Ice Box / Refrigeration Questions...

[Mule]

oK guys. I am a light weight on this issue. I have an oversized front opening home style 12/110 Norcold that is 27 years old. I strongly suspect it is less than efficient. It turns the galley into a cave and if it were gone the whole place woule open up + added counter top.

I have (product of soon to be divorce) a larger bar fridge that pulls 1.4 amps at 110 which is almost 13 amps at 12 volts. I have a 2.5 kw inverter with a 3.5 kw generator. I plan to add a chest freezer ($175) @ 1.7 amps. Right now I have 2, 235 amp 8ds and I might have to add another, but I have not tested the system.

Now, I have it together on the airconditioner (13 run amps) it is only to be used while the generator is running or plugged in at the dock. Now while on the hook, I plan to load the freezer with dry ice stacked at three different levels wrapped in bubble wrap whit additional bubble wrap at the top, with the lid duc taped shut for additional protection against leakage. The fridge I will have frozen gallon containers of water in it and start the trips(s) with duct tape against leakage and maybe dry ice too.

First days out I will live out of an igloo and do all I can not to open either freezer or fridge until absloutely necessary.

Thoughts and or suggestions that might help make this system work for a couple of weeks at a time? Any other tricks shared will be appreciated. You see I get really super ribeyes out of fort Worth @ $4 a lb so I will have about about 100 of em vacumm packed and frozen. might be good trading stock at the islands.

I hope I do not have to bite the bullet and do a marine system,,Thoughts. I would much rather have underway cable tv... Yeah I know but decadence is good...right??

[Minggat]

Shibbershabber,

If you're still weighing options, one more...
Sterling compressor (globalcooling.com) kick on power saving. Lot's of stuff about them on this forum.

I have, embarassingly, over-fridged my boat. I first rebuilt my box, then (not knowing what I know now) decided to back up with a stand alone unit. I do love my Fridgefreeze, and they're a great company. But I simply didn't understand what I was doing wrong to make my built in box so unreliable. By the time I had figured it out, I had a built in box and a stand alone. OK. I still have back up or seperate freezer. Like I said, love it.

Then I dropped the dock lines and headed south. 2 weeks of sailing/passagemaking with a total of 109 hrs of motoring. Let me keep this short. Built in box unit died. So I'm sitting there thinking about which way to go and come acrossed the Sterling compressor. C02 is the refriderant. Very low power draw. So I bought one to bring me back up 2 reefer units.

OK, still trying to make this short. Old unit needed 1 wire reconnected. Works perfect. That box now has it's own backup. The Sterling unit sits on top of the box and cold is ducted (it actually moves air). Negative of the Sterling is the sound I have to listen to because of where it's positioned. When I'm off of the boat or motoring, the Sterling (and the Fridgefreeze) is/are used.

Point is, check out Sterling compressors on this forum.

[chriswheat]

I just started outfitting my "new" Morgan 34 for a trip to the Bahamas and am shopping for icebox retrofit refrigeration options. I searched the forum for relevant info and was surprised to see that the last discussion was in 2010, unless I'm missing something (which would be typical). Does anyone have experience with the isotherm self pumping water cooled thru-hull system? I understand that the first step needs to be making sure the ice box is properly insulated, which is another topic, but I'm looking for opinions on air-cooled vs water-cooled. The water-cooled systems appear to be more efficient, but are they higher maintenance? Any thoughts?

[Hudson Force]

Originally Posted by chriswheat

..........
..................... I'm looking for opinions on air-cooled vs water-cooled. The water-cooled systems appear to be more efficient, but are they higher maintenance? Any thoughts?

I've had both water and air heat exchange systems for refrigeration with little significant maintenance issues. I would agree that the efficiency of heat exchange with water is better than air, but any advantage with this is miniscule compared to the ease of moving air compared to moving the water.

I kept a cold plate system with 2 cubic feet of freezer and 4.5 cubic feet of refrigeration for a continuous one amp draw using a Danfloss compressor and a small "computer" fan as built with the Technautics "Cool Blue" system. You can't do this with a system that requires pumping water.

[a64pilot]

Water also has many other issues, especially if it's just a trickle flow like it is for refrigeration.
In my opinion it's complexity you likely don't need, now maybe if you had to have the compressor in your sleeping space, then maybe as the fan does make some sound, then water cooled maybe.
However the compressor section can be placed quite a distance from the box.
The Technautics system is extremely flexible. I have 14 cu ft of box, roughly split in half freezer / fridge. I have the original 30 yr old insulation, I use five or six times the power that Hudson did, but keep the freezer at single digits and fridge right at low 30's.
It is a custom build, dual cold plates and a BD80 sized compressor, but still the basic Technautics set up.

