Combination 'Fridge / Freezer...Possible?

[Christian Van H]

Hi all! Anyone here have a combination refrigerator and freezer using one holding plate? I am contemplating building a relatively small box with a ton of good insulation and one holding plate w/ an Adler Barbour super ColdMachine. I was considering using a small thermostatic fan to circulate air up to the 'fridge section from the freezer. Is this plausible? Must be viable for most cruising grounds throughout the world... Thanks, Chris

[scotte]

Many people have done this, using a partition to separate the freezer section from the refrigerator section using a panel with holes in it...

[Christian Van H]

Any idea how they regulate the two different temps?

[Hud3]

My Frigoboat system has an evaporator plate in the freezer side only. The digital temperature controller adjusts the speed of the Danfoss compressor to maintain the setpoint temp. The divider has a spillover fan that's temperature controlled and adjustable to whatever temperature you want in the fridge side, but it's trial and error, not a digital setpoint like the freezer side. Once you get the fridge temp in the right neighborhood, you can tweek the spillover fan knob to get it right where you want it.

There's a bunch of good info about the Frigoboat system on the VECO NA website.

[Cheechako]

It works well and I like your simple approach. They sell a SS circular vent that has a rotating plate to open/close the slots. These work great for what you want to do. A very small 12v computer fan works well too. I've seen these down to about 2" diameter in 12v.

[Christian Van H]

Guys, thanks for your responses. Hud, is your divider insulated? Can ya make ice? Ice IS civilization, ya know!

[Hud3]

Christian,

No, the divider is hollow plastic. Before I installed the thermostatically controlled spillover fan, the cold air from the freezer side would simply spill over the top of the divider. The freezer makes ice, but an open ice tray isn't practical. I usually buy a bag of ice and keep it frozen in there. I keep the temp at about 0-10 deg F. Having ice is nice!

[James S]

Chris
My divider is insulated with a 4" hole passing through, near the top...this will have (not done yet) a way of regulating the size of the opening (kind of like what you would see on the air-in side of a wood stove)...I have seen some boxes with an additional smaller hole at the bottom of the box as well. Presumably this enhances the circulation...I think the trick is keeping it small as to not "bleed" to much cold into the Refer side.

[ausieman]

We have two separate compartments about 3" apart and fully insulated. Toward the bottom of the freezer is a 2" hole connecting the two compartments and near the top are 3 x 3/4" holes to allow return air to the freezer. I installed a 2" 12v computer fan in the bottom connector (6 for $2 on ebay) that runs when the Danfoss compressor runs. The thermostat is located in the fridge side and set at 4 degrees and this setting keeps the freezer at minus 6 to minus 10. The system has worked ok for 8 years without the fan and now works very well with the fan. Now if only I could afford to replace the old Danfoss with one of the newer even more efficient models.

[Pelagic]

I think the main downside to having a combi rather than independent fridge and freezer is that we all go into the fridge a lot more and that action tends to ice up the freezer side (especially in humid tropics) by continually bringing warm air into the shared mix

A well insulated independent freezer, rarely opened keeps the frozen goods much better and I would think is a more stable and efficient way to keep frozen goods

[Maren]

Originally Posted by Christian Van H

Any idea how they regulate the two different temps?

Roy M has a novel idea. You can read about it on this thread.

[Christian Van H]

These ideas are great!The Roy M thread is really interesting... fun to read how each cruiser's idea of the perfect Freezer to Fridge volume ratio differs due to use. Makes ya think about adjustability... OK, hows this: I need a front opening unit. Why mount the coldplate against a sidewall of the freezer? Wouldn't it be more efficient suspended above my freezer area which will be in the form of a pull out drawer? Air would be able to circulate around the entire plate. Above that could be the divider and thermo controlled circulating fan feeding the fridge area... Is this wacky?

[Maren]

Originally Posted by Christian Van H

These ideas are great!The Roy M thread is really interesting... fun to read how each cruiser's idea of the perfect Freezer to Fridge volume ratio differs due to use. Makes ya think about adjustability... OK, hows this: I need a front opening unit. Why mount the coldplate against a sidewall of the freezer? Wouldn't it be more efficient suspended above my freezer area which will be in the form of a pull out drawer? Air would be able to circulate around the entire plate. Above that could be the divider and thermo controlled circulating fan feeding the fridge area... Is this wacky?

Just as an immediate reaction: I would not go with a front opening unit unless I was planning to spend a lot of time on the hook or running a generator. I understand that may not work for your situation though. But if you can reconsider, do.

As for your design I am not clear if you are intending freezer on top, like a college dorm room fridge, or on the bottom in the way you see some high end residential units. One thing to keep in mind, could air falls.

[Christian Van H]

Freezer on bottom, with one large drawer. Cold air pushed up to top of fridge with temp controlled fan, then air is allowed to fall back thru divider to bottom freezer again. With front opening, the drawer will occupy whole freezer area and keep cold air in unless pulled out for access. Why do all coldplates mount against box? Should we be keeping one side of insulation frozen all the time? Wouldn't it be better to allow all sides of coldplate to do their job?

[drinky]

Have a look at the idea on ozefridge.com.au. This is for a eutectic system but would work for coldplate also. The stainless duck on the freezer side takes cold from there without any exchange of air so no frosting of the freezer. Haven't tried it yet but on the way.