Refrigeration Refit Challenge

[OzePete]

Hi DHooper, They are both rather large cabinets but the real killer is the lack of insulation specially for the freezer and having a stainless steel interior lining.
Suggest removing the interior SS lining and add 75mm of Dow blue board to the base interior of each cabinet and 50mm to the freezer interior walls. (Leave the top as is) Re-line and vapour seal using a non conductive material like f/glass or say 5mm thickness ABS plastic (Acrylic)
If you like to post or email what the new interior dimensions would be with this added insulation, I can put each of your projects into our 'Heat load and Power consumption' estimator to provide expectations of duty cycle and power consumption.
(Note: Duty cycle should be less than 50% in the most extreme situation.)

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

[TassieBloke]

Originally Posted by DHooper

Thanks Tassiebloke for your thoughts! There is plenty of data on refrigeration throughout this site and extremely knowledgeable and talented folks posting it. A wonderful resource by itself. I don't want to build my own component system but rather purchase a stock off the shelf system capable of meeting these loads ideally with an air cooled constant cycling evaporator but will evaluate water/keel cooled alternatives as well. Just looking first to identify a manufacturer able to meet these large loads based on what may be working on similar sized boxes in the field. How big are your boxes?

Just a little about terminology, in simple terms.

There are air and water cooled (keel cooled and coil) condensers.
There are airflow evaporators, usually thin fin, and eutectic holding plate systems (also an evaporator in a sense)

Both systems have their dis/advantages, and both have been discussed here ad nauseam.

Since you are in OZ, Ozpete would be your best resource as he apparently sells both type of evaporator systems, and contributes his knowledge here regularly. His power consumption excel sheet is a real eyeopener for ones new to refrigeration.

Our fridge is 300lt and our freezer about 120lt. I inherited the system, as it was designed when she was built. It is a 240V Kirby compressor with seawater condenser cooling, with 1 large eutectic plate in the fridge, and 2 plates in the freezer. The freezer is long and narrow, which admittedly is a pain. There is a hand valve in the liquid line that allows me to isolate the freezer should it be empty or require repair etc. I have added a cheap electronic thermostat control (STC1000) on the fridge Danfoss solenoid. The freezer is a little more involved since I need to add a Danfoss solenoid in the liquid line for the thermostat to control.

If I had to design it again, amongst other things, I would reduce the size of the fridge, and increase freezer space. At 300lt, the fridge is huge, and there is a lot of unused space, and so it does cycle more due to the airspace. I have considered increasing the insulation thickness, although it is 100mm wall thickness (haven't yet established the base thickness), it is a law of diminishing returns on how much more you can go to make a real difference.

It is relatively simple, that the larger the refrigeration system, the greater the power consumption. My personal preference is that if you can maximise your solar panel surface area, and supplement with wind generation, then your are going to reduce the need to run a genset or main engine to replace the consumed energy.

Now there will be many comments as to whether you should only run refrigeration during the time of peak solar power production, adjust the temp setpoints on your controller to reduce cycling during the night, fill empty space with water to help hold lower temp during the day; if you running a genset/inboard/outboard/exercise bike for (insert your activity here), then the charging of the house bank is 'free' etc etc etc.

Research as much as you can, ask questions here and you will normally get the best info possible, so then you can determine what is best for YOUR cruising needs. An off the shelf system may not be the best choice, but after you look at all the aspects, it may be the only option.

Just my 2c.
YMMV.
All care, no responsibility.
Read the PDS.
T&C's Apply

[DHooper]

Originally Posted by OzePete

Hi DHooper, They are both rather large cabinets but the real killer is the lack of insulation specially for the freezer and having a stainless steel interior lining.
Suggest removing the interior SS lining and add 75mm of Dow blue board to the base interior of each cabinet and 50mm to the freezer interior walls. (Leave the top as is) Re-line and vapour seal using a non conductive material like f/glass or say 5mm thickness ABS plastic (Acrylic)
If you like to post or email what the new interior dimensions would be with this added insulation, I can put each of your projects into our 'Heat load and Power consumption' estimator to provide expectations of duty cycle and power consumption.
(Note: Duty cycle should be less than 50% in the most extreme situation.)

