The Ultimate Refrigeration System?

[CAELESTIS]

If you were to completely redesign your vessel's refrigeration system using 12v or 24v for power, what components would you choose? The goals would be efficiency, and durability for long term cruising.

1. Frigoboat (keel cooler)
2. Technautics (holding plate)
3. Novacool (air cooled)

How much insulation would you use? What type?

[Bash]

ultimate?

Pacific Sea Breeze Marine Products - Support of Glacier Bay's Marine Refrigeration Systems

[Cheechako]

I had a 1/2 HP 12V belt drive system with cold plates installed in my Passport in 1997. It was expensive. It was also a huge amps draw compared with an air cooled Cold Machine. It takes a lot to power a big cast iron compressor and 1/2 hp DC motor. Mark it up to reading too many "cruising books".
I would go for a low amp draw small unit like the frigoboat. If my box was fairly big I might go for two; one for the freezer and one for the fridge. depending on how the amp draw works out. if the freezer was separate, I might go with an Engle just for that if it could be done that way.

[Richard Kollmann]

You will not find the ultimate refrigeration without defining of what you expect from a mobile ice box boat refrigeration conversion on a C49 boat. Threads like this on the web will generate ten to twenty recommendation of what system they like without considering whether their unit will meat your needs. There are more than a dozen brand name units and maybe one hundred options but only a few that can operate well in your refrigerator application.


If I were to define an ultimate ice box conversion for a boat cruising in a warm climate I would want the following:

• Box temperatures must be capable of being maintained at 33 degrees F in refrigerator and 6 degrees F in freezer 24 hrs per day, much the same a home refrigerator.
• The correct size system with a reliability rate of its small replaceable components must not exceed 0.5 per thousand hours of operation.
• A correctly designed system must have a compressor/condensing unit service life of 15 plus years.
• If owner is not able to make repairs Avoid systems where parts and service is not available locally.

Remember if system is to be powered electrically boat’s electrical power grid must be adequately sized. In a tropical climate I would design for 120 watts of energy that might be required per cubic foot of 33 degree refrigerator box per day and 240 watts for one cu ft of freezer.

Insulation R Value requirement will vary depending on temperature of cruising area climate and size of onboard electrical power grid. Size of power grid is sometimes greater in warm climates as box liquid daily throughput can double daily power consumption. My power consumption figures above consider box increased liquid throughput in tropical climates.

[Cheechako]

"In a tropical climate I would design for 120 watts of energy that might be required per cubic foot of 33 degree refrigerator box per day ......."
Richard..... are you saying 10 amps an hour for one cubic foot..? (P=IV) Or 10 amps per day? either way this doesnt seem remotely close to reality...?

[Sailmonkey]

Originally Posted by Cheechako

"In a tropical climate I would design for 120 watts of energy that might be required per cubic foot of 33 degree refrigerator box per day ......."
Richard..... are you saying 10 amps an hour for one cubic foot..? (P=IV) Or 10 amps per day? either way this doesnt seem remotely close to reality...?

I was thinking the same thing. I have 130 watts total solar, roughly 2.5-3 cubic feet of reefer and can run the refrigerator indefinitely in the tropics( assuming I don't use the watermaker and lights).

[SURV69]

I say if you can forget about needing a freezer and only need to keep things cool, go Peltier . . . simplicity in the making.

The unit takes virtually no space, is very small(the Peltier), and only a small fan to move air off the hot side.

You can take everything you need in a McDonalds bag to completely replace the system 2 or 3 times.

Granted things don't get icy cold, but unless you need icy cold.....

I run mine mainly at night, when the sun's down and my nicely insulated cooler keeps everything cold through the day. I like my milk cold and the Peltier delivers milk cold enough that I can't gulp it. In fact a few years ago I froze some 1% milk on a rather hot day in June because of the overnight running. It was rock hard(like a brick), and I had to throw it out.

About 4-5 amps an hour, but like I said, I only run it at night for about 5-6 hours and maybe during the day for an hour or two. On average it comes to about 1.5 amps per hour on a 24-hour basis . . . 36-40 amps a day when I need it.

Aside from some terracotta jars, sand and wet rags, the Peltier is absolutely simple.

Wait til your somewhere when you $1000 Engle goes on the blink. When mine goes on the blink, I have 1/2 hour work to replace about $10 worth of parts.

[SVTatia]

Originally Posted by SURV69

I say if you can forget about needing a freezer and only need to keep things cool, go Peltier . . . simplicity in the making.

The unit takes virtually no space, is very small(the Peltier), and only a small fan to move air off the hot side.

You can take everything you need in a McDonalds bag to completely replace the system 2 or 3 times.

Granted things don't get icy cold, but unless you need icy cold.....

I run mine mainly at night, when the sun's down and my nicely insulated cooler keeps everything cold through the day. I like my milk cold and the Peltier delivers milk cold enough that I can't gulp it. In fact a few years ago I froze some 1% milk on a rather hot day in June because of the overnight running. It was rock hard(like a brick), and I had to throw it out.

About 4-5 amps an hour, but like I said, I only run it at night for about 5-6 hours and maybe during the day for an hour or two. On average it comes to about 1.5 amps per hour on a 24-hour basis . . . 36-40 amps a day when I need it.

Aside from some terracotta jars, sand and wet rags, the Peltier is absolutely simple.

Wait til your somewhere when you $1000 Engle goes on the blink. When mine goes on the blink, I have 1/2 hour work to replace about $10 worth of parts.

Surv69 - did build yours out of components or you bought it?
Do you have a link? Google didn't return anything useful.

[Saltyhog]

Originally Posted by SURV69

I say if you can forget about needing a freezer and only need to keep things cool, go Peltier . . . simplicity in the making.

