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Fridge/freezer cooling

Nick Newington
 

I am thinking about using the tank water for the fridge cooling.
I know a number of Amels have done this.
The idea would be to T off the pipe that supplies water to the freshwater pressure pump and return the water to the tank ?? Maybe via the water maker product feed?
Wondering what others have done.

Why would I do this?

1. There is shell growth that clogs up the circulating pump valves using sea water. This would solve the issue, and maybe prolong pump life.
2. I can run a fridge whilst out of the water at least temporarily.
3. Fresh water is less corrosive than sea water so maybe the fridge cupronickel cooling coil will last longer.
4. When the pump fails and one needs to change it, only fresh water is spilled in the engine room.

What are the disadvantages?
Struggling to see a downside…


Kind regards
Nick
Amelia (AML54-019) and on my way to Athens and Leros
Ulrich Michael Dangelmeyer
 

Hi Nick we have on Soleil Bleu since more than 10 the freshwater cooling system installed (already by the previous owner). We are in Leros Evros Marina. You are welcome to have a closer look on our setup, we like it.
Best
Ulrich
Soleil Bleu #088 (2008).

Am 26.04.2022 um 11:30 schrieb Nick Newington via groups.io <ngtnewington@...>:

I am thinking about using the tank water for the fridge cooling.
I know a number of Amels have done this.
The idea would be to T off the pipe that supplies water to the freshwater pressure pump and return the water to the tank ?? Maybe via the water maker product feed?
Wondering what others have done.

Why would I do this?

1. There is shell growth that clogs up the circulating pump valves using sea water. This would solve the issue, and maybe prolong pump life.
2. I can run a fridge whilst out of the water at least temporarily.
3. Fresh water is less corrosive than sea water so maybe the fridge cupronickel cooling coil will last longer.
4. When the pump fails and one needs to change it, only fresh water is spilled in the engine room.

What are the disadvantages?
Struggling to see a downside…


Kind regards
Nick
Amelia (AML54-019) and on my way to Athens and Leros
Billy Newport
 
Edited

On my boat, I have a chiller circuit for HVAC.its supposed to be a fresh water glycol mixture. The air handlers are brass. The calpeda pump corroded pretty badly because I don't think there was enough glycol in the system. There is supposed to be 20% or so. The amount of rust circulating in that loop is surprising. Running just fresh water through that pump corroded the pump (cast iron) badly. So, I guess if the pump was stainless or all plastic then fine but otherwise, my own experience would have me worried about tainting my fresh water.
Matt & Michelle
 

Interesting topic.  I find it quite challenging on a yacht with high system complexity as an Amel to keep the original design philosophy built around safety trades intact.  There has to be a significant gain/benefit (or obsolescence issue) to convince me that I know better then the manufacturer (ref. LFP upgrade...I can be convinced).

In this instance, I get the thermal efficiency gain one could achieve with the change in heat sink.  A simplistic first law calc shows that potential gain to be on the order of 7-9%.  I can't justify the risk of my water supply for a thermal efficiency gain that has no measurable/discernable positive livability gain.

Matt      
Ron Hynes <riffhynes@...>
 

I changed to a freshwater cooling system about two years ago and have been very satisfied with the results. I simply submerged the old refrigeration pump into the bottom of the fresh water tank and secured it with zip ties. The exhaust of the submersible pump is plumbed into one of the spare existing pipes that reach the bottom of the freshwater tank.  Even when the temperature of the freshwater is in the 80°F range, I still see very little rise due to the heat generated by my Fridge-a- Boat system. I originally adopted this system since I anticipated living on the hard for several months and didn’t want to go without refrigeration. It works so well, however, that I have retained it. Before hand, I would need to flush out the coolant lines from the Seachest about every three months. Naturally, with the freshwater system there is never any need to remove any debris from the piping. my submersible pump is a March and was about eight years old when I adopted the system. It failed within about six months and I wasn’t sure if it had just reached its natural life or was caused by my new system. The representative from March told me that in his experience these pumps don’t last as long when submersed. He speculated it was due to internal heat buildup, but I find this a little difficult to understand since the warmest I have ever seen the freshwater to be in the mid 80° range and that was on the hard. Most of the time the freshwater temperature is within a few degrees of the ambient sea temperature. 

