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I am looking at purchasing a fridge to take between truck and trailered boat. i am between Engel and Dometic. The Engel MR040 has the reputation of being super reliable and efficient. Is that the model you had to bad? Which cheaper models did you replace it with?
My mr40 engel had the micro leak problem
I suggest looking on amazon where you can find many of similar size for <$350...well under the engel
I think the one I bought..kalamera? 35 qt with more features...was about $320
I wouldn't get stuck on brand names with these products
 

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Yes, I understand your oft-repeated point about the majority of boats not being cruisers. However, I was responding to SanderO's specific comment about how cruising boats use their engines.

You may be misinterpreting my posts - I am not in favor of an engine-driven system, and have yet to personally meet a cruiser who had one.

A holding plate keeps a steadier box temperature profile than a thin evaporator plate. This has nothing to do with how the compressor is powered. An engine-driven compressor driving a holding plate can keep rock-steady box temperatures at any temperature level, out-performing a DC compressor thin plate evaporator, as long as it is run appropriately. That is a matter of planning, and not system type/design.

Mark
The problem with holding plates is that their ability to "hold" a temperature is very limited once the engine has shut down. Once the active cooling from the refrigeration system ceases the holding plate becomes nothing more than an ice block. It will warm up fairly quickly. If the solution is not frozen it will have a very limited holding ability. Think of those blue cooler packs vs regular ice. Sure, they are a bit better, but not much.

You can't point to the thin evaporator plates of a 12v system's evaporator plate and declare the holding plate is superior because of its larger mass. They are 2 very different things.

I have worked on quite a few engine drive systems. They are more prone to leaks than a 12v system and are have more components to fail. The nicest use of an engine drive system I have seen was on a J160 where they had an engine drive holding plate supplementing the 12v system, but even that was more complicated and and expensive than necessary.

You can't claim that running an engine drive refrigeration system is giving you free refrigeration. Any load on an engine uses fuel. If you are running your engine with the alternator bulk charging your bank, and your engine drive refrigeration is pulling down a warm plate you are most certainly burning more fuel than if you were just propelling the boat forward. (Ever notice how your car has less power going up a hill with the A/C on?)

I think it makes more sense to put the energy produced from your engine directly into the batteries which can then be used to maintain much more precise temp control via a 12v system. That is active all the time rather than just when the engine is running.

We have been off grid for the past week, and sitting on the hook for 3 days at a time, with only a couple of hours of motoring between anchorages. (No wind unfortunately!) The whole time the 12v fridge has kept our meats frozen, ice cubes made, and beers at the perfect temperature. A holding plate in this application just could not do that. On most days our 160w solar panel replaced all the energy consumed overnight by 2pm so our batteries are fully charged by evening. It seems to me that is pretty efficient and clean refrigeration. Certainly more so than a diesel driven compressor!




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The problem with holding plates is that their ability to "hold" a temperature is very limited once the engine has shut down. Once the active cooling from the refrigeration system ceases the holding plate becomes nothing more than an ice block. It will warm up fairly quickly. If the solution is not frozen it will have a very limited holding ability. Think of those blue cooler packs vs regular ice. Sure, they are a bit better, but not much.

You can't point to the thin evaporator plates of a 12v system's evaporator plate and declare the holding plate is superior because of its larger mass. They are 2 very different things.
One more time: some of you are conflating holding plates with engine driven compressors. They are two distinct parts of a reefer system and not necessarily married to each other. There are 12V holding plate systems too, and they are generally higher-performance, and lower energy consumption than evaporator plate systems.

I have never advocated here for engine-driven compressors, and one would not be a good fit for us.

For holding down temperature swings in a box, for sure holding plates are superior to evaporator plates. There is no denying the physics, nor the actual experimental data of this. A holding plate is a thermal flywheel - cut the cooling to it and it stays the same temperature for quite a time. Cut the cooling to an evaporator plate and it will be room temperature in minutes. In an empty box, an evaporator plate system will cut in and out 100-150 times each day to hold a set temperature, while a holding plate will only do so 3-4 times a day.

If a holding plate system is operated correctly, the eutectic solution is not allowed to melt, and the overall box performance is more steady than with an evaporator plate. It also is usually more energy efficient, and definitely more robust. Whether running an engine to do this, or using a generator, or using one's batteries - it is all the same in terms of performance, as long as it is operated correctly.

The choice between the two comes down to other factors besides the compressor itself, namely the need to store excess energy produced on shorter periods vs. the amount of box space taken up and a bit more complicated system.

