Frigoboat Keel Cooling Refrigeration in Temperate Cold water?

[Richard Kollmann]

Frigoboat Info, you are correct, you can crunch numbers. I still think this is just creative advertising because pleasure cruising boats without generators could not manage your conclusions. I will leave the question of refrigerating a 20 cu ft box with a single BD50 compressor in tropical climates to the experienced live aboard cruiser. I have never questioned a frigoboat system to perform well in the correct application.

I agree to disagree on 20 cubic foot boxes now devote time to solving Frigoboat’s O-Ring leakage problems a major part of this forum's thread.. The major high cost problem of refrigerant blockage you have taken care of by installing filter in high pressure liquid line on future keel cooler units sold in the US. As you indicated working with these O-ring connectors maybe one cause of capillary tube blockage.

[ShipShape]

Originally Posted by westernspirit

So after reading various opinions I am asking what are people really experiencing with their keel water cooling units in cold water?

I converted the ice boxes on my old boat to refrigerators using the Frigoboat system. Here is a pic I took during the winter when I was living in Baltimore, the top one is the inboard icebox set at 38 degrees and the bottom one is against the hull and set at 52 degrees.



With old insulation you don't need no sitnkin' refrigerator when the water is cold. Two winters in B-more and two summers in south Florida - no problems at all with the keel coolers doing their job.

Follow the installation instructions though! The keel coolers have a green wire that is supposed to be connected to the DC ground bus. These keel coolers are three years old, the installer connected the green wires to a seacock.



All the thruhulls connected to that seacock with the boats bonding system were also corroded.


PS Hey Mr. Kollmann, thank you for your books and taking care of us here on CF too!

[jr_spyder]

That's scary. I'm sure I have this right but ShipShape just made me nervous. In my new keel cooler installation I ran the ground wire from one keel cooler to the other, then to a nearby seacock which is wired into the ground bus. I checked for continuity from the ground lugs on the keel cooler and the negative side of my battery bank which checked fine. No reason to be nervous?

I'll also ditto what others have said: outstanding thread staying informative and civil. I've learned a ton. Thanks guys.

JR

[Frigoboat Info]

To Shipshape and JR Spider:
There are two issues we have to protect against: Stray current corrosion and galvanic corrosion.
Stray current corrosion could occur if any stray dc current happens to somehow be induced on to the copper lines connected to the Keel Cooler. This can happen if a wire rubs through on the tubing, or some other anomaly. Without a return path to the battery, this current will leave the Keel Cooler and find a return path somewhere, taking metal with it, and so we insist that the Keel Cooler is connected to a point which is at the same potential as the boats battery negative.
Galvanic corrosion occurs when dissimilar metals are immersed in an electrolyte, like salt water. All of the components in a Frigoboat Keel Cooler are within 200mv on the noble scale and so are not considered to be in danger of freely eroding from galvanic corrosion, however, we do want to see that a Keel Cooler is connected to a sacrificial zinc for total protection. If the boat has metal thru-hulls and a bonding system that is connected to a zinc somewhere, either on the shaft or a hull zinc, then the Frigoboat Keel Cooler can be connected into this bonding system and will then be protected. If this bonding system is also connected to the boats battery negative, as is usually the case, then that Keel Cooler is protected against both stray current and galvanic corrosion.
If a boat has plastic thru-hulls, or for some other reason there is no bonding system, then we have Keel Coolers available with their own integrated sacrificial zincs, and they will protect the Keel Cooler. However, the connection to the boats battery negative must still be made to protect against stray current corrosion.
So why not only offer only Keel Coolers with zincs? Believe me, that would make life so much easier, and we would be selling a lot more zincs, but it is not in the best interest of the customer. Imagine a vessel with a bonding system and a sacrificial zinc, usually on the shaft, where a Keel Cooler is to be installed. If a version of Keel Cooler with zincs is used and is then connected into the bonding system, we have now introduced another sacrificial anode in addition the existing one, and typically this will take over the job of the one further away, typically at the back of the boat. With this scenario the Keel Cooler zincs will erode a lot quicker than designed, leading to a lot of frustration at having to replace these non-standard zincs so frequently, and to suspicions that maybe there is some form of corrosion taking place. Some years ago there was a lot of gossip about Keel Coolers causing corrosion, etc. When we investigated, we found that there were many Keel Coolers installed with zincs where the zincs weren’t required, and these were needing to be replaced far too frequently. The original hull or shaft zinc typically showed no or very little evidence of erosion, as the Keel Cooler zincs were now doing most of the work. So what’s the remedy? Don’t keep replacing the zincs in the Keel Cooler, but we get a lot of strange looks when we suggest that.

