Eutectic Refrigeration - What to Do ?

[MoonlightSailor]

Howdy all!

We are starting to brainstorm about our refrigeration system. It currently has a 20 gallon eutectic containment system in the freezer side and then spills over into the refrigerator side. The compressor is belt driven by a single cylinder diesel kubota and the system is cooled by sea water. The system is very close to being operable. The captain that delivered the vessell said it started to cool when he fired it up at one point. However, now I believe the sytem is not charged and has a leak because it's not cooling now.

I'm 80% confident that the ice box is very robust and properly insulated. I'm not even going to think about ripping apart the boxes to find out or reinstall. How would I go about finding out how it was insulated other than finding documentation on the install. It's a custom install (aren't they all?)

Here are my thoughts about the system:
1) If I keep the current system, it will be dependent on me running it every day for about 1 hour. I would like a system that is essentially hastle free.
2) If I decide to keep the system and get it up and running, I'm going to have to spend some $$$ and who knows when that will end.
3) I don't want the hastle of having to maintenance another engine and carry more spare parts on the boat.
4) Removing the Kubota will free up more room to install another 2-3 8D batteries to power the DC refrigeration system if I go that route...which would give a total of over 1000amp/hrs.

A refrigeration expert I've been talking to is not giving up the manufacturer of the specific direct drive motor that will power a 1/2 horse compressor with initial loat of 40amps and turn at 675 RPM. Those are the details that I've written down anyway.

Does anyone have any suggestions or know of this alleged motor that he is speaking of?

Matt

[djmarchand]

You certainly have a wierd refrigeration system. Other than recharging the system and using it as is, here are some suggestions:

Replace the condensing unit with a Danfoss system. You might want to contact Richard Kollmann (who may respond in this forum) on his website at KollmannMarine Boat Refrigeration Specialist

The problem as I see it is your existing system has a very large cooling capacity, probably ten times greater than a Danfoss compressor. The mismatch of components may be a problem. Richard will know. At the very least it will take a long time perhaps half a day or more to freeze all of the eutectic solution. Not really a problem in itself as the eutectic will even out the temps.

You must have a big refrigerator and freezer volume. Approximately how many cubic feet?

And what are you going to use to recharge your 1000 amphours of batteries once you dump the diesel?

David

[Blue Stocking]

That little Kubota is a real work-horse of a motor. I not sure which, but I think either Jack-rabbit Marine or Ferris Power systems, built a Kubota which drove an A/C compressor, an alternator, and or various types of pumps at the same time. You might think about getting broader advantage out of the diesel.

[Marinheiro]

The direct drive motor is/was made by Glacier Bay(not sure if they still make them). There were 0.5 & 0.75 hp models, 12 & 24V. Glacier Bay used to couple these to Bitzer compressors. They have got out of the refrigeration game and I notice R-Parts who used to sell these items have just closed their doors - according to their web site.
But as was noted above if you have 20 gal of Eutectic solution, then you are going to need a bigger compressor than one of these electric drive units to pull it down in reasonable time.

[Blue Stocking]

But as was noted above if you have 20 gal of Eutectic solution, then you are going to need a bigger compressor than one of these electric drive units to pull it down in reasonable time.[/QUOTE]

--but boy!!---you would able to balance out global warming

[MoonlightSailor]

Originally Posted by djmarchand

You certainly have a wierd refrigeration system. Other than recharging the system and using it as is, here are some suggestions:

Replace the condensing unit with a Danfoss system. You might want to contact Richard Kollmann (who may respond in this forum) on his website at KollmannMarine Boat Refrigeration Specialist

The problem as I see it is your existing system has a very large cooling capacity, probably ten times greater than a Danfoss compressor. The mismatch of components may be a problem. Richard will know. At the very least it will take a long time perhaps half a day or more to freeze all of the eutectic solution. Not really a problem in itself as the eutectic will even out the temps.

You must have a big refrigerator and freezer volume. Approximately how many cubic feet?

