Refrigeration Refit Challenge

[stormalong]

Originally Posted by ZING

While I'm thinking about it a digital thermostat and display as well as measurement of amp hours used for each frig is also very helpful in understanding what is working and what is not. Otherwise you are just guessing. What are you going to do with "it seems to be running a lot"?

I replaced the stock Adler Barber cold machine thermostats with Corel digital thermostats. Not the cheapest solution but very high quality units. I bought directly from Corel at a significantly lower price than the marine refer companies were asking. Just call them and ask for inside sales. When replacing the original thermostat in any Danfos based system be aware that there is a resistor in series with the contacts that determines the operating speed of the compressor. That resistor value is chosen by the system builder to match the compressor with the evaporator so it is a good idea to match that resistor when replacing the thermostat.

You can easily put an engine hour meter in parallel with the cooling fan or pump motor on any refer system to track actual run time.

[OzePete]

Originally Posted by ZING

Exile,

You're very welcome. Hope it's helpful.

Certainly use only "closed cell" insulation and I believe the blue board is. I've used the board with the reflective aluminum coating on one side. I'm sure there is better stuff somewhere but there is going to be a lot of waste and you always need a little more. But best to also encapsulate with fiberglass and seal it. I've used the 4x8 fiberglass shower sheets and sealed with epoxy. Mostly probably hidden anyway. I would also fill corners, etc with spray foam first. Perhaps this is belt and suspenders but if it helps it last a little longer... Of course nothing on a boat will last forever but once water gets in it is totally useless. I've been looking for reasonable super insulation for a long time but it seems its always just around the corner.



The door gaskets are also important because poor seals mean lost cool as well as more frequent defrosting because of introducing additional moisture to the inside. One day there will be a frost free boat fridge - right?



While I'm thinking about it a digital thermostat and display as well as measurement of amp hours used for each frig is also very helpful in understanding what is working and what is not. Otherwise you are just guessing. What are you going to do with "it seems to be running a lot"?

Great advise Zing, this and your previous post. Digital thermostats are brilliant. There are some now that are also water proof and have dual function so box / evaporator temperature can be controlled and condenser temperature (or whatever) controlled separately. Each are SET point and HYSteresis user programmable, 100% accurate and as you say, also with temperature display. Digitals are also not ambient effected like some of the old mechanical ones. The way to go.

Cheers OzePete

[sailores35]

Reduce fridge to about 9 cubic ft, freezer to no more than 5 with interior insulation on all sides, top and bottom. Frigoboat 12v with speed control on compressor.

[jr_spyder]

Hi Dave, I only saw this thread earlier today. As another Little Harbor owner (46' 1988) and having done this sort of conversion I hope I can help. I have to admit first that I have not read every word of this long thread so I apologize if I repeat anything already said (even tho I never want to be "that guy..."). I'm not a BTU measurement kind of guy, but I am an engineer with a good sense of what works. I obsessively researched what to do, finding there is no perfect answer as this thread points out. There is ultimately the best choice with the least compromises. I have no experience with engine driven systems.

I'm not on my boat (but will be Friday) which is currently in Grenada. I did the refrigeration refit myself 5 years ago so I know my boxes well. I'd guess my fridge is ~11 cf (vertical door), and the freezer ~7 cf (top loader.) Insulation is probably like yours at 3", but I'm guessing. My sense is that it could be somewhat better, but I believe overall I started with quite good boxes. I had a Grunert system with big holding plates in both boxes and two compressors. One ran on 120vac and one on 12vdc. A big manifold managed the flows. Two separate water pumps circulated raw water. The old gear took up three full lockers below the seats of the settee. The boat shook and rattled any time one of the compressors kicked in. You could just feel the energy be consumed/wasted.

I went to the Newport Boat Show and looked at every possible system and spoke with reps in depth, and talked to the experts at my yard. In the end I chose a Frigoboat keel cooler system here: https://www.coastalclimatecontrol.co...frigoboat.html. I have the K50F compressor and 200F evap plate in my fridge . Same compressor and one plate size smaller in my freezer (don't know model #, the seller helped me work out the largest size I could fit in my freezer, and I think it was a special order). I have the digital controls and compressor management add-ons. All good.