Ron Hynes
954.319.0944

On Apr 26, 2022, at 7:44 AM, Billy Newport <billy@...> wrote:



[Edited Message Follows]

On my boat, I have a chiller circuit for HVAC.its supposed to be a fresh water glycol mixture. The air handlers are brass. The calpeda pump corroded pretty badly because I don't think there was enough glycol in the system. There is supposed to be 20% or so. The amount of rust circulating in that loop is surprising. Running just fresh water through that pump corroded the pump (cast iron) badly. So, I guess if the pump was stainless or all plastic then fine but otherwise, my own experience would have me worried about tainting my fresh water.

CW Bill Rouse
 

Nick,

I believe that Amel must believe that they made a mistake when they introduced the A54 with a direct seawater heat exchange for the refrigeration system. Of course, the efficiency argument won the day, but Henri wasn't participating enough to make the practical trouble-free argument. I doubt that anyone participating in that mistake will admit it. The direct seawater heat exchange was abandoned by Amel with the introduction of the A55. The A55 used an indirect seawater exchange with keel coolers, eliminating the "growth in the lines" issue.

If you ask Veco, the manufacturer of your system, if you can use drinking water for heat exchange, they will tell you, NO. The issue is that the heat exchange water circuit for the direct seawater heat exchange is NOT certified for human consumption. Frankly, the issue could be that it was never tested, OR it can be a real hazard. You will find that the only thing people can tell you that have done this is that it works great, it tastes fine, it has not made me sick, and/or nobody has died. Deadly things like lead poisoning creep into the body with no immediate side effects. This is the reason when people ask me, I say I do not recommend using drinking water for refrigeration heat exchange. 

The bottom line is that human consumption testing has not been done on the seawater circuit. 

Ask yourself if you want to take the health risk to yourself and your crew to reduce the required maintenance.

Bill

CW Bill Rouse Amel Owners Yacht School
720 Winnie, Galveston Island, Texas 77550 
   

On Tue, Apr 26, 2022 at 3:30 AM Nick Newington via groups.io <ngtnewington=aol.com@groups.io> wrote:
I am thinking about using the tank water for the fridge cooling.
I know a number of Amels have done this.
The idea would be to T off the pipe that supplies water to the freshwater pressure pump and return the water to the tank ?? Maybe via the water maker product feed?
Wondering what others have done.

Why would I do this?

1. There is shell growth that clogs up the circulating pump valves using sea water. This would solve the issue, and maybe prolong pump life.
2. I can run a fridge whilst out of the water at least temporarily.
3. Fresh water is less corrosive than sea water so maybe the fridge cupronickel cooling coil will last longer.
4. When the pump fails and one needs to change it, only fresh water is spilled in the engine room.

What are the disadvantages?
Struggling to see a downside…


Kind regards
Nick
Amelia (AML54-019) and on my way to Athens and Leros
Bill Kinney
 

I have never been a big fan of pumped cooling water for refrigerators.  The increased efficiency of cooling comes at a high cost of complexity and maintenance. But it is what you have to work with...

Switching to tank water is one of those situations where the benefits of the change are all up front, and the downsides are all potential and of unknown probability. Some more serious than others. The relative risk/benefit also changes based on how and where you use your boat.

The benefits of doing this are all listed in posts above, and are definitely nice to have.

The downsides:  

If you have a leak in your refrigerator cooling lines you have the potential to empty your entire tank of fresh water, and have no way of knowing it is happening. To be fair, this is about as likely as a salt water leak in the cooling circuit, which is arguably a more serious case, especially if you are not on the boat when it happens.

It is REMOTELY possible to have your refrigerant leak into your fresh water supply.  This is the reason (I believe) that the manufacturers of the cooling units recommend against doing this. I do not think refrigerant gas itself is so much an issue, but there is lubricating oil along with it that you would definitely NOT want to have in your drinking water. This is one of those unlikely, but serious, failure modes that are easy to dismiss, until they happen.

