keel cooled refrigeration...need your input

[Terra Nova]

Originally Posted by skipmac

...I tested that issue and did not find that to be a problem...

Where do you think all that heat goes?

[wiekeith]

There is an alternative - a cooler built into a thru-hull. I have one on my boat, and it's been there for ten years with no problems, as far as I'm aware. I've even had the boat on the hard for five days with the fridge operating (I forgot about the thru-hull cooling...) and was living aboard at the time. I can't say that I noticed any inefficiency with the fridge, but, as mentioned, I totally forgot about the cooling method so wasn't specifically checking.

The thu-hull is still functional as a thru-hull (in my case the galley sink drain) so no additional holes are required.

[KRMS]

Surely the heat that is being got rid of in the keel cooler is the condenser heat not the heat from the compressor.

With air cooled this would be into the boat (perhaps with a fan).

With water cooled this would be into a heat exchanger (cooled by sea water being pumped through it) - the pumping of sea water was noisy for us before we we switched to a keel cooled system.

[skipmac]

Originally Posted by Terra Nova

Where do you think all that heat goes?

Into the ether?

My theory is there just isn't that much heat generated. I think Sailorchic did some calculations and determined there weren't a whole lot of BTUs generated.

Regardless, if the boat is ventilated any extra heat produced by the fridge would go out the hatch along with body heat, heat from lights, electronics and any other waste heat in the boat.

[Tortuga's Lie]

I installed a Frigoboat keelcooler on my T-37 and was very satisfied with it after about ten years of use although I did have one issue with water vapor getting into the capillary tubes but I vacuumed out the unit, installed a filter from Frigoboat, recharged and it worked fine.
My new boat, it came with an old air cooled Adler-Barbour that works fine but it does make noise and it does consume more amp-hours than the Frigoboat. I never had any issue with the keel-cooler corroding if that's a worry. I do notice a warm area in my galley from the air-cooled unit but it is localized and probably not significant.
Just my experience......

[Terra Nova]

Originally Posted by skipmac

...My theory is there just isn't that much heat generated...

My theory is your flawed and unobserved "test" led you to an equally flawed theory and conclusion based on one flawed example.

[Captndave1]

If you spend most of your time on the water where there is no tidal flow or river flow, a keel cooled system does not work as well. The keel cooler plate must have the water around it moving. As long as there is moving water, the keel cool system is great. I finally had to replace my 30 year old keel cooled system with an air cooled Vitrafrigo, and I love it.

[senormechanico]

A keel cooler gets a bit warmer than the water surrounding it.
The water in contact with the keel cooler rises and is replaced by more water.
The only way you would require moving water would be if the keel cooler was mounted at the top of a compartment open at the bottom and totally surrounded on the sides. A very unlikely scenario on a boat, although the thruhull cooler could be classified as that.

What am I missing here?

[wannacat]

Our Frigiboat keel cooled fridge/freezer works great both in Florida and the Bahamas. Really efficient and less moving parts [no water pump or condenser fan] to worry about. Internal pressures of the system might be an issue if way up north in Labrador/ Newfoundland/Alaska etc. when the head pressure drops so much and the cap tube feed floods too much refrigerant? A TX system would take care of that. But how many cruisers go there? For the average cruising zones I'd definitely stick with the keel cooler! If thru hulls were such an issue they'd be banned. Your insurance company doesn't care if you have non, one or ten!

[CarinaPDX]

I had a custom keel-cooler system installed while in Turkey, and it works very well. No complaints whatsoever. I also had an air-cooled heat exchanger added, with a fan drawing through it and blowing on the compressor. Since it is located in a small space I would want the fan for the compressor anyway. (Also, because of location air-cooling alone might be a problem.) The keel-cooler is made from a quality cupro-nickel tubing and a bronze thru-hull and shows no sign of corrosion.

This system replaced a pumped sea-water cooled system. I would avoid the pumped systems - there are just too many things that can, and do, go wrong on them, although I admit that the one I had was just designed horribly wrong.

Greg

[SV THIRD DAY]

Originally Posted by Terra Nova

Where do you think all that heat goes?

but the heat from an air cooled unit isn't going to raise the temp of your boat cabin 1.0 deg F....so it's pretty much a talking point internet myth on a BTU basis.

