Refrigeration Refit Challenge

[DHooper]

Originally Posted by Richard Kollmann

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.

Just to clarify Richard, are you suggesting basically to back into a solution based on a reduced box size? For example, vendor A can meet a 5CF freezer with a certain solution and vendor B can meet a 7CF requirement with their specific solution?

[DHooper]

Originally Posted by rbk

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.

I'm worn out reading your note... It will make your time in the woods or on the slopes that much more rewarding.

[OzePete]

Originally Posted by Richard Kollmann

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.

Thank you Richard, when I saw your reply commence with "I agree" I near fell off my perch!

But yes establishing a heat load and power consumption estimate prior to purchase is essential. We put each enquiry through our estimator, as pictured here below, which computes relative to the maximum ambient nominated and at correct fridge 2C to 4C cabinet and -12C to -18C freezer.

As you can see it allows for variation of cabinet dimensions, ambient, insulation thickness etc., specific to each individual application.

As far as I know we are the only manufacturer / supplier who provides this essential service prior to making a system package recommendation.

Estimator below, click on to expand.
Individual factors are entered into the top panel and the outcomes are immediately computed. (We hope to have this posted online shortly and available for user interaction)



Cheers OzePete

[Richard Kollmann]

DHooper has the same problem many others have had with retro fitting an older large sailboats refrigeration. His two refrigerator boxes are large which is not unusual on many 36 to 60 ft sailboats. The challenging questions put to this group are:
1. What is it going to take to replace old refrigeration system keeping present boxes in tack and what type system do you recommend?
2. If keeping boxes as is what would be the daily energy requirement for refrigeration alone.
3. Because the boat’s electrical AC and DC power grids are not large enough for the existing boxes what have others done? There are hundreds of live aboard cruisers that had to address this problem.

There are no data charts in mechanical engineering hand books to solve sailboat refrigeration problems only common sense experiences from other boaters. Having been on a large number of Seven Seas live aboard Cruising boats I am sure DHopper would like to get their impute. Grunert, Seafrost and Glacier have larger 12/24 volt condensing units, boats operating information with these condensing units would be good information. Glacier’s Tecumseh Sierra Masterflux.12/24 volt variable speed compressor when operated at MBP pressures is a good candidate for large boat refrigeration. There does not appear to be any service experience with Glacier systems other than they have been in business for 20 years.

I do not know if DHooper could make sense out of Pete’s chart but using my slide show “What Works and What does Not” to calculate daily Btu required worst case in tropical climates. The boat as it is will need 18,000 Btu of energy per day for refrigeration, or if boat remains in northern Latitudes 9,000 Btu per day.

I can tell you of a limited number of boat solutions for energy generation and storage the most elaborate system I have ever seen was on a 60 plus sailboat Northern Goose with a freezer you can sit in to clean and defrost the mutable eutectic plates. Onboard electrical power comes two large wind generators one on each mast, a prop shaft alternator, an engine alternator. And a engine driven refrigeration compressor to supplement shortages of electrical energy. Supporting all eutectic plates energy storage are two small 12 volt air cooled condensing units.

Many boaters that miscalculated their electrical refrigeration energy needs now carry Honda 2000 portable generators and a 100 amp 12 volt battery charger to charge ships house battery from Honda portable when necessary.

I would wait till you get more responses before making a decision on the suggestions offered.

[OzePete]

Yes, as stated earlier the problem for this project is size and insulation specially the freezer. This is why it is essential to do a heat load / power estimate before purchasing.

Suggest:
Reduce the cabinet capacities at least by adding extra base insulation internally. (The base is by far the area of greatest heat penetration and needs more insulation than the walls )
Use a 3.5cc air /water cooled system with twin 530mm x 350 x 60 eutectic plates for the fridge.
Use two 3.5cc air / water cooled systems for the freezer. Each of these condensing units would be best coupled to a eutectic plate 650mm x 530 x 40 thickness.

