Which Reefer System to Choose

[Richard Kollmann]

Originally Posted by Coolerking

I can't get too deep into specifics here, but our company has been producing cold plates and condensing units for boats of all sizes for more than 30 years, we (me) have recently retrofitted a few sailboats that had big, heavy, noisy belt driven eutectic plate systems, with a new style, 12/24vdc Masterflux driven units that we build, they are seawater cooled.

Most have solenoid panels to control multi zone systems.

Very quiet, variable capacity to fit a wide range of box configs.

They weigh less than half of what they replace.

Anyone interested in replacing these large boat refrigeration will need to get deep into specifics. Many of those who followed Kevin Alston work with Tecumseh in the development of the Masterflux compressor for Glacier Bay refrigeration could see its possibilities with output capacities from 400 to 15000 Btu per hour and low evaporator temperatures of -10 degrees F. This Sierra Masterflux in a low temperature application freezer evaporator will produce 400 to 1600 Btu per hr twice that of a Danfoss BD80, but still only 50% of an old ½ HP unit in many large box systems. Unfortunately Glacier Bay got out of the refrigeration business and RParts.com seams to handle their replacement parts. The problem with 12 volt reciprocating and scroll hermetically sealed brushless motor compressors is their electronic controllers holding up to the marine environment. One look at Masterflux electronics maybe why the industry is not using this compressor in boats known to have dirty electrical current on occasion.

I tried to find your company web site with no success as it seems to be the only company using the Masterflux in marine refrigeration. There are package AC companies using the high back pressure models in truck air conditioning.

[wingssail]

We have used 4 refrigerators in 33 years, starting with a solid-state portable ice box (which was not cold but used plenty of power!), next a $40 used Norcolder 12V system which did work but also used plenty of power.

Then in 2010 we installed an Adler Barbour 12v thin plate evaporator (box shape). The Alder Barbour BD35 worked well, would freeze ice cubes and a couple of weeks worth of meat, and the spill over cooled the smallish refer box. We also re-did the insulation and liner. This system consumed about 120 Ah per day in the tropics, and about 80Ah per day in colder climes. Surprisingly, for an air cooled unit, the outside sea-water temperature made a big difference. The power usage was disappointing considering the 5" of insulation and the small box size but we loved the simplicity of the system.

This year the BD35 compressor failed. While waiting for a new system (we decided to replace the compressor with a Dometic CU85 and put in a slightly larger box shaped evaporator) I again re-did the insulation and the liner, and did a much more thorough job of it.

Now the system is installed and works terrifically. We freeze ice cubes in about 10 hours and freeze 3-4 weeks worth of meat. The refer portion (outside the box shaped evaporator) is very cold and roomy enough. The power usage, in hot tropics, is less, about 80AH/day. There have been some thermostat issues which we have not entirely solved yet, but we're getting there.

We are advocates of simple, air-cooled, 12v systems. This one cost about $1100 (plus shipping to Mexico). I'm certain that other designs have advantages and better efficiency, but the size, weight, and simplicity of this system is what originally sold us on this concept, and still does.

A key is to do a good job on the insulation and liner. No air gaps, no leaks of liquid into the insulation, a good lid, and apparently, careful installation of the thermostat.

[kvstein]

I have had success with a FrigiBoat system. It is a DC system that uses a small Danfoss compressor and an external keel cooler which is highly efficient. The key was heavily insulating the box with 6 inches of foam all around and vacuum lids. This part of the job was much more expensive than the FrigiBoat. But yes I can freeze ice cream in the tropics. I have had one issue with the system in 10 years when the keel cooler leaked due to electrolysis ruining the internal plates.

[FlyingScot]

Originally Posted by a64pilot

It’s really not as simple as just hold over plates vs thin plate evaporator.

The hold over plates original design was I believe intended to be primarily an engine driven large compressor removing a huge amount of heat from a significant amount of eutectic fluid, and then over night the large mass of frozen fluid would keep food cold until the next day and the engine was again run.
However there is more to a system than the evaporator, there is capillary tube systems which are very sensitive to refrigerant charge, so much so that it’s an art getting the charge level correct and there are thermal expansion valve systems that are not at all sensitive to refrigerant level, then does a system have a filter / drier? Finally a system, is well a system and the condenser that never gets much press is as important as the evaporator, plus how is the condenser cooled and is it sized large enough? Is there any additional compressor cooling?
Finally how many proprietary pieces does a system have, meaning can you get replacement parts easily of are they only available in one place?
Finally how is the support? That to me is vital. Any system you consider buying from the Windlass to the Radar or refrigeration etc., before you buy, give customer support a call and see who you are talking to, if it’s a call center that the best they can do is open a service ticket for you, or their answer is box it up and send it in and we will inspect for warranty, I’d give them a pass, cause that’s not going to help much out in the sticks.

If it’s a smaller company, how long have they been in business? Not real important unless there are proprietary parts, then it’s important.

