On 4/16/2018 9:43 PM, Jon Elson wrote:
On 04/16/2018 10:43 AM, Dave Cole wrote:
If you want to get fancy, you can chill water with heat using an
ammonia absorption system (chiller). That's what hospitals and many
large commerical buildings use for air conditioning. But they get
complex and you need to deal with ammonia. Really nasty stuff.
IMO, not worth the complexity.
Nobody is using ammonia absorption chillers anymore (at least in the
US). It is very inefficient.
There was this co-generation fallacy in the 1960's through the 1980's,
maybe. The idea is, if you have to make steam for process heat, then
it is free to extract energy to run turbine alternators to make
electricity from the high-pressure steam, and then send the
low-pressure exhaust from the turbines to the process (hot water,
steam heat, whatever). And, if you have to provide electricity from
the turbines, then the process steam is free. Well, the fallacy is
that neither of these is actually free!
So, everybody finally understood the error in thinking, and cut WAY
back on the size of their boilers.
So, almost anyplace where a steam-powered chiller once stood, there is
now an electric turbine chiller with a variable-speed drive and
variable vane control, and it uses WAY less energy than the old steam
chillers.
Oh, and the ammonia absorption systems were mostly phased out in the
1950's for lithium bromide absorption chillers. Less hazardous and
more efficient.
Jon
I got out of the plant engineering end of things in the early 80's.
If you Google absorption chiller you will see that Ammonia is again
being considered for solar -refrigeration systems. I really don't
understand why, but there is a lot of chatter on that topic.
Ammonia can be a hazard, but its used all of the time by farmers for
fertilizer around me. I've been exposed to ammonia gas and it is not
fun. This was back in the blue print days. As a entry job, I ran off
thousands of blue prints. Sometimes the machine would malfunction and
drive me out of the "blue print room" which was force ventilated to the
outside air because of the ammonia hazard.
Dave
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