And what are you going to use to recharge your 1000 amphours of batteries once you dump the diesel?

David

I'll have to measure what I can and calculate the cu.ft. I was just thinking about the 20gallons....that's 4-5gallon buckets of solution...that is alot! If I got rid of the solution and the box-like donut that it's shaped like, I'd have to cut it up into little parts while it's in the freezer and remove it piece by piece. Not looking forward to that either.

I'm going to post some photos very shortly.

If I dumped the diesel we would power DC system with 4-135w PV panels and probably 2 more in the near future (currently drawing up plans for a tower to mount the panels).

[MoonlightSailor]

Photo from the outside. Freezer on the left. Refrigerator on the right.



Refrigerator: simple spill-over into this compartment.



Freezer: You can see the high and low side copper coming out of the eutectic solution holding tank.

The lids are 4" thick.

From what we can estimate, there is about 14cu.ft. of space (if the tank holding the eutectic solution was removed)

[Richard Kollmann]

I would not recommend removing any of the present engine driven system until you examine the energy power grid requirements for electric refrigeration. It is not realistic to consider operating a boat and a 14 cu ft refrigerator freezer in a tropical climate without running an engine every day even with alternative energy from solar and wind.

If your boat were to remain in San Diego or Latitudes north of it energy requirements would be less than tropical. I ounce approve the selection of a smaller than normal 100 ton air conditioning compressor for a large office complex in San Diego because the heat average degree days there were low and not considered tropical.

What is needed to answer your question of how to proceed with refrigeration will depend on answers to the following?
What temperatures do you want to maintain in each box?
Planed cruising grounds?
How much time will boat be connected to shore power?
Will boat be anchored or tied to moorings?
Will boat be left unattended for more than one day?
Actual size of each box?
What are the three dimensions of eutectic holding plate?
Amount of insulation and approx age?
Size of main engine alternator?
Size of Kabota alternator.
Type and age of house battery bank?

In order to answer questions about re-commissioning engine driven system numerous pictures would help showing Crankshaft pulley, Compressor, all lines with pressure switches, Condenser, and anything else that looks like it is part of refrigeration unit.

[MoonlightSailor]

Originally Posted by Richard Kollmann

What is needed to answer your question of how to proceed with refrigeration will depend on answers to the following?

What temperatures do you want to maintain in each box?
Would like to be able to make ice in the freezer....27deg F. 40-45F in the refer. Sound right?

Planed cruising grounds?
Tropical, tropical, and tropical.

How much time will boat be connected to shore power?
We are planning on being on the hook/ball 95% of the time.

Will boat be anchored or tied to moorings?
When we can, we will be tied to moorings....why is this important?

Will boat be left unattended for more than one day?
Not going to happen very often...we would like to be able to take 1-2 day trips inland in some cases.

Actual size of each box?
Will get back with you on that.

What are the three dimensions of eutectic holding plate?
The holding tank (look closely at the photo) is donut-like and wraps around the inside of the freezer and in the middle of the unit you see the long narrow white colored starboard with ventilation holes in it. Would have to calculate the volume of space that 20 gallons displaces.
1 US gallon = 0.133680556 cubic feet
Answer 2.67 cu.ft.

Amount of insulation and approx age?
Amount of insulation is unknown and can only speculate. If the construction of the rest of the boat is any indication of the quality he put into the insulation, it's a good sign. Door insulation is 4" thick. Boat was launched in '94

Size of main engine alternator?
Pretty sure it's 80amp.

Size of Kabota alternator.
Pretty sure it's 130amp

Type and age of house battery bank?
We bought 2 new 8D batteries in sept of 2009, each with 220amp/hr
They are lead.

In order to answer questions about re-commissioning engine driven system numerous pictures would help showing Crankshaft pulley, Compressor, all lines with pressure switches, Condenser, and anything else that looks like it is part of refrigeration unit.
I will get you the info and photos requested above.

