Water cooled Fridge?

I was on a boat that inexplicably starting to take on copious volumes of water at the start of a delivery trip last year. It turned out to be the water cooled fridge. The pump was busy pumping water into the boat but sadly the pipe was not connected to the fridge.

So - while it might be attractive for various reasons, it must be remembered that it is another hole in the boat - and a hole with a pump designed to bring water into the boat rather than out!

- Nick

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A far more efficient means of cooling the heat exchanger. In climates where air temperatures exceed 25 - 30 C, like England (!) the effectiveness of the convection heat exchanger is greatly limited and the compressor may run almost constantly in trying to reduce the frig' temperature. Water cooling is far more effective, saving lots of volts.

The water supply needed is very low flow for a normal yacht sized frig' and it is sufficient to take a branch off something else, like engine coolant. Return water can be piped int the exhaust silencer, so no extra holes in hull are needed. You could even have a closed loop 'keel cooler', just a pipe running through the hull forward and returning aft. Quite common on steel hulls.

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Not forgetting the IsothermSP, which replaces the galley sink skin fitting, has no pump, no noise and no extra through hull fittings.

I'd have put one on my most recent boat if I could (totally incompatible unfoortunately as it is made of bronze), as it was brilliant on my previous boat.

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I am just being pedantic Vyv, in case someone without experience takes it up - no lack of respect for your views meant at all. It may be unwise to pipe the condensor cooling water into the exhaust silencer, especially if the refrig system is dc powered. Else if the engine is lower than the high point in the exhaust after the trap/silencer, as it usually is, you run the risk of flooding the engine.

Of course, there would be no difficulty piping it into the exhaust beyond the highest point. Our condensor cooling water is pumped out the transom above the water line.

John

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Watercooled fridge/freezers are a wonderful bit of kit, far more efficient than air cooled. You do not need any more holes in the boat, you already have toilet in and out? engine in? then tee in to the inlet and outlet or even put the outlet through a bilge outlet, with a non return on the bilge line, you already have enough holes, use those. I fitted a watermaker and didn't put any more holes in my hull. I get rather fed up with people saying things like "it's another hole in the boat", hogwash!

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Quite agree. I am constantly amazed by the number of holes appearing in the bottom of boats. Saw some layouts somewhere recently of some production boats and it was sea suction for fw'd head, again for aft head, again for a/c, again for engine, again for refrigeration, and again and again. I can only assume it is because it is cheaper to drill a hole through the fibreglass in each location and bung a fitting and valve on it that it is to run back to manifolds off one or two common suctions only. Then it was discharge for forward head, discharge for galley, discharge for aft head, discharge for forward shower/basin, discharge for aft shower/basin, again and again and again.

Surprising there is any room for a bottom left in some of them.

John

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I saw a boat advertised somewhere, which had a Manifold, in a locker, with filters etc. To about four in/oulets, I was very impressed, almost all the seacocks in one place, always available to be checked/operated. If I was to have a new boat built, I would do exactly that, then pipe everything from one location, (apart from toilet /holding tank outlet) an elegant solution. But I've enough holes/seacocks to tie into, so dont need to be drilling anymore in my boat. The same boat had all the engine filters/crossovers in a locker aswell, including the remote oil filters, with a captured drain, to stop any oil or diesel going into the bilges, brilliant!

<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by ccscott49 on 13/08/2003 09:48 (server time).</FONT></P>
 
If it hadn't been for the fact that I am typing with one hand I would have elaborated. At the time I thought that nobody would be so stupid as to pipe a water supply where it would back up the exhaust system. But you are quite right, although silencers that I am familiar with are immediately upstream of the exhaust outlet and located vertically to prevent water from entering the exhaust pipe. A branch into this would allow cooling water to fall straight into the sea. I didn't mean to lead the pipe into the trap.

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I never thought you did! You're a little too experienced for that, thats why I never wrote anything. But some peeps are stupid enough!

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Only 40 ft boat, but we did it with just 2 suctions (one dedicated to the engine cooling and everything else manifolded off the other including salt water services to toilet/basin and galley, refrigeration and deck washdown). Then on out side just one grey water (shower/basin, galley) and one blackwater (toilet/holding tank). Obviously not a good idea to mix blackwater and grey in case of a repulsive backup.

Condensor water was taken out the transom as a tell tail so can see that there is flow.

With the 76 foot catamarans we are doing at the moment, if you count the suction sea chests as one penetration each then I think they have about the same number of penetrations as our own little boat despite the fact they have 160,000 BTU/hr of refrigeration, 2 engines and a generator in each hull, 3 bathrooms, etc. So it can be done.

John

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Yes Vyv, I trust I got the message across that it wasn't you I was concerned about, and that I knew what you actually meant. From what I have seen out in the field, some would not have understood, however.

John

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I have saved lots of energy!

My old Frigoboat air cooled condenser (fan drawing air from the bilges) died completely last season.

I kept the old fridge and bought a new Frigoboat compressor with the condenser built into a sintered bronze plate which I mounted outside the hull approx one metre below w.l.
There are no pumps in the system, but a hole must of course be drilled for the fitting.

The result is - I can assure that the power consumption have dropped by 50 %!

Of course part of this might be the newer, more efficient compressor, and lack of a fan. But still the saving of energy is remarkable.

I must point that I have cruised the Baltic sea with water temperatures this summer from 13 in late June to 20-23 early August, and mostly the air temperature has been much above normal

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What are we saying then???

a water cooled fridge is just an inlet water pipe & an outlet water pipe?
presumably flowing across a baffle? and cooling the air inside a container down to the water temp??

if this is the case then why not just drop the beers in a net over the side??

poter

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Re: What are we saying then???

Bluidy hell oif only it was so simple! A water cooled fridge, is a bit of a misnomer, the water cools the heat exchanger/evaporator, the thing you see like a thin radiator on the back of an air cooled fridge, within a sealed container, the water flows over this then exits back to the sea. A much more efficient cooling medium.

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Re: What are we saying then???

err no you're not right, the water intake out take act as a hear pump, the objective is to move the heat from the condensing coils continuous, the compressed gases in the circuit is where the cooling takes place. It is possible to cool the fridge to a mcuh lower temperature than the sea water hence the freezer part.

If you applied your logic to a domestis fridge then you would only be able to cool the fridge the the same as the air outside DOH!

So it the water aspect is a heat pump rather that a chiller, chilling is already being done by the compressed gas being pumped around the inside of the fridge, when the gas expands outside the fridge in the heat exchanger the water passing over the exchanger pumps the heat away...

Clear as mud!

<hr width=100% size=1>...but then I would say that wouldn't I.....
 
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