Refrigeration

[Snboard976]

We were fortunate to be in Baltimore just as the marina was going to throw away the rest of their ice for the season.  We gladly took 27 10 lbs. blocks off of their hands.  It has lasted just over a month and we need to replenish in Charleston.  The rate at which the ice lasts, the warmer weather in our future destination and the availability of ice in the Bahamas has wondering if installing refrigeration would save us money in the next year.

I was wondering what people do with refrigeration and if anyone has an inexpensive system that they would recommend.   I am willing to seal off part of our ice box because we never use more than a third of it.

[SV THIRD DAY]

Well Chad...

You can take the easy way...or the Hard way.

We added a AB Super Cold machine (at a cost of about $1000) to THIRD DAY and since we are full time cruisers would NEVER even dream of doing without refridgeration...BUT

and this is a HUGE But.  The vast majority of our enegy consumption comes from the AB unit...like 80%, so take that away and we can have a smaller alternator, smaller battery banks, less solar, and run our Honda EU 2000 less.  But we never have to worry about ice, infact we can make our own for boat drinks!

My suggestion would be to take the Easy option and buy either a $50 coleman 12v cooler on the cheap...or an engle on the high end!  That my friend is the easy solution and one we would make ourselves if we wern't a family of four living/cruising on our P365!

Rich
Currently Anchored in La Paz Mexico

[Jim S]

Phantom has the AB Cold Machine installed in 2004 that works well.  We also have a Waeco Coolmatic 25qt. refrigerator/freezer that we occasionally use.  By far, refrigeration is our greatest electricity use, but we prefer this to loading the box with ice. 

[Snboard976]

How many Ah are you guys using with the AB cold machine in the warm weather?  We have an Air Breeze wind gen and a 400 Ah house bank.  I am hoping that might get us close to the power requirements.  Right now the AB cold machine or super cold machine seems like the most economical system for a permanent installation.

Thanks,

Chad

Currently in Charleston S.C. (trying to get south quickly)

[Dale Tanski]

Yes to all of the above.

I would recommend going to http://www.rparts.com/ and give them a look.  I designed and built my own system.  I do have refrigeration experience, but their diy manual is excellent.  The only installation problems that I had, were over confidence issues by not checking the things that I knew (and they told you to) had to be checked.  I had a leak on one joint that I should have checked BEFORE I wrapped it in insulation and buried it in the cabinetry.  It was such a small leak that it took weeks of running before the pressure bled off and the system stopped working.   It took far more skill and determination to fix that one leak than it took to install the entire system.  Someone reading following the manual would not have overlooked my errors. 

When you build a system from scratch you install all of the service fittings, site glass and filters that commercial systems skimp on.  You typically end up with a far better system component wise.

We love our system except it is tooooo cold even on the warmest setting.  If an item is near the coil it freezes.  I am a "When in doubt build it stout" kind of guy and this system is a real workhorse at a fraction of the cost of an out of the box unit.  We do not have a power issue, as we are on shore power, so the box is down to temperature when we cast off.  Lots of power is used to get the box and goodies down to temperature.

If you are particular on how you put it together it will work.  One last advantage, if you build it yourself and something goes wrong, you should/will be able to fix it.  Think it over.

Good Sailing...  Dale Tanski

[captsandy]

No one mentioned a engine driven compressor. mine, self installed, will refreeze the 3 holding plates in 1 hour a day. About 2/3 a gallon of diesel a day, and free if underway, This is the max run time in the hottest climates. Cold beer and ice with No drain on the altenator or batteries.
    Sandy

[Snboard976]

Happy Thanksgiving!  and thanks for all the replies.

I don't think I am going to be looking at the engine driven system just because we plan on staying on an anchor for a while. 

The Rparts prices looked great, but the required tools were extensive.  I don't have a vacuum pump, CO2 tank with regulator, leak detector or a gauge set.  Are these all really necessary?

What is the major difference in the difficulty of installation between buying an AB cold machine unit and a DIY kit from Rparts? 

Thanks,

Chad

[SV THIRD DAY]

We never installed the water cooled option on our super cold machine and find that in "warm climates" our unit runs anywhere from 60% to 80% of the time!  So a little quick math and you can see the AH just sucked out of the battery bank at 80AH/Day on the low end up to 106AH on the high end.   So if you have a 400AH bank, (and you only really have 200AH available to use to not drain below 50%) you will be using HALF of your battery capacity PER DAY just to run your Fridge.

[Dale Tanski]

Chad,

Vacuum pump – absolutely necessary to draw down the system prior to charging with Freon. You place the system under a vacuum for several hours to "boil" off any water vapor (moisture) trapped in the system.  Water boils at room temperature under a high vacuum. I suspect you could rent one of these.

CO2 tank w/regulator – The best way to check for a system leak is to pressurize the system with an inert gas prior to charging with Freon.  Nitrogen is the most common but CO2 will work just as good.  You also could use compressed air in a pinch, however moisture migrates in with the air.  Moisture (water vapor) is the kiss of death for a refrigeration system as it will form ice on the internal control orifices and disrupts Freon flow.  You need to put the system under normal operating pressure which will be over 100 psi..