Cheers OzePete Ozefridge | 12 Volt Refrigeration Systems

Thanks Pete. I would probably reduce the box sizes further if that is the direction I go and I appreciate your suggestions. Jamey ran the numbers and the freezer was nearing 100% run time so box reduction is certainly an option.

[DHooper]

Originally Posted by TassieBloke

Just a little about terminology, in simple terms.

There are air and water cooled (keel cooled and coil) condensers.
There are airflow evaporators, usually thin fin, and eutectic holding plate systems (also an evaporator in a sense)

Both systems have their dis/advantages, and both have been discussed here ad nauseam.

Since you are in OZ, Ozpete would be your best resource as he apparently sells both type of evaporator systems, and contributes his knowledge here regularly. His power consumption excel sheet is a real eyeopener for ones new to refrigeration.

Our fridge is 300lt and our freezer about 120lt. I inherited the system, as it was designed when she was built. It is a 240V Kirby compressor with seawater condenser cooling, with 1 large eutectic plate in the fridge, and 2 plates in the freezer. The freezer is long and narrow, which admittedly is a pain. There is a hand valve in the liquid line that allows me to isolate the freezer should it be empty or require repair etc. I have added a cheap electronic thermostat control (STC1000) on the fridge Danfoss solenoid. The freezer is a little more involved since I need to add a Danfoss solenoid in the liquid line for the thermostat to control.

If I had to design it again, amongst other things, I would reduce the size of the fridge, and increase freezer space. At 300lt, the fridge is huge, and there is a lot of unused space, and so it does cycle more due to the airspace. I have considered increasing the insulation thickness, although it is 100mm wall thickness (haven't yet established the base thickness), it is a law of diminishing returns on how much more you can go to make a real difference.

It is relatively simple, that the larger the refrigeration system, the greater the power consumption. My personal preference is that if you can maximise your solar panel surface area, and supplement with wind generation, then your are going to reduce the need to run a genset or main engine to replace the consumed energy.

Now there will be many comments as to whether you should only run refrigeration during the time of peak solar power production, adjust the temp setpoints on your controller to reduce cycling during the night, fill empty space with water to help hold lower temp during the day; if you running a genset/inboard/outboard/exercise bike for (insert your activity here), then the charging of the house bank is 'free' etc etc etc.

Research as much as you can, ask questions here and you will normally get the best info possible, so then you can determine what is best for YOUR cruising needs. An off the shelf system may not be the best choice, but after you look at all the aspects, it may be the only option.

Just my 2c.
YMMV.
All care, no responsibility.
Read the PDS.
T&C's Apply

Thanks TasiseBloke. Your fridge is even larger than mine. How big are your Eutetic plates. The original Grunert's that I removed are 254mm x 355mmx 76mm (10" x 14" x 3"). My preference is to seek all air first, evaporator thin plate or eutectic holding plate and condenser before engaging in water cooled condenser alternatives. A stock system just may not be possible given these loads but like you said I am here to research and learn what options are available. Thanks for taking the time!

[rbk]

Double post.

[rbk]

Reinsulate, compartmentalize and run multiple units. Might be more efficient to reduce a compartment as it’s not needed and shut it down during completely on long passages, as fresh food gets used up. Or use smaller compartment when coastal cruising and refer food is available. You’ll really need to get that large of a compartment cold and keep it cold. That’s not something you’d want to let warm up, so you’d be more inclined to dock when available, running at say half or one third capacity you’d have no problem at anchor.

[DHooper]

Originally Posted by rbk

Reinsulate, compartmentalize and run multiple units. Might be more efficient to reduce a compartment as it’s not needed and shut it down during completely on long passages, as fresh food gets used up. Or use smaller compartment when coastal cruising and refer food is available. You’ll really need to get that large of a compartment cold and keep it cold. That’s not something you’d want to let warm up, so you’d be more inclined to dock when available, running at say half or one third capacity you’d have no problem at anchor.

Thanks RBK. Reducing box size is certainly an option but one that I am trying to avoid if at all possible. This morning my colleague identified large capacity 12v compressors (1/4HP, 1/2HP) manufactured by Masterflux and offered from Glacier Corp. Their capacities exceed the BD type units so will review as an alternative. Have you began thawing yet? Beautiful country.