This would provide adequate refrigeration at less than 50% duty cycle for both fridge and freezer, even in high temp environments. (40C).

Here is our estimate of the members freezer.. (Interior dimensions estimated to provide for the freezer capacity stated.)

Click on picture to expand... (Chart can only be activated/ loaded by us here. We soon hope to post this as a interactive tool for members to access and do their own estimates.)



Cheers OzePete

[DHooper]

Originally Posted by Richard Kollmann

DHooper has the same problem many others have had with retro fitting an older large sailboats refrigeration. His two refrigerator boxes are large which is not unusual on many 36 to 60 ft sailboats. The challenging questions put to this group are:
1. What is it going to take to replace old refrigeration system keeping present boxes in tack and what type system do you recommend?
2. If keeping boxes as is what would be the daily energy requirement for refrigeration alone.
3. Because the boat’s electrical AC and DC power grids are not large enough for the existing boxes what have others done? There are hundreds of live aboard cruisers that had to address this problem.

There are no data charts in mechanical engineering hand books to solve sailboat refrigeration problems only common sense experiences from other boaters. Having been on a large number of Seven Seas live aboard Cruising boats I am sure DHopper would like to get their impute. Grunert, Seafrost and Glacier have larger 12/24 volt condensing units, boats operating information with these condensing units would be good information. Glacier’s Tecumseh Sierra Masterflux.12/24 volt variable speed compressor when operated at MBP pressures is a good candidate for large boat refrigeration. There does not appear to be any service experience with Glacier systems other than they have been in business for 20 years.

I do not know if DHooper could make sense out of Pete’s chart but using my slide show “What Works and What does Not” to calculate daily Btu required worst case in tropical climates. The boat as it is will need 18,000 Btu of energy per day for refrigeration, or if boat remains in northern Latitudes 9,000 Btu per day.

I can tell you of a limited number of boat solutions for energy generation and storage the most elaborate system I have ever seen was on a 60 plus sailboat Northern Goose with a freezer you can sit in to clean and defrost the mutable eutectic plates. Onboard electrical power comes two large wind generators one on each mast, a prop shaft alternator, an engine alternator. And a engine driven refrigeration compressor to supplement shortages of electrical energy. Supporting all eutectic plates energy storage are two small 12 volt air cooled condensing units.

Many boaters that miscalculated their electrical refrigeration energy needs now carry Honda 2000 portable generators and a 100 amp 12 volt battery charger to charge ships house battery from Honda portable when necessary.

I would wait till you get more responses before making a decision on the suggestions offered.

Truer words haven’t been spoken regarding the lack of technical information for marine refrigeration. I have worked in the energy industry for more than 25 years where engineering standards, practices, load models,etc abound and didn’t think this effort would be such a challenge. Well, every day is an IQ test and I am learning.

Regarding your first point Richard, my lessons learned so far is that unless I want to tear up my countertops to resize my boxes I won’t be able to benefit from an air cooled BD grade system and must consider larger compressors or incorporate an engine driven compressor or both. I plan to investigate the Seven Seas Cruising association for additional input.

I've received mixed reviews about Glacier's 12v Masterflux and Seafrosts DC 5000 systems offering and would enjoy hearing about anyone's personal experience with them since they in theory appear to satisfy my load requirements.

I do understand the conclusions in Pete’s charts but not the relationships governing his calculations. My models differ from yours and his and the result of the absence of practical experience calculating boat cooling loads. My worst case scenario was less than 8K Btu/Day.

I’ve concluded with confidence what won’t work so my research continues. Thanks!

[DHooper]

Originally Posted by OzePete

Yes, as stated earlier the problem for this project is size and insulation specially the freezer. This is why it is essential to do a heat load / power estimate before purchasing.

Suggest:
Reduce the cabinet capacities at least by adding extra base insulation internally. (The base is by far the area of greatest heat penetration and needs more insulation than the walls )
Use a 3.5cc air /water cooled system with twin 530mm x 350 x 60 eutectic plates for the fridge.
Use two 3.5cc air / water cooled systems for the freezer. Each of these condensing units would be best coupled to a eutectic plate 650mm x 530 x 40 thickness.

