# Refrigeration Conservation



## Cruisingdad (Jul 21, 2006)

Refrigeration Conservation... (smile)...​
Well, as this is the cruising forum, I felt it might be beneficial to discuss refrigeration techniques that have worked for us to keep your 12v costs at a minimum. I am not the final expert on this (or anything in life, for that matter), so I urge anyone with other ideas to feel free and chip in.

Refrigeration. It is one of those things that I have had old salts tell me you do not need, but I will be darned if I will do without. There would be a mutiny of kids, wife, and dogs (not sure who would lead it either!!). But, refrigeration has the distinction of being about the biggest electrical hog on a boat on the hook. Many of the modern coastal production cruisers use Adler-Barbor refrigeration, as I do. Short of sticking an ice-pick through it (no laughs... it COULD happen to you!!), it has served us well on our many trips. The general budget for a AB system is about 50-60 ah/day. With that in mind, even large 12v systems will begin to get taxed before long. Thus, here are some key ways you can do your own Refrigeration Conservation:

1) Stick your head inside the box and look around for holes. Sound silly? I bet if you own a production boat (or almost any boat) you will see the refrigeration lines come right into the box and are not sealed!! It is like leaving the door cracked or lid up! Depending on the size, you can use MG caulk or even the can of Foam Stuff to seal it in. If you use the latter, let it dry completely before you cut it to shape. Acetone cleans it up when wet. A putty knife cuts to shape when dry.

2) Plug the drain (foot drain) with a cork or similair object. It might not save you much, but I see no reason to cool the water under the boat. Keep the T-Hull closed too - though I am sure this is a practice most people do anyways.

3) Use thick plastic sheets to cover the inside of the front door. Remember when you would walk through the old grocery stores and you had to reach through hanging plastic to get something that was refrigerated? Make a similair system on your boat. Thick plastic, cut in strips, screw it just to the inside of the door at the top.

4) Resist opening the front door. Even with the plastic strips, when you open the front door the cold air comes straight out. On a passage, I drop a little screw through the "lock hole" so it cannot be opened by those who forget (ie, the kids). On long runs, pack the things you will need most on top through the top-load.

5) Double insulate. Styrofoam, for all of its negatives on the environment, is one of the best insulators and is dirt cheap. I would not do this unless the original box was not well insulated (as this takes up some room in the box), but it is a consideration.

6) Use a "heat blanket" on top. You know the aluminum emergency heat blankets you can buy at about any backpacking store? They keep in cold too. They are cheap. Put one aross the top of your box (on the inside) where you have to push it to the side to get the item(s) you need.

7) Keep your fridge stocked. The more stuff in there, the better. A super-stocked fridge (once it has gotten all of the items cold) will maintain its own temperature better. The cold items act as their own cold plate. You also seriously minimize the air inside, which is most apt to dissapear when you open the door.

I hope some of these tricks help some of you as you gear up to punch off - whether around the bay or around the horn. They have worked for us.

Great sailing and fair winds -

- CD


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## sailingdog (Mar 19, 2006)

cd-

good overview...


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## PBzeer (Nov 11, 2002)

I'd agree, some very good tips. On mine, I put a valve in the drain line, rather than using a cork or other stopper (one of those flat stoppers might make a better surface than a cork).

I've also been trying to think of the best way to insulate around the outside of the box, as the area between the inboard side and hull side of the box isn't really usable for storage. Any suggestions? Would be nice to just fill it up with foam, but I have some concerns about absorption and eventual deterioration of the foam.


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## Cruisingdad (Jul 21, 2006)

In chemistry, we always said the best insulator was styrofoam - believe it or not. I would imagine styrofoam would be viable for a very long time, is cheap, is easy to get, easy to cut, easy to install (if you have acces to that space). Those are my thoughts, PB.

- CD


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## Giulietta (Nov 14, 2006)

CD, I have a regular 12V 100liter refirgerator with ice maker.

As you know my house battery is only 70amp, but this summer I will upgrade and get another battery, maybe 140 amp, just for the cruising.

Twice last summer, we ran the house battery completely flat with the refrigeartor, because normally I run the diesel engine for 1 hour to charge the battery, and those days I forgot.

Assuming I have more amps next time...is there a way to make the refrigerator more power efficient???
I heard that switching on/off on a time basis uses more power than if I let the refirgerato'rs thermostat do the start and stop of the compressor.

