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Old 15-09-2008, 07:07   #31
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Using an ASU as well as Eutectic holding plates can further lower your power consumption.
Excerpt from the catalogue:

Isotherm ASU systems are designed for installations in existing cool boxes and mainly for use in sailing yachts where battery power is at a premium. The ASU system dramatically reduces power consumption while supplying refrigeration in abundance. It senses when surplus power is available from the enginealternator and speeds up the compressor to rapidly freeze the holding plate. When surplus power is no longer available it reduces its energy-use accordingly. The stainless-steel holding plate can be fitted
at any suitable angel high up in the box.....

I have a unit with the ASU and it has reduced the battery drain. By running the compressor at a slower speed, the efficiency improves and it is even quieter.


Keel cooling or via a heat exchanger is a question of what you prefer, the heat exchanger needs a pump to pump the water around, so slightly more energy consimption. Keel cooler needs 2 more holes in the hull, pipe with refrigerant running in the boat with possible puncture risk... refrigerant gets heated up again on the way back from the keel etc..

Take your pick, both will help save power.

Top opening boxes only is another major power saver, as cold air "falls out" of the side opening versions. Also side opening will mean more defrosting will be necessary as you exchange more of the air in the box every time you open the door.

Alan


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Old 15-09-2008, 11:33   #32
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Alan, a proper keel cooler only requires a single hole in the hull, into which the sintered bronze fitting is secured. The boat will already have pipes running to and from the compresssor, and if the item is located optimally, the additional pipes to the keel cooler are not that big a deal.

The question of ASU and holding plates, rather than a condenser really depends primarily on how you maintain the charge in your 12v system. If the charge is obtained through running the engine for a period each day, then the holding plate is an obvious way forward, and the ASU obviously adds to this system. If you maintain your charge via solar/wind, then you are much better off using the condenser, whoes power consumption is better aligned to the longer charge times of the solar/wind systems. This is also dependent on having sufficient solar/wind to not need an engine charge!
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Old 15-09-2008, 12:20   #33
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Talbot,

For me a keel cooler is a pipe led outside the hull and around, or back and forth along the keel. This works as the condenser.

The item you are talking about is probably the SP unit which functions as a condenser as well as the overboard drain from the wash basin. If not please correct me.

The holding plate is built into the evaporator module. I beg to differ regarding the use of the ASU. Even when relying solely on solar/wind for power, if you have plenty of power during the day, the smart solar controller will have the battery voltage over 13.2 V,(as they have discharged during the night) the ASU will see this and speed up the compressor. When the holding plate is pulled down in temperature, the compressor will drop back to a normal duty cycle and the slower speed. In the meantime your solar panels have hopefully managed to charge the batteries enough to go to the float stage.

This will minimise battery drain during the night.
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Old 16-09-2008, 10:56   #34
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Keel cooler is a sintered bronze fitting that acts as a heat sink for the refridgerant, and transfers the heat to the water.. A picture tells a thousand words so:



I understand your arguments about the holding plate, but do not think that the decision between the two systems is as simple as good/bad. I believe in certain charging regimes, that the evaporator does also have utility. It really depends on how much power you are using versus how much you are creating.
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Old 17-09-2008, 12:48   #35
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Thanks Talbot,

I hadn't seen one of those before. I tried to get a picture of the Isotherm one, but couldn't get it out of their catalogue...


Still prefer minimising the number of through hulls though.

Cheers

Alan
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Old 17-09-2008, 13:11   #36
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IMHO with sikaflex sticking it into position, and a good reinforced fixing inside, I dont reallyy think it qualifies as a ThruHull. After all a ThrHull is designed to let water through, and is sealed with a valve. This is designed merely to pass through the hull, and not let water in. Biggest problem I can foresee, is that you are not supposed to antifoul it, and it needs anodes. However, you can include it as a part of the counterpoise for a SSB.

People I know who have used them are very enthusiastic. The clipping is actually a section from PBO where the author is setting up a fridge to run from a solar panel - and he is one of the experts from penguin marine refridgeration, so you would hope that he would know!
Marine Refrigeration - Vitrifrigo, Frigoboat - boat fridge
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Old 19-11-2011, 08:42   #37
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Re: Build a new cat with me?

Agility just pulled into the dock next to us in Panama. Nice boat!

Mark
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Old 19-11-2011, 10:01   #38
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Re: Build a new cat with me?

Cool...so nice to see these builds successful.
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Old 19-11-2011, 13:04   #39
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Re: Build a new cat with me?

Reach,

Are you in Shelter Bay? Agility was here in Las Brisas a couple of days ago. I stopped by to say hi to the skipper, and crew. Yes, it is a lovely looking vessel. They hit 22+ knots at one time on their journey too!......i2f
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Old 19-11-2011, 13:05   #40
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Re: Build a new cat with me?

Yes, we are in Shelter Bay.

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Old 20-11-2011, 08:05   #41
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Re: Build a new cat with me?

Quote:
Originally Posted by imagine2frolic View Post
Reach,

Are you in Shelter Bay? Agility was here in Las Brisas a couple of days ago. I stopped by to say hi to the skipper, and crew. Yes, it is a lovely looking vessel. They hit 22+ knots at one time on their journey too!......i2f
I asked the delivery captain to take it easy. Apparently he didn't.

Kind of a neat picture of Agility going through the locks from the Canal webcam.
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Old 24-11-2011, 09:38   #42
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Re: Build a New Cat with Me ?

22 knots could be easy. I have reached over 18 knots with Imagine. She was smooth, and stable. It was the conditions that made it so perfect. WELL, she's safe, and waiting for you now. BEST WISHES in enjoying the area.......i2f
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Old 24-11-2011, 10:10   #43
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Re: Build a New Cat with Me ?

On thing we haven't solved yet is that the saildrive rubber fairing get's separated from the hull when running that fast. I'm really looking forward to the San Blas Islands.

Happy Holidays
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Old 24-11-2011, 11:56   #44
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Re: Build a New Cat with Me ?

Good luck on your ambitious undertaking. I, for one, absolutely love the Atlantic 57 and am sure it will be worth the effort.

Brad
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Old 26-11-2011, 08:08   #45
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Re: Build a New Cat with Me ?

I got rid of the rubber fairing, and installed fiber ones. I tried everything to seal them for years, and finally gave up.......i2f
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