Mark
 

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Discussion Starter #44
What Mark wrote. My holdover plate is about 3 x 12 x 16 (guess) and it can become a block of ice at well below 0° F. And it doesn't take more cooling to keep it there... unlike water ice which will melt rather quickly. The more you run the compresser the colder it gets. Sure the compresser is a load. I don't notice loss of power.... probably because it is not significant.

If you don't or won't use your engine this is not a system for you. It works for me because i can make refer temps or freezer temps... if compressor runs say 2 hrs. And I use the motor regularly. I don't need shore power or lots of solar or massive batteries. The space the components take seems reasonable. I can change to a 12v compresser. But why?
 

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One more time: some of you are conflating holding plates with engine driven compressors. They are two distinct parts of a reefer system and not necessarily married to each other. There are 12V holding plate systems too, and they are generally higher-performance, and lower energy consumption than evaporator plate systems.

I have never advocated here for engine-driven compressors, and one would not be a good fit for us.

For holding down temperature swings in a box, for sure holding plates are superior to evaporator plates. There is no denying the physics, nor the actual experimental data of this. A holding plate is a thermal flywheel - cut the cooling to it and it stays the same temperature for quite a time. Cut the cooling to an evaporator plate and it will be room temperature in minutes. In an empty box, an evaporator plate system will cut in and out 100-150 times each day to hold a set temperature, while a holding plate will only do so 3-4 times a day.

If a holding plate system is operated correctly, the eutectic solution is not allowed to melt, and the overall box performance is more steady than with an evaporator plate. It also is usually more energy efficient, and definitely more robust. Whether running an engine to do this, or using a generator, or using one's batteries - it is all the same in terms of performance, as long as it is operated correctly.

The choice between the two comes down to other factors besides the compressor itself, namely the need to store excess energy produced on shorter periods vs. the amount of box space taken up and a bit more complicated system.

Mark
so why isn’t commercial refrigeration in a restaurant holding plates vs.evaporators.
why aren’t home refrigerators made using holding plates
why Are most people using evaporators vs 12 volt holding plates


i understood before your point about engine driven refrigeration and that plates can also be 12 volt.
 

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What Mark wrote. My holdover plate is about 3 x 12 x 16 (guess) and it can become a block of ice at well below 0° F. And it doesn't take more cooling to keep it there... unlike water ice which will melt rather quickly. The more you run the compresser the colder it gets. Sure the compresser is a load. I don't notice loss of power.... probably because it is not significant.

If you don't or won't use your engine this is not a system for you. It works for me because i can make refer temps or freezer temps... if compressor runs say 2 hrs. And I use the motor regularly. I don't need shore power or lots of solar or massive batteries. The space the components take seems reasonable. I can change to a 12v compresser. But why?
so what constitutes massive batteries. Why type does your boat have Again, I forgot
 

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Discussion Starter #47
I have batts which fit the space behind the engine. My electrical system evolved over 35 years... 2 flooded probably group 31. Next when I went south 2 gels which fit in the OEM box.. w/ smart regulation and high output alt. Then 2 8D AGMs and an Optima AGM start,.. larger alternator,,,, monitoring and echo charge, I rebuilt the box, same size but stronger, Everything fits in the box and batts are nicely secured. Any suggestions? These 8Ds are too effin heavy!
 

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If holding plate efficiency was so superior to the evaporator kind, why aren’t companies jumping all over this.
You would think that’s a no brainer

is it cost?
Is it surface area?

I don’t think it’s as simple as the physics you claimed. There is more to it than a small chunk of steel keeping all areas of the reefer at an even temp compared to a much larger evaporator.

Assuming that the plate works like an evaporator in that there is refrigerant activated by a thermometer can the temp be set at the 0 degree point or lower even.

Back to the engine driven system , once the engine is turned off, that is the coldest point the steel block gets to and it starts warming up whereas In the 12 volt system there is constant readjustment of temperature as soon as it rises it clicks on. That is whether it’s a holding plate or it’s an evaporator
 

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Discussion Starter #49
so why isn’t commercial refrigeration in a restaurant holding plates vs.evaporators.
why aren’t home refrigerators made using holding plates
why Are most people using evaporators vs 12 volt holding plates


i understood before your point about engine driven refrigeration and that plates can also be 12 volt.
NO.... plates are not electrical,,, they are stainless steel box filled with eutectic fluid with the refrigerant pipes inside,,, a heat exhanger.

Large volume boxes circulate cold air... refer or freezer.
 