I know about opening the door and all, but do you have more ideas?? There is no way the refrigerator is coming out. It was one of those things my wife chose and requested. (I remove it for racing, only) the rest of the time its inside.

G


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## donrr1 (Oct 25, 2002)

It may not be possible for your application, but getting a top opening door setup would be the best suggestion I could give. A side opening door lets cold air spill out every time it is opened. Even the plastic strips will be parted to let this happen when a hand is stuck thru. Cold air sinks, hot air rises, the zone on top of the fridge when opening a top door doesn't exchange air immensly upon opening. It's definately a more neutral situation than a side opening door.

Just my 2 cents...

Don


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## Giulietta (Nov 14, 2006)

Don,

I had absolutely no saying in this whatsoever...I didn't even wanted it...but either that or no boat....


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## PBzeer (Nov 11, 2002)

Actually Giu, what you might consider when not racing, is using a cooler for things like drinks and snacks that you frequently get in the reefer for. A couple of gallon jugs of water, left in the freezer at home for a couple of days should last you a couple of days, and then you have water to drink as well. I have a small cooler that sits in front of the pedestal that I use just for drinks I'll want during the day.


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## Giulietta (Nov 14, 2006)

PB, That is a good idea. We have a large 20 liter water conatiner that we fill with ice and thus have cold drinking water for at least 5 days.

I will get one of those coolers you have all over in the US, not so popular here.

The refrigerator my wife uses to keep the meat, butter, eggs, ham and food that need refrigeration PLUS the drinks.

I will defenetely do that...buying a cooler tomorrow...

thanks


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## PBzeer (Nov 11, 2002)

You're welcome Giu. Sometimes the simple answer works well, eh?


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## Giulietta (Nov 14, 2006)

As you say there KISS....i saw one that even has a 12v fan or something...


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## TSOJOURNER (Dec 16, 1999)

Giu...so your're one of those guys I see around the dock unloading his his boat? Shame on you!


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## Giulietta (Nov 14, 2006)

You have good eyes to see me all the way from there  


no...the crew does...I give orders!!!

We only do it once a year. Say it the other way around...I load the boat in July till september to go cruising!!


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## Cruisingdad (Jul 21, 2006)

Giu,

I have used dry ice on my fridge. There seemed to be some debate amongst the folks here about its safety... but I have used it many times and am still alive. Boats breathe so much (at least mine) that I do not see the big deal anyways. Wrap it in a bunch of newspaper and tear a hole in it for breathing. THe bigger the hole, the colder the box. It will take some load off of your unit. A really big hole will freeze everything in there so be careful. Dry ice is cheap and fairly available (in the US at least). Follow the stuff I said earlier. Stuff it is full as you can... especially in your application because air loss will be your biggest killer. If you stuff it BEFORE you leave you can use the dock power to pull it down to your desired temperature. Allow 24-48 hours, I guess, so plan ahead.

- CD


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## Cruisingdad (Jul 21, 2006)

Thank you SD for the reply. I am heading out. Good night all.

- CD


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## Sequitur (Feb 13, 2007)

Cruisingdad said:


> Keep your fridge stocked. The more stuff in there, the better. A super-stocked fridge (once it has gotten all of the items cold) will maintain its own temperature better. The cold items act as their own cold plate. You also seriously minimize the air inside, which is most apt to dissapear when you open the door.


On two of my previous boats I have had multiple fridges and freezers, allowing me the flexibility of shuffling contents and progressively shutting-down empty units as the cruise progressed. This works very well in keeping the air space to a minimum and reducing power requirements; I have seen two full units draw less power than a single half empty one.

On my new boat I have specified two top-loading freezers and two fridges for the galley.


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## Waymar83 (Jun 5, 2006)

We've got a top loading fridge on Waymar (Jeanneau- Attalia '83) - Fairly small. (especially when we end up with 5-6 on the boat for the long week-end).










We supplement cold storage with a portable 12v cooler.

As mentioned earlier, it helps by cooling everything before, making sure the cooler(s) are full. Easily keeps everything cold for the long week-end.

For longer cruising (1 week) we would run the engine everyday for 1-2 hrs to recharge the batteries (and plug in the electric cooler - I don't let the cooler run only on house batteries).

