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Old 07-04-2012, 12:30   #31
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Re: Fridge reduce amps consuption

At African Cats we use the SP system from Indelmarine
The SP system uses a hull outlet that has the gassed intercooler wound around and a ASU ( auto start unit ) for energy ( cold ) storage
The hull outlet uses the same principle as the unit from Frigo but no extra hole in the boat and not so easy to damage. ( it does not hang on the outside of the hull )
Advantages are:
better cooling
less energy consumption ( no added fan )
Less heat in the boat
No fan noise
easy to replace anode on the outside

We have used these units since 2004 with out problems.
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Old 07-04-2012, 12:43   #32
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Re: Fridge reduce amps consuption

Richard, am I misreading you or are you saying:
1-Some Danfoss designs have some type of defect causing problems by putting current into the metal parts (condensors) that should not be electrically active

2-Some retrofitted keelcoolers create a problem in some installations because they make the refrigerant TOO COLD to function properly in a system.

Or did I misread you?
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Old 07-04-2012, 13:02   #33
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Re: Fridge reduce amps consuption

Richard! you crack me up. could we have that in English please. No, I'm only kidding. I have read your work and I know you are a guru in this field.
Seriously though could you explain that in words of few syllable so that people of normal intelligence can understand you better. Something along the lines of "In order for the liquid to arrive at the place where it can boil into a gas and remove heat by evaporation, it needs to arrive at a pressure and volume that does this efficiently. If it arrives too cold, it will not have enough pressure (for the two are inter-depentent) aka 'energy' to want to evaporate fast and furiously" etc....
I take it you are talking about overcondensing?
Just as an aside, I bought a domestic upright refrigerator, with a compressor sized as close as possible to a BD35f that I had lying around. I fitted the BD35 on R134a into the fridge, and installed a AKO programmable thermostat. Its consuming 30 Ah per day ave. on 24v.
Insulation is pretty good but could be better.

PS. Mr Kollman really does know his stuff in case you have never heard of him. He ALSO is not shy to impart his vast knowledge.
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Old 07-04-2012, 17:34   #34
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Re: Fridge reduce amps consuption

sy_gilana, You are correct process heat is produced as compressor increases gas refrigerant pressure, heat is then removed by transferring it into condenser’s counter flow cooling medium air or water. If too much heat is removed by condenser refrigerant reaching refrigerant expansion device will not have completed its phase change to liquid. Boat’s interior air temperature is more likely 24 hours a day to produce a more efficient high liquid pressure than exterior seawater unless seawater temperature and condenser design are capable of supporting correct refrigerant pressures high and low.

hellosailor , Compressor manufacturers like Danfoss do not have design defects causing metal loss do to electrical corrosion as most of these compressors are designed for air cooled condensers. It’s the system designers that assemble these ice box conversion water cooled units not compressor companies. Yes under the right conditions failures do occur in any seawater cooled system.

Keel coolers and standard condensers do not generally create a performance problem it is the wide variations in seawater temperature that create inefficient energy use on small fractional horse power Danfoss BD compressors. All package pre charged mobile cap tube refrigeration systems are serviced with refrigerant anticipating condenser cooling mediums near standard day temperatures.

fastcat435, There are reports that performance is poor when SP through hull condensers that are not cleaned frequently. And it is recommended that they not be installed on sink drain. One owner recommends installation on cockpit drain so a long handle bottle brush can be used to clean then without getting wet.

s/v Jedi , One BD50 air-cooled condensing unit in a boat will produce about the same amount of heat in boats cabin per hour as a single normal size adult. If you take the amp-hrs refrigerator draws per day convert it to watts then watts to Btu you will have heat added to a closed up boat per day. The engineering standard for calculating heat produce per person in a building is 300 Btu per person per hour.

Cheechako , It is true that eliminating a condenser fan will reduce 3 to 6 amp-hrs energy usage per day. Problem is what about the supplemental fan cooling needed to extend life of compressor and its electronics?

