Water cooling for fridges?

[prv]

The fridge on Ariam is great. Lovely stainless box, good drain arrangement for cleaning, amply powerful, and has a clever two-speed compressor / holding plate system so that it uses motoring time efficiently and minimises battery use in between.

The only problem is that the compressor is located in what would otherwise be a prime stowage locker. So I want to move it.

There is a space under the saloon bunk and outboard of the battery locker which I think it would fit in. The problem is that this is enclosed on all sides by other things, so there wouldn't be much if any ventilation. Obviously this is not good for an air-cooled compressor. I've been pondering various ducts and flues, but it's tricky. It's occurred to me today that the solution may be to use water cooling rather than air cooling.

I don't really want the complexity of a pump-and-piddler solution, so the two alternatives I'm aware of are the dedicated keel cooler block and the equivalent item designed to go onto a seacock in some way (not exactly sure how these fit). The latter is attractive because the galley sink seacock is in this same compartment, but I don't mind drilling a new hole if they have significant drawbacks that mean the dedicated block is better.

The compressor is the ubiquitous Danfoss unit. Presumably more or less any condenser block would be compatible? Is swapping from the air-cooled condenser to the water-cooled one a quick-release plug-and-play type operation, or does it mean emptying and recharging?

How much are the water-cooling blocks, as a rough guide?

To move the compressor, whether or not I switch to water cooling, I'll need to disconnect and reconnect the pipework to the evaporator in the box. These connections are the usual DIY pre-filled kind - can they be disconnected and reconnected without losing (too much) refrigerant, or is it a one-time thing on installation?

Most of this stuff is probably readily googleable, but I know how the forum loves to give its opinion on things

Cheers,

Pete

 

[pvb]

The seacock-mounted condenser is a cunning solution, but would require a refrigeration engineer to modify your compressor unit, extend the pipework and recharge the refrigerant. No idea how much the fitting itself costs, but you could get a price from any Isotherm dealer (see http://www.isotherm-parts.com/index.php?main_page=index&cPath=4_10_60_65 for a drawing of the Isotherm SP condenser).

For a keel cooler, you'd again need big mods to the compressor and piping, and the services of a refrigeration engineer.

Just moving the air-cooled compressor might be possible without losing too much refrigerant - the connections aren't really designed for repeated use.

I'd be tempted to start by moving the compressor and fitting a little computer fan to blow hot air out of the compartment (ideally ducted somewhere, but just getting airflow will help enormously). You can wire the fan so that it comes on only when the compressor is operating, and it would add very little to the current consumption.

I added a computer fan to assist cooling of a built-in fridge on a Broads cruiser once, it made a big difference to the fridge's performance.

 

[prv]

fitting a little computer fan to blow hot air out of the compartment

Yeah, but that's the problem. Aft of it is the fridge box itself, so can't make a vent there. Outboard and below are the hull. Above is a saloon bunk cushion. Ahead is another locker stuffed with stuff. Inboard is the battery locker, and I don't want to vent from there due to hydrogen from charging batteries - I may well mount a Sterling charger in the same space as the fridge compressor and this warns against mounting directly in the battery box for that reason. So there is nowhere that I can make a simple vent, with or without a fan.

Pete

 

[captainboo]

As PVB has stated the units are designed for either air or water cooling and the cost to convert the unit from one to the other plus re-gassing etc. may cost more than buying a new compressor with the water cooling kit.

As far as I understand the connectors are not designed for re-use. You may get away with it but could lose some refrigerant in the process and the instructions with mine said the unit needs to be returned to the manufacturer for the couplings to be cut off and new ones attached with re-gassing at the same time. When assembled they cut into each other to make a gas tight seal.

 

[vyv_cox]

Any modification you make will require refrigerant pipes to be cut. The quick fit type are for once only and cannot be dismantled and refitted. I am told they always leak anyway, so for long term integrity you need brazed connections. Will PM you with a suggestion for consultancy.

 

[pvb]

Ahead is another locker stuffed with stuff.

Can't you duct air in and out via this locker?

Alternatively, can't you allow air in via this locker and exhaust it through the battery box, with a fan on the outlet from the battery box? Most small 12v computer-style fans are brushless, so you're not going to blow the boat up!