Having two pumps tee'd into one draw tube from the fresh water tank increases the opportunity for air leaks that can make priming difficult or impossible for both of them.  I would add a dedicated draw line for the cooling circuit, and add a return line that eliminated splashing into the tank.  The constant sound of that would drive me nuts!

This is a case where there is not a perfect answer. Neither arrangement is ideal.  The tank water case is certainly the better choice, right up until something goes very wrong and suddenly it is not.

There are alternatives, but they quickly get to be complex, and add their own difficulties and require a fair bit of engineering. With some cooling systems, it is possible to retrofit an air-cooled condenser.  This is arguably less efficient in very hot weather, but the difference in the real world is vanishingly small compared to an Amel's overall electric budget.

A not simple solution, but one that (I believe) would work, is to install a coil of copper tubing in the water tank and circulate a solution of non-toxic antifreeze through that.  It gives an extra barrier between contamination from the refrigerant, minimizes corrosion, and is easily maintained.  The most difficult part of the installation would be securing the copper coil in the tank.  This is probably what I would do if it was my boat. I think this has all the benefits of using tank water directly. Other than the design and install effort, I can't think of a downside to this, but I'm sure there are some...

It might be better to just add the plumbing parts to make it easy to flush the salt water cooling circuit with Barnacle Buster, or other product, to clean out the circuit on a regular basis.

I don't have a recommendation for you, just my thoughts for your decision.

Bill Kinney
SM160, Harmonie
Palmas del Mar, Puerto Rico
Barry Connor
 

Hi Bill, Totally agree, I had a mild acid wash done to clear my refrigeration and a/c pipes last year in Le Marin, done by Caraibe Refrigeration.
Lots of little shell bits came out. First time it was done in 15 years. 
The purity of your drinking water is very important.
On another point: can you tell me if Incidences, La Rochelle are making HydraNet sails for individual sail order? If so. Can we still get your special price?
Very Best 

Barry and Penny
“SV Lady Penelope II”
Amel 54.  #17
Rodney Bay 
St Lucia 


On Apr 26, 2022, at 10:03 AM, CW Bill Rouse <brouse@...> wrote:


Nick,

I believe that Amel must believe that they made a mistake when they introduced the A54 with a direct seawater heat exchange for the refrigeration system. Of course, the efficiency argument won the day, but Henri wasn't participating enough to make the practical trouble-free argument. I doubt that anyone participating in that mistake will admit it. The direct seawater heat exchange was abandoned by Amel with the introduction of the A55. The A55 used an indirect seawater exchange with keel coolers, eliminating the "growth in the lines" issue.

If you ask Veco, the manufacturer of your system, if you can use drinking water for heat exchange, they will tell you, NO. The issue is that the heat exchange water circuit for the direct seawater heat exchange is NOT certified for human consumption. Frankly, the issue could be that it was never tested, OR it can be a real hazard. You will find that the only thing people can tell you that have done this is that it works great, it tastes fine, it has not made me sick, and/or nobody has died. Deadly things like lead poisoning creep into the body with no immediate side effects. This is the reason when people ask me, I say I do not recommend using drinking water for refrigeration heat exchange. 

The bottom line is that human consumption testing has not been done on the seawater circuit. 

Ask yourself if you want to take the health risk to yourself and your crew to reduce the required maintenance.

Bill

CW Bill Rouse Amel Owners Yacht School
720 Winnie, Galveston Island, Texas 77550 
   

On Tue, Apr 26, 2022 at 3:30 AM Nick Newington via groups.io <ngtnewington=aol.com@groups.io> wrote:
I am thinking about using the tank water for the fridge cooling.
I know a number of Amels have done this.
The idea would be to T off the pipe that supplies water to the freshwater pressure pump and return the water to the tank ?? Maybe via the water maker product feed?
Wondering what others have done.

Why would I do this?