Unfortunately my web forum is down because of server problems I suggest when it is up and running do a word search and form your own opinions of the facts you are looking for. Other than a couple of job shops that sell these systems you will not find service bulletins or typical upgrade repairs. Only these people know the true problems with their systems. You may believe your unit is repairable but to many manufactures its an expendable so they will say replace it.

If your engine drive system was a problem it was a poor installation or bad design. The engine drive refrigeration in my sailboat performed 1000s of hours for 25 years with only one break down when bracket holding condenser broke in a storm crossing the steam.

Refrigerant line connecters that depend on O rings as a final seal are a poor choice. The Aeroquip’s old final metal torque seals were easy to connect together without loss of refrigerant producing a lifetime seal. Problem with new self piercing disc is disc that is intended not to break until intermediate O ring is in-gauged fully, fractures too soon causing loss of refrigerant.
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Old 07-04-2012, 20:09   #35
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Re: Fridge reduce amps consuption

RIchard-
"Refrigerant line connecters that depend on O rings as a final seal are a poor choice."
Interesting choice of perspective, as the entire automotive A/C industry relies on o-rings, AFAIK. Every maker, every installation, for many years. Perhaps a metal-to-metal conformal seal is better, but "poor" ??
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Old 07-04-2012, 20:50   #36
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Quote:
Originally Posted by Richard Kollmann
One BD50 air-cooled condensing unit in a boat will produce about the same amount of heat in boats cabin per hour as a single normal size adult. If you take the amp-hrs refrigerator draws per day convert it to watts then watts to Btu you will have heat added to a closed up boat per day. The engineering standard for calculating heat produce per person in a building is 300 Btu per person per hour.
Exactly. You sound sarcastic so I recon you have not experienced the difference of extra crew aboard in the tropics. You should, even one person makes it significantly hotter aboard, let alone two or three.

About differing water temperatures reducing the efficiency of water cooled systems; that is why we have to adjust the charge when going into a different climate, but you have the exact same effect with air cooled. In fact, here in the tropics, the air and sea temperature are exactly the same and equal year round.

About O-rings in quick couplings: they leak. After 5 years you have lost a noticable part of the refrigerant charge and the rings are hardened and deformed. I was temped to cut them out and solder but had spare O-rings and replacing them went smooth so I let it go.

cheers,
Nick.
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Old 07-04-2012, 20:53   #37
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Re: Fridge reduce amps consuption

Quote:
Originally Posted by fastcat435 View Post
At African Cats we use the SP system from Indelmarine
The SP system uses a hull outlet that has the gassed intercooler wound around and a ASU ( auto start unit ) for energy ( cold ) storage
The hull outlet uses the same principle as the unit from Frigo but no extra hole in the boat and not so easy to damage. ( it does not hang on the outside of the hull )
Advantages are:
better cooling
less energy consumption ( no added fan )
Less heat in the boat
No fan noise
easy to replace anode on the outside

We have used these units since 2004 with out problems.
20 odd years i did not hear the word Freon in Europe, now it seems to be part of a discussion?????

I hardly call this "hang on the outside of the hull" and yes it has 2 replaceable anodes. (look at the pic.)

And NO i am NOT a GURU, just a simple dutch naval engineer with 25+ years experience.
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Old 07-04-2012, 21:24   #38
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Re: Fridge reduce amps consuption

Let me guess, you all saw the keel coolers at a boat show and they looked super cool and the rep said they worked great.........

I cruised 2 different boats in the tropics for 6 years both with air cooled units. I don't think they make the boat any hotter down below. I suppose if you have 3 units and 60 cubic feet being cooled maybe. I had a 2.5 cu ft freezer and 5 cu ft refer on the first boat with 2 separate air cooled compressors. On the second (larger boat) I built a smaller box with about a 1.5 cu ft freezer and 3.5 cu ft refer. Was really plenty and a lot of countries are introducing new quarantine laws so you don't need to have that big a freezer and can buy USA frozen chicken in the Marquesas for less than it costs in Key West.

