The Worst pleasure boat refrigeration.

[NSboatman]

well... not a lot about the worst systems here! but I suppose that's a good thing!


I currently have a dual system that came with the boat - engine driven sea-frost, plus 12v seafrost (BD35). they share a single holding plate (in the freezer section - spill-over for fridge), but have separate piping systems. It works very well, and has for 5 years. that engine driven compressor hauls the plate down to -12C in 30-40 mins - it's wonderful to be able to show up, load up, and keep stuff frozen reliably without a huge power draw from the batts or alternator. the 12v system is really just a maintenance system - although it will pull the box down if given enough time. I typically turn on the system in May, shortly after launch, and then off in late Nov/early Dec. Cold beer is never a problem...



I really quite like the engine drive for its power and reliability, but there are 2 things I don't like about it:


1 - the V belt wears and spreads that ubiquitous black powder on the front of my engine and everywhere else in the engine compartment. between it and my alternator I'm always fighting alignment and tension to reduce wear and dust. If I didn't have a 1970 vintage diesel I'd probably try and replace pulleys with a serpentine system... but to do that for this diesel and all the belt driven consumers would probably be the equivalent of a good down payment on a new diesel...hmmm.



2 - the cooling system from the engine driven compressor (a coil of 3/8" copper tubing inside a PVC pipe - the copper is full of R12 refrigerant) dumps all its heat to the incoming raw-water for engine cooling. Up here in the cold north that is not an issue - and given the flow rates I doubt it is in the tropics either - but having the two systems intimately linked worries me. In my mid-sleep, involuntary explorations of what possible disasters could befall me on my hypothetical sailing trips, I manage to come up with scenarios where the diesel cooling is somehow compromised by the reefer cooling, or vice versa.



I think the engine drive systems got a bad rap from a couple of decades of rushed and very poor installations in the Caribbean charter fleets. I know I replaced a good number of the compressors during my time there, and a few diesels too - whose bearings were sent to an early demise by the rigidly mounted compressor pulling the entire flexibly mounted engine out of line. boy those were crap installations! It should have been a great application for those systems tho - all those boats required some engine run time each day.



only other minor point is the effect on RPM, as has been noted already. I like to tune my idle rpm down to a nice quiet level where there are few sympathetic vibrations in the boat, and the shifts are kinder to my Hurth 250 mechanical gearbox. When I get to the nice level for general shifting and idle, and clutch in the 5hp reefer compressor, the engine doesn't stall - but if I clutch in and then shift into gear with a relatively cold engine, I end up in this terrible half-choked, gutless, unable to rev-up, rattly and coughing diesel engine fit. SO don't do that, says the doc!! amen.

[slug]

Originally Posted by NSboatman

well... not a lot about the worst systems here! but I suppose that's a good thing!


I currently have a dual system that came with the boat - engine driven sea-frost, plus 12v seafrost (BD35). they share a single holding plate (in the freezer section - spill-over for fridge), but have separate piping systems. It works very well, and has for 5 years. that engine driven compressor hauls the plate down to -12C in 30-40 mins - it's wonderful to be able to show up, load up, and keep stuff frozen reliably without a huge power draw from the batts or alternator. the 12v system is really just a maintenance system - although it will pull the box down if given enough time. I typically turn on the system in May, shortly after launch, and then off in late Nov/early Dec. Cold beer is never a problem...



I really quite like the engine drive for its power and reliability, but there are 2 things I don't like about it:


1 - the V belt wears and spreads that ubiquitous black powder on the front of my engine and everywhere else in the engine compartment. between it and my alternator I'm always fighting alignment and tension to reduce wear and dust. If I didn't have a 1970 vintage diesel I'd probably try and replace pulleys with a serpentine system... but to do that for this diesel and all the belt driven consumers would probably be the equivalent of a good down payment on a new diesel...hmmm.



2 - the cooling system from the engine driven compressor (a coil of 3/8" copper tubing inside a PVC pipe - the copper is full of R12 refrigerant) dumps all its heat to the incoming raw-water for engine cooling. Up here in the cold north that is not an issue - and given the flow rates I doubt it is in the tropics either - but having the two systems intimately linked worries me. In my mid-sleep, involuntary explorations of what possible disasters could befall me on my hypothetical sailing trips, I manage to come up with scenarios where the diesel cooling is somehow compromised by the reefer cooling, or vice versa.