ShipShape: Your Keel Cooler is most likely properly connected and protected, but the loss of metal from the sintered bronze encapsulation suggests that there was some stray current getting on to the bonding system somewhere, but not down the tubing to the Keel Cooler. This is backed up by your report that all your other thru-hulls are deteriorating. The most common source of these stray currents is from the ground of the shore power connection. Do you have a zinc Saver or similar installed? If not I would highly recommend that you get one, and in any case get a marine corrosion consultant to take a look.

[Tortuga's Lie]

Frigoboat,

I installed my new filter/dryer over the weekend and it couldn't have been simpler, especially with the color coded tape and the male-female connections making virtually fool-proof. Hopefully, I'll not have a moisture issue again!

On another note, I am interested in making my refrigeration unit as efficient as possible and as I had mentioned in an earlier post, my system is made up of new and used components. I do not currently have a "smart" controller but one that came with the BD 35. I do have a new digital thermostat that I installed last winter. Is it worth it to install a Merlin smart controller??
Tom

[Richard Kollmann]

Originally Posted by ShipShape

I converted the ice boxes on my old boat to refrigerators using the Frigoboat system. Here is a pic I took during the winter when I was living in Baltimore, the top one is the inboard icebox set at 38 degrees and the bottom one is against the hull and set at 52 degrees.

Attachment 62165

With old insulation you don't need no sitnkin' refrigerator when the water is cold. Two winters in B-more and two summers in south Florida - no problems at all with the keel coolers doing their job.

Follow the installation instructions though! The keel coolers have a green wire that is supposed to be connected to the DC ground bus. These keel coolers are three years old, the installer connected the green wires to a seacock.

Attachment 62166

All the thruhulls connected to that seacock with the boats bonding system were also corroded.


PS Hey Mr. Kollmann, thank you for your books and taking care of us here on CF too!

Ship Shape, You may not realize it but your boat is at risk of sinking when anyone of the metal through hulls breaks off with so much corrosion on keel cooler. Any boater that is exposed to one of these conditions needs test for galvanic corrosion:

• Spends time connected to shore power
• Has an onboard power inverter
• Has an onboard Generator
• Boat normally parked at dock near aluminum boat connected to shore power
• Zincs on your boat need to be replaced in less than three months.
• Boat is equipped with any form of water cooled refrigeration.

A survey qualified electronic engineer is a good idea. If problem is not as serious as yours Ship Shake I would recommend buying a test Silver/Silver-Chloride probe of your own you can find them on the web, hear is a sample address that also includes instruction manual $124
http://www.boatzincs.com/corrosion-reference-electrode.html

On boats with metal loss problems spending time connected to shore power or equipped with generators galvanic isolation transformers are available to handle stray voltages. One boater with two keel cooler systems extended his keel cooler zincs life beyond six weeks by installing galvanic isolators on both shore power and generator.

[Frigoboat Info]

Tom: Glad to hear that the installation of the Filter/Drier went smoothly.