Anyway, the best advice is a small box, well insulated and air cooled. I had a NovaKool unit in the freezer and adler barbour refer on the first boat and had Nova Kool make a custom unit for me for the second boat so I had one refer plate and 2 freezer plates all in series running on a BD 35. Was very happy with that unit. Did get a bit much condensation on the refer plate, but no big deal. Could perhaps have tweaked the charge a bit to eliminate but didn't bother. Biggest problem with either units was the mechanical thermostats.

Will like go with Nova Kool again for boat #3 when the time comes in a similar box design. They were very good about getting me what I asked for 4 years ago, but I had to accept responsibility if it didn't work.

BTW: Used to live in Richards neighborhood and he helped me with both boat #1 and #2. Glad to see his health is holding up.
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Old 08-04-2012, 11:53   #39
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Re: Fridge reduce amps consuption

"About O-rings in quick couplings: they leak."
Must be something that one industry does differently from the other. O-rings should deform, acutally they should conform to make the seal. Hardening just indicates someone cheaped out on the proper material, or the system was not in regular use. Even in the AC systems the o-rings will dry out if the system is not run monthly, to lubricate the o-rings with the oil that is part of the gas charge.

Memo, use automotive parts for next fridge?

Matter of fact, home a/c systems rely on o-rings as well. Usualkly the maintenance fill valve was a Schraeder valve (new types similar) which relies on an o-ring seal and seat, one in the valve, the other under the cap which serves to limit losses through the valve.

Must be something different about boats.
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Old 08-04-2012, 16:55   #40
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Re: Fridge reduce amps consuption

Quote:
Originally Posted by hellosailor View Post
"About O-rings in quick couplings: they leak."
Must be something that one industry does differently from the other. O-rings should deform, acutally they should conform to make the seal. Hardening just indicates someone cheaped out on the proper material, or the system was not in regular use. Even in the AC systems the o-rings will dry out if the system is not run monthly, to lubricate the o-rings with the oil that is part of the gas charge.

Memo, use automotive parts for next fridge?

Matter of fact, home a/c systems rely on o-rings as well. Usualkly the maintenance fill valve was a Schraeder valve (new types similar) which relies on an o-ring seal and seat, one in the valve, the other under the cap which serves to limit losses through the valve.

Must be something different about boats.
Well, the Schraeder valves also leak. I used to have a compressor with those on both high and low sides and they had caps screwed over them to hermetically seal them. The high side one would pop if taken off. Glad I got rid of that old system (Glacier Bay '93 stuff).

The system with leaking O-rings I described has run continuously... 365 days a year. Cheap O-rings? possibly... takes a lifetime to test...

ciao!
Nick.
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Old 08-04-2012, 18:20   #41
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Re: Fridge reduce amps consuption

When I recently installed my Vitrifrigo system, it specified the Schrader valve cap on the compressor low pressure side be left installed to prevent (eventual) leakage.
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Old 02-09-2012, 10:11   #42
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Re: Fridge reduce amps consuption

I have the frigoboat unit installed in a 6 CUFT iceboat and the units seems to run fine with the keel cooler. The unit runs so quite I can hardly hear it at high speed. Power consumption is cut almost in half from using the old alder barbour cold machine. Hauled boat after 6 weeks in the water and growth on the external cooler had started to show up with small barnacles and algae. I did do a light spray coat of transducer paint to see if it will slow the growth of the sea monster. Going south this winter and will see how it does in warmer waters but a friend has same unit and has been south 6 times with no problems. Good unit, but slightly costly.
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Old 02-09-2012, 10:23   #43
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Re: Fridge reduce amps consuption

Quote:
Originally Posted by rfarley View Post
I have the frigoboat unit installed in a 6 CUFT iceboat and the units seems to run fine with the keel cooler. The unit runs so quite I can hardly hear it at high speed. Power consumption is cut almost in half from using the old alder barbour cold machine. Hauled boat after 6 weeks in the water and growth on the external cooler had started to show up with small barnacles and algae. I did do a light spray coat of transducer paint to see if it will slow the growth of the sea monster. Going south this winter and will see how it does in warmer waters but a friend has same unit and has been south 6 times with no problems. Good unit, but slightly costly.
Yep, same experience my friends had on a South Pacific circuit. Trouble free, quiet, small and reduced consumption........
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