1. There is shell growth that clogs up the circulating pump valves using sea water. This would solve the issue, and maybe prolong pump life.
2. I can run a fridge whilst out of the water at least temporarily.
3. Fresh water is less corrosive than sea water so maybe the fridge cupronickel cooling coil will last longer.
4. When the pump fails and one needs to change it, only fresh water is spilled in the engine room.

What are the disadvantages?
Struggling to see a downside…


Kind regards
Nick
Amelia (AML54-019) and on my way to Athens and Leros
Mark & Debbie Mueller
 

Using a direct heat exchanger circuit where drinking water goes thru the refrigeration cooling circuit & is discharged back into the drinking water would normally be considered an unsafe industry practice for all the reasons listed above.  If you use separate cooling circuit such as a keel cooler style with a heat exchanger immersed in the drinking water with the appropriate “human friendly” components the system would be much better.  This should include an expansion tank vented to the atmosphere to visually inspect the heat exchanger fluid level in the tank allowing you to determine if a leak is present.  Couple this with a food grade propylene glycol antifreeze solution in the event a leak occurs into the fresh water tank.  I believe you would have an effective and safer system.  Using an Antifreeze Refractometer, approx. $20, you have an easy way to check for cross contamination.  Alternatively, change the compressors to air cooled versions.

 

A couple of snippets from the internet – propylene glycol is …”Generally Recognized As Safe (GRAS) food ingredient, meaning it has been deemed safe for its intended uses in food. It was classified as GRAS by the U.S. Food & Drug Administration (FDA)” & “Why is propylene glycol used in food? Propylene glycol is often used to maintain the moisture in prepared foods and works to maintain their flavor quality for longer periods of time. It is also found in flavorings, such as vanilla or almond extracts used in baking, and in some types of food coloring”.


--
Mark Mueller
former Brass Ring  A54
Dimitris Krasopoulos
 

Dear Bill,

First of all the Amel 54 has a big problem in the refrigeration sea circuit as it is working day and night without major interruption contaminating the system with barnacles and destroys the pumps . It is not well well thought for sure. After changing it to fresh water from the tank ( after cleaning the system till clear water comes out) the systems works excellent and no contamination of the sea chest is present anymore which can create a big problem as increasing the motor temperature and some time cancelling trips due to that, till I found out the reason of the motor overheating and to start a long journey without knowing the reason is not a good idea. I always had a second sea chest filter to replace the old but the contamination is much more serious in the bronze curvature of the engine room intake and you need to clean the engine with barnacle buster.

I would suggest that it is not great to drink the water directly from the tank anyway as with time the tank starts to smell and dirt is on the walls asking for thorough cleaning. The compartment under the refrigerator is a bad design anyway making the cleaning very difficult. A suitable marine high capacity filter can help on that . 

So my point is if you do not drink the water of the tank you should immediately change from sea water circulation to fresh water tank, this is an easy work. If you want to drink the water from the tank a filter is the only solution in the exit in the kitchen unless you want to drink water from the bathroom .


Best Regards

Dimitris Krasopoulos
Dubai Mob: +971 564602575
Greek Mob:+306944302318



Στις Τρί 26 Απρ 2022 στις 5:03 μ.μ., ο/η CW Bill Rouse <brouse@...> έγραψε:

Nick,

I believe that Amel must believe that they made a mistake when they introduced the A54 with a direct seawater heat exchange for the refrigeration system. Of course, the efficiency argument won the day, but Henri wasn't participating enough to make the practical trouble-free argument. I doubt that anyone participating in that mistake will admit it. The direct seawater heat exchange was abandoned by Amel with the introduction of the A55. The A55 used an indirect seawater exchange with keel coolers, eliminating the "growth in the lines" issue.

If you ask Veco, the manufacturer of your system, if you can use drinking water for heat exchange, they will tell you, NO. The issue is that the heat exchange water circuit for the direct seawater heat exchange is NOT certified for human consumption. Frankly, the issue could be that it was never tested, OR it can be a real hazard. You will find that the only thing people can tell you that have done this is that it works great, it tastes fine, it has not made me sick, and/or nobody has died. Deadly things like lead poisoning creep into the body with no immediate side effects. This is the reason when people ask me, I say I do not recommend using drinking water for refrigeration heat exchange. 

