On 9/9/2011 11:24 PM, Richard wrote:
I've asked a few people about this personally, but I'd like to throw it
open to the larger group as well.

I'm trying to cool the boat for a few days at a time...

A normal 5000 BUT marine air conditioner can pull up to 30 amps of 12
volt power. If my house battery were new and fully charged, that's 4 or
5 hours. That won't get it for even for a weekend.

If we had a diesel engine (and ran it all day) we could use an
automotive approach. But we don't - and can't.

So, quoting Kelly Johnston (one of my favorite heroes),
"Simplicate, and add lightness".

Statement of Problem:
I want to air condition the boat for up to 3 or maybe 4 days at a time.
Independent of dock power.
With as low of a battery load as possible.

Proposed Solution:

A cooler type container with a load of dry ice and a way to move large
amounts of air across the cooler.

A sketch at:
http://www.home.earthlink.net/~cave-1/images/ac-3.jpg

I'm already thinking glycol for the fluid.

But what to make the rest of it from?
Cheap, off the shelf stuff preferred!
A pump that can handle antifreeze?
High torque low power 12 volt DC motors?
What to use for the heat exchangers?
Coils of tubing? Or auto parts?


Other than a drip pan (and a handful of brain cells),
what am I missing?


Thanks all,


Richard

have you calculated the heat capacity of dry ice? there is a reason we
employ equations first to determine feasability