Why this choice:
- Very low energy usage. Having no water pump and no fan is an obvious elimination of power draw. Of course modern compressors change everything compared to my old beasts.
- I couldn't imagine having a fan blowing across the coils and putting that heat into the boat, especially in hot climates. That just seems crazy to me, but maybe I'm over thinking that and it's not noticeable.
- Simplicity of installation. It's all pre-set and charged. Literally plug-and-play. No help needed to evacuate and fill the refrigerant. That said the installation is not for the faint-of-heart handyman. There's a lot to it.
- My boxes got noticeably roomier by removing the freeze plates and putting in evap panels.
- the promise of it being nearly dead silent - and it is.

Does it work?:
- It's been flawless operationally. It just runs.
- I've seen comments here about run-time per day for various solutions but I have to say that they are so quiet, and so out-of-mind, and so enormously better then the old stuff that I've never really measured it. Clearly the freezer runs a lot more than the fridge, but I can't give an honest answer to the power consumption other than to say it is not an obvious killer burden on my system.
- I've had no trouble in the warmer waters from Bermuda to Grenada. I'm sure they run more frequently just like any fridge would with a higher temp differential between inside and outside the box. I have no sense that the keel coolers are less happy in warmer water. They just work...

What would I change:
- In practical usage both my boxes are bigger than they need to be. Even with six crew aboard for an ocean race or transit my wife can provision 10-12 days of frozen meals and fresh stuff in the fridge. But that's the extreme case, not our normal 2 - 4 person island hopping/coastal cruising. For normal cruising we have more cold room than we need, so using more energy than we need to. If I had known this when I did the refit job I may have added insulation and shrunk the boxes.
- With the above lesson learned I may have designed the fridge to have a small freezer section - enough to make/hold some ice for sundowners - and only run the big freezer box on long passages or in places where regular provisioning is more sketchy. That's not really in our cruising plan. We won't be doing a circumnavigation.

Just for fun here's a picture of one of my old compressors with a new one sitting in front of it. If I didn't tell you the new one was there you probably wouldn't see it:

Multiply this disparity by two. When I'm back on the boat I'll send a picture of the new setup. I have both compressors in a small locker under the stove that I never really used for anything, so it feels like they take up no space and are invisible. I absolutely loved getting back all the space the old system took up, and the boat probably lost 300 pounds.

I hope this helps. Good luck with your system.

JR

[DHooper]

Originally Posted by jr_spyder

Hi Dave, I only saw this thread earlier today. As another Little Harbor owner (46' 1988) and having done this sort of conversion I hope I can help. I have to admit first that I have not read every word of this long thread so I apologize if I repeat anything already said (even tho I never want to be "that guy..."). I'm not a BTU measurement kind of guy, but I am an engineer with a good sense of what works. I obsessively researched what to do, finding there is no perfect answer as this thread points out. There is ultimately the best choice with the least compromises. I have no experience with engine driven systems.

I'm not on my boat (but will be Friday) which is currently in Grenada. I did the refrigeration refit myself 5 years ago so I know my boxes well. I'd guess my fridge is ~11 cf (vertical door), and the freezer ~7 cf (top loader.) Insulation is probably like yours at 3", but I'm guessing. My sense is that it could be somewhat better, but I believe overall I started with quite good boxes. I had a Grunert system with big holding plates in both boxes and two compressors. One ran on 120vac and one on 12vdc. A big manifold managed the flows. Two separate water pumps circulated raw water. The old gear took up three full lockers below the seats of the settee. The boat shook and rattled any time one of the compressors kicked in. You could just feel the energy be consumed/wasted.

I went to the Newport Boat Show and looked at every possible system and spoke with reps in depth, and talked to the experts at my yard. In the end I chose a Frigoboat keel cooler system here: https://www.coastalclimatecontrol.co...frigoboat.html. I have the K50F compressor and 200F evap plate in my fridge . Same compressor and one plate size smaller in my freezer (don't know model #, the seller helped me work out the largest size I could fit in my freezer, and I think it was a special order). I have the digital controls and compressor management add-ons. All good.

