I'm an A/C convert

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Jimmyt
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Re: I'm an A/C convert

Post by Jimmyt » Tue Jul 03, 2018 2:55 pm

Option 3: You could put in a true marine ac or heat pump unit. A Salt Weapon did one - maybe mounted under the V-birth. Not a mod for the faint of heart (or light of pocket), but a sweet result when done. It does require thru hulls.

http://www.macgregorsailors.com/modt/in ... ?view=2016

https://www.marinaire.com/Marine-air-co ... gLFBvD_BwE

There used to be thru hatch air-cooled units available. Used ones around, but didn't see any new ones after a quick look.

https://www.ebay.com/itm/Carry-on-Porta ... 0011.m1850

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eodjedi
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Re: I'm an A/C convert

Post by eodjedi » Thu Jul 05, 2018 10:22 am

Well I installed a Marine A/C unit in mine, 5000 btu's. This past weekend was the first time I ran it continuously for two days as the weather was unbearable. It worked great and we all slept comfortably. I power mine with a WEN 2000 gen I picked up on Amazon.com . Please see attached photos.

Image
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Last edited by eodjedi on Thu Jul 05, 2018 10:24 am, edited 1 time in total.

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eodjedi
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Re: I'm an A/C convert

Post by eodjedi » Thu Jul 05, 2018 10:23 am

Image

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Jimmyt
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Re: I'm an A/C convert

Post by Jimmyt » Thu Jul 05, 2018 1:50 pm

You did a nice job - looks like it came that way. Thanks for sharing the pics!

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eodjedi
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Re: I'm an A/C convert

Post by eodjedi » Thu Jul 05, 2018 2:13 pm

I need to put up some pictures of the plumbing. As of now, I have the discharge through hull exiting out the stern. I want to move it to the bow near the anchor locker discharge. I also use Marvair CR330 Condensation Removal Kit for the condensation. Works great and plumbs right into the discharge line.

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1st Sail
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Re: I'm an A/C convert

Post by 1st Sail » Fri Jul 06, 2018 10:59 pm

I'm still considering my options:
Least cost:
window AC small 100+
Minimal install, easily adapted to companion way
Cabin access requires long first step
dual purpose when traveling, runs on land or water

Moderate cost:
Portable upright dual hose AC
$349 https://www.amazon.com/s/ref=nb_sb_noss ... al+hose+ac
less than marine air. more than window/ dual hose, http://www.climax-air.com/documents/Cli ... cSheet.pdf, variable speed DC motor, claims to be significantly more efficient power use.
Minimal/moderate install, mounts behind ladder, route dual hose around latter to 5-6" companionway slat board
Cabin access easier than Window AC
Available in 8K+ btu
dual purpose when traveling, runs on land or water

Most cost:
Most cost, more efficient with water cooled evaporator
Ducted ventilation
Complex install
May not be used on the hard

vizwhiz
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Re: I'm an A/C convert

Post by vizwhiz » Sat Jul 07, 2018 10:42 am

How cool is the water where you overnight? This is an example of the product i was describing...
http://www.cabincooler.eu
I would venture that someone who is handy could make something functionally similar at low cost from “recycled” parts. I have an idea of how to do it, but I couldn’t use one in my sailing grounds. The water’s too hot. But a place like Lake Powell or up north where the ocean stays very cold...

I bet it’s way cheaper than marine a/c, maybe more than a window unit...

DaveC426913
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Re: I'm an A/C convert

Post by DaveC426913 » Sat Jul 07, 2018 10:38 pm

vizwhiz wrote:How cool is the water where you overnight? This is an example of the product i was describing...
http://www.cabincooler.eu
I would venture that someone who is handy could make something functionally similar at low cost from “recycled” parts. I have an idea of how to do it, but I couldn’t use one in my sailing grounds. The water’s too hot. But a place like Lake Powell or up north where the ocean stays very cold...

I bet it’s way cheaper than marine a/c, maybe more than a window unit...
I ... can't believe no one's thought of this before.

Here in L. Ontario, I'm surrounded by 400 cubic miles of icy cold water!

Why lug an entire A/C around, when all I need is a heat exchanger?

kurz
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Re: I'm an A/C convert

Post by kurz » Mon Jul 09, 2018 1:10 am

great idea.

I also was thinking about at jus pump the cold water und rins it on the cabin top...

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Jimmyt
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Re: I'm an A/C convert

Post by Jimmyt » Mon Jul 09, 2018 7:43 am

Kurz has an interesting concept, which might be even better than the cabin cooler. If I understand correctly, he is suggesting sprayed roof cooling for a boat. This would address the daytime solar radiant heat load effectively. Of course, spraying seawater over your decks might bring a few issues, but it's a cool idea. Basically, stop the heat from getting into the boat in the first place... and provide radiant interior cooling through the cooler outside surfaces. Neat idea that might be easier to try than to analyze.