I think the engine drive systems got a bad rap from a couple of decades of rushed and very poor installations in the Caribbean charter fleets. I know I replaced a good number of the compressors during my time there, and a few diesels too - whose bearings were sent to an early demise by the rigidly mounted compressor pulling the entire flexibly mounted engine out of line. boy those were crap installations! It should have been a great application for those systems tho - all those boats required some engine run time each day.



only other minor point is the effect on RPM, as has been noted already. I like to tune my idle rpm down to a nice quiet level where there are few sympathetic vibrations in the boat, and the shifts are kinder to my Hurth 250 mechanical gearbox. When I get to the nice level for general shifting and idle, and clutch in the 5hp reefer compressor, the engine doesn't stall - but if I clutch in and then shift into gear with a relatively cold engine, I end up in this terrible half-choked, gutless, unable to rev-up, rattly and coughing diesel engine fit. SO don't do that, says the doc!! amen.

Space on the front end of a marine diesel is very expensive

Many folks prefer to use this expensive real estate for a second alternator

[Q Xopa]

Originally Posted by Richard Kollmann

If you are happy with your eutectic plate system and electrical power upgrade that is all that matters. And yes I have studied and replied to the charts you mentioned. Performance success is in powering eutectic plates with a small 12/24 volt compressor is having a source of alternative power from wind, solar or a water propeller alternator. Without sufficient alternative electrical power or major increased battery capacity engine alternator needs to be operating too many hours per day. Anyone who believes eutectic plates create energy is wrong.

Hopefully we can hear from experienced boaters with eutectic plates frozen from small 12 volt compressors I sold many of them.

I must of missed it, but did someone mentioned eutectic plates 'creating' energy?

[RaymondR]

Originally Posted by Richard Kollmann

If you are happy with your eutectic plate system and electrical power upgrade that is all that matters. And yes I have studied and replied to the charts you mentioned. Performance success is in powering eutectic plates with a small 12/24 volt compressor is having a source of alternative power from wind, solar or a water propeller alternator. Without sufficient alternative electrical power or major increased battery capacity engine alternator needs to be operating too many hours per day. Anyone who believes eutectic plates create energy is wrong.

Hopefully we can hear from experienced boaters with eutectic plates frozen from small 12 volt compressors I sold many of them.

I agree on the alternative charging sources but tend to the opinion that a eutectic tank allows one to get by with a smaller battery capacity or extend the life of a larger capacity through diminishing the over night voltage draw down.

Definitely doesn't create it and not really accurate to say it stores energy either. Probably more accurate to say it's a heat sinking and storage device but that's a bit cumbersome.

I also tend to the opinion that we should avoid the term "eutectic plates" reserving plates for "evaporator plates" and use "eutectic tanks" which are both more appropriate in a descriptive sense.

[Uncle Bob]

Originally Posted by RaymondR

Ahh Q Xopa,

By the time they got finished trying to out-argue each other those of us that read every post had gained so much both general and aspect-specific information on boat refrigeration systems someone should have awarded us doctorates in the discipline.

It was one of the most informative threads I've seen on the forum. I'm hoping they are both out there researching and experimenting and that we can get them both cranked back up on the subject sometime in the future.

Sadly I believe that Ozepete has been run out of town!

Originally Posted by Q Xopa

Hmm, I remember that discussion a little different. I'm pretty sure the both sell and advocate hold over plate systems.
Pete has as you point out a water cool option, and Richard uses TX valves was the main differences I recall.

I could be wrong.

Different Richards I believe.

Originally Posted by Q Xopa

I must of missed it, but did someone mentioned eutectic plates 'creating' energy?

This seems to be a pet peeve of mr Kollman's, it is trotted out every so often even when no one has made or implied it.



There appears to be some here that do not understand or refuse to accept that the advent and utilization of reasonably efficient solar panels have fundamentally changed some systems used on recreational boats. What was inefficient 20 or so years ago is now very efficient and effective.

[ayates]

Originally Posted by RaymondR

In actual side by side tests Pete demonstrated that electricity consumption was not only moved to when plenty of solar power was available, it was actually about halved by using the eutectic system because the compressor was not cycling on and off.

Here is the referenced test: https://www.ozefridge.com/trial-data


Allan.

[s/v Jedi]

That test does not say much either. It records energy consumption at the compressor and for a fridge, not a freezer. It is setup to favor the outcome promoted by the author.

