The refrigeration project - love and hate on a boat
There are some old school boaters (very old school) who don't really need much in the way in refrigeration on their boat. Some even just have iceboxes but they are pretty rare except on much smaller boats. We are in the opposite end in that we want to have ice cream and ice cubes in our freezer and room for as much vegetables, cream, and beer/wine as we can in the reefer side. Some have very small reefer boxes and even smaller freezer compartments. Some do not ever make ice although most would say that having a cold beer or wine is essential.
We like our cold ones, especially in the tropics, so this project is to ensure that is possible, with the least fuss and muss, and using the least power necessary. Reefer systems are usually the largest use of power on boats. Bigger boats often just run generators (gensets) to power their systems but they are noisy, stinky, take up lots of room, and expensive. Some of them are AC only and don't rely on the batteries. Our boat came with both AC and DC since the boat was mostly a liveaboard in marinas so it was plugged in to AC and the DC used when cruising. Both were older systems and the DC system decided to die this year. So at a minimum it had to be replaced.
With good batteries and charging systems, you don't really have to have an AC system, so even though that works, I decided to remove it and simplify the whole. The DC side had to be replaced completely with a new modern and much more efficient system. Both the old systems had holding/cold plates instead of evaporator plates in the boxes. Cold plates are large containers of a special cold holding liquid which the system freezes and they absorb heat from the boxes for a long time in between times they have to be recooled. Evaporator plates are like you have in house reefers. They basically have to run all the time as they don't store the cold in the boxes.
There are adherents for both types of systems and pros and cons for both. I am replacing our dual AC/DC cold plate systems with one DC cold plate system. Right now I am planning on putting in the Technautics Cool Blue system which is what I had put in Maggie Drum and which I believe is the best available at this time. It is efficient, powerful, reliable, and has the best support in the business (IMO). It is not the cheapest but not the most expensive either. You have to pay for quality usually. And we want a reliable system that won't kill our batteries.
The project has multiple phases. 1) Remove the old AC and DC compressors in the engine room. 2) Remove the old cold plates in the freezer box. 3) Rebuild the freezer and reefer boxes to make them more efficient with better insulation and more water/vapor tight. 4) Install new cold plate. 5) Install new Cool Blue compressor in the engine room. 5) Pull old refrigerant lines from engine room to boxes and replace with new. 6) Remove the old thermostats, hour meters, and controls for the old systems and trim out the existing holes in the cabinetry.
Removing the old compressors was relatively easy and cleared up a lot of space in the engine room. The existing DC compressor support is perfect for the new one so all that is needed is to patch the old holes and repaint it. Removing the old cold plates was not easy at all. I got the last one out yesterday. Access was terrible (per usual on a boat) and I had a hard time reaching the refrigerant tubing lines and connectors coming in to the boxes. I ended up just cutting the tubing with a hack saw and finally a Sawsall. It is a very bad sign when you bring a Sawsall on to a boat. They are not finesse tools!
Unfortunately, my plan to just replace the compressor and holding plates was destroyed when I got my trouble light and mirror in closer to the plates and I found big cracks in the gelcoat paint around them. That meant the watertight integrity of the boxes was gone, leading to wet insulation, which ruins it, meaning the system has to run more to keep things cold, and may not even allow freezing temps. I also knew I had to inspect the insulation to make sure it was adequate for a good system even if it wasn't compromised as it was. I've taken a lot of pics and I'll post them with annotations later.
Above the top holding plate I found I could pull off the gelcoat paint and underlying single ply of fiberglass with my hands. Pulling it off a bit farther I found the plywood it was on was black and rotten. And underneath that was the often found old open cell foam. It was crumbly and certainly not good. The wood was also mildewed so it all has to be taken out. Now the project is huge. I have to remove all the old plywood and the foam down to the hull on the port side and to all bulkheads to the galley, nav station, and companionway. Then I have to rebuild it all using better insulation.
