"Mark W" wrote in message ...
Now you're just being mean.
Actually it's worse, normal weather comes from ESE but every couple of weeks
through winter we get a southerly direct from Antarctica. Still rather live
where it actually changes...

Mark.

"Parallax" wrote in message
om...

Mark, being in NZ, even in summer, you are surrounded by a big heat
sink called the pacific Ocean. In summer, we have a huge heat source
called the Gulf of Mexico very close by. Last week, the water temp
was 91 F (about 32C) and the air temp was 38 C with not even a breath
of wind and 95% humidity.

I would take a while getting used to weather coming from the ESE rather than WNW.

Dan Best wrote:
Swamp coolers work well in a low humidity environment and while very
energy efficient when compared to "heat pump" refridgeration, consume a
fair amount of fresh water. I've never heard of one that used salt water.

Upon thinking about it, corrosion might become an issue, but as long as
you let most of the water drain off so the water never gets too briney,
it seems like it should work.

Hank wrote:

Do a search for "swamp cooler" - they're the evap coolers used in AZ,
NZ etc before we all got rich and burn up electricity.

They might work well in the Sea of Cortez in MX because of the very
low humidity - but I wouldn't want a boat in FL to be any wetter
inside than it normally is.

Buy a solar panel and a fan.


On 6 Jul 2004 08:44:14 -0700, (Parallax) wrote:


Spent a day working on my boat at the dock her in NW Florida and
nearly died of heat stroke while being down in the cabin even with all
hatches and vents open. I dont have too many fans because I have no
connection for shore power. There was an obvious temp differential
'tween outside and inside that got me thinking.

So..... Make a long fabric tube, say 10" diameter and 15' long with
upper end held up with the jib halyard and lower end in the forward
hatch with edges around it sealed. Upper half of the tube is black
and lower half is white. Here is what happens:

With a temp differential (hot inside, cooler outsside), you get a
chimney effect with hot air rising out of the tube and pulling cooler
air in from other ports. I can imagine getting a susbtantial flow
this way.

With little or no temp differential, sun still heats the black upper
half and heats air inside causing it to rise causing air to be pulled
through the tube giving air flow in the cabin. Steps could be taken
to maximize solar heating of teh upper part of the air column such as
better conducting baffles, passive solar fabric panels connected to
the upper tube etc. I could even imagine a fabric reflector shining
light onto the upper tube to maximize the effect.

All of this works compared to not working in a house because the
volume of the boat is fairly small compared to the volume of a house.

Let's go further. Now that we can produce air flow, can we use such
to actually produce cooling? Evaporation of water can produce a huge
amount of cooling. Close all vents to the outside except for a 10" or
so port and fill it with wetted baffles. Baffles can be wetted by
osmosis from a reservoir. Evaporation will cool the air stream.
Unfortunately, this will increase the humidity in the boat and reduce
the air flow (conservation of energy).

Any thoughts?


Plumb an old car heater radiator or alternating direction layered
plastic signboard material, to circulate sea water and air through
it, using a small pump of some sort, or locate the radiator
underwater and plumb the airlines to it. (air is easier to move,
especially with a convective chimney) route your ventilation air
through the radiator. The air should be cooled somewhat and it
should lose a lot of water if it is really humid. That water would
be fresh, and possibly useable r.

Mixing the cooled air with outside air should give you a net
reduction in temperature and humidity. Every little bit helps when
it's desperate hot and muggy. Deeper water is cooler than surface
water.

Perhaps a few feet of plastic 3" pipe could push an air box down to
deeper, cooler water? Two such pipes could conduct air through the
radiator. You might even construct a device to be left behind,
sitting like a deadhead at a mooring with flex hoses to attach your
boat when moored? A bilge pump of sorts would be necessary to keep
the radiator from filling up with distilled water. Perhaps a soda
straw extended to the bottom of the air box would keep you hydrated
as you work?

Evaporative coolers clog with salt if the water used is not fresh.
Possible alternative forms of evaporator use a fabric only damp with
water laid against the side of the air handler box. The cloth is
removed, rinsed, and re-wet, possibly on a conveyor system. Large
amounts of water defeat the evaporative cooling process by cooling
the water on the evaporator with only a very little cooling of the
air traveling through it.