Oh, we do sail in Canada (Lake Ontario) so although a few weeks in summer it gets fairly warm, water temperature rarily gets above 21-22C 
.


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## denby (Feb 21, 2007)

Hi, I'm Dennis, new to sailnet. bein in the refrigeration field for 42 years.
PB, there is a spray foam that is used for wet spaces and once cured repells water. It mite be found at homedepot or lowes. Plugging the drain with cork is a good idea because cork is an insullator


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## sailingdog (Mar 19, 2006)

I prefer top-loading refrigerators to front-loading for a couple of reasons.

1) The cold air tends to stay in the refrigerator better.
2) The stuff in the refrigerator tends to stay in the refrigerator better, especially when the boat heels.


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## camaraderie (May 22, 2002)

SD...yes,,,but the third law of top load refrigeration is that the item you want is on the bottom of the bin encrusted in 2 inches of ice and reachable only with arms the length of Shaquille O'niel!


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## sailingdog (Mar 19, 2006)

camaraderie said:


> SD...yes,,,but the third law of top load refrigeration is that the item you want is on the bottom of the bin encrusted in 2 inches of ice and reachable only with arms the length of Shaquille O'niel!


Picky, picky, picky... that's what I have crew for.


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## TSOJOURNER (Dec 16, 1999)

When I had my refrigeration system rebuilt a couple years ago, I divided into two seperate systems, AC and engine driven. Both with their own accumulators. The problem was two doors for the freezer and two for the refrigerator, top and side. With a 180 amp alternator, I can run the AC while underway with throttle at 60% On the hook, I run the power engine driven unit for 1/2 hour every two days. Keeps everything below 30F. 

The problem has been ice accumulation on the coldplates (3" X 18" X 20") two in the freezer and one in the refer. As 1-2 inches of ice accumulates, space inside decreases dramatically, and the cold plates become insulated from the interior. I was told by the expert that this is caused by air entering the interior through either of the doors. 

To help to solve this problem, I sealed the front doors, which I never used except for cleaning, and added wide, thick strips of weather stripping tape to the tops. The plates now have a light frost on their surface, no heavy icing, and have cut down on engine running to 1/2 hr every 3 days.

The solution is to keep air out in order to maintain efficiency.


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## TSOJOURNER (Dec 16, 1999)

*low budget*

Well, don't know how usefull it will be. I am a low budget saylor from south Brazil and thinks here are not so easy and cheap to find, like equipments and materials. So on my 27' I did a very good insulation on the ice box with those boards used to protect itens on a package. Don't know how it is called in english, we call it isopor. I used 6 mm thik boards. Then I took apart an old 220v house refrigerator and put this parts inside the ice box. As most of the time the boat is at the dock (when I am on board) it works with land power suply. And when i am sailing for more then 2 or 3 days I use the boat 12v system with an inversor, charging the batteries thru a gasoline generator. It all for about 100 USD.


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## TSOJOURNER (Dec 16, 1999)

i thought about that too....we have an engine driven system but i wanted an AC system for when we are in our slip. i tried taking apart a cheap mini fridge to try and make it work but i could not get the right parts inside the box and the right stuff outside the box....

anyone else tried this?

mike


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## Freesail99 (Feb 13, 2006)

I have a Engel 45, while not a big fridge/freezer unit, it works and works well. It can be plugged into both ac and dc so when when goes out it switches to the other. It will also run on ac oonly if you so desire. It uses .7 amps per hour on fridge mode. The Engel can be had for under $700.00.


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## TSOJOURNER (Dec 16, 1999)

Here's what I've found on my boat.

I accquired this vessle in August of '06. She had been 'abandoned' by the po, so I was pleasantly surprised when the refridgerator and the Yanmar diesel started and ran. But this is about refrigderation.

I never did a fan check on the condenser side of the Alder/Barbour unit. Surprise, surprise . . . when I finally did a close inspection (yesterday) . . . the fan had failed.

Now, I am looking forward to much more efficient cooling.

A check of that fan might be in order. And cleaning the condenser heat exchanger.