Why this choice:
- Very low energy usage. Having no water pump and no fan is an obvious elimination of power draw. Of course modern compressors change everything compared to my old beasts.
- I couldn't imagine having a fan blowing across the coils and putting that heat into the boat, especially in hot climates. That just seems crazy to me, but maybe I'm over thinking that and it's not noticeable.
- Simplicity of installation. It's all pre-set and charged. Literally plug-and-play. No help needed to evacuate and fill the refrigerant. That said the installation is not for the faint-of-heart handyman. There's a lot to it.
- My boxes got noticeably roomier by removing the freeze plates and putting in evap panels.
- the promise of it being nearly dead silent - and it is.

Does it work?:
- It's been flawless operationally. It just runs.
- I've seen comments here about run-time per day for various solutions but I have to say that they are so quiet, and so out-of-mind, and so enormously better then the old stuff that I've never really measured it. Clearly the freezer runs a lot more than the fridge, but I can't give an honest answer to the power consumption other than to say it is not an obvious killer burden on my system.
- I've had no trouble in the warmer waters from Bermuda to Grenada. I'm sure they run more frequently just like any fridge would with a higher temp differential between inside and outside the box. I have no sense that the keel coolers are less happy in warmer water. They just work...

What would I change:
- In practical usage both my boxes are bigger than they need to be. Even with six crew aboard for an ocean race or transit my wife can provision 10-12 days of frozen meals and fresh stuff in the fridge. But that's the extreme case, not our normal 2 - 4 person island hopping/coastal cruising. For normal cruising we have more cold room than we need, so using more energy than we need to. If I had known this when I did the refit job I may have added insulation and shrunk the boxes.
- With the above lesson learned I may have designed the fridge to have a small freezer section - enough to make/hold some ice for sundowners - and only run the big freezer box on long passages or in places where regular provisioning is more sketchy. That's not really in our cruising plan. We won't be doing a circumnavigation.

Just for fun here's a picture of one of my old compressors with a new one sitting in front of it. If I didn't tell you the new one was there you probably wouldn't see it:

Multiply this disparity by two. When I'm back on the boat I'll send a picture of the new setup. I have both compressors in a small locker under the stove that I never really used for anything, so it feels like they take up no space and are invisible. I absolutely loved getting back all the space the old system took up, and the boat probably lost 300 pounds.

I hope this helps. Good luck with your system.

JR

Great information JR, thanks! Frigo also caught my eye because of their large evaporator plates and your experience is helpful. I would hope your seller completed a load analysis to size your plates. The dimensions of our boxes are similar so I'm curious about the basic functionality of ice cream in the freezer and beer in the cooler. Hopefully they are frozen and cold? Also any idea about your power consumption or compressor duty cycle/ run time? The simplicity of installation associated with air cooled compressors and thin plate evaporators is enticing to say the least but not worth mediocre cooling performance and lost freezer content so your experience is quite helpful, thanks!

[jr_spyder]

I have to admit we didn't get deeply scientific about it. Instead I went on reliable advice and experience. I bought my Little Harbor through the original LH yard (now owned my Hinckley) in Portsmouth, RI, and kept it there for the first year. The yard is still full of Little Harbor alumni and many LH owners come back there for refits. No one knows more about these great old boats. So when my service manager Bobby Hood (yes, that Hood) told me they had lots of luck with Frigoboat on refits and it was a good choice that's all I needed. There's really only one choice for compressor, then go with the largest evap plate that will fit in each box. Done.

Certainly I could have done much further analysis but I knew I wanted a keel-cooler system so it was easier to look at what was available (which is a finite range for DIY) and have reasonable certainty it would be good enough. The LH experience was the clincher.

I keep the freezer at 14 degrees F (not zero like at home) and it stays there no problem. Ice is ice, and ice cream is a little soft. We've had some good laughs with visitors on board that couldn't believe we had any ice cream at all - on a boat! We keep a gallon jug of water frozen solid in the bottom of the freezer as a good practice but it has never mattered. The fridge stays a constant 40 degrees. We never lost any food due to refrigeration.