In all Danfoss/Secop BD35/50 installations except pumped-water cooled or with a holding plate, slowing the compressor down will result in increased efficiency and lower overall current draw. There are two ways to do this. You can do it manually with the Speed Board that came with your BD 35 compressor, by gradually reducing the speed day by day until you see the box temperature start to rise in the heat of the day and then speeding it up a tad from there. Or you can install a Merlin Smart Speed Control and let it do all the fussy stuff for you. One extra feature of the Merlin is its built-in Warm Start Ramp-Up sequence to protect the electronics. When a system is first started, especially under warm/hot conditions (think a closed up boat, in mid afternoon in southern Florida), then if it is set to the highest speed, the loads through the controller during the first few minutes will be a lot higher than the normal running amperage, and can seriously strain the electronics. That is why all BD35/50 systems must be protected with a 15 amp fuse/breaker even though they may never draw more than 5 or 6 amps max when cycling, as they can and do exceed 10 amps on start up. The Merlin will start up in medium speed to keep the loads on the electronics down to an acceptable level, and will then ramp-up one speed every 5 minutes until it reaches maximum speed, at which point the danger is past.
There are other advantages of Smart Speed Control also. If you have an evaporator that is wrapped around so as to be enclosed and with a base added, maybe even a lid if it is horizontal, then the inside should be a freezer. Frigoboat designates these as “B - Bin” and “H - Horizontal” evaporators and these come in various sizes. By running the compressor at the lowest possible speed, we are running the system for long periods, and this ensures that the freezer portion inside these evaporators gets to be super-cold. Rock-solid ice cream is very much a reality! We sometimes have customers who want to install the largest B or H evaporator in a box that is theoretically too small for it, but they want the larger freezer section. Before we had variable speed compressors we would advise this customer that he would have to experiment by adding some stick-on insulation to the front of the evaporator in order to decrease the surface area, as this makes the system run longer and ensures lower internal temperatures in the freezer portion. Now we can simply rely on Merlin to take care of things.
And there are benefits of Smart Speed Control for flat-plate (F) evaporator installations also. One problem often found in all-refrigerator flat-plate installations can be condensation. If a flat evaporator plate is installed that is larger than necessary, the run time can be so short that a firm coating of frost does not fully develop before the thermostat is satisfied and the system shuts down. This wet frost then melts and drips off the evaporator before the compressor starts again, causing moisture problems in the box. Slowing the compressor down will increase the run time and ensure a thin coating of hard frost that should stay on the evaporator until the next compressor run period.
BTW If you are suffering from excessive frost build-up, altering the compressor speed will not help much, if at all. Excessive frost means that cold air is escaping from the box and warm, humid air is being drawn in to replace it. Typically the cold air escapes from poor front-opening door seals or unplugged openings in the box (heaven forbid there is a drain open to the bilge …..). Warm air is typically drawn in through a top seal, which is why you’ll find the most frost build-up at the top of the evaporator, at the point where the warm air is entering.
Hope this answers your question ….. and more.

[Tortuga's Lie]

Thanks for the info!
I have the vertically mounted bin type evaporator, it's the smaller of the two sizes you offer and again, it's for an 8 cu ft box. Since I just spent a bit for the dryer/filter, I may want to wait for the smart controller for my boat bucks to build back up

[Frigoboat Info]

From Richard Kollmann.
Frigoboat Info, you are correct, you can crunch numbers. I still think this is just creative advertising because pleasure cruising boats without generators could not manage your conclusions. No Mr. Kollmann, this is not “creative advertising”, but fact. Have you ever considered how rare a 20 cu ft all-refrigerator box is on a cruising boat? If a boat is big enough to need a 20 cu ft refrigerator it will no doubt have plenty of power available to run it. With modern batteries and charging systems, including wind/hydro generators and solar panels, plus the use of LED lighting, today’s cruising boats can produce plenty of power for large refrigeration systems, especially if Frigoboat Keel Cooled systems are employed. So what is your suggestion as an alternative for a 20 cu ft refrigerator box? We could use two systems, as we do on many freezers larger than 10 cu ft, but then we would stagger the t/stat settings and still use primarily just one system and slow it down, with the other “on standby” for quick cooling when required. Boxes of 14 to 18 cu ft boxes are very common on cruising boats, and we have thousands of such boxes being cooled very efficiently by single Keel Cooled systems running at reduced speeds and therefore being very efficient. I will leave the question of refrigerating a 20 cu ft box with a single BD50 compressor in tropical climates to the experienced live aboard cruiser. I have never questioned a frigoboat system to perform well in the correct application.