Fair winds,

Tom


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## camaraderie (May 22, 2002)

The Engel looks like a good solution for minimal refrigeration needs. The model Freesail uses is actually a 1.6 cubic boot box which can be cooled to 40 degrees with a 77 degree ambient temperature on less than 1 amp/hour assuming the box stays closed. Obviously, how often it is opened for one of those 60 beers will influence the amps used greatly. Running 100% of the time it draws about 2.75 amps which would be a very worst case scenario. 
Here are the power curves for various temps outside and inside the box. 
http://128.121.204.56/engel/MT45F curve.jpg


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## Freesail99 (Feb 13, 2006)

The secret is to freeze a jug a water and put that in another cooler with the beers.........


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## Valiente (Jun 16, 2006)

Freesail99 said:


> The secret is to freeze a jug a water and put that in another cooler with the beers.........


You aren't wrong with that. If you aren't going to pack the fridge with nearly frozen food (meaning you can turn it RIGHT down for the better part of a week if you have a decently insulated box), you should throw in a block of ice in a rubber bag to hold the melted water.

Alternatively, throw ice into a Koolatron (3-4 amp draw), pack it with cold beers...uh, supplies...and then unplug it and wrap it in a sleeping bag or a Mylar "space blanket". I've gone two days this way on the old, fridgeless boat keeping things at bacteria-discouraging temperatures.

Of course, a rethink of what actually requires refrigeration is helpful, as well. Old cruising books talk about getting fresh eggs (never refrigerated) and coating them...they last six weeks. Certain vegetables, if kept ventilated, last a long time. Bread needs a bin, and so on. Cheese can be preserved in jars. Milk can be UHT. And so on. If we just needed refrigeration for keeping canned beverages cold, we wouldn't need a lot of refrigeration, or rather, we could run it less extravagantly.

At least I could...I don't drink on passage!


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## TrueBlue (Oct 11, 2004)

We have an Engel upright, undercounter AC/DC refrigerator built into the galley cabinetry. It is a front access however, an option Nauticat offered over the standard top access units. I believe Engel only makes portable units now though.

We do like the convenience of a front access unit but agree it is not the most energy efficient - due to amperage draw and the fact that cold air drops out each time the door is opened.

One tip we have that works for our Igloo cooler - used for beverages when cruising for a few days, is to freeze water in those 7 litre silver mylar wine bags - contained in those cheap wine boxes. We never drink the stuff, only vintage wines for us. But, our dockmates do and save the empties for us.

They're reusable - the pour spout/cap pops off for refilling. Just place in your home freezer a couple days before packing the cooler - 2 bags last for three days with us - before having to buy blocks as replacement, and no water mess when they thaw. We do have a full enclosure Sunbrella cover for the cooler, with a built-in cushion seat -which helps with the insulation.


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## sailingdog (Mar 19, 2006)

I have an Engel on my boat... Love the little beastie... since it works like a champ. Since it is top loading, it tends to lose very little cold air when it is opened.


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## Mkfcdl (Mar 11, 2003)

Just a little note regarding top-loading doors: using a top door instead of a front-loading door definitely saves the cold air but always use a backup method to keep the door open, especially in a seaway. I learned the hard way that the latch that keeps a top-loading door propped open can self-unlatch if the boat makes a quick rolling motion in the same direction as the lid opens. And when the boat comes back the other way that heavily insulated door gets moving pretty fast--fast enough to cut off a finger. Always use a bungee cord or other secure method to keep the door from slamming shut should the normal latch fail.

Regards,
Mark


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## sailingdog (Mar 19, 2006)

Good point Mark, but not much of a worry for me, since the refrigerator I have is a tiny Engel unit... and it is installed along the long axis of the boat...so rolling isn't much of an issue.


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## TSOJOURNER (Dec 16, 1999)

If you are in the market for a replacement, Performance Cruising's Gemini 105MC comes with a 4cuft LP refer like RVs use - Made by Dometic, but others have products too. Usually you can cruise for 2 weeks from a 20lb tank including stove use. Nice thing -- not one amphr spent on refrigeration.


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## sailingdog (Mar 19, 2006)

TOMINDC2 said:


> If you are in the market for a replacement, Performance Cruising's Gemini 105MC comes with a 4cuft LP refer like RVs use - Made by Dometic, but others have products too. Usually you can cruise for 2 weeks from a 20lb tank including stove use. Nice thing -- not one amphr spent on refrigeration.