Thanks for your insight ahead of time.

Regards,
Matt

[Marinheiro]

Are you sure about your volume calculations? Looking at the pictures appears to me somewhat less than 14 cu ft.

[MoonlightSailor]

Update on diesel driven compressor for freezer/refrigeration...

Spent $500 diagnosing and ascertaining the viability of the current system. It's currently running with R12. He added 3lbs of R12, then run the system for several hours. When he was done he recovered 7-8lbs of R12 from the system. I think he is wanting to change the system to a different type of refrigerant which was going to be a two step process to get all the oil out of the lines.

The compressor currently being driven looks like one of these which is a cast iron casing.

I also have an aluminum York compressor. He said these are compressors that are used in automotive applications. Parts are also very difficult to come by for these units.

Refrigeration man recommends the following if we are to keep the current engine driven system:

"Suction Line Should Be Larger. System Needs Suction
Accumulator To Protect Compressor On Start Up. Expansion Valve
Should Be Changed To External Equalization To Improve Performance.
Compressor Has Leak At Shaft Seal & Needs Repair Or Replacing."

Dad and I have discussed this at length. We would like to have a system that is more "hassle free". A DC system makes the most sense to us. It would mean 2 fewer hours of engines running (less peace). I don't want to have to run a diesel for 2 hrs per day and be confined to the boat. One less diesel engine is ok with us = fewer parts to carry on the boat. One less engine worry about.

Our refrigeration man is Robert Van Ness out of San Diego. Over the years he has put together a DC system that would suite our needs. I'm going to attach the photos and price list of the components. I think, maybe I'm wrong, but it does seem to be very pricey. What do you think? Suggestions? Comments? Thanks...

[MoonlightSailor]

Originally Posted by Marinheiro

Are you sure about your volume calculations? Looking at the pictures appears to me somewhat less than 14 cu ft.

Here are my latest calculations:
25920 cu in - total volume
minus stove inset (not shown on 3D view) - 1323 cu in
minus 20 gallons of solution in plate - 4613 cu in
-------------------------------------------------------------
19984 cu in or 11.56 cu ft

[Richard Kollmann]

I can not understand why someone would charge $500 to troubleshoot a simple system like your single plate engine driven system. Isolating the problem with your system should take about one hour restoring it to a reliable condition does take time. If compressor clutch was engaged and there was little or no cooling it only takes 15 minutes to connect gauges adding two pounds of refrigerant and testing a Cast iron Tecumseh compressor by closing Rotolock valves. It takes another 15 minutes to check for correct refrigerant flow. If at this point temperature coming out of expansion valve is not below 32 degrees it would indicate a refrigerant flow problem and not a loss of refrigerant. Adding 3 pounds of refrigerant and removing 8 pounds confirms that low on refrigerant was not the problem.

If compressor was turning and failed first test it would need to be replaced probable with a new Climate Control ( York under a new name) and interchangeable with Tecumseh mounting bolts.

If compressor clutch stays engaged and there is poor or no cooling then refrigerant flow is restricted or condenser cooling is in question.

It is true that engine driven refrigeration compressors were designed for auto and industrial mobile equipment installation. When a refrigerated box’s size and heat load is too large for 12 volt refrigeration or a boat’s DC power grid lacks the ability to support DC refrigeration like yours engine driven refrigeration is the answer.

There are successful large belt driven 12 volt compressor systems but motor repairs limit service life and add un-necessary costs and down time. The direct drive 12 volt motor units like the one pictured have the same motor problems with added flex shaft coupling failures between motor and compressor.

It appears the salesman is only trying to sell his unpopular unit by indicating your system design is the cause of present cooling problem by saying: "Suction Line Should Be Larger. System Needs Suction Accumulator To Protect Compressor On Start Up. Expansion Valve Should Be Changed To External Equalization To Improve Performance”

The Question I have is why is a system that must have worked at one time with its present design not working now? If the compressor has failed why not simply replace it and correct the reason it failed? These compressors have demonstrated 20 years of service in many live aboard boats in tropical condition.

