled box opening on top.

I have a pretty good picture of how much power my recent aircooled system used up on a daily basis.
I´ll get back when I have some figures for the water-cooled thing! That might be interesting!

 

[Guest]

Re: I just talked...

i have the frigoboat system using the sintered bronze keel cooler. it works well, though i have no way of saying whether a conventional air cooled system would be any worse. the physics says that it should be worse, but thats theory!

i have used the sintered bronze cooling shoe as the earth for my ssb, and that has been less successful. when using ssb i have to switch the fridge off, or i get interference.

also, the temperature of the fridge is affected by whether the boat is moving or not. when under way, the fridge thermostat has to be turned down, or i freeze the tonic for the g&t's

finally, to my surprise, the keel cooler fowled up quite quickly, and you cannot use antifoul on it.

if i were sailing in uk waters, i would not go to the expense of the water cooled system. however, in warm climates where the extra heat from an inside air cooler is not welcome, then i would buy the same equipment again.

 

[ccscott49]

Re: I just talked...

In the meddy, the fouling problems are really bad, I wonder whether keel cooling is really worth it down here, as opposed to sea water pumped cooling. I use air cooling and don't have any trouble with it, not sure what my power consumption is though! Hate to think!!

 

[gunnarsilins]

Hmmm, interesting...

...points.
I normally sail in the Baltic sea, where the water temperatures must be in the same region with those in UK and the fouling less.
But we will do a longer trip year 2004-2005 to Spain, Canaries and Med. where the the keel-cooler would be more effecient. But then I have the problem with fouling. I assume the fouling is even worse there than in the UK.

 

[ccscott49]

Re: Hmmm, interesting...

The fouling in the med is bad, but not as bad in the canaries or anywhere else Atlantic, you dont get as much fouling in the Baltic as the Atlantic.