Nice idea and all, but generally unwise on most sailboats. IIRC, the refrigerator in question uses an ammonia-based refrigerant, and works by heating the ammonia. *However, this refrigerator needs to be kept fairly level to work properly.* While this works on a boat like the Gemini 105MC, which is a multihull, specifically a catamaran, which heels about 10˚ maximum... on a monohull, this refrigerator would probably be a fire risk, and definitely a waste of money.

In fact, I even doubt that this refrigerator would work on most trimarans, which heel about 15˚ maximum under sail.


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## TSOJOURNER (Dec 16, 1999)

*insulating paint*

regarding insulation ,I was associated several years ago with a company which sold an insulating paint called ceramicote.Space shuttle technology came up with a latex based paint containing ceramic spheres which when applied in a 6mil thick layer had the same insulating properties as 6" of styrofoam.It is easily applied with a brush or roller or even a slinger type paint sprayer.applied internally and/or externally to an ice box or refrigerator it will drastically increase the efficiency of the box.It will adhere to plastics ,fiberglass and all types of metal.

House Paint for Insulating Home, Roof, Siding, Ceilings, Walls, Attic Radiant Barrier Paint


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## TSOJOURNER (Dec 16, 1999)

Refrigeration? Just repeat after me, "Baby, let's dine out tonight?"


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## labatt (Jul 31, 2006)

We have the Adler-Barbor cold plate 12v system. On the way back in from our first sail we heard a screeching noise coming from under the cockpit. After much concern (was it our prop?) we tracked it down to the reefer compressor. According to the guys who looked at it, we need a whole new compressor unit. I don't know enough about it to disagree, so they are trying to track down a replacement (our unit is probably 15 years old). It sounded like a bearing failed.

Anyway, what's the general operation of these units? How long do you need to run them for? I thought you ran the unit until you reached the desired temp (we have thermometers in our reefer) and then once it reached a certain temp you turned it off. Then once it warmed up some, you ran it again. Is this correct?


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## TSOJOURNER (Dec 16, 1999)

sailingdog said:


> Nice idea and all, but generally unwise on most sailboats. IIRC, the refrigerator in question uses an ammonia-based refrigerant, and works by heating the ammonia. *However, this refrigerator needs to be kept fairly level to work properly.* While this works on a boat like the Gemini 105MC, which is a multihull, specifically a catamaran, which heels about 10˚ maximum... on a monohull, this refrigerator would probably be a fire risk, and definitely a waste of money.
> 
> In fact, I even doubt that this refrigerator would work on most trimarans, which heel about 15˚ maximum under sail.


SD,

Sounds like a paid up boat fire insurance policy with an propane powered refer could turn a sailing momohull into a liquid asset?


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## TSOJOURNER (Dec 16, 1999)

labatt said:


> Anyway, what's the general operation of these units? How long do you need to run them for? I thought you ran the unit until you reached the desired temp (we have thermometers in our reefer) and then once it reached a certain temp you turned it off. Then once it warmed up some, you ran it again. Is this correct?


Labatt,

Almost. The thermostat is the control for the cooling compressor an if it's working properly it is automatic. Set it "thermostat" to the desired temperature and forget it.


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## sailingdog (Mar 19, 2006)

RickBowman said:


> SD,
> 
> Sounds like a paid up boat fire insurance policy with an propane powered refer could turn a sailing momohull into a liquid asset?


Yup... but I doubt you could get insurance if they knew you were installing a propane powered refrigerator...


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## TSOJOURNER (Dec 16, 1999)

*Improving energy efficiency of refridgerators on board.*

Hello,

As a future investment i'm thinking of getting a compressor refridgerator wich has an automatic feature that freezes icepacks at full power for ~3 hours and the shuts off - cooling the contents for zero power draw - until a sensor discovers renewed need to freeze the packs. (Indel Isotherm ASU).
Quite nifty , i must say.

I currently still use a thermoelectric cooler on my boat. 
I greatly improved the cooling by mounting a stronger 12 volt(PC fan) and insulating the inside with 3cm thick 'finnfoam' , thats a special hot compressed styrofoam that doesn' crumble when cut.

Now it cools up to 35 °c under the surrounting temp. (used to only manage 15°c). the volume though now is down to 20 liters(from 30).

Its also important to ensure that there is cool air circulating around the unit.
12v Deck vents .

I am planing to install a thermostat or timer - And see if that brings down the 4 amp per hour draw.

Erik.


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## Cruisingdad (Jul 21, 2006)

Bump to top for user.

Brian


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