Any tips for reducing frost/ice build up on cold plates ?

[sailcrazy]

Following. We have both a refer box and a freezer box, maintained a different temps. Both are cooled by holding plates and a system that runs 2x/day (ie, when we run the genset-it's a 230vAC system)...and both frost up significantly. We've considered upgrading to a 12vDC system and evaporator plates, so it would run as needed (more often but for shorter periods each run) and I'm sure the box insulation could be improved--the boat is 33 years old--but that would require major surgery/not a real option.

[rwaldrop13]

Originally Posted by Rjt

Couple of things worked for me.
A) as above, stop moisture getting in.
B) add a small PC style fan. 50mm 12v works wonders. Fridge temp evens out. Fridge uses less power too.
C) put a drain in the fridge. Coil the drain tube below the fridge (stops cold air leaking out) and run it to your bilge or a jar.
Good luck finding your best solution.

I actually was a service manager for a transport refrigeration and temp control dealership. The fan, drain tube and door seals are key. The trouble with a cold plate system is you'll never keep it frost free. The truck units we would see were notorious for clogged drains, which contributed as the water would build up and contribute. One suggestion is see if you can find or make a 'duckbill' for the drain hose to allow water out but keep air in.

[ItDepends]

Frost build up in a cold box is more than just an annoyance. It takes a LOT of energy to make all that ice, and it insulates the evaporator, reducing its effectiveness.

One of the biggest sources of water (ICE) in a lot of boat freezers that people do not seem to recognize is making ice cubes. When you put open trays of water into the freezer the relatively warm water evaporates very quickly in the very dry air of the freezer, and the water vapor collects on the evaporator as ice. Even after the ice cubes freeze, they continues to evaporate (technically, "sublime") and migrate to the coldest place: the evaporator or cold plate.

ALWAYS make ice in trays that have tight fitting covers. Always store ice cubes either in sealed zipper bags or other air-tight container.

It is also a good idea to keep the temperature cycle as small as reasonably possible, if it is adjustable. If the temperature of the air in the box cycles from a high that is much higher than the low, the pressure changes, and the box "breathes" in room air, adding water.

The traditional test for door seals is to close the lid or door on a dollar bill. It should be very hard to pull it out (but because this is a boat you need to use a $100 bill for a proper test ).

A proper boat fridge should be sealed tight enough (preferably with double seals) that you can feel the suction as you open it.

If you are designing and building your own box, be sure you do not over-compress the gaskets. For foam and hollow gaskets more "squish" is NOT better. Most gaskets perform best and last longest if compressed 30% of their thickness--no more. Check the specifications for the gaskets you are using. If you can't get specifications, find another source who can get you the specs you need to engineer your sealing system properly.

In the attached photo of our chest freezer, note the double seals, the covered ice cube tray, the zip bag storing ready ice cubes, the baskets for storage allowing good air circulation, all food sealed in vacuum bags. You can see the evaporator in the corner of the photo. This is the amount of ice that accumulates in this box in 4 weeks of operation--almost none. This freezer is kept at -20C for long term food storage. A proper box CAN be built. Even if you are stuck with an existing build, the way you use and maintain it will make a huge difference in performance.

[Moontide]

Pretty much a fact of life. The more humid the location and more openings are the culprits. Your home refrig has same issue, except they have auto defrost cycles so you don't see it.

[jamhass]

I assume this is a top loading freezer.

Cut a yoga mat to fit and put it on top of the reefer/freezer. It will reduce leaking and provide a nice non slip surface

[sailcrazy]

JAMHASS...are you talking about a "yoga mat" that covers the counter-outside the refer/freezer boxes, or one that fits inside the box and over the food?

[Locquatious]

Our refrigerator at home pulls a vacuum inside the fridge after a door is shut. This helps to tighten the door seals. It evacuates some of the humid air. And it actually lowers the air temperature inside the fridge.

[goboatingnow]

Mines build up over about 8 weeks so defrost as needed

[jamhass]

Originally Posted by sailcrazy

JAMHASS...are you talking about a "yoga mat" that covers the counter-outside the refer/freezer boxes, or one that fits inside the box and over the food?

Outside

[Brewgyver]

Originally Posted by hzcruiser

As I'm about to build my own fridge/freezer combo, I'm also thinking:

How about covering the evaporator(s) with a thin silicone film or cover? Once there is ice on that it would be a matter of quickly shaking it off?

Don't do it. ANYthing covering the surface of the evaporator will insulate it. This will lead to some amount of liquid refrigerant NOT evaporating, and eventually slugging the compressor with liquid. This will kill the compressor, sooner or later.

[FlyingScot]

Sail in places with less humidity.
Open the door less times.
Perfect door seals. Air is always trying to get in due to lower pressure inside the box.
Air flow across the evaporator plates.
Don't put wet things in there.

No magic here.

It's a huge problem for us with front loading original equipment fridge.

We did solve one problem by turning the whole box into a fridge so it automatically defrosts, but it is still wastefull by using energy to clearn phase change the water vaport to frost.

[Nicholson58]

Originally Posted by Imagineou812

Does anyone have any novel methods for reducing ice and frost build up on cold plates ? I have a Seafrost air cooled refridgeration as well as freezer system and am getting abundant frost build up on the refer side of the 2 seperate systems ?

Keep an open bag of ice near the door so humid air looses its moisture on the ice. Helps but not a total fix

[No_Agenda]

We put a sheet of bubble insulation inside the icebox opening and also over the freezer plate opening to provide a barrier. This has reduced the amount of defrosting needed to once every 6-8 weeks.

[windcastle1]

If you have the room, make a simple “S” drain at the bottom of your ice box similar to a “P” type drain that you have under every sink/shower drain in your home. Allows the water to drain and the small water retained keeps the “stink” out.🤗

[hzcruiser]

Originally Posted by Brewgyver

Don't do it. ANYthing covering the surface of the evaporator will insulate it. This will lead to some amount of liquid refrigerant NOT evaporating, and eventually slugging the compressor with liquid. This will kill the compressor, sooner or later.

Interesting comment, but how can it insulate if it is fully inside the freezer compartment itself?