# Water Cooled Air Conditioners For Sailboats?



## Armchair Sailor (Jul 30, 2012)

I was reading an interesting thread about types of useful air conditioners for boats in the summer heat sailnet. com/forums/general-discussion-sailing-related/89598-no-c-when-motoring.html

There was no mention of using (naturally) water cooling for sailboat air conditioners. Does anyone have any experience with water cooled air conditioners on boats?


----------



## theartfuldodger (Sep 4, 2006)

I'm not sure what you have been reading but any airconditioning unit on sail boats I've seen are all water cooled.


----------



## Minnewaska (Feb 21, 2010)

My marine air systems units are raw water cooled.


----------



## misfits (Dec 9, 2011)

I think armchair sailor was curious about using raw water for cooling in lieu of a compressor/evaporator coil that uses freon.

There was a discussion on this subject over the summer. Some folks say they have used or have know someone that uses "yankee" air conditioning. Typical ac units have a discharge air temperature of 55-60 degrees @ 95 degree outdoor temperature up here in New England. 

Bottom line, if the water is cold enough you can condition the air with raw water, but as the water temperture rises, the a/c discharge air temp also rises.


----------



## Minnewaska (Feb 21, 2010)

Shallow water temps easily get up into the 70s in Southern New England, which would do nearly nothing if just run through coils to heat exchange with the air. However, Armchair lists their location as Cal, which may be California? I believe water temps are cooler there, although, maybe not in shallow water.

Still, I would sooner install a bunch of 12v fans around the boat than spend the money on raw water to air heat exchanger.


----------



## TakeFive (Oct 22, 2009)

Raw water reverse cycle A/C is pretty standard. In cold water areas it's possible that you might get enough cooling just from the raw water without a refrigerant compressor to remove the heat.

The Delaware River peaks at around 85 degrees mid-summer, which even makes it difficult for reverse-cycle air conditioners to keep up. The guy who used to have his boat two slips up from me figured out a clever workaround: he hooked up the marina's fresh water system to the intake of his reverse cycle system. Then the marina got the $3000 water bill and went looking for where all the water was going. That's why he no longer has his boat there - he got kicked out.


----------



## RichH (Jul 10, 2000)

The problem with raw water AC, in lieu of freon, etc. systems is the heat exchange cycle which normally requires a 15°F 'approach temperature' - the resultant temperature of the max. cooling will only be 15° warmer than the inlet temperature of cooling water. eg.: If the inlet water is 70 degrees, the 'best' output from the AC will be 85°. 

Normal AC and refrigeration uses the expansion of pressurized/compressed gases which subcools the air and that takes 'energy' to so.


----------



## Barquito (Dec 5, 2007)

Well, what about in a place like on Lake Michigan? The water probably doesn't get much warmer than mid 50's at about 30' depth. The summer temps get near 100. Is there some passive way (no electricity) of getting that cold water up to the boat?


----------



## Armchair Sailor (Jul 30, 2012)

Thanks for all replies. I now found several vendors for water cooled marine air conditioners such as this marinaire. com/Marine_air_conditioner_p/msba6k2.htm
and this aquaair. net/SSIG_Self_Contained_Units__80706-11.pdf

They make smaller and more efficient units now. The prices for the smallest 5000 BTU units seem to be around $1500 after you include the water pump.


----------



## Frogwatch (Jan 22, 2011)

Boat AC seems to use such crappy tech. Its the same old compressor/condensor as land based systems when boats have access to the worlds biggest heat sink. You'd think somebody would make an absorption/type of AC using the ocean as the heat sink
There are actually zeolite based AC systems for buildings where heat is used to remove the water from the zeolite. Normally, boats have access to almost unlimited sunlight too for heating it. Somebody needs to combine these into a good small marine AC.


----------



## MedSailor (Mar 30, 2008)

<$100 air conditioner: http://www.sailnet.com/forums/gear-maintenance/50044-low-buck-projects-lets-see-em-43.html#post913870

MedSailor


----------



## ccriders (Jul 8, 2006)

Where's Denise? Calling all ac guru's. There is a fortune to be made with 5 - 10 K btu acs that can be powered by sunlight.


----------



## SchockT (May 21, 2012)

Lol! There is no fortune to be made in refrigeration and air conditioning for boats! Sailors are too cheap to pay for innovation!

We gurus have gone to where the real money is: commercial and industrial hvac-r.

(even residential is more profitable than marine!)


----------



## DannyboyUpstate (Aug 27, 2012)

SchockT said:


> We gurus have gone to where the real money is: commercial and industrial hvac-r.


THAAAAT'S RIGHT! Meet me in the chemical plant!


----------



## Minnewaska (Feb 21, 2010)

SchockT said:


> Lol! There is no fortune to be made in refrigeration and air conditioning for boats! Sailors are too cheap to pay for innovation


There is an exception. A sailor stuck in a remote anchorage with failing refrigeration will trade copious amount of alcohol for a repair.


----------



## SchockT (May 21, 2012)

Minnewaska said:


> There is an exception. A sailor stuck in a remote anchorage with failing refrigeration will trade copious amount of alcohol for a repair.


This is true! But you better have GOOD rum on board! Bacardi just won't cut it!


----------



## MedSailor (Mar 30, 2008)

SchockT said:


> This is true! But you better have GOOD rum on board! Bacardi just won't cut it!


Actually I was quite surpirzed to find out that bacardi 8 year is a really good rum! It's not heavy on the vanilla and spice (which I think is good) and has the woody character of a good whiskey.










MedSailor


----------

