New Fridge - Choice?

Jonny_H

Jonny_H

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Well, with serious sailing now edging closer we've got some big decisions to make in the winter re-fit before we leave.

Firstly - fridges.

We're replacing the old air-cooled Weaco unit which doesn't make the beers very cold. Question is - what to replace it with. We have done some research and had good feedback on two units - any opinions:

1) Frigoboat water cooled unit (the one with a small sintered bronze plate mounted outside the boat).
2) The Isotherm SP series (the one that uses water passing round a below waterlevel seacock to cool)

The Isotherm unit is looking good at the moment - power consumption is the same as the Frigoboat, but its cheaper and doesn't require an additional below waterline hole drilling in the hull!

Jonny
 
Personally I'd go with the isotherm.
But I have air cooled fridges and freezer in the meddy and never had any problems, my beer is always cold.
 
Spoke to someone about getting it done - but was told that if it needs regasssing there is a gas leak and therefore this will need to be found and fixed.

Also, the current compressor is air cooled and runs quite hot in the cupboard under the sink - it was suggested it would be more efficient and use less power if it was water cooled - especially for the tropics.

Jonny
 
We have the Isotherm with the water cooling via the galley sink drain seacock. We live in Spain, and have been very pleased with the performance/power consumption. We have enclosed the cooling unit with a home made door, which gives us ice cubes pretty quickly, or keeps a small amount of prefrozen food. Depends on the size of the fridge. Ours is quite small, and if it was a lot bigger, we would go for a eutectic(?) holding plate. Main reason for going for the seacock cooling was to avoid heating the cabin and it is pretty efficient.
 
air cooled compressor definitely needs a source of cool air, preferably from the bilge. I have seen this done by using a computer fan or by setting up some form of trunking that sucks the air from as low n the boat as possible.

I had a failing system that I was told was totally knacked and needed to be replaced by an "expert" I called in a normal domestic fridge expert (non-marine) who replaced a thermocouple (or somfing lik dat) and it worked perfectly
 
There is a chap in our marina who is a sailor and a domestic engineeer by trade. He said he would take a look for us when he has time. Apparently its quite common to get a blockage on the evaporator plate in the pipes that run inside?

The current compressor has access to the bilge, but this is mostly filled with fuel and water tanks. As the cupboard is reasonably small and has some galley stores in it it does get quite warm when the compressor is running.

Also, as the current unit is 10 years old, we thought it would be best to replace it before we set off and then we know we have a good new unit which shouldn't (famous last words) cause any trouble.

Jonny
 
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Also, as the current unit is 10 years old, we thought it would be best to replace it before we set off

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Fundamental point!
 
I am looking at both systems ie bronze plate or Isotherm sp and it seems the sp can clog up with "critters", the jury is still out.
 
Johny - It is also worth looking at the insulation you have, as the best fridge system in the world will be costly to run if it is badley insulated. We have a Wwesterly Oceanlord - the Fridge is huge, Penguin enginnering say that the unit installed by Westerlies is only man enough for half the capacity - let alone the lack of insulation - only 1 inch.

So we have a potentially huge job to take the old fridge compartment out and completely replace it. with a slighly smaller unit - with at least 3 inches of insulation. Means completely removing the work surface, ripping the top off, and starting again. - But every cloud has a silver lining - SWIMBO hates the original brown tile finish so typical of Westerlies of this age! so she will get her new surfaces!
 
We have an Isotherm with the skin fitting cooling system. We've found it fine - although it obviously less efficient in the tropics than it is in the UK it was still more than adequate for our needs and our solar/wind charging regime happily kept up with the power demand).

The most important thing (in our opinion) is the insulation of the fridge box. We've got three inches on top, six inches on the side and eight inches on the bottom (surrounding a custom make plastic liner built very economically by TekTanks to our design).

Should you be as nerdy as us and interested in a picture of the installation we can send you one. Would post it here but thought it was unfair to inflict such nautical geekiness on the poor forum readers.
 
OK, Just to add my real pennies worth to the mayhem.

I have a domestic fridge and freezer, running on an inverter, which is just as good as running with a 24v compressor, maybe a tiny bit more power due to inverter losses and with more insulation than your average built in marine fridge.
The fridge is three times the capacity of my old galley fridge. Of course the fridge and freezer, cost (both) 258 quid, that leaves a lot of dosh over from, about 600 for the fridge and 600 for the freezer, if I had bought 24v ones.

