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would you give up 12 volt refrigeration for?

5K views 48 replies 21 participants last post by  deniseO30 
#1 ·
This?


or do you have a non working engine driven system with holding plates? (it can be fixed)

don't dismiss it out of hand.. if you had a much larger boat you could have a full size refrigerator, freezer and even a walk in!

I could imagine a boat with an on-board generator doubling it's duty to run a compressor but the horsepower would need to enough for all the loads.

why this post? I love to see ya'll get into these discussions! :grin
 
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#5 ·
Denise

What you diagrammed is exactly what I recently replaced. I ripped the old unit from the boat and gave away the pieces, including a very nice coldplate. These system were state of the art in the '80s, using monster compressors (by today's standard) but solar power has changed everything. Also, the system in the diagram is a cruisers refridge system, which won't work without the engine running. My boat spends a lot of her time in my slip as I use her on weekends and solar now replaces the need for the engine running.

I believe what's missing from Denise's diagram is a timer.
 
#6 ·
I too pulled this engine driven refrigeration system out of my 1986 boat when I pulled my engine out when I converted to Electric Propulsion in 2008. Don't miss it and my Engel(s) work fine with just two 75 watt solar panels. Old ice box works better for storage like canned beverages that I move into the 12 volt Engel as needed. Modern refrigeration running off solar panels is the way to go these days IMO.
 
#9 ·
Engine look tiny and undetailed on my poor browse-o-matic.

But the diagram seems to omit:
1-Engine fuel tank and supply system, filters and fuel gauge
2-Engine air intake and exhaust, and proper thru-hull on exhaust
3-Engine starter and battery system (co-incidentally capable of running a 12V reefer)
4-Engine auto-start system, to power reefer as needed. And silencer, because I'm cranky when things get noisy.

Fifty years ago, IF you had a reefer on your YACHT, it was engine driven. Twenty years ago, often not. These days? Remind me, which conspiracy theory explains why engine-driven reefers just aren't used on recreational small craft, even on cruisers, very often any more. Surely, it must be a conspiracy, not just evolution.
 
#11 ·
Engine gas diesel or electric driven systems are used in refrigerated transport. Often seen hanging on the front end of a big trailer. How they work is large cooling capacity that freezes a eutectic solution in large holding plates that keep the space cold when the power is off. boat systems evolved out of that type of application.

This was "state of the art in the early years of boat refrigeration.

Guys, the photo was off seafrost's site. it's just a basic. Yeah allot is missing.

No conspiracy hellos, the breakthrough was the emergence of the DC powered compressors.
 
#13 ·
Who starts the engine when you aren't around?

With my 12V system my boat sat out on it's mooring Mon-Fri for 5 years with the refrigerator on keeping the beer cold and the food fresh with the solar charging the batteries, all on its' own.
 
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#16 ·
Who starts the engine when you aren't around?
engine driven systems are not the best choice for boats that are not used often. Holding plates keep the temp for long periods but not more then a day or two.. but that again depends on size and insulation.

With my 12V system my boat sat out on it's mooring Mon-Fri for 5 years with the refrigerator on keeping the beer cold and the food fresh with the solar charging the batteries, all on its' own.
amazing isn't it?
 
#14 ·
I'd say it depends on the boat.

On a large luxo-cruiser with a generator that runs continuously this might make sense (maybe) but if the generator runs all the time, why use holding plates instead of evaporators?

Running it off an auto-start generator could work but sizing the generator would be tricky and the control system to manage battery charging and refrigeration could get complex.

I defer to you @deniseO30 on the numbers. If you think the idea makes sense I'd like to understand why. I don't see it.
 
#19 ·
actually only the 12/24/110 volt unts make sense to me. with holding plates I'd go with a +10 on the list of best. However as many of us know the food and liquids work as a buffer when they are that temp needed. so holding plates are not absolutely necessary
 
#15 ·
We chucked the engine driven system when were built the 110 volt system. I wish we hadn't for it was a backup for the 110 and that was nice.
With boxes built in 1980, I doubt that a 12 volt system would be practical as it would probably run almost continuously. Rebuilding the boxes and installing a 12 volt system would run near 10 grand considering the galley cabinetry that would have to be dismantled and reassembled.
Our eventual goal is to add a 12 volt system with the 110 volt system, using the 110 to draw it down then the 12 to maintain the present boxes.
Interestingly enough, this winter has been far from normal weather wise. No Christmas Winds at all and lots more overcast and rain than usual. We are struggling to keep up with our present electric consumption using the wind and solar charging alone. I'd hate to be relying on either or both only, this winter.
 
#17 ·
Capta, none of this stuff is cheap. Many of the 12/24 volt units are set up for 110 volt also. like norcold and engel

If the boxes were insulated well enough for the old system it's a good chance they are near ok for 12/24 volt too. but that always starts the insulation war just by saying it.

Box size may be a problem. how big are they?
 
#20 ·
I have the Sea Frost engine driven system on my boat, it works very well here in New England. I plan on adding their 12 V. Trade winds system to it having the best of both worlds. Engine running, bring the cold plates down, use the 12 v. to maintain temps. Using the engine when ever it is running will conserve many Amps, lightening the load on my house bank.
 