The bottom line is that human consumption testing has not been done on the seawater circuit. 

Ask yourself if you want to take the health risk to yourself and your crew to reduce the required maintenance.

Bill

CW Bill Rouse Amel Owners Yacht School
720 Winnie, Galveston Island, Texas 77550 
   
View My Training Calendar

On Tue, Apr 26, 2022 at 3:30 AM Nick Newington via groups.io <ngtnewington=aol.com@groups.io> wrote:
I am thinking about using the tank water for the fridge cooling.
I know a number of Amels have done this.
The idea would be to T off the pipe that supplies water to the freshwater pressure pump and return the water to the tank ?? Maybe via the water maker product feed?
Wondering what others have done.

Why would I do this?

1. There is shell growth that clogs up the circulating pump valves using sea water. This would solve the issue, and maybe prolong pump life.
2. I can run a fridge whilst out of the water at least temporarily.
3. Fresh water is less corrosive than sea water so maybe the fridge cupronickel cooling coil will last longer.
4. When the pump fails and one needs to change it, only fresh water is spilled in the engine room.

What are the disadvantages?
Struggling to see a downside…


Kind regards
Nick
Amelia (AML54-019) and on my way to Athens and Leros
Bill Kinney
 

There is NO filter I would ever trust to remove the contaminants from a refrigerant leak into the drinking water without rather sophisticated testing to be sure it actually worked with the actual chemicals at issue.

Propylene glycol is the basis for many of the non-toxic heat transfer solutions used in the food industry. It is usually easy to detect by taste in plain water before most onboard test methods would measure its presence.  You likely consume some every day in your normal food intake.  If you are concerned about it, you COULD just circulate water, but you would have issues with biological growth and corrosion, but still way better than using salt water!

Bill Kinney
SM160, Harmonie
Palmas del Mar, Puerto Rico
Danny and Yvonne SIMMS
 

Hi Bill et al. Your post forestalled me. A win win using the copper coil idea. Since the SM water tank is in the keel it will achieve sea temp which would put it in the same efficiency as external keel tubing
 However I have operated Ocean Pearl for months at a time in tropical areas. My two fridges and one freezer are all air cooled and work well. If I wanted an improvement I would focus on insulation.
Kind Regards
Danny
SM 299
Ocean Pearl 

On 27/04/2022 03:01 Bill Kinney <cruisingconsulting@...> wrote:


I have never been a big fan of pumped cooling water for refrigerators.  The increased efficiency of cooling comes at a high cost of complexity and maintenance. But it is what you have to work with...

Switching to tank water is one of those situations where the benefits of the change are all up front, and the downsides are all potential and of unknown probability. Some more serious than others. The relative risk/benefit also changes based on how and where you use your boat.

The benefits of doing this are all listed in posts above, and are definitely nice to have.

The downsides:  

If you have a leak in your refrigerator cooling lines you have the potential to empty your entire tank of fresh water, and have no way of knowing it is happening. To be fair, this is about as likely as a salt water leak in the cooling circuit, which is arguably a more serious case, especially if you are not on the boat when it happens.

It is REMOTELY possible to have your refrigerant leak into your fresh water supply.  This is the reason (I believe) that the manufacturers of the cooling units recommend against doing this. I do not think refrigerant gas itself is so much an issue, but there is lubricating oil along with it that you would definitely NOT want to have in your drinking water. This is one of those unlikely, but serious, failure modes that are easy to dismiss, until they happen.

Having two pumps tee'd into one draw tube from the fresh water tank increases the opportunity for air leaks that can make priming difficult or impossible for both of them.  I would add a dedicated draw line for the cooling circuit, and add a return line that eliminated splashing into the tank.  The constant sound of that would drive me nuts!

This is a case where there is not a perfect answer. Neither arrangement is ideal.  The tank water case is certainly the better choice, right up until something goes very wrong and suddenly it is not.