What needs to be added is the factors of the freezer needing more energy (I.e. at least one freezer and one fridge) plus the batteries and solar panels. We want to see depth of discharge of the battery cycles as well as compressor run time during solar production vs during the non production period.

When you put big solar arrays forward as the new era then you also must put LiFePO4 batteries in that mix.

It all comes down to this: during solar production hours we generate more energy than we need, so we need to find a way to store that. One way is to put it in a battery in the form of stored electric energy. Another way is to put it in a holding plate in the form of stored thermal energy. For both cases we must make sure that we have enough storage space for all the excess energy produced.

So, which storage method is more efficient?

Candidate 1: solar > battery charger > battery > compressor > evaporator plate > fridge/freezer cooling
Candidate 2: solar > compressor > holding plate > fridge/freezer cooling

This has not been tested. Also, with candidate 2 we assume that the holding plate is big enough to provide needed fridge/freezer cooling. it may be too small, requiring the compressor to draw from the battery... that would be bad.

Also, lists of advantages for holding plates are given, but no disadvantages. Reduction of available fridge/freezer space is one, and one trick pony is another (can’t power a light from the holding plate). This needs much more consideration and to be done by someone without any sticks in the fire

[slug]

Originally Posted by s/v Jedi

That test does not say much either. It records energy consumption at the compressor and for a fridge, not a freezer. It is setup to favor the outcome promoted by the author.

What needs to be added is the factors of the freezer needing more energy (I.e. at least one freezer and one fridge) plus the batteries and solar panels. We want to see depth of discharge of the battery cycles as well as compressor run time during solar production vs during the non production period.

When you put big solar arrays forward as the new era then you also must put LiFePO4 batteries in that mix.

It all comes down to this: during solar production hours we generate more energy than we need, so we need to find a way to store that. One way is to put it in a battery in the form of stored electric energy. Another way is to put it in a holding plate in the form of stored thermal energy. For both cases we must make sure that we have enough storage space for all the excess energy produced.

So, which storage method is more efficient?

Candidate 1: solar > battery charger > battery > compressor > evaporator plate > fridge/freezer cooling
Candidate 2: solar > compressor > holding plate > fridge/freezer cooling

This has not been tested. Also, with candidate 2 we assume that the holding plate is big enough to provide needed fridge/freezer cooling. it may be too small, requiring the compressor to draw from the battery... that would be bad.

Also, lists of advantages for holding plates are given, but no disadvantages. Reduction of available fridge/freezer space is one, and one trick pony is another (can’t power a light from the holding plate). This needs much more consideration and to be done by someone without any sticks in the fire

Hard to justify holding plates on a small boat

The plates take up precious refer capacity and the compressor and system equipment consumed too much space

[Q Xopa]

Originally Posted by s/v Jedi

That test does not say much either. It records energy consumption at the compressor and for a fridge, not a freezer. It is setup to favor the outcome promoted by the author.

What needs to be added is the factors of the freezer needing more energy (I.e. at least one freezer and one fridge) plus the batteries and solar panels. We want to see depth of discharge of the battery cycles as well as compressor run time during solar production vs during the non production period.

When you put big solar arrays forward as the new era then you also must put LiFePO4 batteries in that mix.

It all comes down to this: during solar production hours we generate more energy than we need, so we need to find a way to store that. One way is to put it in a battery in the form of stored electric energy. Another way is to put it in a holding plate in the form of stored thermal energy. For both cases we must make sure that we have enough storage space for all the excess energy produced.

So, which storage method is more efficient?

Candidate 1: solar > battery charger > battery > compressor > evaporator plate > fridge/freezer cooling
Candidate 2: solar > compressor > holding plate > fridge/freezer cooling

This has not been tested. Also, with candidate 2 we assume that the holding plate is big enough to provide needed fridge/freezer cooling. it may be too small, requiring the compressor to draw from the battery... that would be bad.

Also, lists of advantages for holding plates are given, but no disadvantages. Reduction of available fridge/freezer space is one, and one trick pony is another (can’t power a light from the holding plate). This needs much more consideration and to be done by someone without any sticks in the fire

Yes all sounds reasonable.

I fully agree it would be nice to see some other data on this. Even better from independant non vested interested sources.

I guess re holding plate not powering a light. I don't think anyone would suggest no battery. So it could also be said that seeing less batt capacity was drawn down for the fridge more was available for lights.