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Discussion Starter #50
If holding plate efficiency was so superior to the evaporator kind, why aren’t companies jumping all over this.
You would think that’s a no brainer

is it cost?
Is it surface area?

I don’t think it’s as simple as the physics you claimed. There is more to it than a small chunk of steel keeping all areas of the reefer at an even temp compared to a much larger evaporator.

Assuming that the plate works like an evaporator in that there is refrigerant activated by a thermometer can the temp be set at the 0 degree point or lower even.

Back to the engine driven system , once the engine is turned off, that is the coldest point the steel block gets to and it starts warming up whereas In the 12 volt system there is constant readjustment of temperature as soon as it rises it clicks on. That is whether it’s a holding plate or it’s an evaporator
It's not a small chunk of steel... it's a ss encased block of super cold ice. They have T stats anbd they can have fans to circulate cold air.

Evaporate Or Holding Plate?

There are two variations on this basic method of keeping food and drink cold. One, already mentioned, is the evaporative plate system. The other is the holding plate (or, some say, the energy accumulator) system.

The market offers many evaporative refrigeration systems. They operate just like the refrigerator at home. An evaporative system will run frequently to keep the refrigerator chilled. It switches on and off as demand requires.

The Norcold is a classic example of an evaporative system refrigerator, ready to install under the counter.

A much more costly choice is cold plate refrigeration. The plate is a box, two to four inches thick, sized to fit inside the refrigerator, across the side or top. The plate is filled with a fluid (alcohol, antifreeze or calcium chloride compounds), in a network of tubes that carries the refrigerant.

As the compressor works, the fluid freezes. It then holds its chilly temperature for many hours without further effort by the compressor. A holding plate does a good job of maintaining the 40 degrees required in a refrigerator without turning the compressor back on for at least 12 hours. Some super units last even longer.

Major builders of marine refrigeration components and systems offer both evaporative and cold plate units. These companies include Grunert, Adler/Barbour-Crosby, Glacier Bay, Sea Frost, Frigomatic, Technautics and others, including local shops that build custom systems with off-the-shelf components.

The problem with holding plate systems is that they are enormously expensive, costing three to four times more than evaporative systems. Or more.

The only real advantage of a cold plate system is that the owner chooses when a holding plate compressor is to operate; he or she has no control over when an evaporative refrigerator turns on or off.

When holding plates were first introduced to boaters, they were a blessing for sailors, whose boats had insufficient battery capacity to run a refrigerator, and whose feeble engine alternators would have trouble keeping one charged. A sailboat owner would only have to run his engine twice a day to drive the compressor just long enough to freeze the holding plate.

Today, with the availability of deep cycle batteries and high-capacity engine alternators, holding plate refrigerators offer no benefits to powerboaters and few advantages to sail boaters-except, perhaps, for circumnavigators and others on long ocean crossings. A powerboat making an ocean crossing certainly has the ability to handle the frequent energy demand of an evaporative plate refrigerator.

An evaporator plate draws a little power fairly often. A holding plate system hits the energy supply hard twice a day for a prolonged period. Both kinds work well."
 

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I have batts which fit the space behind the engine. My electrical system evolved over 35 years... 2 flooded probably group 31. Next when I went south 2 gels which fit in the OEM box.. w/ smart regulation and high output alt. Then 2 8D AGMs and an Optima AGM start,.. larger alternator,,,, monitoring and echo charge, I rebuilt the box, same size but stronger, Everything fits in the box and batts are nicely secured. Any suggestions? These 8Ds are too effin heavy!

We both have optima starters and echo charge them

So you have
2 - 8D= approx 254 lbs generating 490 amps

I have
6-6 volt 4ct lifelines = approx 396 lbs generating 660 ah ( each weighs 66 lbs and I can pick up).
I could have got 4-6 volt 6ct lifelines = 360 lbs generating 600 ah

Not exactly a massive battery bank. But I could cut down if I had solar .
I could cut down to 4- 6 volts = 264 lbs generating 440 amps

This is what makes the LiP04 so attractive..the weight and discharge profile. I still have 7 plus years hopefully left on my LifeIines before I need to replace. Probably the same amount of time before I get out of sailing.
 
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NO.... plates are not electrical,,, they are stainless steel box filled with eutectic fluid with the refrigerant pipes inside,,, a heat exhanger.

Large volume boxes circulate cold air... refer or freezer.
I understood that as yours are engine driven. I’m now talking about 12 volt driven ones compared to evaporators also using 12 volt. I already established I won’t run a diesel with limited life using fuel just to make ice or cool our reefer. You set your up differently

My last few comments are about the 12 volt plates and why they aren’t the standard.
 