Biggest effect on efficiency I believe is insulation, I'm sure if properly insulated I could cut my consumption in half and likely push the freezer into negative temps.

[Hudson Force]

a64pilot's comment about the significance of insulation is very important. I should add the note that the efficiency of the system that I described above was largely due to reducing an 11 cubic foot ice box to 6.5 cubic feet with the use of extensive quality insulation.

[Auspicious]

Originally Posted by chriswheat

Does anyone have experience with the isotherm self pumping water cooled thru-hull system? I understand that the first step needs to be making sure the ice box is properly insulated, which is another topic, but I'm looking for opinions on air-cooled vs water-cooled. The water-cooled systems appear to be more efficient, but are they higher maintenance? Any thoughts?

I have two Isotherm SP systems (one for fridge and one for freezer). They are 11 years old and have required no maintenance and one repair (a thermostat failed). My experience with a wide range of ice and refrigeration systems on deliveries makes me a firm believer in water cooling with a preference for the Isotherm SP and Frigoboat keel cooler systems.

I've never NEVER seen anyone do proper maintenance on air-cooled systems.

[Hudson Force]

[QUOTE=Auspicious;2415225.......................
........................ I've never NEVER seen anyone do proper maintenance on air-cooled systems.[/QUOTE]

"..never seen" might be because there'e not much to look at. Everything is the same within the basic systems of the compressor and cold plate; so there's only the fins for increased surface area to promote heat exchange and the little fan. These little fans rarely fail and the only proper maintenance is to keep the dust from collecting on these fins and fan blades.

I like the keel coolers too, but I'd rather dust my fins and fan blades than deal with keeping the marine growth clear from increased surface area on the hull.

[Auspicious]

Originally Posted by Hudson Force

"..never seen" might be because there'e not much to look at.

What I see time and again are cooling fins with enough dust and often hair to construct a small colony of rabbits. How hard is it to vacuum out the fins every few months. I've seen so much accumulation that you couldn't clean it without disassembly.

The maintenance is easy. Failing to perform it makes it a full scale project.

It's great that you keep your air heat exchanger clean. You are the exception rather than the rule.

[Hudson Force]

Originally Posted by Auspicious

What I see time and again are cooling fins with enough dust and often hair to construct a small colony of rabbits. How hard is it to vacuum out the fins every few months. I've seen so much accumulation that you couldn't clean it without disassembly. .......................

Here's where your experiences cover a far bigger range than mine. There are some times when I offer to help a fellow boater with problems, but I'm not in a position to look at many different people's maintenance. You might be in a position with a boat yard or some service where you see the full spectrum of boat owner's equipment. I've always just been responsible for my own stuff and I tend to be attentive to details on my own boats. I often have little observation outside my own responsibilities.

[Auspicious]

Originally Posted by Hudson Force

I often have little observation outside my own responsibilities.

The burden of a delivery skipper. *grin*

I think it's funny that so many people worry about water on board. Yes, leaks are a real problem. The biggest issue I see is dust and other debris, especially on liveaboards and long-term cruisers. Ventilation fans, air-cooled refrigeration, air-conditioning, and especially computers get badly plugged up with dust.

Cleanliness is important.

Irrespective of one's approach to refrigeration on a boat, keeping everything clean--heat exchangers, filters, strainers, and the box itself--is very important to performance. Figuring out a way to get you head and at least one arm all the way to the bottom of the box so you can get it really clean is important. I need a step stool. *grin*

[chriswheat]

I thank all of you! As always this forum is a wealth of information. I can ask you guys anything...and you'll tell me anything! Seriously though, I appreciate all the input and will put it to good use.

[softdown]

FWIW....my new $400 ice chest seems to make ice last almost twice as long as my cheap old chest. They would seem to make some good insulation these days.

One of the cheaper ways to get a small and decent propane fridge/freezer is to pull one from an older camper.

I know the refrigerators are often, by far, the largest energy consumers in solar homes. Mine seems to be on almost half the time during July and August....though that is likely a large exaggeration. Good thing the solar panels are enjoying their best months.

[GrowleyMonster]

Icebox, or even a high quality ice chest that is kept in the shade and seldom opened, is great for a weekend. At a dock, a cheap cube refrigerator run off shore power is inexpensive and convenient. For cruising, with multi day or multi week passages, You will have to do without cold stuff, or go with something more involved. I have seen some dandy homebrew refrigerators and freezers made out of old household fridges. If you go with a chest type design, cold air doens't spill out every time you crack the lid to get something. There are turnkey marine systems that are very efficient and flexible, if you don't mind paying a pretty good sum out the gate for it.