I'll be sailing in the Grenadines for at least the next two weeks. I'll try to keep a better eye on run cycles and report back, although we may decide not to run the freezer. Our only source of power is our diesel generator and/or engine. So our electricity cost is high. Just haven't taken the plunge for solar/wind yet other than a trickle charger tending the batteries when we're off the boat and no loads are on.

[Richard Kollmann]

Originally Posted by jr_spyder

I have to admit we didn't get deeply scientific about it. Instead I went on reliable advice and experience. I bought my Little Harbor through the original LH yard (now owned my Hinckley) in Portsmouth, RI, and kept it there for the first year. The yard is still full of Little Harbor alumni and many LH owners come back there for refits. No one knows more about these great old boats. So when my service manager Bobby Hood (yes, that Hood) told me they had lots of luck with Frigoboat on refits and it was a good choice that's all I needed. There's really only one choice for compressor, then go with the largest evap plate that will fit in each box. Done.

Certainly I could have done much further analysis but I knew I wanted a keel-cooler system so it was easier to look at what was available (which is a finite range for DIY) and have reasonable certainty it would be good enough. The LH experience was the clincher.

I keep the freezer at 14 degrees F (not zero like at home) and it stays there no problem. Ice is ice, and ice cream is a little soft. We've had some good laughs with visitors on board that couldn't believe we had any ice cream at all - on a boat! We keep a gallon jug of water frozen solid in the bottom of the freezer as a good practice but it has never mattered. The fridge stays a constant 40 degrees. We never lost any food due to refrigeration.

I'll be sailing in the Grenadines for at least the next two weeks. I'll try to keep a better eye on run cycles and report back, although we may decide not to run the freezer. Our only source of power is our diesel generator and/or engine. So our electricity cost is high. Just haven't taken the plunge for solar/wind yet other than a trickle charger tending the batteries when we're off the boat and no loads are on.

Of the three most popular boat ice conversion units Adler Barbour, Seafrost and Frigoboat, your selection of Frigoboat is currently the most popular. For the last sixteen years I have tracked these systems and no other system can outperform the Keel cooler in less than tropical water temperatures. I have found that the small compressor cooling fan added by frigoboat is still not large enough in tropical waters.

[DHooper]

Originally Posted by jr_spyder

I have to admit we didn't get deeply scientific about it. Instead I went on reliable advice and experience. I bought my Little Harbor through the original LH yard (now owned my Hinckley) in Portsmouth, RI, and kept it there for the first year. The yard is still full of Little Harbor alumni and many LH owners come back there for refits. No one knows more about these great old boats. So when my service manager Bobby Hood (yes, that Hood) told me they had lots of luck with Frigoboat on refits and it was a good choice that's all I needed. There's really only one choice for compressor, then go with the largest evap plate that will fit in each box. Done.

Certainly I could have done much further analysis but I knew I wanted a keel-cooler system so it was easier to look at what was available (which is a finite range for DIY) and have reasonable certainty it would be good enough. The LH experience was the clincher.

I keep the freezer at 14 degrees F (not zero like at home) and it stays there no problem. Ice is ice, and ice cream is a little soft. We've had some good laughs with visitors on board that couldn't believe we had any ice cream at all - on a boat! We keep a gallon jug of water frozen solid in the bottom of the freezer as a good practice but it has never mattered. The fridge stays a constant 40 degrees. We never lost any food due to refrigeration.

I'll be sailing in the Grenadines for at least the next two weeks. I'll try to keep a better eye on run cycles and report back, although we may decide not to run the freezer. Our only source of power is our diesel generator and/or engine. So our electricity cost is high. Just haven't taken the plunge for solar/wind yet other than a trickle charger tending the batteries when we're off the boat and no loads are on.

Unfortunately I suffer from the "paralysis of analysis" and find the numbers helpful. Bob Hood has been very helpful over the years and tries to maintain his Dad's LH legacy. I would greatly appreciate you keeping an eye on the compressor run times or daily loads and the conditions you're sailing in. This would be very helpful.