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Discussion Starter #53
I understood that as yours are engine driven. I’m now talking about 12 volt driven ones compared to evaporators also using 12 volt. I already established I won’t run a diesel with limited life using fuel just to make ice or cool our reefer. You set your up differently

My last few comments are about the 12 volt plates and why they aren’t the standard.
plstes do not use electricity. Refrigerant circulates through them... freezes the eutectic solution....

 

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so why isn’t commercial refrigeration in a restaurant holding plates vs.evaporators.
why aren’t home refrigerators made using holding plates
why Are most people using evaporators vs 12 volt holding plates


i understood before your point about engine driven refrigeration and that plates can also be 12 volt.
You can't use commercial refrigeration and small boat systems as comparison for anything. Commercial reefers have humongous cooling capacities and are not worried about energy or its storage. They simply aren't comparable any more than a 10kbtu contained marine A/C is to a commercial chilled water A/C.

Same with home reefers, where efficiency and energy use isn't a concern.

Many boats use evaporator systems for the reasons I mentioned as tradeoffs - more space in the box, cheaper, and easier to install. However, they are not even close to universal. Many, many boats are using 12V holding plate systems from common major manufacturers like Cool Blue, SeaFrost, Isotherm, and others. I don't know the percentage of cruiser boats with each, but we meet and know very many using holding plates instead of evaporator plates.

Mark
 

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Discussion Starter #55
I understood that as yours are engine driven. I’m now talking about 12 volt driven ones compared to evaporators also using 12 volt. I already established I won’t run a diesel with limited life using fuel just to make ice or cool our reefer. You set your up differently

My last few comments are about the 12 volt plates and why they aren’t the standard.
Who knows.... ask a refer installer why they don't use them, Holdover plates take up more volume.

12v systems use lots of amps
engine drive uses essentially none


If you use lots of amps you need to replace them - engine, genset, shore power, alt systems and large banks
 

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If holding plate efficiency was so superior to the evaporator kind, why aren’t companies jumping all over this.
You would think that’s a no brainer
My last few comments are about the 12 volt plates and why they aren’t the standard.
There is no "standard", and I think that is what is tripping you up. There are many large companies selling holding plate systems, and many of those sell both holding plates and evaporator plates to go with their compressors. It is horses for courses, and there are tradeoffs for both.

I suspect you see most boats in your roaming grounds having evaporator plate systems because those are cheaper, energy isn't as much as a concern, and the boxes are smaller - generally a tiny ice cube compartment formed by the evaporator for a freezer with convection cooling of the same box as a reefer. On larger boxes, and split boxes, evaporator plates need to be very large, and the smaller compressors cannot hold the refrigerant volume, nor deliver it accurately without going to the expense and complication of thermo-expansion valves, refrigerant holding tanks, and large dryers to keep it operating.

For an example, the 6/4 cubic foot spillover system on our previous boat I mentioned earlier required the largest custom evaporator plate made - it cost $800 and needed to be custom bent - and drove the BD50 compressor at its maximum specifications. Any larger, and it would be holding plate time, or separate compressors and evaporator plates for each compartment. While this is quite a large box for a typical boat in your experiences, it is not a large box for many cruising boats.

We had both a holding plate and evaporator plate systems on that reefer/freezer at different times. The holding plate was driven by a 120Vac compressor, and after a couple of years we got rid of it for a 12Vdc evaporator plate system because the 120Vac was not meshing well with how we used the boat (in hindsight now with lithium batteries and more solar, that system would have been fine). So I have direct experience with both types of cooling plates on the exact box on the same boat. The holding plate definitely had less box temperature swing than the evaporator plate, and it pulled down the box much (much) quicker when loaded with warm stuff. Energy use was difficult to compare because the holding plate compressor could handle at least twice the size of box we had (and operating through an inverter), while the evaporator compressor was close to maximum limit. But adjusting for the differences and questimating, I would say they used about the same amount of energy.

Mark
 

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Discussion Starter #57
the choice is driven by your boat's architect... your available electrical energy, how much food you need to refrigerate and how you use the boat. AND as Mark wrote there are hybrid systems.
 

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so why isn’t commercial refrigeration in a restaurant holding plates vs.evaporators.
why aren’t home refrigerators made using holding plates
why Are most people using evaporators vs 12 volt holding plates
My wife is a trained Chef also and worked most of her career for Whole Foods in store management. The bane of our existence at one point was a faulty refrigeration system that would malfunction at 2 in the morning and she would get a call from the alarm system.