[Typhoon]

A human body gives off approximately 330 BTUs , these little Danfoss compressors are only able to remove approximately 200 BTUs an hour at -10f

So temperature rise in a cabin will never be an issue.

"Its just as internet myth"

Regards John

[SV THIRD DAY]

Originally Posted by ColdEh Marine

A human body gives off approximately 330 BTUs , these little Danfoss compressors are only able to remove approximately 200 BTUs an hour at -10f

So temperature rise in a cabin will never be an issue.

"Its just as internet myth"

Regards John

Yep...almost as big as the myth about a water condenser being more efficient as an air condenser. All we can do is continue to educate John, and take the arrows with a smile. It is nice that ColdEh is on the market because it was easy to write off CoolBlue and me as a snake oil salesman ...at least now they have to call us both names when we show the value of air cooling and a TXV.

[SV THIRD DAY]

Originally Posted by Anna Sail

John, I'm disappointed to hear you join the small group of technicians/sales people dissing the Keel-Cooler, usually from lack of understanding or the wish to sell their product instead.

It's a fact: water is a better heat-exchanger than air. Keel Coolers (a generic term) have been used for decades on the large commerical fishing boats, for example. Eliminates the need for a pump and the extra power needed to run it. Frigoboat simply makes that technology available on a much smaller scale for the ice boxes found on pleasure boats, over 40,000 of them world-wide. That's a rather large number of happy/repeat customers for a product you call "troublesome".

I have been called a member of the Vast Right Wing Conspiracy, but now as a member of the "small group of con-artists" that advises against water cooling, I've found that the folks that use the "water is a better heat-exchanger than air" comment usually comes from a lack of technical understanding. There is a false assumption that the same size condenser is used in a water vs air based system, but that's a red herring argument.

A condensing unit is designed to remove the necessary heat given the medium of operation. So a properly sized and designed air and water condensing unit will have NO difference in heat dissipation characteristics. So with that technical misunderstanding out of the way, you are then left with what medium (air or water) would you rather deal with. Would you rather deal with the corrosive nature of sea water, zincs, bottom cleaning, and an additional hole in your boat VS air cooling with the fan noise, job of de-dusting the condenser and heat generated being discharged into the cabin. How much heat...about the same as a 50W lightbulb.

Richard Kollerman has long argued that water cooling on the BD35/50 sized compressors is a mistake and he is not a evil con-artist salesmen. He has books published on the subject as well as a long respectful history in the marine refrigeration business.

What people confuse is a properly designed for the Tropics air condensing unit on a system using a TXV vs one for a Capillary Tube. This technical discussion is everywhere out there on the net, so in summary TXV systems can have a MUCH larger and more efficient condensing unit and operate without efficiency loss up to 120-134-degs F ambient temp. However air condensing units on Crapillary tube systems start losing efficiency at 90-degs. Why...again it's due to the design of the overall system.

From a Maintenance standpoint, I don't understand why someone would want zincs, bottom cleanings and having no refrigeration when on the hard for a water cooled system when they can have an air cooled system for the same and oftentimes (in the Case of ColdEh and CoolBlue) more energy efficiency system.

Technautics hasn't been making Air Cooled systems since 1968 and not scamming customers...there's a reason Technautics has been around for coming up on 50yrs.

[Typhoon]

Originally Posted by SV THIRD DAY

Yep...almost as big as the myth about a water condenser being more efficient as an air condenser. All we can do is continue to educate John, and take the arrows with a smile. It is nice that ColdEh is on the market because it was easy to write off CoolBlue and me as a snake oil salesman ...at least now they have to call us both names when we show the value of air cooling and a TXV.

Yeah , Rich , these things just don"t work . Maybe we should try water cooling .
Never !

Sometimes I don't have the time...... , I remember you warning me about this . Now there are two of us to deal with , snake oil is taking off.

Funny how our test results are the same , you on one coast and me on the other . I understand it is really hard to educate everyone over the forums , one reason I do so much testing , so they can see for themselves.

We can only hope people do there own research and make an educated decision. These systems are a lot of work to install.

And yes I keep ducking the arrows

Regards John.