I agree to disagree on 20 cubic foot boxes now devote time to solving Frigoboat’s O-Ring leakage problems a major part of this forum's thread. Under normal conditions, and if not distorted or damaged, the o-rings in Frigoboat couplings have a long and trouble-free life. They are unaffected by oils and refrigerants and have a working temperature range from -30C to 100C (-22F to 212F). In normal use the couplings should not see temperatures anywhere close to these extremes. The small o-rings that are permanently sealed in the ends of the coupling halves should never be disturbed unless it is proven beyond doubt that they are leaking, but the main o-ring that is visible when the coupling is disconnected can be changed at any time without loss of refrigerant and with simple tools. This is the one o-ring that can be damaged during installation, and that is why we include spares with every new condensing unit.
From experience, we have heard of o-rings that have been suspected of leaking even though it was never definitively proven that they were. Many problems are often mis-diagnosed as refrigerant leaks, and it seems that the o-rings are typically the first target for suspicion if there’s no obvious damage. All one has to do is to run a finger around a coupling to see if there are any traces of clear refrigerant oil, as where refrigerant leaks out there will almost certainly be traces of oil.

[ShipShape]

Whoa Frigoboat Info and Richard Kollman: THOSE ERODED KEEL COOLERS ARE NOT MY BOAT, that was a boat I surveyed several years ago. You can rest easy, the owners renewed both the keel coolers and all the eroded thru hulls that haul out. Thanks for your concern though, and all the great advice about it!

Here are my keel coolers, see? they are just fine:



Oh, wait, no you can't see them because they hadn't been cleaned in four months. Here they are after pressure washing:



That was Baltimore - can you believe stuff can grow in that polluted water?!
Here is a pic of them from last year in Florida. I knew I was going to haul my boat so I saved money and didn't use a diver for six months:



In Florida you *really* do need a diver to clean the bottom every month. I plan to only cruise where the temperature is never lower than my age so ... so ... well, I'm really tired of dealing with cleaning the keel coolers. They're gouged from divers hacking at them, and every time I haul I always have to plan for several hours to (try to) remove the critters and barnacle bases. One of my fridges has quit working, I couldn't figure it out from Mr. Kollmann's books nor the Frigoboat manuals or web site, so when I renew the fridge insulation in a year or three I am going to replace that unit with something that doesn't use a keel cooler.

[Frigoboat Info]

ShipShape:

Did you know:

1. That you can apply anti-fouling to Frigoboat Keel Coolers if the Keel Cooler is not being used a a ground for SSB or Ham radio. It is obviously most efficient not painted, but if you have ongoing problems with excessive fouling, then a light coat of anti-fouling will reduce the efficiency less than serious fouling, and probably not so much that you will notice any difference in performance and energy use.
2. The sintered bronze encapsulation is 90% copper so is a natural anti-foulant, and most Keel Coolers you'll see on the hard are a nice green color. Typically, in warm waters, Keel Coolers may accrue a coating of slime after a few months that can be removed with a brush.
3. The longer the system runs the less chance of barnacle growth, as the heat is a deterrent. This is another bonus for those with a Smart Speed Control that is running the system for long periods at low speed.
4. There are some very effective enzymatic barnacle removers available that will not damage the surface of the Keel Cooler.
5. We have available a pre-charged air cooled condenser with a 12v fan, the Air Add-On, that can be installed on any Keel Cooled (or pumped-water cooled) system to give air cooling when a vessel is hauled for any reason. This was introduced at the request of cruisers who had existing Keel Cooler systems but were planning major voyages and wanted some back-up for if they ever got hauled out for emergencies, etc. The fan is switched off while the vessel is in the water, as activating it will make the system less efficient. We have also used this item as a stop-gap measure when a customer has damaged or compromised a Keel Cooler in some way and cannot haul out in the immediate future.
6. We spend a great deal of our time providing Customer Service, but we can only help those that we know have a problem. Frigoboat is the expert on Frigoboat, and while there are some well meaning but generally less informed individuals offering advice out there, we would hope that any Frigoboat owner with an issue would call, e-mail, or even stop in and see us for advice. With over 23,000 Keel Coolers sold over the past 19 years, there are bound to be issues with some, and there cannot be much that we haven't heard already.

