I work in a large industrial refrigeration plant. We have a 125,000 lb ammonia charge here, it is a two stage system that operates a suction of 5" hg, an intermediate of 38 psig, and an average condensing pressure of 135 psig. The plant was built sometime in the sixties and has been added on to and taken away from over the years. There is very little in the way of OEM literature on the really old stuff but on most of the things acquired in the last 20 yrs there has been good record keeping. What I am trying to say is that it isn't possible to calculate cooling capacity from equipment manuals alone.
I do however know the horsepower of each compressor and the total horsepower in the engine room is 8700 hp. I understand that this along with the operating pressures in the plant can be put into a formula that will give me the tons of refrigeration per HP.
I came across the following diagram online during my search:
ROT for ammonia refrigeration that I found in the literature:
For "air" condensation at about 120oF:
Can someone please tell me where all of those numbers came from? Thanks in advance.
I do however know the horsepower of each compressor and the total horsepower in the engine room is 8700 hp. I understand that this along with the operating pressures in the plant can be put into a formula that will give me the tons of refrigeration per HP.
I came across the following diagram online during my search:
ROT for ammonia refrigeration that I found in the literature:
For "air" condensation at about 120oF:
HP/TR = 2.1444 - 0.02668x + 0.000152x2
For "water" condensation at, say, 106oF:HP/TR = 1.6952 - 0.02657x + 0.0001373x2
where x : evaporation temperature, oF.Can someone please tell me where all of those numbers came from? Thanks in advance.