Building a fridge

nickrj

nickrj

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Now that I have a reasonable amount of power, what would it take to build a fridge? I can do all the actual construction, ie. boxing it up with insulation etc, but what about the pump? Is it possible to just buy a 12v fridge pump for little money? I want to build a fridge for peanuts - Anyone done it?

n!
 
Nick, well done on the crossing.

Being over on that side of the pond you'll be looking for a Waeco/ Adler Barbour Cold Machine. It uses the Danfoss compressor. For your installation I'd be looking for the air cooled version which has a Danfoss BD50F compressor.
You build your own insulated box, insulation being the key to success, and then fit the compressor in some convenient place within 15' of the box.
The evaporator, basically an alloy open ended box in which you keep the ice cube trays and anything you need to keep particularly cold, is fixed inside the box and provides the cooling.
The two componants are connected by the refrigerant cooling lines which have a clever sealing system so the gas doesn't escape when you connect and disconnect during installation. A simple thermostat tells the compressor when to run and when to switch off.
These systems take up to 5 amps when running; the success of your insulation, size of box, ambient temp etc will determine how many hours a day it runs. Reckon in 50% running time in the Tropics.

All the bits for a fridge can be had second hand in Florida, at such places as Sailorman in Ft Lauderdale - just look for 'Cold Machine'; you can buy new from West Marine, Defender etc.

An alternate system is to buy a complete 12v fridge, such as the Norcold - which you can also pick up second-hand. They make installation very easy - no box to build - and they work very well. We had one on Adriana for three years in the Caribbean.
Power consumption for the Norcold on Adriana was around 60 - 100 amps per day. This is about the same as for the Cold Machine on our 41' ketch, also in the Caribbean.
 
Oh Nick, a word of warning is in order!

Once you have a fridge, and the cold beer and crispy salads that it represents, you will become a slave to the amp.

You will be constantly trying to figure out how you can squeeze more amps into your batteries whilst trying to minimise the amount that comes out of them. Engine running hours will creep up, solar panels will proliferate; don't say I didn't warn you!
 
Nick, it is cheaper in the long run to buy a small unit complete designed for diy installation.. the smallest on the market should work for you on the tessa.

Surely I can see another sponsorship deal coming on (Fridge tested on round the world trip etc - Might get Ocean Promotion without Comotion involved)

/forums/images/graemlins/wink.gif
 
Thanks for the tips everybody -

@sarabande - Yikes, those kits are nice, but $$! I'll take a look around ebay and see what can be found in the secondhand arena...

@saltyjohn - I know I know, soon you'll see wind generators, another solar array... /forums/images/graemlins/smile.gif But I actually think I'd save money - It's so hard cooking for one person without a fridge, because you have to buy more than you can eat, and then it just goes bad within hours...

@captainslarty - Now that's the kind of thinking I like! Ocean Promotion without Commotion is going to have to get into top gear with the advice from Roach! What I need, is a sponsorship generator - You type in what you need, ie. 'fridge' and it automatically builds and sends off the proposal... !

@Roach1948 - Brilliant! /forums/images/graemlins/smile.gif
 
We just built ours and it's great, but...the build took hours and hours and days and then weeks and weeks to finish as my husband is a bit obsessive and wants everything to be perfect--inside and out (the early build pictures are up on our blog at www.sailblogs.com/member/seaventure and I'll upload the finished ones soon.) It does work very well and very quietly. It's a Frigoboat unit, water cooled, so the only thing we hear is the gentle waterfall over the side. We were going to get the keel cooler, but didn't want to haul now for the installation. Insulation is 4" on the refrigerator side and 6" on the freezer side. We also doled out the funds for two Glacier Bay doors, only because I kept counting those weeks and wanted the project finished so we can get sailing again!

For the 18 months previous to the build we used an Engel--which works in an auto for camping as well. We used it on the trip down to Mexico when Sea Venture was on the hard, then had a ready-built refrigerator for sailing. Plug it in and you don't have to deal with all those weeks of construction. The new units come with better insulation than our old one, though it didn't seem to mind even in the 107 degrees F we experienced in La Paz a few years back. It always kept things cold, sometimes too cold. Michael would use it as a seat and not notice that he'd turned the thermostat up a notch or two. We'd end up with frozen everything. /forums/images/graemlins/ooo.gif
 
I can answer your last question
They are very easy to install.

I have just fitted a Fridgoboat compressor with separate plate. Yes the plate and connecting pipes come filled with gas. Clever non-return valves in the couplings so no gas is lost when you connect it all up.
Just require power to the compressor, and a cable run from the thermostat control back to the compressor.
Only tricky part was running the copper pipes from the cooling plate to the compressor through the cockpit locker without kinking the pipe.
Compressor is air cooled and can be converted to water cooling later if required.
 
I converted an existing cool box on Kate to a proper fridge using an Isotherm Compact 80 kit. It was dead easy and it is very efficient, partly because the cooling compartment is very much smaller than the capacity of the unit (30 litres for a max of 80) and it is very well insulated. Remember, you only have to pump out the amount of heat that can get in.
The cool beer is wonderful, so is the fresh milk and if I catch a big fish I can save a fillet for tomorrow. /forums/images/graemlins/smirk.gif
 
Thanks everyone - That's actually quite a good idea to convert a normal cool box (in Australia we call it an 'Eski'...) to a fridge. The Isotherm stuff is still pricey though. When I say 'peanuts'... I mean like $50!!

Maybe I should be looking at 'auto fridges', since anything boat related has an instant 50% markup? Surely in the caravanning arena you can get a secondhand fridge pump for next to nothing?
 
If you are building your own box put as much insulation around it as possible. This will reduce the power consumption. On my previous boat I had 50 mm of polyurethane foam. This was OK but on my new boat I am increasing this to 150mm with through hull condenser. Previous boat has internal heat exchanger with pumped sea water. Seawater pump was the noisyest part of system. As far as I know all kits use the danfoss compressor.
 
I have the frigoboat water cooled unit. We use it on the lowest compressor speed which uses 2.5 amps when running. It runs less than 50% of the time as we have a very well insulated box. Generally works on about 1 amp average consumption. It struggles on the low speed if we fill it with warm food so I usually up the speed until it has cooled every thing down then back to the lowest setting
 
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