Properly designed, a thin plate evaporator system can be as efficient as a cold plate, in theory it can be more efficient as it’s cooling the food directly where a cold plate system is first cooling the plate and the plate is cooling the food.

However it’s almost a certainty that all inexpensive systems are always thin plate, capillary tube systems, that doesn’t mean that are all junk, but it’s certainly a lot less expensive to manufacture.

In other words I’m afraid your going to have to do your due diligence and do some reading, this is a good place to start.

Myself, personally I’m a fan of KISS, the fewer the parts, the more common those parts are and how simple is the system to service means a whole lot to me, I’m, not a fan or electronic controls, in my opinion they really don’t do much to increase efficiency and are very often the source of problems.
You want a simple system that you can jumper the thermostat for example until a replacement comes in, or use a computer fan for the condenser until the proper fan comes in etc.
Carry a spare controller, no matter who’s system you buy, that’s the one thing that is irreplaceable and you can’t jury rig

I agree with this and I have spent quite a bit of time getting my system working well. Our is a Sea Frost BDxp air cooled with a BD80 compressor and R134a.

My perfect system would be two small BD50 air cooled units. One for the fridge another for the freezer. They would have stainless steel evap plates (like Sea Frost) and a real TXV (like Rich's). Also a sight glass and dryer module. Each hooked to a 3 speed + AEO controller. We use old style themostat, but I see the appeal of the digital thermostats. Fantastic insulation is a dream of mine. Heat loss just chews up the amp hours.

I recommend a separate Engel if you have the space. It's always nice to have a backup plan. We don't like warm drinks. This assumes you have a spillover system like ours. If you have two separate ones then this is less critical.

A64, what thermostat do you use to control the spillover fans inside your box?

Edit: I'd consider a 404a refrigerant system to get the ice cream really cold.

[Cpt Mark]

Originally Posted by wingssail

We have used 4 refrigerators in 33 years, starting with a solid-state portable ice box (which was not cold but used plenty of power!), next a $40 used Norcolder 12V system which did work but also used plenty of power.

Then in 2010 we installed an Adler Barbour 12v thin plate evaporator (box shape). The Alder Barbour BD35 worked well, would freeze ice cubes and a couple of weeks worth of meat, and the spill over cooled the smallish refer box. We also re-did the insulation and liner. This system consumed about 120 Ah per day in the tropics, and about 80Ah per day in colder climes. Surprisingly, for an air cooled unit, the outside sea-water temperature made a big difference. The power usage was disappointing considering the 5" of insulation and the small box size but we loved the simplicity of the system.

This year the BD35 compressor failed. While waiting for a new system (we decided to replace the compressor with a Dometic CU85 and put in a slightly larger box shaped evaporator) I again re-did the insulation and the liner, and did a much more thorough job of it.

Now the system is installed and works terrifically. We freeze ice cubes in about 10 hours and freeze 3-4 weeks worth of meat. The refer portion (outside the box shaped evaporator) is very cold and roomy enough. The power usage, in hot tropics, is less, about 80AH/day. There have been some thermostat issues which we have not entirely solved yet, but we're getting there.

We are advocates of simple, air-cooled, 12v systems. This one cost about $1100 (plus shipping to Mexico). I'm certain that other designs have advantages and better efficiency, but the size, weight, and simplicity of this system is what originally sold us on this concept, and still does.

A key is to do a good job on the insulation and liner. No air gaps, no leaks of liquid into the insulation, a good lid, and apparently, careful installation of the thermostat.

Thank you for your thoughts, info and experience

[Cpt Mark]

Originally Posted by kvstein

I have had success with a FrigiBoat system. It is a DC system that uses a small Danfoss compressor and an external keel cooler which is highly efficient. The key was heavily insulating the box with 6 inches of foam all around and vacuum lids. This part of the job was much more expensive than the FrigiBoat. But yes I can freeze ice cream in the tropics. I have had one issue with the system in 10 years when the keel cooler leaked due to electrolysis ruining the internal plates.

Keel cooler on a cat I can beach is a non-starter and the electrolysis issue scares me. Thanks for posting.

[Cpt Mark]

Originally Posted by FlyingScot

I agree with this and I have spent quite a bit of time getting my system working well. Our is a Sea Frost BDxp air cooled with a BD80 compressor and R134a.

My perfect system would be two small BD50 air cooled units. One for the fridge another for the freezer. They would have stainless steel evap plates (like Sea Frost) and a real TXV (like Rich's). Also a sight glass and dryer module. Each hooked to a 3 speed + AEO controller. We use old style themostat, but I see the appeal of the digital thermostats. Fantastic insulation is a dream of mine. Heat loss just chews up the amp hours.

I recommend a separate Engel if you have the space. It's always nice to have a backup plan. We don't like warm drinks. This assumes you have a spillover system like ours. If you have two separate ones then this is less critical.

A64, what thermostat do you use to control the spillover fans inside your box?

Edit: I'd consider a 404a refrigerant system to get the ice cream really cold.

Thanks Chris