Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 26-05-2013, 06:29   #1
Registered User

Join Date: Jan 2011
Location: Alaska and Caribbean
Boat: Tashiba 40
Posts: 16
StoneCold fresh water cooled refrigeration

I have two Danfoss compressors which have air and water cooling. The fresh water system draws water directly from the fresh water tanks. Heating the water in the tanks has not been a problem but the water from the tanks has been reacting with the metal in the compressor heat exchanger and filling my water tanks with a fluffy brown suspended material. The goop filters out and is nt toxic but it continually clogs the filters. There has got to be some damage to the compresor heat exchangers. StoneCold advertises this set up and there must be hundreds of sytems out there with it. The answer is to install a stainless or monel coil in your fresh water tank and have a closed system filled with a non-reactive cooling fluid.
__________________

__________________
SAIL23692 is offline   Reply With Quote
Old 26-05-2013, 06:42   #2
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
You can pop a Frigoboat system with keelcooler in, mounting the keelcooler to be in the watertank.

Metal boats can weld a mini-tank with the hull forming part of it, fill it with coolant or oil and pop the keelcooler in there.
__________________

__________________
s/v Jedi is offline   Reply With Quote
Old 27-05-2013, 13:00   #3
Marine Service Provider

Join Date: Aug 2004
Location: Ft. Lauderdale
Posts: 784
Re: StoneCold fresh water cooled refrigeration

Jedi, I once was asked to examine and recommend what to do about boat's aluminum hull interior damage inside integral fresh water tank.. Low voltage discharge from electrically driven compressors are common in seawater cooled refrigeration systems. Boat in question was a five year old live aboard and vapor refrigerant to liquid condensing action was not in a keel cooler but from copper tubing placed in fresh water tank. Zinc and Aluminum are both close together on the Anodic scale. Even with copra-nickel water cooled condensers failures occur this is why zincs are used to prevent system failures.

It is bad enough when seawater cooling mediums can destroy a complete refrigeration system but allowing aluminum hull to act as the anode spells disaster.
__________________
Richard Kollmann is online now   Reply With Quote
Old 27-05-2013, 13:58   #4
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Quote:
Originally Posted by Richard Kollmann View Post
Jedi, I once was asked to examine and recommend what to do about boat's aluminum hull interior damage inside integral fresh water tank.. Low voltage discharge from electrically driven compressors are common in seawater cooled refrigeration systems. Boat in question was a five year old live aboard and vapor refrigerant to liquid condensing action was not in a keel cooler but from copper tubing placed in fresh water tank. Zinc and Aluminum are both close together on the Anodic scale. Even with copra-nickel water cooled condensers failures occur this is why zincs are used to prevent system failures.

It is bad enough when seawater cooling mediums can destroy a complete refrigeration system but allowing aluminum hull to act as the anode spells disaster.
Agree. The bronze keel cooler should be electrically isolated from the hull. Not a problem I think. A 5 liter tank is big enough, all we need to do is transfer a little bit of heat to the aluminium hull and on to the sea water. I would never use a water tank.
__________________
s/v Jedi is offline   Reply With Quote
Old 27-05-2013, 16:58   #5
Marine Service Provider

Join Date: Aug 2004
Location: Ft. Lauderdale
Posts: 784
Re: StoneCold fresh water cooled refrigeration

Jedi, You are assuming fresh water does not contain minerals in it that can conduct current to anode aluminum hull.
__________________
Richard Kollmann is online now   Reply With Quote
Old 27-05-2013, 17:08   #6
Senior Cruiser
 
Cheechako's Avatar

Cruisers Forum Supporter

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 19,342
Re: StoneCold fresh water cooled refrigeration

re Frigoboat: and what about when the water in the tank runs low?

"the water from the tanks has been reacting with the metal in the compressorheat exchanger and filling my water tanks with a fluffy brown suspended material."

Are you sure its that and not the warm water growing things? hard to logic why a heat exchanger would cause that... if it's copper, it should kill things not grow them....?
__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Old 27-05-2013, 17:14   #7
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Re: StoneCold fresh water cooled refrigeration

Quote:
Originally Posted by Richard Kollmann View Post
Jedi, You are assuming fresh water does not contain minerals in it that can conduct current to anode aluminum hull.
The tanks that I refer to do not have minerals. They are filled with coolant or oil so that heat gets transferred into the hull plating as efficiently as possible. They are only 5 liters or so (a gallon).
__________________
s/v Jedi is offline   Reply With Quote
Old 27-05-2013, 17:16   #8
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Re: StoneCold fresh water cooled refrigeration

Quote:
Originally Posted by Cheechako View Post
re Frigoboat: and what about when the water in the tank runs low?