There are significant usage and structural differences in commercial refrigeration and a boats needs. One being permanent shore power, the other is the need to have a huge walk in door opened many times a day.
 

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There are, but I didn't write that (at least not on purpose) - I think it was Capta who talked about hybrid engine/AC/DC systems. These would definitely be holding plates, though.

Mark
You can't use commercial refrigeration and small boat systems as comparison for anything. Commercial reefers have humongous cooling capacities and are not worried about energy or its storage. They simply aren't comparable any more than a 10kbtu contained marine A/C is to a commercial chilled water A/C.

Same with home reefers, where efficiency and energy use isn't a concern.

Many boats use evaporator systems for the reasons I mentioned as tradeoffs - more space in the box, cheaper, and easier to install. However, they are not even close to universal. Many, many boats are using 12V holding plate systems from common major manufacturers like Cool Blue, SeaFrost, Isotherm, and others. I don't know the percentage of cruiser boats with each, but we meet and know very many using holding plates instead of evaporator plates.

Mark
I think we both get tripped up. Some statements which sound like they are facts are not able to be backed up.

For instance . Many boats use evaporator systems for the reasons I mentioned as tradeoffs - more space in the box, cheaper, and easier to install. However, they are not even close to universal. Many, many boats are using 12V holding plate systems from common major manufacturers like Cool Blue, SeaFrost, Isotherm, and others. I don't know the percentage of cruiser boats with each, but we meet and know very many using holding plates instead of evaporator plates. Reading that and I’m not trying to be a wordsmith.....many use evaporator systems and many many use plates. Sounds like you beleive there are more boats using plates. I very very strongly doubt that.

I venture to say that that even amongst cruisers, a small % of total sailboat owners I don’t even see most of them using plates. The majority of sailboat owners are not cruisers. The percentage of boats manufactured under 40 ft in totality are much greater than those over 40 ft. Even on sites like Yacht Work non cruising boats greatly outnumber those over 40 ft by 5:1.

We live in two different uses for our boats. It isn’t our home. Though we may actually average as many miles per year as many cruisers we are actually in a minority in weekenders/ costal vacations.

I would venture to say most sailboats that have refrigeration have the evaporator type ( tomorrow I will call my friend in Annapolis to ask him what he sees) . I would consider him much more an expert than us. He sells many different brands of plates and evaporator units in addition to the new trend, the self contained dorm style ones. He carries many of the brands you mentioned. He also services them. So let’s see what he says.

I want to hear from him what deters people from buying a plate ( other than price) and what deters people from buying an evaporator.

The OP when he chose this thread has gotten many cruisers responses, but we know the majority of sailboats are not.
In the marina I’m in, 140 sailboats length 22-45 ft, I venture that over 1/2 have refrigeration. ( we’ve had seminars inviting marine refrigeration techs to educate us, just like we have for rigging and diesels. We used to get Mac Boring but they have backed off this service recently.

Other of the marina boats use ice or portable refrigerators. Having a nice cool beverage or keeping food safe is a quality of life thing making use of the sailboat more comfortable and an option. To a cruiser, it’s not an option, though we know some minimalists who cruise the world without it.

Other than a layman’s statement over the way the plate works are there any SN who could explain the fluids in the plates and what their technical properties are, I can read this and have on the internet, but I find the experts really understand this. How does the plate get colder than 0 degrees. I understand how the Refrigerant in an evaporator system works. I’m trying to figure out how Jeff can claim his engine driven plate can keep the internal chemicals at their temp. In the 12 volt models the refrigerant is continually circulated. I guess that’s why we see combo units being sold. I brick of ice or a mechanical brick of ice will continually warm and loose its effectiveness over time. The 12 volt systems won’t. So why is the brick a more efficient way compared to a large surface are of plates.

A little off topic. Some time ago I took out our reefer box and rebuilt it with 3 inches aerogel (R20) covered by a Mylar sheets. My ah usage on an average day dropped from 47 ah from a super cold machine which cools 6 cubic feet reefer and 3 cubic ft freezer to less than 20 ah on a hot Chesapeake July day. The lid ( it’s a top loader) I redesigned with a plastic air screen like commercial refrigeration walk-ins have. The dramatic drop in ah usage was a big saver .
I found it easier to reconstruct the box in the open, then drop it back in the space it occupied(s). Having reliable non moist cold drinks , blackberries, lettuce , ice is a great psychological plus for using the boat and making it comfortable.
 
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