There are alternatives, but they quickly get to be complex, and add their own difficulties and require a fair bit of engineering. With some cooling systems, it is possible to retrofit an air-cooled condenser.  This is arguably less efficient in very hot weather, but the difference in the real world is vanishingly small compared to an Amel's overall electric budget.

A not simple solution, but one that (I believe) would work, is to install a coil of copper tubing in the water tank and circulate a solution of non-toxic antifreeze through that.  It gives an extra barrier between contamination from the refrigerant, minimizes corrosion, and is easily maintained.  The most difficult part of the installation would be securing the copper coil in the tank.  This is probably what I would do if it was my boat. I think this has all the benefits of using tank water directly. Other than the design and install effort, I can't think of a downside to this, but I'm sure there are some...

It might be better to just add the plumbing parts to make it easy to flush the salt water cooling circuit with Barnacle Buster, or other product, to clean out the circuit on a regular basis.

I don't have a recommendation for you, just my thoughts for your decision.

Bill Kinney
SM160, Harmonie
Palmas del Mar, Puerto Rico

Sv Garulfo
 


My two cents:

* Risks of freshwater contamination from refrigerant leak:

1. A refrigerant leak will soon be visible by the fridge malfunctioning. It wouldn’t be a case of a silent killer,

2. A leak in the condenser is made less likely by circulating freshwater,

3. If a refrigerant leak happened in the condenser, the r134a refrigerant would bubble up and not dissolve to any significant amount in the water,

4. If a leak happened in the condenser, the oil carried out by the refrigerant (however small amount) would stay at the surface (being less dense and dropped in from the top of the tank). It wouldn’t be sucked in the freshwater circuit. 


* Risk of circulating circuit leak emptying the freshwater tank:

5. It’s low risk but could happen. The symptoms would be the same as with saltwater (in the bilge or in the various compartments in the saloon), but the consequences far less worse (salt vs no salt). At a pump rate of a few litres per min, even a (how likely?) fully breached circuit would take time to empty the tank. 


* Health risk of freshwater contact with condenser:

6. The condenser is most likely made of cupronickel. There is no real study that I could find of the health impact (as per Bill R.’s point regarding liability), probably because it’s an expensive and pointless freshwater carrier, when copper is available and widely used. So unknown, but probably not very relevant, given Nickel is used in some platings of freshwater application. And to be put in balance with the other possibly worrying health hazards (VOCs in varnishes, PVC, anti fouling paints when you swim, clean the hull or make water, UV or antiUV cream, alcohol intake, ...) and benefits (insert you favourite here) of boat life.
As a side note, keelcools are made of cupronickel too, so they don’t help as a replacement of the condenser with circulating freshwater. 

* risk of warming the fresh water to unsafe temperature: 

7. Well, that’s difficult to theorise. Fibreglass conductivity, heat exchange with the surface air, freshwater replacement rate, etc. In practice, I’ve met Amels with full freshwater circulation and none could measure a difference between tank water and surrounding sea water temperature, and I’m not shocked. I would even think the frequent circulation and aeration of the freshwater helps prevent growth in the tank. 
If one worries about the temp of their freshwater tank rising, one should stay in high latitude sailing grounds. Ceramic filtering is a must, if only for taste.

So in conclusion, I think freshwater cooling (copper coil plunging condenser or freshwater water circulation) has more benefits than drawbacks, the main one being the shipyard not having the regulatory means to implement it. 


Best,

Thomas 
GARULFO
A54-122
Tahiti 



On 26 Apr 2022, at 10:06, Bill Kinney <cruisingconsulting@...> wrote:

There is NO filter I would ever trust to remove the contaminants from a refrigerant leak into the drinking water without rather sophisticated testing to be sure it actually worked with the actual chemicals at issue.

Propylene glycol is the basis for many of the non-toxic heat transfer solutions used in the food industry. It is usually easy to detect by taste in plain water before most onboard test methods would measure its presence.  You likely consume some every day in your normal food intake.  If you are concerned about it, you COULD just circulate water, but you would have issues with biological growth and corrosion, but still way better than using salt water!

Bill Kinney
SM160, Harmonie
Palmas del Mar, Puerto Rico
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