I can't find any performance data for the cabin cooler. The only video I found on YouTube was not very informative - not even a single temperature measurement.

I've done chilled water cooling design on numerous buildings, and find the basic concept of the unit to be sound. There are conditions, and equipment selections which could work well using this concept. Performance will be determined by the ambient conditions, desired cabin temperature, water temperature, fan air flow rate, coil characteristics, water flow rate, and in this case, the under water heat exchanger.

In the south US, we typically use a chilled water temp of 45 deg F - primarily to create an indoor dew point condition around 55-60 deg F. We are looking to dehumidify significantly while cooling to produce comfort. If your ambient dew point is already about 55-60 deg F, dehumidification is not really essential, so you could get away with warmer water. Looks like the water temp at Vancouver is around 53-54 deg F in July. If you were using direct sea water, you could expect a leaving air temp in the 65 deg range without getting a really deep coil with a lot of heat transfer surface. At an air approach temp of 10 deg F, you could probably maintain a cabin temp around 75 deg F in a dry climate with a good coil and 150-200 cfm air flow (wag numbers), as long as ambient conditions weren't too harsh.

The cabin cooler appears to use a closed loop concept with an underwater heat exchanger. So, we have two separate heat exchanges for the water and two approach temperatures to deal with. You can't move heat without a temperature difference. So to push heat from the cooler heat exchanger to the loop water, there will be an approach temperature, and from the loop water to sea water there will be another. Now, our 65 deg F leaving air is looking more like 70-75 (in the absence of actual performance data). Plus, I've got a closed loop system to fill and air-bleed to get working properly; and re-bleed until the majority of dissolved air is removed from the water loop. We can still cool the cabin with these air temps if we have a large enough fan and coil for the conditions.

The way the video shows the unit being used, is blowing directly on the occupant who is lying in front of the air discharge. If the cabin is 90-95, or even 85, and you're lying in a 75 deg air stream, it's an improvement. If you expect to cool your entire cabin down to 75 deg, you probably need to ask for performance data before buying. The only price I saw referenced on the net was around $450. For that money, I'd want more to go on than just pictures of the equipment. That's getting up in the range of equipment with rated performance data - granted modifications will be necessary to adapt for 12volt use.

Now, if you can get cooler water, say 45 deg F, you get into a situation where the unit is likely to produce condensate. So, you're lying in bed with something that's wetting the sheets like weird Uncle Joe after a hard night drinking.

Being from the Deep South where our water temp is well into the 80's now, I have to wonder if night cooling is a necessity when you're sitting in a large body of 54 deg F water. I get it for daytime, when the temp might spike up due to solar radiation, but in the dark, everything below the waterline, including the ballast tank will be approaching 54 deg in a reasonably short time - producing significant radiant cabin cooling. I guess I'm wondering if this unit is really necessary, for other than mid-day naps, in the regions where it will actually work.

https://m.youtube.com/watch?v=vKs9h_-7sVo

kevinnem
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Re: I'm an A/C convert

Post by kevinnem » Mon Jul 09, 2018 4:35 pm

1st Sail wrote:I'm still considering my options:


Moderate cost:
Portable upright dual hose AC
$349 https://www.amazon.com/s/ref=nb_sb_noss ... al+hose+ac
less than marine air. more than window/ dual hose, http://www.climax-air.com/documents/Cli ... cSheet.pdf, variable speed DC motor, claims to be significantly more efficient power use.
Minimal/moderate install, mounts behind ladder, route dual hose around latter to 5-6" companionway slat board
Cabin access easier than Window AC
Available in 8K+ btu
dual purpose when traveling, runs on land or water

I am thinking this is the way to go ... dual hose would be best, if you can find it, but most units are single hose. I think I know the best place to put it - it it on starboard side - rear berth so it "shoots" in to the main area. (on a 26 X this would be the hole right behind the bathroom) on top of the rear berth. This way, the exhast hose can go about 2 feet, and then tap in to the "locker" under the seats , and it would vent out were your feet are if your above deck.

Did I explain that very well?

Kevin.

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Re: I'm an A/C convert

Post by kevinnem » Mon Jul 09, 2018 4:40 pm

DaveC426913 wrote:
vizwhiz wrote:How cool is the water where you overnight? This is an example of the product i was describing...
http://www.cabincooler.eu
I would venture that someone who is handy could make something functionally similar at low cost from “recycled” parts. I have an idea of how to do it, but I couldn’t use one in my sailing grounds. The water’s too hot. But a place like Lake Powell or up north where the ocean stays very cold...