I also have to increase the R rating of the insulation - R30 for the reefer and R40 for the freezer. Doing so will mean increasing the depth of all sides too, dramatically decreasing the interior volume of the boxes. That means less beer and that won't do. The existing depths are 5" at the hull and bottom and a little over 3" on the other sides and top. It will have to be at least 5" for the reefer and 7"-8" for the freezer. That takes away more space than you might thing. The reefer would be way too small. The freezer was already bigger than it needs to be so that's not too bad.
Fortunately, or unfortunately, there are some new tech insulation materials that are much thinner than the traditional foams. The unfortunate part is the cost. We are talking going from $2/square foot to $20-$40/square foot, depending on how much depth you need to reduce. You can get vacuum panels but they are easy to destroy by pricking the thin covers with a screw or sharp corner. They also have to be custom made as you can't make them on your own. There are some very new tech material from Aerogel. Fantastic stuff but it costs between $7 and $13 per sq ft but that is only for 10mm and you need at least 30mm for R30 and 40mm for R40, which means it really costs $21 to $84 per sq ft. The boxes right now are about 50 sq ft which quickly adds up to way over $2500 just for the insulation. Ouch!!! Two and a half boat bucks just for the insulation plus $2700 for the compressor and holding plate. Good thing I can do all the labor!!
So what I plan to do today is to relook at all the dimensions I have now that I know how much space i have to work with (I did not until I took the cold plates out and started tearing holes in the interior panels). Tearing up the boxes inside was the point of no return. I am committed now. I have calculated what the square foot cost would be for mixing and matching the different materials in layers to achieve the R values, what the depths would be for each, and the costs for each. E.g., it would take 4 layers of 2" blue closed cell foam to get to R40 for the freezer but if I used that for all sides the holding plate would not even fit - not even close not to mention no room for ice cubes.
Eleven layers of the Aerogel (specifically Cryogel Z) would give R40 for 4.3" depth at a cost of $77/sq ft. for the freezer box (three sides). I can get R30 for the reefer three sides with 8 layers at 3.2" depth for $56/sq ft. I'm thinking I will go with a blend of the blue foam and the Cryogel. E.g. 4" of blue foam combined with 30mm of Cryo for the bottom of the reefer - 5.2" depth at $22/sq ft.
More later:
Top loading doors and frames
Side loading door and frame
Taking off the top (or not)
Damage to the teak framing
Interior skinning & sealing
Freezer/reefer divider
Cool Blue compressor
Other projects
We like our cold ones, especially in the tropics, so this project is to ensure that is possible, with the least fuss and muss, and using the least power necessary. Reefer systems are usually the largest use of power on boats. Bigger boats often just run generators (gensets) to power their systems but they are noisy, stinky, take up lots of room, and expensive. Some of them are AC only and don't rely on the batteries. Our boat came with both AC and DC since the boat was mostly a liveaboard in marinas so it was plugged in to AC and the DC used when cruising. Both were older systems and the DC system decided to die this year. So at a minimum it had to be replaced.
With good batteries and charging systems, you don't really have to have an AC system, so even though that works, I decided to remove it and simplify the whole. The DC side had to be replaced completely with a new modern and much more efficient system. Both the old systems had holding/cold plates instead of evaporator plates in the boxes. Cold plates are large containers of a special cold holding liquid which the system freezes and they absorb heat from the boxes for a long time in between times they have to be recooled. Evaporator plates are like you have in house reefers. They basically have to run all the time as they don't store the cold in the boxes.
There are adherents for both types of systems and pros and cons for both. I am replacing our dual AC/DC cold plate systems with one DC cold plate system. Right now I am planning on putting in the Technautics Cool Blue system which is what I had put in Maggie Drum and which I believe is the best available at this time. It is efficient, powerful, reliable, and has the best support in the business (IMO). It is not the cheapest but not the most expensive either. You have to pay for quality usually. And we want a reliable system that won't kill our batteries.
The project has multiple phases. 1) Remove the old AC and DC compressors in the engine room. 2) Remove the old cold plates in the freezer box. 3) Rebuild the freezer and reefer boxes to make them more efficient with better insulation and more water/vapor tight. 4) Install new cold plate. 5) Install new Cool Blue compressor in the engine room. 5) Pull old refrigerant lines from engine room to boxes and replace with new. 6) Remove the old thermostats, hour meters, and controls for the old systems and trim out the existing holes in the cabinetry.
