Evaporate cooling?

[DreamBig]

An ammonia chiller will do what you want, and only burn a little propane in the process. Swamp cooler would not be worth the effort in a humid environment. I would build an ammonia chiller outside of confined spaces, and use water (or heat transfer fluid (Think antifreeze)) as a close loop heat transfer fluid... Remember that you are not cooling anything, you are removing water (condensate) and removing heat. Water could cool hot decks, and you could see a small to large difference from removing latent heat transfer, but that all depends on boat construction, r value, and infiltration. Solid glass would probably be the worst r value, and glass foam cored would probably be the best. If you could drop your humidity to 50% range, you would be surprised at how comfy 80 degrees F is, actually. If you had access to deep water, and a bunch of sayvinyl hose, say 3/4"- 1", You could do a close loop water chiller, and essentially just circulate water with a very small pump. Then build some sort of evaporator to run chilled water through (or htf).. The concept is relatively simple get a heat sink inside to below dew point, and convey the heat outside to be absorbed by the water.. Dew point is normally around 68 degrees F +/- 5 degrees F. That means with a 10 degree absorption you would need to be at the very least 58 degree F. 42 degree F would be perfect!!! Using a pressure-temperature sensitive material (refrigerant) can allow this to happen with the change of matter states,, most often liquid to vapor and back as a great deal energy is exchanged in a very short temperature exchange. The key here is to understand that refrigerant is pressure/ temperature sensitive, so you can use a pump to increase pressure, or use heat to increase pressure. The basis of an ammonia chiller is to use very little heat to generate pressure to allow for good pressure differential across a metering device, (meters high pressure to low pressure.) The same can be done with propane and various other (Refrigerants) 134, 22, 12, 410, and so one. They are all pressure temperature sensitive , if one goes up so does the other, and vicea-versa. At some point I will get there, as yes I am an Air Conditioning contractor, I plan to do some very interesting stuff on my Cross 38 when I get her Sailing, you can follow along here

https://www.cruisersforum.com/forums...ad-235071.html

Personally, I will scavenge an air to air split system inverter system, and make it an air (evap) to water (condense), force low system operation for humidity control, and air movement. I should be able to eliminate 9 dc fans that will compensate for 70% of the power to run the system. I will caution everyone that dew point can be like chasing your tail. If you screw up and make it happen between a deck or in a wall, you can create a HUGE mess of mold, mildew, rot and I am sure other stuffs.

Time for a bourbon and some cards with the family,

Cheers,

James
s/v Ameris

[a64pilot]

Originally Posted by valhalla360

If you are talking about a dark colored hull (maybe a teak deck) and you are spraying 70F water onto a 130F deck in 90F weather, yes, it will have a big effect as it is just the water absorbing heat and running off the deck.

If it's the typical white fiberglass deck, in the same conditions, the deck is likely pretty close to 90F...maybe few degrees higher. The water won't be able to pick up nearly as much heat as it rolls off. To be effective, you really need significant evaporation to have an effect.

My deck is pretty close to white, and in the heat of Summer it’s hot to bare feet and usually about 130f, take an IR temp gun to one at about 3 PM and see.
IP’s are almond colored, but after 30 years or so they turn pretty close to white.

When it’s 130 on top it’s 100 or so inside as IP’s cabin tops are decently insulated, but other boats can be much hotter. So if the roof is over 100f, it’s going to be tough to cool the boat.
Shade will drop that temp by up to 40F.

If your in 70f water, your not in a hot climate.

Solar heat gain in a hot climate in Summer even on a white boat is enormous, shade helps tremendously.

My friends Amel Super Maramu which has some kind of fake teak is so hot you can’t go barefoot, I’d guess it’s at least 150F. I have stood on his boat and it was way hotter than the concrete dock, way hotter

[Franziska]

That makes perfect sense!

Originally Posted by bstreep

As others have said, swamp coolers ONLY work where the humidity is low. We live in South Texas, about 120 miles from the coast, and they are only partially effective here.


They REQUIRE a temperature above the dew point. And they will only cool to the dew point. It's simple chemistry. Coastal environments rarely have nights that don't hit the dew point - so they won't work at night. Zero possibility of success if there's dew overnight.