I bet it’s way cheaper than marine a/c, maybe more than a window unit...
I ... can't believe no one's thought of this before.

Here in L. Ontario, I'm surrounded by 400 cubic miles of icy cold water!

Why lug an entire A/C around, when all I need is a heat exchanger?
FYI I have done the calcs on something like this bot for cooling air, .. and also to increase the efficiency of thermo couple refrigerators -- you need a shockingly little amount of water too cool of the air. I was thinking the best system would have a reservoir, . even 1 gallon would be alot ... and once that reservoir reached a certain temp, . it would flush it with fresh cool water, that way the pump would only cycle every now and again.

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Jimmyt
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Re: I'm an A/C convert

Post by Jimmyt » Mon Jul 09, 2018 5:14 pm

Yep, about 1.2 gallons per minute at a 10 degree temperature rise will give you 6,000 btu/hr of cooling; roughly equal to the Home Depot window unit in a Billy Box. Of course, the temperatures and flow rates are subject to equipment availability and those pesky laws of thermo, heat transfer, etc.

DaveC426913
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Re: I'm an A/C convert

Post by DaveC426913 » Tue Jul 10, 2018 11:55 am

Jimmyt wrote: The cabin cooler appears to use a closed loop concept with an underwater heat exchanger. So, we have two separate heat exchanges for the water and two approach temperatures to deal with. You can't move heat without a temperature difference. So to push heat from the cooler heat exchanger to the loop water, there will be an approach temperature, and from the loop water to sea water there will be another. Now, our 65 deg F leaving air is looking more like 70-75 (in the absence of actual performance data). Plus, I've got a closed loop system to fill and air-bleed to get working properly; and re-bleed until the majority of dissolved air is removed from the water loop. We can still cool the cabin with these air temps if we have a large enough fan and coil for the conditions.

The way the video shows the unit being used, is blowing directly on the occupant who is lying in front of the air discharge. If the cabin is 90-95, or even 85, and you're lying in a 75 deg air stream, it's an improvement. If you expect to cool your entire cabin down to 75 deg, you probably need to ask for performance data before buying. The only price I saw referenced on the net was around $450. For that money, I'd want more to go on than just pictures of the equipment. That's getting up in the range of equipment with rated performance data - granted modifications will be necessary to adapt for 12volt use.
Ah. Good point. Performance should be measured.

I contacted them for a price, and they confirmed $470CDN, including air freight.

Not sure what you mean by mods for 12 volt use. The specs do say it runs on 12 volts.

Jimmyt wrote: Being from the Deep South where our water temp is well into the 80's now, I have to wonder if night cooling is a necessity when you're sitting in a large body of 54 deg F water. I get it for daytime, when the temp might spike up due to solar radiation, but in the dark, everything below the waterline, including the ballast tank will be approaching 54 deg in a reasonably short time - producing significant radiant cabin cooling. I guess I'm wondering if this unit is really necessary, for other than mid-day naps, in the regions where it will actually work.
Here in Toronto Canada, the temp went into the 90s and stayed there the whole weekend. I would not normally complain - or do much about - daytime temps (you should be on deck anyway!) it was nighttime temps and trying to sleep that prompted me to start this thread.

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Jimmyt
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Re: I'm an A/C convert

Post by Jimmyt » Tue Jul 10, 2018 12:13 pm

I get it. I'm too old and cranky to try to sleep in 90 deg heat.

Sorry, what I meant was, if I bought a piece of commercially available equipment with published ratings - it would need to be adapted for 12 v usage. Would have to swap the fan motor out, as it would likely be 120 v - or use an inverter. I would have a hard time spending $470 on something that might be nothing more than a person cooler.

Example of commercially available chilled water fan coils...

http://www.trane.com/content/dam/Trane/ ... (HFCA).pdf

If it's hanging in the 90s all night long, and you have 54 deg seawater to work with, you should be able to get significantly better conditions in the cabin using a fan, coil, and pump. Today, Toronto is around 90 deg F with a dew point of 48 deg. So, today you could use 54 deg F water to cool the cabin without concerns that you would produce condensate on the cooling coil - provided that you had a bit of fresh air coming in to remove the moisture coming out of the occupants. As long as your cooling water is above dew point (in the conditioned space), you can't create condensate on the coil or piping. This is one of our biggest concerns, as it quickly turns into a mold/mildew problem if not handled correctly. At the conditions in Toronto today, you could cool the cabin down to 75 deg F without concern that you would have humidity or condensate issues. Sounds like paradise...

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