Dometic Portable vs Installed Refrigeration

[sailscubasurf]

Hello,

I have a well-insulated icebox (30lbs of ice kept food cold for 11 days in 85 degree temperatures with a small bit of ice remaining at end of 11 days.)

I want to install refrigeration, but I am considering two options:

Option 1. Purchase Dometic Portable and use as freezer to freeze water bottles, which I then place in icebox to refrigerate food. Cost would be approx. $450

Option 2. Purchase Cool Blue system and install in ice box - cost would be about $2500.

Either way, I will be running this off of batteries charged by 300 watts of solar panels and a 40a MPPT controller.

Anyone tried both these ways, and/or what are your considered opinions?

[Typhoon]

Hi there , it may take more energy and time to freeze a large amount of water in one of those small ice boxes . It may melt faster then you could freeze it .
I would go with the second option . Of course it all depends on how you cruise as well . If you are a weekend warrior then the cheapest solution may be all you need , if you spend extended time aboard , then bite the bullet and spend the money . I build what I believe is the best system on the market. Have a look , both the coolblue and my ColdEh systems are strictly air cooled .

We will be at the Annapolis Spring Boat show if you want to see our system up and running and take a look at the copper plates .

Regards John Tully

[Polar Opposite]

See my thread "Portable Freezer and Icebox Management" for a discussion of the Dometic option. Please feel free to PM me any questions.

[Cheechako]

Dometic does not have a very good rep. Or maybe I should say they didn't have. They may be better now days. Maybe an Engel would do it?

[Lepke]

Freezing water takes a temp well below freezing to do in a timely manner. There are several companies selling either a cold plate or a freezing plate that could be added to your cold box.
The portable refers I have tried sometimes will keep already frozen stuff frozen, but don't have the heat transfer power to freeze a large volume. Especially if the bottle water is warm.

[SV THIRD DAY]

We cruised with a family in Mexico that did exactly what you are describing.
They had a very well insulated box that was their Refrigerator and then an Engle 40qt portable. They rotated frozen water bottles each morning and evening from the Engle to the refrigerator box. They cruised for years like that and it gave them a refrigerator and some small freezer space in-between the cycling in/out of the water bottles. They did have pretty big swings of their refrigerator temp, but managed to live with it.

If I was going on a short term cruise and budget was a huge concern in getting me AWAY from the Dock...heck...I'd do it myself. Will it work? Sure, they did it and in essence you are using a "portable and rechargeable eutectic holding plate"...but...isn't their always a "But".

The negative here is that you will most likely be asking your portable unit to run 24hrs/day. Sure 2.5A is small...but at 24hrs per day that's a 60AH per day load. For half that power you could have a 6-7CF Box with an installed CoolBlue freezer/refrigerator and "set it and forget it". (but yes more cruising kitty money)

Don't be tricked by the "low" real time amp usage of a portable. When I keep my Engle (Yes...even the owner of CoolBlue has an Engle on his boat) set to a hard freeze it never shut down when we were in Mexico...never...it just ran 24hrs per day at 2.7A. Here in Morro Bay where the boat temp is between 60-75degs it still runs from 60% to 80%% of the time when I keep it in hard freeze mode. So you are not going to save any power and if anything you will use more than a built-in system. The built in system will also give you more of a true single digit temp Freezer and True 35-38deg refrigerator.

Next, the hang-up I would have a hard time getting over would be the convenience issue. Having to add the water bottle cycle game to the daily to do list on a cruising boat may not sound like a big deal and perhaps if I was younger and more into camping I wouldn't care a much, but you could be setting yourself up for a hassle that sounds good at first, but then irks you by losing food when you forget to do the bottle swap out.

The important thing at the end of the day is that you cast off.
So I say if saving some money on the ships refrigeration system makes it more likely that you will be one of the few that really makes it off the dock...then by all means...do it! Sure you will use more power, sure it won't be as convenient, but I'd rather use more power and not be as comfortable than to never get off the dock!

Tech Note:
Now if you do go the frozen bottle route, don't use water. Beer maybe...but not water.
Fill your liquid containers with a 25% Glycol 75% water mixture (or maybe 30%/70%). That will lower the freezing point of your eutectic solution allowing you to store more energy absorption BTU's than plain water. This could require some testing/trial and error because you may find that your portable unit won't get cold enough to freeze the bottles if you lower the freezing point too much and get greedy on the amount of BTUs you want to "store" in the eutectic solution.

Tech Note 2:
When you do a Amp Hour per Cubic Foot volume comparison of the small portable Engle and Dometic units compared to say a 7CF box 1/3 Freezer and 2/3 refrigerator with a CoolBlue system in it. That's when the "efficiency myth" of the small portable units falls apart. What makes these small 35 and 40Qt portable units appear to be efficient is their small cubic foot size. 40Qts is a 1.33CF Box that's nothing when you compare it to a set-up that has a 2.1CF Freezer plus a 4.9CF Refrigerator and can run on less daily power with good insulation.

Cheers

[1mardiv]

I have a Dometic 65 which is is a freezer/frig combo or it can all be frig or all freezer. It depends on how you arrange the panels and set the temp. I opted for this instead of buying ice all the time for my ice box and keep it in the quarter berth running on 12v DC. It works well and I now use the ice box for dry storage. This was the most economical way of installing refrigeration without having to modify my icebox, insulating it better and spending over $1500. It works well for us and uses about the same as any installed refrigeration. Btw, it will flash freeze any water container in no time and you can get the temp down to -20 if you want.