Removing the old compressors was relatively easy and cleared up a lot of space in the engine room. The existing DC compressor support is perfect for the new one so all that is needed is to patch the old holes and repaint it. Removing the old cold plates was not easy at all. I got the last one out yesterday. Access was terrible (per usual on a boat) and I had a hard time reaching the refrigerant tubing lines and connectors coming in to the boxes. I ended up just cutting the tubing with a hack saw and finally a Sawsall. It is a very bad sign when you bring a Sawsall on to a boat. They are not finesse tools!
Unfortunately, my plan to just replace the compressor and holding plates was destroyed when I got my trouble light and mirror in closer to the plates and I found big cracks in the gelcoat paint around them. That meant the watertight integrity of the boxes was gone, leading to wet insulation, which ruins it, meaning the system has to run more to keep things cold, and may not even allow freezing temps. I also knew I had to inspect the insulation to make sure it was adequate for a good system even if it wasn't compromised as it was. I've taken a lot of pics and I'll post them with annotations later.
Above the top holding plate I found I could pull off the gelcoat paint and underlying single ply of fiberglass with my hands. Pulling it off a bit farther I found the plywood it was on was black and rotten. And underneath that was the often found old open cell foam. It was crumbly and certainly not good. The wood was also mildewed so it all has to be taken out. Now the project is huge. I have to remove all the old plywood and the foam down to the hull on the port side and to all bulkheads to the galley, nav station, and companionway. Then I have to rebuild it all using better insulation.
I also have to increase the R rating of the insulation - R30 for the reefer and R40 for the freezer. Doing so will mean increasing the depth of all sides too, dramatically decreasing the interior volume of the boxes. That means less beer and that won't do. The existing depths are 5" at the hull and bottom and a little over 3" on the other sides and top. It will have to be at least 5" for the reefer and 7"-8" for the freezer. That takes away more space than you might thing. The reefer would be way too small. The freezer was already bigger than it needs to be so that's not too bad.
Fortunately, or unfortunately, there are some new tech insulation materials that are much thinner than the traditional foams. The unfortunate part is the cost. We are talking going from $2/square foot to $20-$40/square foot, depending on how much depth you need to reduce. You can get vacuum panels but they are easy to destroy by pricking the thin covers with a screw or sharp corner. They also have to be custom made as you can't make them on your own. There are some very new tech material from Aerogel. Fantastic stuff but it costs between $7 and $13 per sq ft but that is only for 10mm and you need at least 30mm for R30 and 40mm for R40, which means it really costs $21 to $84 per sq ft. The boxes right now are about 50 sq ft which quickly adds up to way over $2500 just for the insulation. Ouch!!! Two and a half boat bucks just for the insulation plus $2700 for the compressor and holding plate. Good thing I can do all the labor!!
So what I plan to do today is to relook at all the dimensions I have now that I know how much space i have to work with (I did not until I took the cold plates out and started tearing holes in the interior panels). Tearing up the boxes inside was the point of no return. I am committed now. I have calculated what the square foot cost would be for mixing and matching the different materials in layers to achieve the R values, what the depths would be for each, and the costs for each. E.g., it would take 4 layers of 2" blue closed cell foam to get to R40 for the freezer but if I used that for all sides the holding plate would not even fit - not even close not to mention no room for ice cubes.
Eleven layers of the Aerogel (specifically Cryogel Z) would give R40 for 4.3" depth at a cost of $77/sq ft. for the freezer box (three sides). I can get R30 for the reefer three sides with 8 layers at 3.2" depth for $56/sq ft. I'm thinking I will go with a blend of the blue foam and the Cryogel. E.g. 4" of blue foam combined with 30mm of Cryo for the bottom of the reefer - 5.2" depth at $22/sq ft.
More later:
Top loading doors and frames
Side loading door and frame
Taking off the top (or not)
Damage to the teak framing
Interior skinning & sealing
Freezer/reefer divider
Cool Blue compressor
Other projects
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