Leak detector – there are leak detectors that "sniff" Freon.  They are useful after the system is charged and you suspect a leak.  I have been dappling with refrigeration systems for over ten years and I do not own one.  Dishwashing detergent in water makes an excellent leak detector when you first pressurize the system.  Brush a little on each joint with a disposable brush and if you see bubbles you have a leak. You can also purchase Freon that has dye in it.  When you charge your system, and you have a leak it will show when the dye escapes.

Gage set –another absolute necessity.  A gage set consists of a high side gage and a low side gage connected to a manifold with control valves.  Three hoses are also part of the set.  The low pressure hose goes to the low pressure side of the system screwing on to a service fitting.  The high pressure side goes to the high side and the hose in the center of the gage manifold goes to your Freon tank.  The two gages are designed to tell you the operating pressure and the corresponding temperature it is operating at for a specific number Freon.  You are probably going to be using R134.  The valves allow the flow of Freon and connection of the desired gage for monitoring.  Once you own a set of gage you will use them for life to diagnose refrigeration system problems.  They will work on your car, home AC, refrigerator and so on.  All small mechanical refrigeration systems operate on the same principles and once you can fix one you should be able to fix most.  You could easily sell you gages on Craigslist or E-Bay if you decided to do so after your install, or you could earn cruising kitty money by fixing other peoples systems.

The difference between a premade system and a build from scratch system is huge.  Thus the cost difference.  An AB system is a snap to install and you need no special tools.  You install the evaporator coil in your ice box (high side) and install the condenser with compressor (low side) somewhere in your boat that has good ventilation.  Each half comes with a tubing set that has special connectors that screw together and each half of the system is precharged with the proper amount of Freon.  The only exciting part is screwing together the fittings QUICKLY.

Dale Tanski

[RayNWanda]

Refrigeration will probably be our next big project. I am leaning toward an A/B Super Cold Machine because I have doubts that I am competent to design a system myself. I guess that when it comes down to it I know just enough about refrigeration to be dangerous. I have a gauge set, can get a vacuum pump, I can do a little basic troubleshooting. I would really like to build a system like Dale did, but...
My biggest concern is that I would end up with a bunch of mismatched parts that won't work together.
Dale, it sounds like you could install a partition and end up with a deep freeze and refrigerator, which is what I want.

[RayNWanda]

I guess I am going to have to bite on this. The more I look at it, the more doable it looks. I ordered Nigel Calder's book "Refrigeration For Pleasure Boats". I am going to do some study and decide if I want to build a system or buy one. I worked up a tentative parts list, and it looks like you can save quite a bit over an A/B system. Either way, the book will be good to have on board.

[Snboard976]

Thanks for the reply Rich and Dale.  I can confidently say that I will not be able to install a DIY kit anytime soon.  Renting or buying those tools would also offset the savings.  Right now we are planning on testing how much ice we use in a warmer climate then reevaluating an AB system.

[RayNWanda]

Still looking at what is available- I am kind of intrigued by the Frigoboat keel cooled systems. It looks like the best of both worlds- watercooling without a water pump or plumbing. The only moving part is the compressor. You do have to haul the boat to install it but if you do a bottom job at the same time, that offsets some of the haulout cost. It looks like we could go with the very large stainless freezer evaporator (bent to fit) and make a spillover system. The stainless evaporators are a little less efficient than aluminum, but more durable than aluminum. As long as you bond the keel cooler, there should'nt be any corrosion issues. They come precharged with 134A, which is cheap and readily available here. Also, their quick connect fittings can be disconnected to change components without losing the refrigerant charge. Does anybody here have any experience with these systems or know anybody that has one?
Practical Sailor just tested the Capri 35F and ranked it the highest, but it is a smaller capacity air cooled unit. They did say it is extremely well made.

http://great-water.com/pages/Frigoboat/50K-380F-F.htm

[RayNWanda]

 I thought I would update this thread for anybody considering adding refrigeration.
We purchased a 2M watercooled kit from Rparts and are in process of installing it now. I have the compressor/condensor unit built and leak tested- It goes in the boat today. It is a fairly impressive system in that it has service valves, a sight glass and a BD-80 compressor. The instruction manual is excellent and very detailed. The manual can be downloaded from their website, which is what I did to see what is involved in building it. We upgraded to the "C" freezer holding plate, which is 13X20 inches. We also got the Carel digital thermostat. I plan to install a divider in the box to make a spillover system. We are expecting to cycle the holding plate between 0 and -10 degrees, so it should be a fairly robust system. The power module on the compressor is jumpered so that the compressor runs on low speed only. Expected power consumption is about 7 amps with a hot box, then dropping as the box cools down. I would like to see it cycle on for about an hour, then off for 3-4 hours with a cold box. We'll see how it works out.

[eveningebb]

Just a few questions on your installation:

Where will you mount the compressor?
What have you done to the box -- have you added any insulation?
Did you fill in the low part of the box? 
Will you be adding a separate hatch for the freezer? 

Thanks for all the information.