Is there any way to cool a cabin using the river water?
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Gdavid
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Lowering the humidity without raising the temperature does help, my point is that a dehumidifier creates heat from the compressor and fan motors creating heat. If it is hot enough and humid enough to seek relief, it is probably at least 80 degrees out. If you seal off the boat and start adding heat, you will quickly exceed 100 degrees which is miserable no mater how dry the air is. Your small A/C that was unable to lower the ambient temperature was at least offsetting the heat that the mechanism was generating. I'm not trying to dissuade anyone from experimenting, if you have already have a household dehumidifier and shore power, give it a shot but I would not encourage buying one and then buying and installing an appropriate sized inverter just to be disappointed. I'm a mechanical engineer and my background is HVAC design, the calculations are pretty straightforward.
sunchaser
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The story I heard
Yup, back in 1790 the iron bar confused the French in that it changed length between summer and winter. So they invented the atomic clock with the known vagaries of how black holes affect sub atomic species. Unfortunately the French Revolution beheaded the smart French guys that were working on this. So the French Navy stuck with nautical miles to allow for stolen English charts to be used.
However, in the real world, we engineers were educated and trained to use English and Metric units. Being numerically multi-lingual is mandatory for world wide business. It really gets goofy when not understanding the country differences for construction steel, nuts, bolts and rail.
Sea Word
Senior Member
I’m one of the few people who appreciates the imperial systems for several reasons which are met mostly with ire when I try to explain them to the metric lemmings who are too stupid to use math and logic correctly. I’m glad that I was raised in the USA so that I am able to use both systems fluently, because it’s very easy to use metric and maybe slightly less for our less intuitive systems, but being easy to use isn’t enough of a reason for me to give up my imperial which was developed over centuries for use in the real world. Metric was invented to address specific scientific issues that are valid.
There was a thread recently about split a/c units entitled Mini-Split Ductless A/C.. Talk me out of it.
"Gree (Chinese appliance manufacturer) Sapphire brand of mini-splits (air cooled) have efficiencies as high as SEER 38. Compared to a typical marine packaged a/c unit (water cooled), you're looking at 6A draw versus 8A (with water pump). Also they state will provide heat (heat pump) down to 22 degrees F below zero.
https://www.greecomfort.com/wp-conte...081318_Web.pdf"
Sea Word
Senior Member
6.2A@240VAC is probably too power hungry for my application.
Ski in NC
Technical Guru
In my fwd cabin I run a 6.5kbtu/hr Mermaid package unit. It draws about 6-7A by itself and about 8-9A with pump running. Pump is bigger than it needs as the pump also feeds the pilothouse 12k. This is all on 120V.
Mack McGahee
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You would be basically building a swamp cooler. These worked best in high heat areas such as cleaners and restaurant kitchens. As stated above these units did nothing for the humidity removal. Kind of like in the old days of putting the fan behind the block of ice.
IronZebra
Senior Member
These guys site says PNW is low enough humidity for their boat swamp cooler.
https://www.turbokool.net/
https://www.turbokool.net/
ssobol
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Swamp coolers work best in high temp/low humidity environments (e.g. PHX, ABQ). Don't think the PNW (particularly when you are near the water) qualifies.
In those environments, the extra humidity introduced by a swamp cooler is often an added benefit.
RT Firefly
Enigma
W
That humidity map is total fiction.
The PNW ( and nearby SW BC) never see less than 31%.
The desert in So Cal never sees above 30%.
That humidity map is total fiction.
The PNW ( and nearby SW BC) never see less than 31%.
The desert in So Cal never sees above 30%.
OldDan1943
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Are you thinking about a 'swamp cooler'?
The air needs to low in humidity but they do work very well
Sea Word
Senior Member
No, I’ve experimented with swamp cooling and I’d rather sweat than be slimed by the damp feeling they provide. I believe they could be a useful ad-on component for a high tech compressor AC to add comfort and humidity but as a primary cooler they suck.
Last edited:
Lepke
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Before AC was common in homes, people in hot climates made a homemade AC by pumping water from the bottom of a pond, pool or river and running it thru car radiators and air circulated thru the radiator with a blower. I've seen it done in Sacramento where it's hotter than hell in the summer.
The ground temperature stays about 60°F. So water on the bottom of a river, etc, is near that temp. But running a pump and blower on 12 volts all night could be an issue. I have a 12v blower about the right size and it draws 15 amps and I guess a pump with a decent volume would be near that, too.
The ground temperature stays about 60°F. So water on the bottom of a river, etc, is near that temp. But running a pump and blower on 12 volts all night could be an issue. I have a 12v blower about the right size and it draws 15 amps and I guess a pump with a decent volume would be near that, too.
I guess I may be the only one taking the opposite view than the rest.
Reason is I have not done this but know another boater that was in our marina that did exactly what you suggest and it worked - not as effective as AC but better than nothing. Our lake temps run in the 50°s F range early season and 60°s F mid season it's only Aug that it gets up to 70s.
If the bilge air is water temp and is an improvement it's only a matter of getting enough cooling area on the heat exchanger for the air flow.
The experiment is simple & relatively cheap... why not try it. Any small pump, fan and a salvaged heater core. Temp hook up to an existing through hull... wash down? And try it.
The key my boater had to do was close up early... don't let cabin get over heated... and start running it sooner rather than later. Other key is minimize heat gain... block windows... it would help to shade large areas like fwd deck do keep direct sun off. You might try an old blanket sprayed down w water just as an experiment.
If bilge is more comfy than top side it's because the cool water is keeping it cool and there is no/little solar gain in the bilge. You should be able to get close topside. And why not draw bilge air to blow across the heater core? Eventually bilge temp will rise as you pull cooler air and replace w warmer so the heat xchgr should help keep it cooler longer.