This would provide adequate refrigeration at less than 50% duty cycle for both fridge and freezer, even in high temp environments. (40C).

Here is our estimate of the members freezer.. (Interior dimensions estimated to provide for the freezer capacity stated.)

Click on picture to expand... (Chart can only be activated/ loaded by us here. We soon hope to post this as a interactive tool for members to access and do their own estimates.)

Attachment 186778

Cheers OzePete

Thanks for taking the time Pete! Running 3 compressors presents it's own challenges but at least the duty cycle is reduced to more acceptable run times. I could the achieve hardware reduction by reducing the boxes size as you suggested too. Nothing is easy is it.

[stormalong]

Perhaps my suggestion of having two systems controlled by one thermostat in in a large refer box was missed. Obviously twice the energy consumption but better than an engine driven solution. Also offers some redundancy.

I am curious what the pros think.

[Exile]

Originally Posted by Uncle Bob

Hi, I don't know where in the world you are however if in north america you have two good refrig manufacturers, Cold machine ? in Canada and Rich Boren in USA, or if in Australia, Ozefridge. I am sure there are others and asking the question of one of them will give you the answers that you need and if you choose to buy from them it will be dearer than a system assembled with the best intentions but will stand the test of time, therefore cheaper long term.

Here are links to the two N. American vendors mentioned, i.e. ColdEh (Canada) and CoolBlue (Rich Boren in CA):

https://www.coldeh.com

CoolBlue Overview

[DHooper]

Originally Posted by stormalong

Perhaps my suggestion of having two systems controlled by one thermostat in in a large refer box was missed. Obviously twice the energy consumption but better than an engine driven solution. Also offers some redundancy.

I am curious what the pros think.

Originally I planned on dual compressors and evaporators for both the fridge and freezer controlled with their own T-Stat. Unfortunately my loads were underestimated and task the BD based systems excessively. Both Pete & Technautics suggested dual compressor, dual plate system for the freezer. Your configuration "may" be satisfied with the Masterflux unit since their systems range between 800 Btu -3000Btu with 134A at 12v.

[DHooper]

Originally Posted by Exile

Here are links to the two N. American vendors mentioned, i.e. ColdEh (Canada) and CoolBlue (Rich Boren in CA):

https://www.coldeh.com

CoolBlue Overview

Thanks Bob! Already discussed my requirements with Rich at Technautics and received similar recommendations as Pete's for a dual compressor, dual plate system for the freezer. I have contacted ColdEh and saw their videos on You Tube and will reach out again.

[OzePete]

Originally Posted by stormalong

Perhaps my suggestion of having two systems controlled by one thermostat in in a large refer box was missed. Obviously twice the energy consumption but better than an engine driven solution. Also offers some redundancy.

I am curious what the pros think.

Not really Stormalong, having two systems on a large single cabinet will not double the power consumption as the duty cycle (run time) is halved. In fact two systems operating within their optimum range would most likely have a combined consumption that is less than a single system operating at its extreme. Again it's a matter of calculating the cabinets heat load first then look for an appropriate refrigeration system to suit.

Cheers OzePete

[Exile]

Originally Posted by DHooper

Thanks Bob! Already discussed my requirements with Rich at Technautics and received similar recommendations as Pete's for a dual compressor, dual plate system for the freezer. I have contacted ColdEh and saw their videos on You Tube and will reach out again.

That was 'Uncle Bob' from post #3, not me! I just filled in the links. But it sounds like you were way ahead of us both since you can't go wrong with either vendor. If you haven't already, another stellar vendor is Cleave at Seafrost.

