Seawater air conditioning

[StuM]

Originally Posted by BriaF

Stum if you paid attention to the original post you would see
That he is talking about feeding warm sea water through
Something like a radiator then blowing air through it to
Cool the boat.
He was not talking about sea water cooled aircon
Yes sea water cooling would be more effective than air
But with that come fouling of internal sea water passages
My original post stands as FACT
Unless you can provide reasoned debate .
But what I said is what I have personally observed
& experienced
So please mind your manners

No, look at the image he posted. "condenser coil". While he didn't explain himself well he was clearly talking about aircon. Just as you were in your posting, which I still say is nonsense. Your "fact" that water cooled aircon won't work in those conditions is clearly negated by the fact that I am using it successfully in the same conditions

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[hellosailor]

All pointless speculation unless you add a few factors that have not been mentioned here. In the Florida Keys you can go down 30' and still not hit a thermocline, so that water is at 85-88F exactly like it is on the surface.


Go to the NE US and you hit that thermocline at 10-20' and the water usually is 10-20F colder than the surface.


Now, is you hull deep enough so that your intake is sucking in COLD water from below a thermocline? Or are you using a drop hose to suck from below the thermocline?


And even if you conjure it up and get it right, really? Seawater cooling systems with pumps and intake strainers and filters and cooling pipes to clean out as the critters grow in them? Oh, what, you don't have little crusty things growing in your waters, because they are so toxic? (Ain't always a bad thing.)


Yeah the little things don't make any difference at all. Swamp coolers have been around for a long time and like anything else, they only work in the right places when they're correctly engineered. Won't find 'em in the movie theatres in Dallas though, will you?

[Ironman162]

Apologies for creating the confusion Gentlemen. If I knew all about the system there would be no point in asking opinions here.
I saw the diagram in my first post an it looked like good idea so started the discusdion eith my uneducated interpretation of it.
So that's my excuse I was hoping to learn more about it from someone who has had some exposure to it but instead it turned into a heated argument as do often happens here.
It appears to me that people on here are strong willed and very able hence ybe heated discussion!
Its all good pne dont have to read evetything do one...

Thank you to those who share their experience!

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[StuM]

The thread topic is Seawater air conditioning, not swamp/evaporative coolers. And to repeat, you don't need "cold" water for that to work. It just needs to be a bit cooler than the hot side of the heat exchanger. I find that occassionally cleaning a strainer is a small price to pay for the comfort and convenience of effecient air conditioning in warm tropical waters - which is exactly where I use it successfuĺly regardless of the unfounded claims that it can"t work by those who have obviously never tried it.
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[StuM]

Originally Posted by Hudson Force

Confusion was introduced in the original post when the question was posed about blowing air over simple coils of seawater for cooling; however, the diagram shown in the first post included .

He said seawater "pumped through a radiator of sorts". That also loosely describes the seawater [Bold]aircon [/Bold]which is the. thread title.

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[Reefmagnet]

The old eutectic refrigeration (since ripped out) in my boat had a seawater cooled heat exchanger as I'm sure most do. The exchanger was about the size of a water filter. I would have thought a marine specific air con would employ water cooled coils.

[J Clark H356]

What does work and provides both heating and cooling is a water to air heat pump. That is what I have. It uses seawater instead of air and does a great job. Look at MarineAire units. My Hunter 356 has a single 16,000 BTUH unit. There is no real problem with critters growing in the system. A simple strainer on the thru-hull works fine.


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[Ironman162]

This is what makes discussion so interesting...if we all agreed on everything it would be so boring snd nothing will come of it!

Please don't take what I said in the original posting as gospel I know very little about the subject hence the discusdion. It looked like a radiator of sorts to me with my limited understanding.
All I know is that the seawater is pumped through a system of pipes and back out again as shown on the diagram.

There is overwhelming evidence that it does work well in Australia and elsewhere but might be climate specific of that Im not sure.

I do have an evaporative cooler (convair mastercool) that works very well if the humidity is below 50 and it often is on very hot days (30+)

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[Ironman162]

Thanks J Clark H356 the MarineAire unit sounds terrific! I will certainly follow up on that option.
You just can't beat style and dedicated marine equipment if only the price tag wont break the bank! But certainly sounds just perfect and will he nice if it could be retro fitted.

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[Ironman162]

Couldn't help smiming when I saw this one!
Now this is NOT what I had in mind Gentlemen but thought we could do with a bit of a smile by now!

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[Ironman162]

Wow just think about it...aircon for a couple of bucks mate! ..geez if the critters crawl in we replace the pipe and sell the scrap copper for beer money! A bit of Ozzie humour bear with us...lol!!

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[darylat8750]

From the original post I assumed that there would be no compressor involved. My father had a small shop in a small town and had to control his expenses very carefully. He was also a guy who could build most anything he needed. He was uncomfortable in the hot humid summer so he got a radiator out of a truck in the local junk yard, mounted it in a wooden frame with a fan behind it and ran a very slow trickle of water from the sink through it. He bent up a metal pan to catch the considerable condensation that was emptied a couple of times a day. The runoff went down the sink drain and his monthly water bill was for a minimum amount that he never exceeded. The system worked well. When I read the OPs first post this is what I envisioned. Dad's water came from a well and while I don't know the temp. it was cold enough that you wouldn't want to try swimming in it. I don't think the temperature delta between the sea water temp. and air temp. would be enough to be very effective.

I have two 12000btu mini splits from a Mexican big box store on my trawler. The compressors are mounted under the cowl of the fly bridge with custom made SS vent grills. The condensers are mounted one in the Salon and one in our sleeping cabin. Draining the condensate was the trickiest part. Been working fine for 5 years. With 30AMP shore power or 5kw genset i have to be aware of total electrical load but it is manageable. Newer units are available that are more efficient than mine and I wouldn't hesitate to do this again.

[Ironman162]

Just Love your fathers ingenious idea with the radiator! Great post many thanks!
It moves me to drop a thermometer into the Parramatta river to collect actual temperatures as Im convinced it could work.
Im not really keen on running the generator as I enjoy the piece quiet and have substantial dc available. Certainly enough to run a raw seawater pump. So will try to keep it simple economical and effective...a bit like your father did.
It was a time when they had to be inventive, had little money and worked very hard.


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[Hudson Force]

Whoa! 'my mistake back earlier. I remembered the diagram labeled "compressor", but it was "condenser coil". Regardless, it's good to see less conflict in the thread.

I always understood that the flow of air over cold coils to work very well. The problem is how to make the contents of the coils cold. As some have said, a source of cold water can make it done easy and cheaply, but in most places you can only obtain a sufficiently cold fluid in the coils if you compress it and then allow it to cool at evaporation. Of course, this is the expensive equipment of marine air conditioning systems.

We can only run our air conditioning at the dock or while using our diesel generator. My favorite cooling is anchored with the bow facing a breeze and air flowing in the forward hatch while I'm laying in the V-berth. Funny to realize that that's about the same system. Your heart is pumping the fluid through all your blood vessel tubes and the heat exchange is occurring at your skin. Old engineering developed long ago!

[Ironman162]

So very true!
The body is a marvelous machine! Self repairing too!!
Thanks for a very positive contribution I will measure the water temp at various depths and post the results.
Funny but I too like the V berth window open on a swing mooring. Always a nice cool sea breeze is still the best!

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