It works for me and quite a few other liveaboards I know.

I have had a mains freezer onboard for 12 years. It worked fine. Top loading admitted and the new one is front opening, but with a little intelligence, only opening when genny running to get stuff out to defrost is not too brain taxing, even for bears of very little brain.

Long distance cruisers I have met swear by engine driven fridge compressors and BIG holding plates built in highly insulated top opening cold spaces. I have met a LOT of long distance cruisers.

Electric compressors are fine with adequate cooling and of course can be run when in marina's, solar panels, wind gennys or even with engine and dedicated gennys. Voltage sensing ones are ideal. But seperate thermostst ones are also good but need a regime putting in place, whereby when lots of power available turn them up, when on low power turn them down.
I would (and do) go with leccy, but I would also consider cheap, (I mean really cheap) worldwide readily available mains compressors. Especially if one already had an inverter for all ones other "toys". Just fit a bigger pure sine wave one.

OK, thats my two peenies worth.
 
We are having to rebuild our whole fridge unit this winter to increase the insulation. I suppose techtanks will make the liner from a cardboard former. What about the insulation, is it spayed on or made of solid slabs - and where do you get it from?
 
Johnny

Having spent the summer in the Med in my Moody 425 I have found my top loader Frigoboat fridge (air cooled - no fan ) to be man enough for the job keeping the beer cold and anything placed next to the cooling plate frozen!

During the winter I intend to upgrade the insulation as this is undoubtedly its weak spot causing near continuous operation of the compressor and I shall probably follow Englander's example of fitting a fan to keep the air moving.

Like you I was going to go for water cooled but if you read Nigel Calder's chapter on the subject he reckons they are are not more efficient than air cooled until the ambient temp averages 38C. If I remember the argument correctly although water cooling makes the heat exchange more efficient you more than lose what you gain using energy to pump water around.

The old hands I have talked to say insulate and put in a PC type cooling fan.

Good luck whatever you do
 
Hi all
when a fridge is water cooled via a keel cooler plate or skin fitting it is not neccesary for the water to be pumped in any way as the movement of the boat in the water provides adequate cooling of the refridgerant.
 
not being in the med but have a waeco system I find that the cuboard gets hot so I have put a small computor fan to draw air in and on the other side of the cuboard I have fitted a grill where the tea towels etc hang and fitted another computer fan that blows the air out. Dry tea towels and much cooler cuboard
 
We have a Frigoboat unit with the separate bronze keel cooler plate. We have 100mm minimum insulation thickness using Kingspan insulation. The fridge is approximately 95 litre capacity. One third converts to freezer mode. We used 1 amp per hour in the Caribbean using it in fridge mode and 2 amps using as freezer mode. Very pleased and would go with this arrangement again. Also the Keel cooler is a handy ground plate for the ssb. It is actually designed for it.
 
Hi,

Read Nigel's book - however the Isotherm SP's are Self Pumping - blerb from the website:

Isotherm SP is a sea water cooled refrigeration system
for sailing yachts and power boats. This unique
system means reduced power consumption and noise
level. It has no fan or pump. The sea water cooled
skin fitting/heat exchanger replaces the air cooled
condenser and cooling fan. The heat is transferred
directly to the surrounding water instead of being circulated
as hot air inside the boat.

Sounds like its the best of both worlds?

Looking at budget we seem to have two options if we go Isotherm:

Air cooled ASU unit (with a holding plate) (£650 ish)
SP water cooled with evaporator plate (£550 ish)
Classic - Air cooled with evaporator plate (£360 ish)

Any opinions (you can get an SP ASU (theres a mouthful!) but it costs around £820 so more than we wanted to spend really).

Which would people plump for? If I go ASU aircooled, the compressor doesn't run as often so air cooling shouldn't be an issue re keeping the cupboard temp down (and can fit a 12v computer fan). ASU will be the easier to fit - no need to mess with skin fittings - so the extra £100 would be saved in getting someone to help me replace the skin outlet fitting which is required with the SP.

Help /forums/images/graemlins/confused.gif

Jonny
 
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