The Worst pleasure boat refrigeration.

[Richard Kollmann]

I would like to know from boaters about all the 12/24 volt boat icebox conversion refrigeration systems which one they least would want to install in their boat? When questions in the past were ask about best refrigeration every response is favorable even on less than desirable units.

If you respond list at least three reasons you would not want that refrigeration unit, Examples:
It requires water cooling to be efficient as air cooling alone is not enough.
It would require more maintenance than a much simpler system.
The evaporators available for this system are incorrectly sized for my boat’s box shape.
I believe this unit is reported to have more refrigerant leaks than other similar units.
Technicians and myself may not be able to keep it running where I will operate the boat.
I prefer a less expensive unit with the same performance.

[slug]

Gee

All the common name brand marine refer systems I’ve used have been reliable

Air cooled can be worthwhile on some boats

The import piece of a refer system is a well insulated box

[Dennis.G]

Likely not really answering your question, but two observations:
1) The 12v solid-state thermoelectric coolers (truck driver coolers) are simple but pretty much useless for any long-term refrigeration. Just do not get down to correct temperatures for keeping food fresh and don't see any that freeze.
2) The old-style open compressor coupled with a DC motor (either direct shaft coupling or belt drive) seem very robust, but efficiency wise can not compete with modern hermetic DC compressor systems.

[StuM]

[QUOTE=Dennis.G;3080029
1) The 12v solid-state thermoelectric coolers (truck driver coolers) are simple but pretty much useless for any long-term refrigeration. Just do not get down to correct temperatures for keeping food fresh and don't see any that freeze.
[/QUOTE]


Yep, anything using Peltier cooling on a boat is a useless energy hog. They use about 4 times as much energy as a compressor system for the same amount of cooling and have a limited temperature differential.

[robert sailor]

Agree with Slug and Stu...I think most aircooled systems are up for the job as long as the compressor is getting good airflow and the box is well insulated and well sealed.

[slug]

Air cooled can be a bit power hungry

If you must be a power mizer get one of these


http://www.isotherm-parts.com/product-range/cooling-units/compact-systems/sp-cooled

[billknny]

I think modern DC refrigeration systems are like modern automobiles. So vastly improved over older models the average user just doesn't see many problems. Most of them run without problems for years.

The difference between the 'best' and the 'worst' are really only visible to professionals who see a much larger data sample. Many of us are running units 10 or 20 years old and they just keep jugging along.

[RaymondR]

Originally Posted by slug

Air cooled can be a bit power hungry

If you must be a power mizer get one of these


SP Cooled : Isotherm-Parts, Isotherm Marine Refrigeration and Parts

Ozefridge does a clever air/water cooled condenser which they recommend you pipe from your water tank for fresh water cooling rather than sea water.

My air cooled condensing unit is under the sink and I cruise mostly in the tropics and it's amazing how much hotter it is in the galley on a hot day than in the rest of the boat.

[Dockhead]

Friends of mine built their (very expensive custom) boat leaving spaces for portable commercial duty air cooled reefer boxes. I think this approach has a lot to say for itself -- you can pull it out and take it in for service, and even replace the whole thing without ripping your galley apart.


I have had a lot of different types of refrigeration on different boats. It was all more or less satisfactory.


One system I used had a main engine-driven compressor and freeze plate. This worked great, used no electrical power, and was remarkably trouble free.


What I have now is separate fridge and freezer with Isotherm SP. The SP system is terrific in regions with cold water like where I am. It even works with the boat on the hard, because air circulates pretty well through the deck drain in which the condensing coils are mounted. Don't know whether it's any good in the tropics.