[rbk]

Originally Posted by DHooper

Thanks RBK. Reducing box size is certainly an option but one that I am trying to avoid if at all possible. This morning my colleague identified large capacity 12v compressors (1/4HP, 1/2HP) manufactured by Masterflux and offered from Glacier Corp. Their capacities exceed the BD type units so will review as an alternative. Have you began thawing yet? Beautiful country.

That’s was my concern, you’ll have to crank that compressor all the time and depending on location and cruising style maybe a bigger pain with power requirements. Removable dividers is more what I had in mind and not permanently reducing the size. Not thawing yet but we’re already into our spring swing with cold nights and warm days, sun has heat again. I need more time to finish this electrical boat project, get my winter hunt in and maybe some spring skiing still. Not enough time.

[Richard Kollmann]

Dhooper. I am surprised why no one is asking where you plan on using the boat and what temperatures they recommend to maintain in each box. You are refitting the old refrigeration having small holding plates so it must have had a very large compressor and it ran many times a day.

I can give you two good examples of 46 foot sailboats that operated in the Bahamas with refrigeration powered by BD50 compressors and maybe they will respond with first hand opinions. A 46 Hylas with two four ft factory insulation boxes were refitted with ice box Frigoboat BD50 keel cooler conversions units. They reported to me the AEO module on freezer box ran at full speed almost all the time. Refrigerator box compressor ran about 50% of the time. The engine 60 amp-hr alternator was replaced with a 220 amp-hr alternator the rest of the Direct Current power grid consisted of two 8D batteries and a Diesel generator. The other example is a 46 ft Morgan owned by Skip a frequent poster here. A single 10 cu ft box with new six inches of insulation. Maybe he will step in to tell his story of improving the boats power grid enough to support refrigeration on a true live aboard cruising boat.

A word of advice find satisfied customers with comparably equipped conversions and how they achieved enough energy to support refrigeration.

[Cheechako]

Those are huge. I think you are in Generator + 120 volt refrig zone with those.

[OzePete]

Fitting a refrigeration system to a cabinet requires prior heat load calculation so that an appropriate system to suit the use and one with adequate refrigeration capability to cope with the job under the most extreme conditions to be encountered can be chosen.

As a previous post reported a BD50 (2.5cc compressor) operating on a 4 cubic foot cabinet in the Bahamas will struggle yet would be fine in colder climates.

I would encourage anyone selecting refrigeration for their project to firstly have a comprehensive 'Heat load and Power Consumption' estimate done specific to that cabinet. (One size, brand or type will not suit all!)

The heat load estimate can only be computed from your specific cabinet details including:
1: Cabinet interior dimensions.
2: Insulation type and thickness (if known)
3: Interior lining material. (If non-conductive, ie not metal)
4: Lid / door opening size and if front or top.
5: Is his cabinet to be a fridge, freezer or combination.
6: What is the hottest environment to be cruising through.
7: How many persons does this cabinet service.

With this information a system can be chosen that will provide adequate refrigeration. For example a BD35 system on a 7 CF fridge may work ok in say 20C environments but the beer will be hot when you get to the tropics, just when you need it most!

We have developed a simple XL spreed sheet estimator and can do estimates if the above information is provided. For forum members simply email answers to points 1 to 7 above and we will send back a print out, free and no obligation. E: ozefridge@ozemail.com.au

Cheers, OzePete Ozefridge | 12 Volt Refrigeration Systems

[DHooper]

Originally Posted by Richard Kollmann

Dhooper. I am surprised why no one is asking where you plan on using the boat and what temperatures they recommend to maintain in each box. You are refitting the old refrigeration having small holding plates so it must have had a very large compressor and it ran many times a day.

I can give you two good examples of 46 foot sailboats that operated in the Bahamas with refrigeration powered by BD50 compressors and maybe they will respond with first hand opinions. A 46 Hylas with two four ft factory insulation boxes were refitted with ice box Frigoboat BD50 keel cooler conversions units. They reported to me the AEO module on freezer box ran at full speed almost all the time. Refrigerator box compressor ran about 50% of the time. The engine 60 amp-hr alternator was replaced with a 220 amp-hr alternator the rest of the Direct Current power grid consisted of two 8D batteries and a Diesel generator. The other example is a 46 ft Morgan owned by Skip a frequent poster here. A single 10 cu ft box with new six inches of insulation. Maybe he will step in to tell his story of improving the boats power grid enough to support refrigeration on a true live aboard cruising boat.