The unit takes virtually no space, is very small(the Peltier), and only a small fan to move air off the hot side.

You can take everything you need in a McDonalds bag to completely replace the system 2 or 3 times.

Granted things don't get icy cold, but unless you need icy cold.....

I run mine mainly at night, when the sun's down and my nicely insulated cooler keeps everything cold through the day. I like my milk cold and the Peltier delivers milk cold enough that I can't gulp it. In fact a few years ago I froze some 1% milk on a rather hot day in June because of the overnight running. It was rock hard(like a brick), and I had to throw it out.

About 4-5 amps an hour, but like I said, I only run it at night for about 5-6 hours and maybe during the day for an hour or two. On average it comes to about 1.5 amps per hour on a 24-hour basis . . . 36-40 amps a day when I need it.

Aside from some terracotta jars, sand and wet rags, the Peltier is absolutely simple.

Wait til your somewhere when you $1000 Engle goes on the blink. When mine goes on the blink, I have 1/2 hour work to replace about $10 worth of parts.

Peltier is extremely inefficient. And you still need a way to remove the heat from the hot side. Maybe you found a way to do that for "your installation", but as Richard said, your installation is different than someone elses. To the OP, I'd buy Richard's book. I did. It pretty much answers all your questions and a few you don't know to ask.

[Capt Phil]

Best freezer system I ever worked around was on an Alaska halibut boat manufactured by Bellingham in WA State. It took a 120 HP Gen set to run it but kept the freezer bays at around -15 degrees, held about 60 tons of frozen halibut along with our ice cream!
Had a Bellingham fridge/freeze unit on our DeFever 54 which also worked a dream, quiet compressor on wheelhouse top, don't knew what it drew, amp-wise, but easily handled by cruising generator on starboard engine and inverter when anchored. Only kicked on 2-3 times in 12 hour period for about 10 minutes.
Sounds like there are quite a few smaller, efficient packages available now. If I were in the market, I would consider my lifestyle, ie., can I just think ice or must I have it in my sundowner?, how far will I be between fresh food replenishing stops?, can I live a quality life on canned food, dry/reconstituted foods for long periods?, will my cruising be in high or lower latitudes?, how many should I count on feeding?, one, two or a bunch?, Lots to consider before making the decision, I would think.
Lived and worked aboard in the PNW with only an ice box for a lot of years... so it can be done. Phil

[Jimbo485]

A peltier cooler is very inefficient but if you have plenty of energy, it is fine. We bought one for $200 as a second fridge for drinks etc.

Do the sums and compare between
A). Efficient Engel type, ($1000 - $1500)
B). Peltier type plus additional lead acid battery, wiring and extra solar panel.($200 + $250 + $100 + $400 = $950)

Or build your own peltier fridge with an eBay kit.

Your costs may vary but solar is cheap enough now to allow one to forget about being super efficient. Just use more of that sunlight!

[Cotemar]

1) Use a Danfoss BD35F compressor which works on 12/24V DC,100-240V AC

2) Insulate box with Aerogel Spaceloft which has an R-Value of R10.3 per inch.
Aerogel is .4 thick X 8 layers = R33 at 3.2 inches thick

[Richard Kollmann]

Cheechako, maybe you misunderstood the question “If you were to completely redesign your vessel's refrigeration system using 12v or 24v for power, what components would you choose? The goals would be efficiency, and durability for long term cruising.”

Long term cruising to me means possible cruising in warm tropical climates so equipment selected should be designed for worst case climate conditions 90 degrees seawater and 90 degrees ambient air temperatures while maintaining desired box temperatures. If your boat is not in tropical waters subtract 2% from energy estimate for each degree of cooler seawater. You can apply the same 2% per degree if you increase box temperatures above my desired ultimate box temperatures. A box refrigerated as a drink cooler off the North West coast of Washington may need only 3 amps per cu ft per day.

[Richard Kollmann]

Open Cell insulation
Unless a boat in the water has full time air conditioning to keep moisture out it will be attracted to material cooler surfaces. Open cell refrigerator insulation will become over time saturated with moisture Open cell insulation functioning as a dehumidifier saturated with moisture is useless unless moisture is kept out of the open gas/air spaces. Continued compressor cycling allows open cell air to enter and leave each cell and deposit moisture in these cells. It is true that spun glass and materials like Aerogel will not absorb water but it will still condense there. I have some Spaceloft insulation but static testing is all I can do with it. The real test would be to experiment with Aerogel as has been done with other open cell insulations. If heat conducting water filled cells that cannot expel water insulation will be of little value and can structurally collapse into the bilge.

[Weyalan]

Originally Posted by Richard Kollmann

Open Cell insulation
Unless a boat in the water has full time air conditioning to keep moisture out it will be attracted to material cooler surfaces. Open cell refrigerator insulation will become over time saturated with moisture Open cell insulation functioning as a dehumidifier saturated with moisture is useless unless moisture is kept out of the open gas/air spaces. Continued compressor cycling allows open cell air to enter and leave each cell and deposit moisture in these cells. It is true that spun glass and materials like Aerogel will not absorb water but it will still condense there. I have some Spaceloft insulation but static testing is all I can do with it. The real test would be to experiment with Aerogel as has been done with other open cell insulations. If heat conducting water filled cells that cannot expel water insulation will be of little value and can structurally collapse into the bilge.

In our recent refrigeration system build we used 3" of Spaceloft, but with 5 laters of foil (moisture barrier / heat reflector) over that 3". We hope that these will be sufficient to prevent moisture ingress. We also laid glass / epoxy resin on the inside of the outside structure and the outside of the inside structure.