Water-cooled or air-cooled fridge in tropical waters?

[vyv_cox]

Having an aircooled fridge in a hot climate , I find that the cockpit air temp is so warm around the fridge that it runs almost continuosly . This is a new fridge too . I am thinking it needs a cooler air supply , so as its a cat I wondered about making a , say , 50mm hole in the bridgedeck , which is well out of the water , to feed cool air directly under the fridge .
A water deflector would need to be fitted to stop any splashing water and then , perhaps a solar vent in the coachroof to expel the hot air ?
Is this a bit desperate, or may it work ? ?

Many people find a small fan blowing on the coils to be quite effective. I think the extraction of the hot air is more important than a cool air supply. The air to mine came from low in a locker where it was cooled by the sea. The problem was getting the hot air away, as it followed a tortuous route back into the same locker. Even in Holland the fridge was working hard.

 

[charles_reed]

I have to replace the compressor on my fridge which uses a sea-water cooled condenser.

I am getting conflicting advice as to the best approach in tropical waters - to replace with another water-cooled unit or to go for an air-cooled unit?

Locally (Brazil) they say go for air-cooled. So I can't help wondering that they must know what's best for their waters.

On the other hand I am told by a major UK supplier that the water cooled is the best option and that it uses less amps than the air-cooled option.This is disputed by the Brazilians who say the exact opposite.

The sea water temperature is 27 C at the moment and the ambient temperature inside the boat gets close to 40C most afternoons, especially rainy afternoons when I can't open the hatches fully.

So what I am after from the distinguished members of this forum are first hand experiences of what actually worked for them when in tropical waters.

Many thanks.

Interesting to read the highly partisan proponents of the two alternatives.

In practice little to choose between either, providing they're effectively fitted (I hesitate to use the word "professional").
The majority of air-cooled units are so badly fitted that water-cooling cannot help but be more effective, but if properly ducted they can be very efficient especially in smaller capacities.
Their drawbacks are usually not apparent in the unchallenging European climate.
Water-cooled become increasingly efficient as the volume to be cooled increases, but will need more consistent maintainance and power draw between the two will, counter-intuitively, be little different.
The most important variable in any refrigeration system is the efficiency of the insulation, especially the door - the method of cooling the condensor is secondary.

 

[BigART]

My experience after 7 years in the tropics.

We have a Danfoss BD35F hermetically sealed, air cooled system as a fridge and are very happy with it. It uses around 30-35AH perday and just works. The heat output into the cabin is not particularly noticeable as the boat is well ventilated. A simple system, it may not be the most efficient but we are happy with it.

On the other hand, we have a friend who fitted watercooled systems at considerable expense and has had electrolysis problems - not sure which system they fitted. I am sure it would not be an issue with a good quality, well installed system.

Angus

 

[john_morris_uk]

From Penguinfrigo...

Quote

The keel cooler http://www.penguinfrigo.co.uk/shop/#E50361Z is shown in the link it can be mounted within 1.5 m of the compressor and in any part of the hull under water. The lower the keel cooler in the water the better but on my own boat which dries out it is 30 cm from the waterline and works very well.

A water cooled system can be converted to keel cooled at a later date as well as an air cooled system. The self-sealing couplings mean the condenser (keel cooler) is just installed between the evaporator and compressor.

Unquote

That's the one we have. My wallet and eyes did water a bit when I paid for it.

 

[steveallan]

The original, secondhand Shurflo pump that I used was still working OK after about six years in service. I changed it because I thought I could save power by going to a small pump but this proved not to be the case. I fitted an ammeter at the same time and found both pumps to consume the same. I spoke to Jabsco before buying the Par Max 1 and their advice was that if running it on 6 volts and without pressure it would last indefinitely. It has been in for two seasons now, no problems. My fridge runs continuously May to October.

/QUOTE]

Would using a 24v pump at 12v achieve the same results?

 

[vyv_cox]

The original, secondhand Shurflo pump that I used was still working OK after about six years in service. I changed it because I thought I could save power by going to a small pump but this proved not to be the case. I fitted an ammeter at the same time and found both pumps to consume the same. I spoke to Jabsco before buying the Par Max 1 and their advice was that if running it on 6 volts and without pressure it would last indefinitely. It has been in for two seasons now, no problems. My fridge runs continuously May to October.

/QUOTE]

Would using a 24v pump at 12v achieve the same results?

I imagine so. The Isotherm voltage reducer is available from various UK sources but this one gives more information and a photo. It is suitable for 24 volts.