Fridge off overnight

[geem]

We happily run ours 24/7. It is water cooled with a hull mounted sintered bronze cooling plate outside the hull. Compressor is separate from the cabinet allowing extra insulation all around the cabinet. About half the power consumption of the same volume air cooled unit it replaced. Standard Danfoss compressor but not noisy enough to disturb sleep.

Water cooled certainly helps in the UK as the water is so cold. Very little energy benefit here in the Caribbean. Sea water temperatures are often higher than air temperatures at night. Sea temperature in Antigua has been 26degC all winter but cabin temperature has been 21-23 degC at night. I liked our water cooled fridge on our last boat but we chose not to go that route with the current fridge knowing we would be in the Caribbean.

 

[bitbaltic]

They’re such a fantastic resource to have, chilled milk, retaining fresh food for longer, etc, but in addition to being power hungry they’re noisy. Well ours is. Through the day you sort of zone out to it switching on humming away and then switching off, but at night all is peaceful and then suddenly….donk… it switches on and hums away for a bit and it’s loud when all about is so quiet!
So I switch it off last thing and keep the fridge doors firmly shut thereafter. Keeps the coolness reasonably and on rising next morning, switch it back on. By the time I’ve finished making the tea, it switches off and goes into its daily cycle, having re established its cool float temp. But it is so noisy.
Let me know, anyone, of an efficient fridge that’s quiet and not power hungry and I’ll go for it. Possibly.

+1 for that. It’s not that the fridge is particularly noisy when running but it’s the on-off ‘clonk’ that I can’t sleep through. So it’s off at night (unless I’ve had sufficient beer not to care).

 

[srm]

Water cooled certainly helps in the UK as the water is so cold. Very little energy benefit here in the Caribbean. Sea water temperatures are often higher than air temperatures at night. Sea temperature in Antigua has been 26degC all winter but cabin temperature has been 21-23 degC at night. I liked our water cooled fridge on our last boat but we chose not to go that route with the current fridge knowing we would be in the Caribbean.

It would be interesting to see an objective comparison between the two systems working in your environment.

Water conducts heat around 26 times more efficiently than air. Also, an air cooled fridge inside the boat (in any environment) needs very efficient air circulation over the cooling coils, otherwise they will create a local hot spot. Presumably your daytime air temperatures are higher than sea temp thereby loosing any marginal advantage during those hours.

Although purchased in the UK my water cooled fridge is an Italian product so I assume the cooling plate is sized for Med water temps, perhaps a second plate would improve the efficiency in hot waters. However, without measured real life comparisons it is all speculation.

 

[michael_w]

My last boat had a keel cooled frigoboat system. Kept my beer frosty cold in Florida when the seawater temperature was 30°. Powered by 450ah flooded batteries.

 

[geem]

It would be interesting to see an objective comparison between the two systems working in your environment.

Water conducts heat around 26 times more efficiently than air. Also, an air cooled fridge inside the boat (in any environment) needs very efficient air circulation over the cooling coils, otherwise they will create a local hot spot. Presumably your daytime air temperatures are higher than sea temp thereby loosing any marginal advantage during those hours.

Although purchased in the UK my water cooled fridge is an Italian product so I assume the cooling plate is sized for Med water temps, perhaps a second plate would improve the efficiency in hot waters. However, without measured real life comparisons it is all speculation.

Higher day time temperature in the cabin is not a big issue. The fridge can run with air temperatures of circa 40degC it just gets inefficient. With an excess of solar that really doesn't matter to us. The maximum cabin temperature we see is in Curacao in October when we have had 35DegC during the day. Fridge works fine. Cabin temperature drops to 27/28 at night. The sea is 30degC all the time so nothing in it in terms of efficiency. You can't cool the water cooled condenser below 30 so there is no efficiency advantage in those conditions. It doesn't matter that water is a more conducive media. The water is hot. The disadvantage of air cooled is you need to remove that heat from the boat efficiently or the boat gets hot.

 

[peter gibbs]

Higher day time temperature in the cabin is not a big issue. The fridge can run with air temperatures of circa 40degC it just gets inefficient. With an excess of solar that really doesn't matter to us. The maximum cabin temperature we see is in Curacao in October when we have had 35DegC during the day. Fridge works fine. Cabin temperature drops to 27/28 at night. The sea is 30degC all the time so nothing in it in terms of efficiency. You can't cool the water cooled condenser below 30 so there is no efficiency advantage in those conditions. It doesn't matter that water is a more conducive media. The water is hot. The disadvantage of air cooled is you need to remove that heat from the boat efficiently or the boat gets hot.

I was once offered a bag of ice by a kind mobo neighbour in a marina - surplus to his requirement. A revelation. The ice stood firm for several days in my frig and kept it cooler. Importing a low temp block for a "weekend trip" can contribute to reduced power drain in my experience.