[MoonlightSailor]

I've posted some photos of the refrigeration system. Refrigerant is cooled by seawater pump on the Kubota. That coil is on the ceiling above the Kubota. Compressor is belt driven.

The filter/drier is at the floor against the wall. Mr Frost suggested that the filter/drier be relocated at a high point in the system.

You can see that the lines are on the wall and above some electrical wiring and inverter/charger. We have talked about moving the lines or moving the electrical components away from the wall that are directly above the lines. The lines are not currently insulated.

From what I can ascertain, the insulation on the box is a minimum of 4" thick and sometimes 4.5".

The Kubota is model EA300E.

I spoke with the $100/hr refer man (Mr Frost) tonight at length some more. I wish I could record our conversations so that I could go back and listen to him explain again.

When He was here the first time, he put temp probes on the high and low lines inside the freezer box, monitoring the temp difference between the two. He was comparing those temperatures to the readings on the gauges at the compressor and made the determination that all the lines should be 1/2" to help achieve the right pressures in the lines.

He also explained that the compressor I'm running was built for a 5:1 compression ratio, not the 12:1 ratio that the system needs to run it at to get the cooling done. Hence, working them over twice as hard will make them fail sooner. But he said you can carry a back up compressor unit because they are not that expensive ($350)?

He did mention that there are compressors that are 12:1 compression ratio but it would not fit the form factor that is set up right now on the Kubota.

That's all I can think of right now.

[Richard Kollmann]

MoonlightSailer, I would have preferred you emailed pictures to me and not used band space on this forum for pictures. Hopefully you misunderstood Mr Frost’s comments because it appears to me his efforts were only trying to sell his system and no attempt to restore operation to your present system. I do not know why he removed the refrigerant and if he did not put it back that would be an unfair practice. Now if refrigerant is missing unit can not be tested and re-commissioned without buying more refrigerant. I am also surprised Frost did not say compressor was good or bad. The only thing he indicated with his line temperature test is there was a refrigerant flow problem. This is an older system that must have worked at one time with the size lines and TXV it has now, so what is wrong with it now?

I have several concerns with the Capt Frost's 12 volt units, first they’re too expensive for a pleasure boat at $5,500 for a ½ HP and $6,000 for a one HP unit and this price does not include installation costs. If Mr. Frost charged $500 to tell you that you needed to buy his unit what is he going to charge to install it. Frost’s unit is much the same as Glacier Bay direct drive that they have stopped selling. It is true Frost’s system has an added pump down cycle but it will have the same problems that GB’s units experienced.

Large Twelve volt compressors do overstress most normal size battery banks. Refrigeration for a 12 cu ft combination refrigerator freezer will require 160 amp-hrs per day in a tropical climate or 100 amp-hrs per day in San Diego’s climate conditions. The ships house battery bank needs to be 4 times boat’s total use of DC amp-hours. In order to achieve reasonable life from batteries amp-hrs used daily need to replaced daily.
Engine daily run time will be far greater with a large1/2 HP 12 volt refrigeration unit then it would be with an engine driven refrigeration system unless house battery bank is almost new and exceeds 800 amp-hrs.

If your refrigerant is back in your system and you had a set of gauges I could show you how to identify the problem and maybe correct it without any other major expense. Your refrigeration system is home made one of kind using all conventional components with exception of an over sizes liquid reciever. From the pictures I could not find the high and low pressure switches required that are wired in series with compressor clutch wire. Compressor drive pulley and Kubota’s governed speed may run compressor faster than I would recommend for extended compressor life. On the first picture you sent looking at top of plate I see a unit in suction line coming out of plate that I can not identify, need a better look at it. I see no reason why this unit as built can not freeze holding plate in one hour after the first days extended run. Actual temperatures in each box will depend on box’s heat loss and ability of holding plate’s thermo heat conductivity.