#22 ·
Engine running, bring the cold plates down, use the 12 v. to maintain temps. Using the engine when ever it is running will conserve many Amps, lightening the load on my house bank.
I'm not sure that is true. I haven't run the numbers - perhaps @deniseO30 will. Given the efficiency of engine-drive v. alternator charging batteries to run a modern 12V compressor what is the Wh energy requirement? Apples to apples ...
 
#24 ·
Engine running, bring the cold plates down, use the 12 v. to maintain temps. Using the engine when ever it is running will conserve many Amps, lightening the load on my house bank.

My thinking is while motoring or motorsailing, flip on the engine driven compressor to freeze the holding plates and cool down the box. The 12 V system will not have to run as often to maintain temps until the holding plate temps rise a bit and the thermostat then calls for it.
 
#29 ·
My 12 V refrigeration system has an "automatic start up" feature, whereby the compressor kicks into high gear when the system voltage increase--such as when the engine is running. The purpose is to accelerate freezing of the cold plate. This takes some of the pressure off the house bank to keep the temp down when shore power or engine-powered alternator power are not available.
 
#25 · (Edited)
I'll write more from my desktop later on because I'm on my cell phone, now, but The holding plates Will keep the boxes cold for a long period of time

One of the arguments people try to enforce about current draw of 12 volt Refrigeration I don't agree with. For weekend/a week
The draw is so low that you almost don't have to make modifications in your electrical system since many boats already have around 200 amp hrs and 2 banks.

Weeks away at sea on the hook for weeks will Evoke a different argument.

I've not looked But the engine driven compressor He's usually big enough to cool the whole boat Horsepower wise I would say 3 to 5 horsepower

Edit (from my desktop)

The factors to use as a guide are easy to find.

watts to btu W X 3.415 (3.4 is ok)

1 horse power = about 745 watts.

horse power of refrigeration effect 12,000 btu = ton (old schoolers call it horsepower.

boxes should be at around R-25 per sq ft. some more.. many much less.

CAPTA 8 cu ft is not a big box. are they side by side?


On engine driven systems, you can have more then one box (or device like evaporator or holding plate.) the capacity of the device is determined by the refrigerant metering device (cap tube/s or TX valves.)

many if not all 12 volt condensing units draw around 40-60 watts.

Most people with boats know how to figure out amp hours and "wattnot" :)

You are all of course welcome to have a field day with this information. :) It's not written in stone and I don't pretend to be a total expert, it's just stuff I know from being in HVAC all my life.
 
#28 ·
When I found a brand new Grunert Passage Maker with eutectic holding plates for $125.. at the sailors exchange I just knew my Pilot of the Pinta was lookin out for me .Already had built the 6" insulated box in the aft cabin so all I needed was water in and out and some wiring .It;s 110v only but will run from main or the Kobota thru inverter or shore. Since the Hagendaz was good for 4 days and I lived aboard to keep track of things like that ,It was great. No more canning the ocean farm and total cost less than $300. Still works trouble free after 15 years. May be old tech but for useful/frugal hard to beat.
 
#30 ·
We have both engine driven (Sea Frost) and DC in the same box, the best of both worlds.. You'd need to pry the engine driven system from my cold dead fingers. It serves 95% of our refrigeration needs when out cruising. We only use the DC system to extend silent time at anchor.. The DC system is supplementary..
 
#31 ·
We have both engine driven (Sea Frost) and DC in the same box, the best of both worlds.. You'd need to pry the engine driven system from my cold dead fingers. It serves 95% of our refrigeration needs when out cruising. We only use the DC system to extend silent time at anchor.. The DC system is supplementary..[/QUOT

I had both for many years as the boat was originally equipped with a huge tecumesh engine driven compressor, with a massive 32f holding plate. Great combo with the 12v adler barber combo. The engine driven unit would really bring the box temps down and allow the 12 v freezer unit to work effortlessly.

However, long term, at anchor, remote cruising, the engine driven unit was to inefficient to operate. With Solar and wind I can go for virtually months at a time without starting the engine. Pretty shocking numbers to calculate the hour a day or more over close to 18 years off shore that the engine driven system would have required.

When the engine driven system finally crapped out I ripped out all the auxiliary parts..all that remains is the holding plate. Anybody want a tecumseh compressor for a good deal?
 
#32 ·
We love our Isotherm DC refrigeration system with the heat exchanger in the galley sink drain thru hull. The thru hull is shown in the thumbnail (after haulout last Fall). There is absolutely no fouling of the coil and no antifouling paint is used, as shown.

When cruising, we typically turn the engine on to maintain hot water, usually in the morning and evening, depending on how much hot water has been used for showers and dishes. The engine time to heat the water is often consistent with the time needed to keep the AGM batteries charged--thus maintaining the DC refrigeration along with other electrical loads.

BTW, our icebox has 3 1/2" of insulation and that helps to keep the compressor time to a minimum.
 

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#49 ·
wrapping up this discussion. clearly engine driven systems although great in many ways.. have been surpassed many ways.

Thanks all for the input!
 
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