"the water from the tanks has been reacting with the metal in the compressorheat exchanger and filling my water tanks with a fluffy brown suspended material."

Are you sure its that and not the warm water growing things? hard to logic why a heat exchanger would cause that... if it's copper, it should kill things not grow them....?
May be the heat exchanger has failed and it is emulsified compressor oil?
__________________
s/v Jedi is offline   Reply With Quote
Old 27-05-2013, 17:58   #9
Marine Service Provider

Join Date: Aug 2004
Location: Ft. Lauderdale
Posts: 784
Re: StoneCold fresh water cooled refrigeration

Years ago Cruising World published a design of mine that used the minerals in fresh water tank to provide quantity level indication of water in tank. Unless there is distilled water in tank fresh water will provide a path to conduct low voltage current to corrode aluminum hull skin inside tank. If you want to stop all corrosion you can not. What can be done is send it to a control zinc other than the aluminum hull.
__________________
Richard Kollmann is online now   Reply With Quote
Old 27-05-2013, 18:01   #10
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Re: StoneCold fresh water cooled refrigeration

Quote:
Originally Posted by Richard Kollmann View Post
Years ago Cruising World published a design of mine that used the minerals in fresh water tank to provide quantity level indication of water in tank. Unless there is distilled water in tank fresh water will provide a path to conduct low voltage current to corrode aluminum hull skin inside tank. If you want to stop all corrosion you can not. What can be done is send it to a control zinc other than the aluminum hull.
Like I said, filled with coolant or oil, not fresh water
__________________
s/v Jedi is offline   Reply With Quote
Old 28-05-2013, 16:31   #11
Marine Service Provider

Join Date: Aug 2004
Location: Ft. Lauderdale
Posts: 784
Re: StoneCold fresh water cooled refrigeration

Jedi, How would you propose preventing damaging low voltage from discharging to an aluminum hull? Nice thinking bad Idea what non conductive material would it be that remained non conductive? Simple solution is avoid water cooling of small refrigeration systems on aluminum boats.
__________________
Richard Kollmann is online now   Reply With Quote
Old 28-05-2013, 17:29   #12
Do… or do not
 
s/v Jedi's Avatar

Cruisers Forum Supporter

Join Date: Feb 2009
Location: in paradise
Boat: Sundeer 64
Posts: 9,198
Quote:
Originally Posted by Richard Kollmann View Post
Jedi, How would you propose preventing damaging low voltage from discharging to an aluminum hull? Nice thinking bad Idea what non conductive material would it be that remained non conductive? Simple solution is avoid water cooling of small refrigeration systems on aluminum boats.
Richard, this has been solved by engineers many decades ago. If you want to isolate electrically while conducting heat, mica is a good candidate. It will never become conductive and a very thin sheet can be used.
__________________
s/v Jedi is offline   Reply With Quote
Old 31-05-2013, 17:08   #13
Marine Service Provider

Join Date: Oct 2006
Posts: 95
Re: StoneCold fresh water cooled refrigeration

We know of many owners of aluminum and steel hulled boats with Frigoboat Keel Coolers installed, with Mylar (or similar material) shims isolating the Keel Coolers from the hull material. It's not really neccessary on steel-hulled vessels, but some owners just want that piece of mind.
BTW. Steve Dashew's Wind Horse, and also his FPB powerboats, have three Frigoboat Keel Coolers mounted in an aluminum skin tank inside the aluminum hull, and electrically isolated from it. To date there have been no issues with this arrangement.
__________________
Frigoboat Info is offline   Reply With Quote
Old 31-05-2013, 17:18   #14
Marine Service Provider

Join Date: Oct 2006
Posts: 95
Re: StoneCold fresh water cooled refrigeration

BTW. We hear of our customers installing Keel Coolers in fresh water tanks or using the boat's fresh water for cooling a pumped-water system, but we can never approve or condone such an installation. The materials used by marine refrigeration manufacturers is not approved as food-grade, and these systems are specifically designed to use the sea water outside of the boat, not the boat's fresh water inside a limited and varying capacity reservoir.
__________________

__________________
Frigoboat Info is offline   Reply With Quote
Reply

Tags
refrigeration, water

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 09:40.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.