I'm in a similar situation, btw. A similar boat in fact, with somewhat smaller (but still large) separate frig/freezer boxes. I inherited two well-functioning Seafrost systems that supply both boxes, a 110v and engine drive that tap into the same holding plates. Like you, I need to beef up my 30+ year old insulation. Also like you it sounds, I'd like to replace with 12v systems so as to hopefully reduce genset & engine run times.

So following along with interest . . . .

[DHooper]

Originally Posted by Exile

That was 'Uncle Bob' from post #3, not me! I just filled in the links. But it sounds like you were way ahead of us both since you can't go wrong with either vendor. If you haven't already, another stellar vendor is Cleave at Seafrost.

I'm in a similar situation, btw. A similar boat in fact, with somewhat smaller (but still large) separate frig/freezer boxes. I inherited two well-functioning Seafrost systems that supply both boxes, a 110v and engine drive that tap into the same holding plates. Like you, I need to beef up my 30+ year old insulation. Also like you it sounds, I'd like to replace with 12v systems so as to hopefully reduce genset & engine run times.

So following along with interest . . . .

Yes, the Bristol is very similar. I hope this thread is useful for your analysis. How big are your boxes and what type of Seafrost system do you have? Are they small enough for a 12v system or are you considering box reduction too? I would prefer to keep my boxes the same size but learned a 12v system may not be appropriate for the loads.

[Exile]

Originally Posted by DHooper

Yes, the Bristol is very similar. I hope this thread is useful for your analysis. How big are your boxes and what type of Seafrost system do you have? Are they small enough for a 12v system or are you considering box reduction too? I would prefer to keep my boxes the same size but learned a 12v system may not be appropriate for the loads.

This and many other refrig threads have been most useful. Usually some combo of the gurus of the trade like Richard Kollman and the owners of Ozefridge, CoolBlue and/or ColdEh generously chime in so I've learned a lot. Unlike you, however, this learning combined with my lack of technical background may only risk making me dangerous.

I inherited my two Seafrost systems when I bought the boat 11 years ago now. They have not been without some minor problems, but remarkably reliable given their age (and compared to other boat systems). I've therefore been reluctant thus far to make any big changes (other than insulation) in light of competing boat upgrade/maint. priorities.

My 110v system is a SF Shore Assist III. One, water-cooled compressor in the engine compartment with separate thermostat switches for fridge & freezer. The upside is that, even with my 30 year-old insulation, it works very well while plugged in at the dock. The downside is that it takes 2-3 hours of genset run time otherwise, sometimes 2x/day in the tropics (but that's probably weak insulation, not the unit itself).

My SF eng drive system also works very well, and is much more efficient than the 110v. I was warned they are prone to failure due to eng vibration but mine has been reliable. If the boxes are already cooled down to any degree, the eng drive seems to take no more than 40 mins. or so to get them back down to desired temps. If I'm stopping at marinas or anchorages, then the eng drive is turned on with the propulsion engine while coming & going, thereby eliminating the need to run the 110v off the genset. The downside is that, on a multi-day sail or anchor when I would not otherwise use the engine, I'm firing up the genset long before I need to charge batts. or use ac appliances. (probably more efficient to run the engine & eng drive if no ac appliances needed). Cleave @SF advised against trying to run the 110v off an inverter, btw.

So converting to 12v would eliminate a lot of genset & maybe engine run time, but then there would be a much larger draw on the batts so solar, etc. would be essential (and maybe a larger batt. bank) to avoid being back in the same position I'm in now. Pick your poison, right?

I'm not on the boat right now and don't have exact measurements, but my best guesstimate is that the refrig is ~11 cu.ft. and the freezer ~7 cu.ft. I could be off. From talking with the gurus over the years, I know I would need, at a minimum, one BD50 for each box. There are differing opinions on whether it's advisable to use the same holding plates. Cleave @SF for one recommends sticking with water cooling, but CoolBlue & ColdEH said I'd be fine with air cooled units.

Questions Re: Insulation:

1. When beefing up insulation, why is it recommended to remove the stainless steel liners?

2. Is the blue board closed cell, i.e. resistant to water saturation?