The plastic signboard material available is like a flat layer of
square soda straws, is polyester or polyethylene, and is used as a
heat exchanger in home heat exchanger ventilators because it
conducts heat very well. I got a bunch of castoff campaign posters
after the last election, for experimentation. With November
approaching, you may get a windfall of signs to pick for cheap, the
day after the election. You might ask permission to assist cleaning
up signs after the big day. They likely won't mind if a few go
missing after action.

The nicest signs are on this material, and tell a tale of who has
the most money to blow on advertising. Layered in alternate
directions, it makes an excellent heat exchanger for air, and should
handle low pressure water OK.

5200 sticks to it quite well, especially under a little compression
in final assembly from clamps, etc. Plastic sewer pipe could be used
for air box ends, etc. Heck, painted aluminum and flipped up out of
the water, it might make a cool radar reflector if you take it with
you sailing. Flexible air lines might enable towing a flat air
cooler through the water.

With your smokestack ventilator providing air evacuation from the
cabin, you will need to ensure the cabin is almost airtight to
ensure control over air inflow. A stork nesting at the top could
asphyxiate occupants. Other air routing arrangements seem possible.

Submerged heat exchangers would need some regular cleaning, so you
would want to be able to disassemble or otherwise access the layered
signboards, fortunately, you only need to scrape the flat outside
surfaces, and sea growth shouldn't stick to it real well. Instead of
alternating direction, perhaps simple spacers between the air
carrying layers would enable easy cleaning without total
disassembly. An appropriately sized scraper might make rodding out
the water spaces a snap. The heat exchanger material might be cheap
enough to enable simple swaps of the fouled elements.

It should work with minimum external energy input.

Let us know how you make out.

If you get rich off of this, you owe me a fair royalty.

Good luck!

Terry K

Good points, especially the clogging with salt. I also like your idea
of possibly collecting the water that condenses out for reuse.

Instead of putting the radiator underwater and running air pipes down,
it might me just as effective and easier to keep the radiator on board
and drop a flexible hose with a weight on it to pick up the cooler water
at the bottom.

Terry Spragg wrote:

Plumb an old car heater radiator...
Perhaps a few feet of plastic 3" pipe could push an air box down to
deeper, cooler water? Two such pipes could conduct air through the
radiator....

Evaporative coolers clog with salt if the water used is not fresh.


--
Dan Best - (707) 431-1662, Healdsburg, CA 95448
B-2/75 1977-1979
Tayana 37 #192, "Tricia Jean"
http://rangerbest.home.comcast.net/TriciaJean.JPG

Dan Best wrote:

Good points, especially the clogging with salt. I also like your idea
of possibly collecting the water that condenses out for reuse.

Instead of putting the radiator underwater and running air pipes down,
it might me just as effective and easier to keep the radiator on board
and drop a flexible hose with a weight on it to pick up the cooler water
at the bottom.

Yes, but then you need to pump sea water in addition to
moving air. KISS suggests that fewer pumps use less power.

I know, I know, a 'bilge pump' would be required to remove condensed
water inside the heat exchanger used below the water, but the amount
of water would be less, and fresh water doesn't promote fouling
inside the water lines. 6:1/2dozen?

If you used a deeper pickup for cooler water, the discharge should
also be below water, using the syphon effect to reduce the power
needed to raise the water from the deep to effectively only that
required to overcome friction inside the pipes and temperature
difference density * head, far less than that required for raising
water above the surface to be discharged above the waterline.

Ducting might allow an engine compartment blower to be double dutied
as cooling ventilator if the chimney doesn't produce enough airflow,
or if sealing the cabin to control airflow is undesirable. My engine
blower sucks a little air from the cabin as is, and would do better
if ducting arrangements closed the normal engine compartment air
intake line or switched it to a cabin air intake. I believe that
engine air intakes would be safer if they did not provide a direct
duct between cabin and engine compartment in the event of engine
fire or exhaust leak, while engine is running.

Additionally, cooler cabins under intense sun would result from
overhead insulation and shade arrangements.

-TK


Terry Spragg wrote:

Plumb an old car heater radiator...
Perhaps a few feet of plastic 3" pipe could push an air box down to
deeper, cooler water? Two such pipes could conduct air through the
radiator....
Evaporative coolers clog with salt if the water used is not fresh.