[robert sailor]

I have/had the isotherm thru hull cooling system and found it a bit of a pain to keep clean. We get lots of bottom growth in the Western Caribbean, I had a special brush made to clean it with. It was also eating zinc faster than expected. I used this system in the Mediterranean with reasonable success for a couple of years but the Caribbean has warmer water so I had a fridge guy install a air cooled radiator just on a test basis. I carefully measured the use of both cooling systems on our boat and found the air cooling to be just as efficient as the thru hull cooler so I changed the system over the following year and removed the thru hull cooling system. All of our sailing is in the tropics. Now another boat with another fridge could get different results so this is not a recommendation. Our fridge is 8 cubic ft and is insulated with Aerogel and has foil reflector and proper vapor barrier and uses very little power

[robert sailor]

Was going to add..the worst system I ever had was a danfoss 35 running an air/water cooled system in a Tartan 44. We were sailing the South and North Pacific and due to poor insulation that system was eating almost a 100 amp hours a day. I added a bunch of interior insulation which made the box smaller and added water cooling and on a good day I could get it down to 75 amp hours but maintenance on those water cooled systems was a chore and eventually I wasn't able to keep it running. The water pumps are terribly under built for almost continuous service. That system was really under spec'd for the job, poor choice.

[slug]

Originally Posted by robert sailor

I have/had the isotherm thru hull cooling system and found it a bit of a pain to keep clean. We get lots of bottom growth in the Western Caribbean, I had a special brush made to clean it with. It was also eating zinc faster than expected. I used this system in the Mediterranean with reasonable success for a couple of years but the Caribbean has warmer water so I had a fridge guy install a air cooled radiator just on a test basis. I carefully measured the use of both cooling systems on our boat and found the air cooling to be just as efficient as the thru hull cooler so I changed the system over the following year and removed the thru hull cooling system. All of our sailing is in the tropics. Now another boat with another fridge could get different results so this is not a recommendation. Our fridge is 8 cubic ft and is insulated with Aerogel and has foil reflector and proper vapor barrier and uses very little power

I’d be surprised if a fan cooled refer used less or the same energy as a passive keel cooled unit

[Cpt Mark]

#1. The most important thing is the box itself. How much insulation and of what quality. 20 year old boat with 2" isn't going to work well in warm areas which brings up the question of where you will be using the boat. It is a different equation if you live and cruise in the far North than in the Caribbean.

2. Size of box. You will not be able to cool a 20 cu ft box with a small cheap unit.

3. My choice is to keep it simple. Less fancy stuff to break or wear out means less maintenance and repair.

4. How will you power it? How much power will you need and where will it come from. Related. How much battery storage will you need.

In answer to your question tho, which is the worst. I don't know that there is a worst anymore. Any of the modern ones will be your worst if you have not answered the above questions or will be your best if you've answered them honestly and thoughtfully. I decided on air cooled because it's simple. I put in 2 units (1 reefer, 1 freezer) because they are relatively inexpensive and now I'm not pushing the boundaries of my system and have redundancy.

[robert sailor]

Originally Posted by slug

I’d be surprised if a fan cooled refer used less or the same energy as a passive keel cooled unit

I'm not suggesting that you reach for your Ronald McDonald mask but the power use was so close it's not worth mentioning. I'm sure if I had your typical poorly insulated and poorly sealed box the difference might have been more but it wasn't. My reefer uses in the neighborhood of 35 amp hours in a 24 hour day here in the tropics.

[RaymondR]

There were a couple of threads on the forum a couple of years age in which Richard Coleman and Ozepete battled out the pro and cons of the various systems.

Ozepete manufactures systems which have both air and water cooled condensors incorporated in the one package and recommends using hold over, or as they are also called eutectic tanks, to time shift the electricity consumption to the daylight hours.

In actual side by side tests Pete demonstrated that electricity consumption was not only moved to when plenty of solar power was available, it was actually about halved by using the eutectic system because the compressor was not cycling on and off. The economic benefit of Pete's system was the big reduction in battery discharge cycling and the extended life thereof.

In contrast Richard appeared to favor the constant cycling evaporator plate solution and the battle raged for weeks. However, for us lay folks it imparted an enormous quantity of valuable information and if you are trying to build yourself a knowledge base is well worth the read. Pete manufactures systems as "Ozefridge" and Richard installs and services boat refrigeration and they are both very knowledgeable on the subject.