Waste steam from a cogeneration system obviously produces
the same level of cooling as boiler generated steam, Low pressure waste
steam sources (say 14 psig) typically require 18-20 pounds of steam per
hour to produce one ton of cooling in a single-stage absorption chiller.
That performance improves to 10-12 pounds per ton-hour of steam when steam
pressures are in the 50 to 130 psig range and used in a 2-stage (double
effect) absorption chiller.
Steam absorption chillers are nominally rated as follows:
Capacity ratings are decreased as steam pressure drops
below nominal. For example, a nominal 100-ton unit's capacity will drop to
84 tons with 78.5 psig steam.