Refrigeration question

[CJ]

Has anyone out there built their own refrigeration system for their boat recently? I am having trouble finding an existing refrigerator/freezer (approx 4-5 ft3) that will fit any convenient place in my boat. I'm considering buying the separate compressor, condenser, evaporator setup and some insulated panels to build my own, odd shaped unit and wanted to see if anyone out there has had any great successes, tips, advice or negative experiences doing this. Ideally, the unit will have a separate fridge and freezer (with separate doors), be AC/DC, have a thermostat and be air cooled (no sea water cooling).
So, how 'bout it, should I consider doing this, or stay away from it? Thanks!

[capt jake]

There was a thread here not long ago pertaining to this topic. Try the search feature and I am sure you will find it. I believe it was in Building and Repair.

Here it is.
icebox/refrigeration (http://media5.hypernet.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=010405)

[ 11-29-2004, 11:45 PM: Message edited by: capt jake ]

[Ian McColgin]

Rethink the air cooled. It will create an incredible battery drain, thinkable only for a motor vessel that's run a lot. If you go air cooled and have a genset, the thing will run all night and any others in the nice cove you're anchored in will hate you.

[mmd]

IMHO, make it a chest-type refrigerator with top-loading doors. A minimum of two inches of closed-cell foam insulation all-round (top, too) and more is better (I try to arrange for four inches in my designs). The liner should be smooth and easy to keep clean - I prefer a one-piece fiberglass liner with rounded corners. Don't make it so deep that you have to stand on your head to reach the bottom. A drain hole in the bottom is a real boon when it comes time to clean it; and if the bottom is kept ten inches above the cabin sole the drain can be fitted with a valve & hose so that you can drain washwater into a basin for easy disposal. With the freezer portion less deep than the refrigerator portion, the refigeration panel(s) can be placed in only the freezer portion and an insulated divider panel placed between compartments. The refrigerator side can be kept cold by a thermostatically-controlled sliding "trapdoor" between the compartments. This uses the thermal mass of the frozen food to reduce the demand on the refrigeration unit. And I vote for water cooling, too.

[Dan McCosh]

I've been researching something similar, althouth smaller. There doesn't seem to be any problem with building your own with the compressors, etc. available. There are two problems, as I see it. One is getting a reasonably finished-off interior, which would require some acceptable fiberglass work. Rough surfaces, corners, etc., become very difficult to clean and maintain in the long run. Also, a good airtight door or lid is problematic. There are some of these units separately available.
Also an issue is the type of system--air vs. water, holding plate or no, and what type of compressor. These issues affect average current drain, and are significant either in high-temp areas, or for offshore work. I'm leaning towards a small, air-cooled unit, as I don't plan sailing in either conddition.

[Dave Hadfield]

I scrapped my whole (antique) shore-power type refrigeration system and just use the thing as an icebox.

A well-designed icebox will hold block ice for a long time. And there's no place we've been sailing to (in the Great Lakes) where you can't get ice every 4 days or so. We can stretch it longer if we have to, and have even used dry-ice to start a trip with everything frozen very hard.

I just thought refrigeration was an unnecessary, expensive, time-wasting complication. When faced with the $1500 bill for removal and replacement, I thought, "Why not let a shore-based corporation do my refrigerating for me?", and it's worked out fine.

This is of course, for my own home waters, which are not that hot except for a few weeks of mid-summer.

[Alan D. Hyde]

A sensible solution, Dave, IMOOP... :D

Alan

[Tom Lathrop]

I agree with Dave. I built my ice box to fit a space on our small powerboat that allowed 8" closed cell blue foam on the bottom, 4" on top and a minimum of 5 1/2" on sides. At 3 1/2 cu ft, it holds a temp of 40 to 45 degrees in the summer in NC. I can, if needed, load enough ice to last for a whole week and still have enough room for the food.

I used 1/4" plywood faced with white formica for the interior. The formica was cut back about 1/16" on the corners to lock in white pigmented epoxy filets. The top is split in two sections so only a small opening is usually necessary. A drain with air vent completes the box.

Has worked fine for five seasons. I went through the analysis of trying to feed a power hungry compressor and decided that it was just not practical for us.

As Michael said, ice is not very hard to find most anywhere.

[Peter Malcolm Jardine]

A lot of this depends on what you're doing, and the boat you're doing it with If you are weekend tripping or cruising areas that have easy access to ice, great. If you are going on more extended trips, that may take you some distance from a port of call, then you need something more.

First thing to tell you: most refrigerators that are ac/dc have two problems. One is not enough insulation, which contributes to power usage, and the second is no configuration for getting rid of heat. Remote compressors help with that, but you have to get rid of that heat too, even if by passive ventilation. Top loading, as MMD stated is more efficient, because cold air falls. When you open the door, all of your cold falls out.
\
Space is always a factor for sailors, not so much for power boaters. I have a 36 foot chris, and I just replaced my refrigerator with a more modern one. If I remember right, it's draw is 3.2 amps at 12v per hour when running. It's a 4.3 cu ft. I modified it two ways. First, I ran a dedicated line to my fuse panel that was twice the gauge I needed it to be. I don't want loss. Second, I insulated around the cabinet of the fridge with 1" Tyvek, the sheathing with the foil covering for the outside of houses. I taped and glued all the joints. Last, I installed a small 12v boxer fan at the top back of the cabinet in the galley so that hot air would be expelled into the engine room. I figure I gained about .5 of an amp per hour. That brings a 3 cu ft into probably the 2 amp hour range. That's pretty good. Certainly you can build a chest, but figure out if there is any advantage based on cost, size, and efficiency.

I have sufficient battery capacity to last me several days without starting either my generator or engines. However, if I was looking to save space and gain capacity for an electric fridge cheaply, I would isolate a house bank using 6 volt golf cart batteries. They are deep discharge, have lots of capacity, have a slim profile so they're easy(er) to find space for.. and... they're cheap. (relatively). Wire two together to give 12 volts and away you go. You also end up with a good stable house bank.

Having stable, dry refrigeration is something I would never do without..... and my SWMBO is extremely grateful for this attitude. ;)

Edited to add: I think most refrigeration choices are more about electrical capacity management than anything else. battery, charger, and electronics technology has improved enough to deal with all of them. The boat I have presently is the first one that has ever had a genny. I don't use it, except in the spring to make sure it still works. My father has spent 3 out of the last five years south, including the Exumas, without a genny, just a properly designed 12 volt system on a 36 foot trawler, single screw.

[ 11-30-2004, 08:52 PM: Message edited by: Peter Malcolm Jardine ]