[donradcliffe]

I don't think there is much difference in efficiency in the compressor/evaporator between the domitec and the cool blue systems--its all about how well insulated the box is and what temperature you run it at. You can improve efficiency in both systems by putting extra insulation inside the box. You will use a lot less power if you set the temperature higher.

[uncle stinkybob]

I ordered a new Dometic CFX-35us and the insulated cover. $540. for freezer on Amazon. $38 for insulated cover, $52 for Dometic bluetooth remote controler. I will post results after I pick up at daughters house and plug in at boat. I have heard that the older model CF's had problems. The newer CFX is getting great reviews.

[Ding Duck]

[QUOTE=sailscubasurf;2300966]Hello,

I have a well-insulated icebox (30lbs of ice kept food cold for 11 days in 85 degree temperatures with a small bit of ice remaining at end of 11 days.)

I want to install refrigeration, but I am considering two options:

As others have said, It going to be a selection based on numerous factors.

Obviously budget, Usage (live aboard or Weekend), Space and Power
As Rich has said, your small Engel will be running 24/7 trying to make ice, but at the end of the day, it can only deliver x BTU's. Compared to a Cool Blue or Coldeh system which will deliver far greater. This means less run time. Water that is frozen to a couple of degrees below freezing won't last the same as 'real' ice.
You may also want to consider the amount of power required as from a previous post. Check your solar panels and see how much they actually deliver per day. How often is the boat facing the right way, is the angle of the panel optimal and is it effected by shading from rigging, mast etc. I have a 180W panel and the best I've seen was about 100w, then a cloud came over. You could always start the engine

On a side note, just like to say thanks to John at Coldeh for his assistance in a refrig problem I'm having. If his products are half as good as his service, you'd be on a winner
Good Luck

[Typhoon]

Hi Ding Duck , thanks for the kind words . Sorry we couldn't get your machine up in running , if you were close by I would have dropped by to take a look , down under is a bit far from Canada [emoji15]

Your right on choosing a system , if you are a costal weekend sailor , a top quality system with the support and price to go with it is a little over kill . But if you are heading to far off remote places in the world, the best will only do . As for efficiency. A watt is a watt , a btu is a btu . The trick is choosing a system that is simple and efficient in all temperatures and dead nuts reliable . Captube systems suffer as condensing temperatures rise , hence water and keeled cooled add/ons with there challenges . Then trying to keep that heat out of your box. Insulation will make or break any system , the more the merrier . Refrigeration seems to be one of those overlooked parts in a boat , but it is surprising how much it effects your cruising life when it is not working properly and efficiently .

Let us know how your repair goes , remember that service I have is there if you think it would help .

Regards John

[Ding Duck]

John, no problems. I certainly appreciate the unreserved assistance you (& Richard) have given. You can't learn everything from a book and no substitute for real world experience. Somehow, I didn't think you'd make a house call, but I do owe you a beer or 3
We've still got a few things to try before we get to the Repair policy 101 - "When in doubt, give it a clout", but the hammer is on standby.
Cheers

[uncle stinkybob]

Originally Posted by uncle stinkybob

I ordered a new Dometic CFX-35us and the insulated cover. $540. for freezer on Amazon. $38 for insulated cover, $52 for Dometic bluetooth remote controler. I will post results after I pick up at daughters house and plug in at boat. I have heard that the older model CF's had problems. The newer CFX is getting great reviews.

Out of the box.
Very well built. assembled with stainless steel allen heads. removable handles, reversible lid, replaceable corner protection. both 12/24v d.c. and 120 a.c. cords.
Plugged into 12v dc at 60 degress ambient.
30 minutes running= 10
42 minutes running= -9

opened lid, placed 1/2 gal water inside, closed lid.
temp rose to -6 10 minutes later back to -9
approx 5 hours to a solid half gal ice block. very hard ice.

It runs 3 to 4 times an hour for around 7 minutes per cycle.
Very quite, I had to feel for compressor running.
I used a craftsmen laser temp gun on the outside housing.
When running , the area where the compressor is was 10 to 12 degrees warmer.
I found no cold spots including the lid and seal area. Insulation seems very good.

The wireless remote is worth every bit the $52. I have the freezer in the stern portion of an unused quarter birth with plenty of air space but it's hard to see the control panel. The remote gives me actual temp, voltage, alarm function setting and allows full adjustment of temp and alarm. runs on 2 aaa bats or 12v hardwired.

I'm very impressed with the unit, one of my best buys.
Now to buy a vacuum pump with gauge set, H.F. for $135. a can of r134a, a refer repair for dummies book and try repairing my old Nova Kool LT-200. Everything runs perfect but nothing get's cold anymore.

[Typhoon]

NovaKool make a fine product . If you say the compressor runs and you are not getting any cooling, it could one of three things . Refrigerant flow problem , lose of refrigerant, or contamination of refrigerant . Do you get any sound from the evaporator plate ?

Regards John

[uncle stinkybob]

Originally Posted by ColdEh Marine

NovaKool make a fine product . If you say the compressor runs and you are not getting any cooling, it could one of three things . Refrigerant flow problem , lose of refrigerant, or contamination of refrigerant . Do you get any sound from the evaporator plate ?

Regards John

Hi.
No nothing from cold plate. cooling fan operate's compressor running, no unusual noise, very little heat even after running for 20 min. I hope for 134a loss, right?