Eutectic Fridge Compressor Performance

[BruceK]

I had Moorebank Refrigeration replace my compressor unit about 7 years. Still works, not as well as initially, task has been to improve efficiency.It powers a fridge and separate freezer.
The unit is a commercial shop type,made in Italy,240v, a like for like replacement (though I wanted a Danfoss). The "heat exchanger"/condenser is a conventional air cooled type, with fan.
The unit is located in the ER, so if the engines have been running it`s warm down there. A squirrel type 12v exhaust fan helps, but the condenser is in warm air and the compressor works hard.
Our marina neighbour is a refrigeration engineer,he suggested leaving a hatch to the ER open to let heat escape,and even switching to a seawater cooled condenser.
I thought about airflow. A 240v fan,the kind used in hydroponics to grow "plants", run in tandem with the compressor. But it needed air supply and removal, ie.a flow,for it to work.
Then I thought,the ER 12v exhaust fan is more or less above the compressor, there are ER vents either side of the hull. I wouldn`t run the 12v fan 24/7 at the marina, but running the compressor away from the marina, genset on, I could run the fan,using the battery charger to feed it via the batts.I tried it, got good improvement in run time getting temps down. Just using existing equipment,differently.
We`ll see how it goes,the weather is cooling as a late autumn arrives,which may be giving false positive results. Thought I`d share the experience. Maybe others will contribute thoughts and experiences.

 

[BrisHamish]

Hi Bruce,
I have a 240v seawater cooled condenser on my eutectic system, it works a treat regardless of winter or summer. It’s always powered on at the dock when on shore power, and whenever I have my genset on while anchored, although it only actually turns on when the temp in the fridges drops.
Just guessing, but an air cooled system might struggle at the peak of summer (even in Sydney)? It would be worse the further north you head.
Once you put in a seawater cooled condenser (a 240v pump, a new condenser, a bit of pipe for the water loop), I reckon you would see the back of this problem forever.
Hope this helps you in your deliberations!
Hamish.

 

[FF]

The key to a eutetic system is having a LARGE compressor so the cooling times can match a power supply.

The quicker the temps can be brought down the more efficient the system, with in reason.

A monster compressor doesn't help much as the fluid in the plate freezes on the internal tubing , and ice is an insulator , which is the limit to how fast heat can be renoved.