[Richard Kollmann]

Frigoboat info, As I said before I will leave Compressor capacity versus insulated box sizes to the refrigeration industry and boating community without changing my recommendations

I do have problems with the lack of interest in solving the costly leaking O-ring problem and blaming the installer and boat owner for refrigerant leaks. Yes the keel coolers location may cause two of the line disconnects to reach or exceed 130 degrees C ( 266 F ) but there are 134a refrigerant O-rings available that are advertised to handle much higher temperatures. There are also extended shelf and in service life O-rings available. As to your comment refrigerant leak must be proven beyond a doubt as leaking before questioning O-rings. What about compressor is running and evaporator has frost cover missing on half of evaporator’s surface. I can understand why a technican might confuse refrigerant flow blockage on keel cooler systems for O-ring leakage. Finding traces of oil at a leak in any small system is unlikely and besides two line connecters are located in hot gas line before keel cooler. Very few people even technicians can not adjust the level of refrigerant in one of these very small systems to match a well designed factory charge. Chances are even a technician will not get refrigerant volume correct with in 5 grams on first service call. Maintenance on any refrigerator after initial first year’s product improvements were made should be limited to only cleaning skills. It is true that in the past other icebox refrigeration conversion companies have had line connecter leak problems. Remember a satisfied costumer will help you sell 3 more units and a dissatisfied costumer will cause you to lose 13 sales. Another marketing tip is sales improve by a liberal warrantee policy as good as or better than others in this industry.

Having had technical equipment problems over 50 years ago with a foreign manufacturer I made several trips overseas to meet with good very proud engineers who would not consider improving their products reliability. I understand what you must be up against on O-rings and Filters. Fortunately this several million dollar contract I refer to contained maintenance cost and performance language similar to a construction performance bond. A sizable cash settle was made then later equipment was disposed of.

[Frigoboat Info]

From Richard Kollmann:
Frigoboat info, As I said before I will leave Compressor capacity versus insulated box sizes to the refrigeration industry and boating community without changing my recommendations

I do have problems with the lack of interest in solving the costly leaking O-ring problem and blaming the installer and boat owner for refrigerant leaks. This is no lack of interest, as I have shown in my previous posts. Yes the keel coolers location may cause two of the line disconnects to reach or exceed 130 degrees C ( 266 F ) Please explain to myself and others how temperatures at a coupling could reach 266F under normal working conditions but there are 134a refrigerant O-rings available that are advertised to handle much higher temperatures. There are also extended shelf and in service life O-rings available. Yes, we are well aware of what o-ring materials are available. As to your comment refrigerant leak must be proven beyond a doubt as leaking before questioning O-rings. What about compressor is running and evaporator has frost cover missing on half of evaporator’s surface. There are several reasons for that to happen besides refrigerant loss, and if there is a leak it should not automatically be assumed that the o-rings are the culprits. I can understand why a technican might confuse refrigerant flow blockage on keel cooler systems for O-ring leakage. You see, there’s one reason right there! Finding traces of oil at a leak in any small system is unlikely Totally incorrect Mr. Kollmann! Oil is always circulating with the refrigerant and will almost definitely been seen at a leak location. Ask any technician, or even some of our customers that have found such traces. and besides two line connecters are located in hot gas line before keel cooler. This is irrelevant. Traces of oil at leak locations will invariable be found on both gas and liquid lines/components. Very few people even technicians can not adjust the level of refrigerant in one of these very small systems to match a well designed factory charge. Actually, the refrigerant charge of a component-style marine capillary system adjusted on-site will be the ideal. The factory charge will normally be close to ideal. Chances are even a technician will not get refrigerant volume correct with in 5 grams on first service call. It is impossible to use weight to accurately charge these small systems in the field. Maintenance on any refrigerator after initial first year’s product improvements were made should be limited to only cleaning skills. I’m not I understand what this means. It is true that in the past other icebox refrigeration conversion companies have had line connecter leak problems. Remember a satisfied costumer will help you sell 3 more units and a dissatisfied costumer will cause you to lose 13 sales. Another marketing tip is sales improve by a liberal warrantee policy as good as or better than others in this industry.

