Re: ammonia absorption cooling



On Tue, Jan 29, 2002 at 12:58:31AM -0500, Lee Bonnifield wrote:
> hello... hello... is this thing on?
> 
> I'm new here. I heard there's interest in using solar powered ammonia
> absorption cooling to condense clean water out of the atmosphere. I
> hadn't thought of doing that before, but it sounds like a good idea.
> 
	Welcome, Lee! I'm still backlogged in mail, so I never replied to
this, but glad to have you on the list!

> I think I know some technical details I can share regarding ammonia
> absorption cooling. Around 1975 I studied "The Ammonia Absorption
> Refrigeration Machine: Advanced Theory and Practice" written by
> Voorhees about 1920. This described in great detail the state of the
> art for large industrial cooling machines.
> 
> I've forgotten a lot, and I don't have a copy of the book (stuffed
> with graphs which I manually digitized) but luckily when it was fresh
> knowledge I wrote a PL/I computer program to go thru the same solution
> steps Voorhees described. Twenty years later I translated it to run in
> QBASIC, which I can still run. I may be able to answer questions about
> the interactions of variables like these:
> 
> EVAPORATOR TEMP
> AIR TEMP
> TEMPERATURE STRONG INTO GENERATOR
> TEMP WEAK FROM GENERATOR
> TEMP RISE IN GENERATOR
> TEMP DIFFERENCE: CONDENSER - AIR
> TEMP DIFFERENCE: ABSORBER - AIR
> 
	[...]

	This is fantastic stuff! Thanks for posting it! 

> 
> This is ALL THEORY, I have never built an ammonia absorption system,
> and Voorhees is not alive to check that I correctly programmed his
> equations. These calculations are for continuous operation but many of
> the results could be applied with some thought to batch operation.
> 
> I am very ignorant of modern practice -- please send me URLs or emails
> describing current real ammonia absorption systems, and catch me up
> with what has been said / asked here.

You can find web-archives of previous list postings here: 
http://reality.sculptors.com/~hyprmail/clean-water/

	Check also this post, which I made just a few days before you
joined, which has a data table on some of the condensation/dew points at
different temperatures:

http://reality.sculptors.com/~hyprmail/clean-water/0087.html

I'm also not too familiar with ammonia absorption details, just the overall
theory. One cool device I saw at Real Goods is a Solar Ice Maker that runs
on the ammonia absorption cycle. This is what originally gave me the idea
of using ammonia for a condenser, since if they could get cold enough to
make ice, they could certainly make it cold enough to condense water. The
machine is custom-built, and pricey, but considering that it can supply a
remote village with refrigeration for between $10,000-$14,000 it's actually
quite affordable. 

http://www.realgoods.com/renew/shop/product.cfm?dp=3104&ts=1062532&kw=ice%20maker

Seems like we could make only slight modifications to a system like this in
order to produce a conenser unit. 

I'm also currently (slowly) working on a new proof-of-concept condenser
which uses a solid-state thermoelectric heat-pump to cool water for pumping
through the coils. I haven't fired it up, yet, but am almost ready to try it. 

> 
> Lee Bonnifield
> 

-- 
Pat
	   ___________________Think For Yourself____________________
	 Patrick G. Salsbury - http://reality.sculptors.com/~salsbury/
 Autopilots for ground- and air-cars: http://reality.sculptors.com/lists.html
	   ---------------------------------------------------------
		    || loka samastha sukhino bhavanthu ||
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