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Posted by Tony Conner on June 12, 2002 at 11:27:17:
In Reply to: calculating steam load posted by Phil on June 12, 2002 at 08:05:44:
You'll need to do (or have done) a heat loss/gain on the building. If it's an existing structure, and you can look at some fuel & chiller data, you can get some info from that. Usually data is pretty sketchy, though. If it's got an existing hot water loop that you'll be feeding through a heat exchanger, try to get the supply & return water temps, and the GPM off the circ pump(s). Delta-T in *F, times GPM times 500 will give you BTU/hr required. Remember that you'll need enough steam to meet the peak load, not just the average.
Single stage absorbers can use low pressure steam, or even hot water. The two stage machines I'm familiar with used 125 PSIG steam. Single stage needed about 20 # of steam per hour per ton of refrigeration, and two stage need about 11. It's a lot cheaper to run two stage units, unless you've got something like exhaust steam from a process that you can utilize. Remember that absorbers are physically large machines & need more cooling tower capacity, as compared to centrifugals of the same tonnage.