Having had technical equipment problems over 50 years ago with a foreign manufacturer I made several trips overseas to meet with good very proud engineers who would not consider improving their products reliability. I understand what you must be up against on O-rings and Filters. Fortunately this several million dollar contract I refer to contained maintenance cost and performance language similar to a construction performance bond. A sizable cash settle was made then later equipment was disposed of. I have no idea what relevance this has to this discussion unless it is to take a shot at foreign manufacturers in general.

[s/v Jedi]

I have found that O-rings need to be replaced every 5 years. I found the most obvious evidence of quick connects leaking oil at the first fitting between compressor and keel cooler.

Are better O-rings available that last longer?

[Richard Kollmann]

Frigoboat info, As I said before I will leave Compressor capacity versus insulated box sizes to the refrigeration industry and boating community without changing my recommendations

I do have problems with the lack of interest in solving the costly leaking O-ring problem and blaming the installer and boat owner for refrigerant leaks. This is no lack of interest, as I have shown in my previous posts. Yes the keel coolers location may cause two of the line disconnects to reach or exceed 130 degrees C ( 266 F ) Please explain to myself and others how temperatures at a coupling could reach 266Funder normal working conditions
A. Your figure quoted earlier in this thread is compressor vapor gas temperature 130 C from Danfoss Spec sheet.


but there are 134a refrigerant O-rings available that are advertised to handle much higher temperatures. There are also extended shelf and in service life O-rings available. Yes, we are well aware of what o-ring materials are available. As to your comment refrigerant leak must be proven beyond a doubt as leaking before questioning O-rings. What about compressor is running and evaporator has frost cover missing on half of evaporator’s surface. There are several reasons for that to happen besides refrigerant loss, and if there is a leak it should not automatically be assumed that the o-rings are the culprits. I can understand why a technican might confuse refrigerant flow blockage on keel cooler systems for O-ring leakage. You see, there’s one reason right there! Finding traces of oil at a leak in any small system is unlikely Totally incorrect Mr. Kollmann! Oil is always circulating with the refrigerant and will almost definitely been seen at a leak location. Ask any technician, or even some of our customers that have found such traces.
A. I ask this question to boaters in trouble with refrigerant loss on small systems containing less than 5 ounces of refrigerant and they rarely finding leaks. I believe there are better ways for a DIY boat captain to find leaks. On your keel cooler system I recommend testing all line connectors first then keel cooler inside boat through hull where refrigerant lines inter cooler.

and besides two line connecters are located in hot gas line before keel cooler. This is irrelevant. Traces of oil at leak locations will invariable be found on both gas and liquid lines/components. Very few people even technicians can not adjust the level of refrigerant in one of these very small systems to match a well designed factory charge. Actually, the refrigerant charge of a component-style marine capillary system adjusted on-site will be the ideal. The factory charge will normally be close to ideal. Chances are even a technician will not get refrigerant volume correct with in 5 grams on first service call. It is impossible to use weight to accurately charge these small systems in the field.
A. I agree

Maintenance on any refrigerator after initial first year’s product improvements were made should be limited to only cleaning skills. I’m not I understand what this means.

A. Warrantee information feedback leads to product improvements. Refrigerant systems are believed to be maintenance free once bugs are worked out.

It is true that in the past other icebox refrigeration conversion companies have had line connecter leak problems. Remember a satisfied costumer will help you sell 3 more units and a dissatisfied costumer will cause you to lose 13 sales. Another marketing tip is sales improve by a liberal warrantee policy as good as or better than others in this industry.

Having had technical equipment problems over 50 years ago with a foreign manufacturer I made several trips overseas to meet with good very proud engineers who would not consider improving their products reliability. I understand what you must be up against on O-rings and Filters. Fortunately this several million dollar contract I refer to contained maintenance cost and performance language similar to a construction performance bond. A sizable cash settle was made then later equipment was disposed of. I have no idea what relevance this has to this discussion unless it is to take a shot at foreign manufacturers in general.

A. Having supervised for years a department with Mechanical,Electrical,and Industral engineers in this country I know it is difficult to change their minds on a pet project. It is even more difficult overseas if you do not speak their language.

e cash settle was made then later equipment was disposed of.