A word of advice find satisfied customers with comparably equipped conversions and how they achieved enough energy to support refrigeration.

There's never enough time to hunt and work on the boat let alone ski. I must be doing something wrong since the boat takes all my time. Good luck and enjoy the sun!

[rbk]

Originally Posted by DHooper

There's never enough time to hunt and work on the boat let alone ski. I must be doing something wrong since the boat takes all my time. Good luck and enjoy the sun!

Add two toddlers, dog, house, cabin and you’re just scratching the surface if the chaos that is my life. Boat projects were suppose to be done before Xmas (lol ya right) but as usuall one thing led to another. I work hard and play harder.

[DHooper]

Originally Posted by Richard Kollmann

Dhooper. I am surprised why no one is asking where you plan on using the boat and what temperatures they recommend to maintain in each box. You are refitting the old refrigeration having small holding plates so it must have had a very large compressor and it ran many times a day.

I can give you two good examples of 46 foot sailboats that operated in the Bahamas with refrigeration powered by BD50 compressors and maybe they will respond with first hand opinions. A 46 Hylas with two four ft factory insulation boxes were refitted with ice box Frigoboat BD50 keel cooler conversions units. They reported to me the AEO module on freezer box ran at full speed almost all the time. Refrigerator box compressor ran about 50% of the time. The engine 60 amp-hr alternator was replaced with a 220 amp-hr alternator the rest of the Direct Current power grid consisted of two 8D batteries and a Diesel generator. The other example is a 46 ft Morgan owned by Skip a frequent poster here. A single 10 cu ft box with new six inches of insulation. Maybe he will step in to tell his story of improving the boats power grid enough to support refrigeration on a true live aboard cruising boat.

A word of advice find satisfied customers with comparably equipped conversions and how they achieved enough energy to support refrigeration.

Thanks Richard! Those examples is what I am trying to avoid, if possible with a 12v off the shelf system although I must admit to losing faith. An alternator upgrade in conjunction with some wind and solar is acceptable in lieu of a generator to supplement power. The boat will be sailed between Chesapeake Bay, Bermuda and the Caribbean and no further south than Panama. I am hopeful that other members with similar size boxes will respond with their solutions. Thanks!

[Richard Kollmann]

Originally Posted by OzePete

Fitting a refrigeration system to a cabinet requires prior heat load calculation so that an appropriate system to suit the use and one with adequate refrigeration capability to cope with the job under the most extreme conditions to be encountered can be chosen.

As a previous post reported a BD50 (2.5cc compressor) operating on a 4 cubic foot cabinet in the Bahamas will struggle yet would be fine in colder climates.

I would encourage anyone selecting refrigeration for their project to firstly have a comprehensive 'Heat load and Power Consumption' estimate done specific to that cabinet. (One size, brand or type will not suit all!)

The heat load estimate can only be computed from your specific cabinet details including:
1: Cabinet interior dimensions.
2: Insulation type and thickness (if known)
3: Interior lining material. (If non-conductive, ie not metal)
4: Lid / door opening size and if front or top.
5: Is his cabinet to be a fridge, freezer or combination.
6: What is the hottest environment to be cruising through.
7: How many persons does this cabinet service.

With this information a system can be chosen that will provide adequate refrigeration. For example a BD35 system on a 7 CF fridge may work ok in say 20C environments but the beer will be hot when you get to the tropics, just when you need it most!

We have developed a simple XL spreed sheet estimator and can do estimates if the above information is provided. For forum members simply email answers to points 1 to 7 above and we will send back a print out, free and no obligation. E: ozefridge@ozemail.com.au

Cheers, OzePete Ozefridge | 12 Volt Refrigeration Systems

I agree if you want to avoid the mistakes others have made and be convinced of what you have already been told that present box sizes and boat's power grid will not support 12 volt refrigeration. So a practical energy and equipment projection is required. But it should be evaluated on worst case mobile refrigeration standards not standard day temperature of 69 degrees F. Also refrigerator temperature maintained at 34 to 37 degrees F and Freezer at zero to +15 degrees F.

Once there is a better understanding recommendations for box size and boat's power grid upgrades by vendors can better recommend icebox conversion refrigeration components.