SC - Period cooling (was ice)--Semi OT

[Bethany Public Library]

Let's not confuse "air conditioning" with keeping individual items cold.
Both are called refrigeration, but the systems, while somewhat similar,
provide different effects. Air conditioning's purpose is to cool air
(gasses) which cool rather easily. The cooled air may, in turn, cool other
items (solids) through contact and cold-transfer, at a slower rate that
direct thermal transfer. Roughly like the way in which your home
refrigerator works, I guess. The stone box immersed in a stream of water or
saltwater is cooling in a slightly different manner---through direct cold
conduction. It was probably an added benefit and a smart use of resources
that the castle chamber with the seawater stream used BOTH methods.  If
you're going to accidentally get cold air, you might as well use it.

The unglazed pottery/water evaporation type cooling system certainly isn't
new, though we might be surprised how far it does go back into history. I'd
be interested to know if anyone come up with other examples. Some of you
already own one of these systems, I bet, if you own a "wine cooler", which
is a terra-cotta clay vase-shape that gets immersed in water for a while,
then removed. The wine bottle is settled inside, and the whole left alone to
do it's thing. 1/2 hour later, you've got cool wine. That's thermal
conduction due to water evaporation, at it's finest and simplest level.

The "small area" evaporative air cooling system, though, was certainly known
to the southwest US. It was the custom to use just such a  cooling method on
verandas and smaller ventilated rooms in better houses  in the 1800s in the
Mexican-American area of the world. The pots were attached to posts/pillars
with wrought iron brackets, IIRC, since they were quite large. Those
flat-sided terra cotta half-pots we see so often as decorative items,
sometimes stuffed with silk flowers and ivy, for a south-west theme decor,
are the originals used for evaporative cooling. Even today the preferred
method (most economical) is to use evaporative cooling in dry climates
(though the equipment looks modern and is more likely to be mounted on the
roof of a house). At least it was when I lived in Tucson in my highschool
and college days.

I own a book entitled "Roughing It Easy" (obviously modern) that recommends
several ways in which to cool food items without the use of a cooler. A
great one uses light, portable materials to fashion an evaporative cooler
for food.One constructs a 3-shelf set, plus a board for the roof, of 1 foot
square boards (light as you can make 'em) to be hung from a tree limb. The
shelves, through drilled holes at the corners, are separated by knotted
rope, which also serves to secure it to the tree. The entire structure is
covered in two layers of burlap, with an overlapping "door flap". The burlap
extends above the top of the roof. On the roof you place a pan of water, and
drape the excess burlap in the pan. The burlap uses wicking to soak the
water from the pan and drain it downwards, through the fabric. In the
process, much of the water in the fabric evaporates and the cooling effect
thus keeps the food items inside cool. It's vital to check the water level
several times a day, and it's also important to have the cooler in a shady
spot. The whole unit is collapsible enough to be handy for packing into a
rustic area.

There are lots more recommendations for ice-free camping in the florilegium,
if anyone is interested, before this thread gets totally off the original
topic.

Cheers

Aoife

                ________________________________-
I was reading through the cargo listing of a 9th cent shipwreck ...and among
other things, the list
included 'cooling pottery'.  Now, I seem to remember reading somewhere that
thin-walled clay pots were filled with water, and hung from the ceiling near
windows, so that the water would slowly seep through the sides of the pots
and
provide some degree of cooling via evaporation.  Would this support such an
early form of air conditioning to the 9th century?

wajdi

Lady Ysabeau of Prague wrote:

> Greetings,
>
> I seemed to have read somewhere about a way to make a cooler out of
unglazed
> pottery, like terracotta flower pots. The theories involved could have
> worked in period. Basically, all you did was soak the pot in water, place
> the food on a plate or the saucer of the pot and turn the pot upside down
> over the two. As the water evaporated, it reduced the temperature inside
the
> pot keeping the food cool.
>
> I would think it would be too cumbersome to use for large items or for an
> extended period of time but I could see it being used to keep items
brought
> from a spring house cold until serving time. I have been thinking about
> giving it a try at an event sometime. A "period" ice chest?
>
> I don't have any documentation on it and I think I saw in Mother Earth
News.
>
> Ysabeau of Prague