Yes also true holding plates take valuable fridge real estate. I suppose it could save on some battery space.

[slug]

Originally Posted by Q Xopa

Yes all sounds reasonable.

I fully agree it would be nice to see some other data on this. Even better from independant non vested interested sources.

I guess re holding plate not powering a light. I don't think anyone would suggest no battery. So it could also be said that seeing less batt capacity was drawn down for the fridge more was available for lights.

Yes also true holding plates take valuable fridge real estate. I suppose it could save on some battery space.

The secret to a good refer system is a very well insulated box and top lid

Unfortunately when dealing with standard production boat construction , improving the system can be impossible

[Richard Kollmann]

Originally Posted by ayates

Here is the referenced test: https://www.ozefridge.com/trial-data
Allan.

With reported thousands of these systems sold and only one boater providing his satisfaction with some details. On another forum where these units are manufacture-red there was a complaint about excessive power consumption on this unit. Hopefully we can hear from a number of satisfied users of this systems performance with details and without the ban dads of alternative energy sources to mask true performance.

Everyone uses creative marketing but customer satisfaction is what creates more customers for a product.

[a64pilot]

Ref the test that “proved “ cold plates are more efficient, wasn’t I don’t think a set up. But was I believe two systems manufactured by the same person For sale or the public.

However if you drilled in the it, the biggest reason for the difference in efficiency between the two didn’t have anything to do with cold plate vs evaporator.
It had to do with evaporator size, the cold plate had a smaller evaporator, so that meant for it to do the same amount of cooling it had to be run much colder, by running it colder that took the compressor or a much lower COP “Coefficient of efficiency” and that is why it consumed more power.

In theory if everything is perfectly designed a thin plate evaporator will be more efficient as it’s always more efficient to cool something directly than it is to cool something for it to then cool the food. A cold plate is similar or freezing blocks of blue ice that you then put into a cold box to keep you food frozen, it’s more efficient to freeze the food directly.

Having said that I have a cold plate system and am very happy with it. Very. But as Richard says it’s not really a cold plate system, the reason it’s not is that it doesn’t go through a phase change daily, and since the plaid always stays frozen, it operates as an evaporator and not as a hold over system.

[GILow]

Originally Posted by Richard Kollmann

With reported thousands of these systems sold and only one boater providing his satisfaction with some details. On another forum where these units are manufacture-red there was a complaint about excessive power consumption on this unit. Hopefully we can hear from a number of satisfied users of this systems performance with details and without the ban dads of alternative energy sources to mask true performance.



Everyone uses creative marketing but customer satisfaction is what creates more customers for a product.

Well, I’m a satisfied user of this system. Only been using it for a couple of months, but so far I am very happy.

Power consumption figures are as good as predicted by Ozefridge.

230 litre spillover fridge/freezer with twin eutectic tanks. 50 AH@12V per 24 hours, in Adelaide in summer in a non-air conditioned boat, so cabin temps over 30 degrees very much the norm. Fridge insulation as per Ozefridge’s recommendation, 150 mm for the base, 100 mm on the sides and 50 mm on the top. Using extruded polystyrene as it was all I could easily source.

I am a 100% solar for my house bank, the fridge barely makes a dent in my power capacity.

When I hear about excessive power consumption on any refrigeration system I am more inclined to ask about the state of the insulation.

[GILow]

Originally Posted by Richard Kollmann

With reported thousands of these systems sold and only one boater providing his satisfaction with some details.

There may be a demographic problem here. I’ve met dozens of happy Ozefridge users here in Australia, but few, if any of them have heard of Cruisers Forum, and of those that have, most do no more than skim-read here from time to time.

I think it is a reasonable assertion to say that Cruisers Forum is predominantly North American membership and posting.

[bobty]

Originally Posted by Richard Kollmann

With reported thousands of these systems sold and only one boater providing his satisfaction with some details. On another forum where these units are manufacture-red there was a complaint about excessive power consumption on this unit. Hopefully we can hear from a number of satisfied users of this systems performance with details and without the ban dads of alternative energy sources to mask true performance.

Everyone uses creative marketing but customer satisfaction is what creates more customers for a product.

Yes me too. I decided on Ozefridge because of other satisfied customers https://www.cruisersforum.com/forums...ws-136455.html and am a very happy customer now.
I also had been following Ozepetes thread on eutectics until it disappeard. I see there is a copy here of those tests https://www.ozefridge.com/trial-data
Thanks