period two
Absorption Chiller Types
notes
period two
Figure 21
Lithium bromide-and-water absorption chillers are classified by the firing method—that is, how the primary generator is heated and whether it has a single- or a multiple-effect generator. Indirect-fired chillers are heated with steam or a hot liquid (such as water) that is typically supplied by an on-site boiler or a local utility. It can also be heated by waste energy that is recovered from the exhaust of a gas turbine or by some other heat recovery device. Direct- fired chillers are heated via the combustion of fossil fuels. An absorption chiller with a single generator is called a single-effect chiller. Multiple-effect chillers have multiple generators.
Like vapor-compression water chillers, absorption chillers can also be classified by the condensing method employed, either air-cooled or water-cooled. Physical size limitations typically constrain air-cooled condensing to ammonia- and-water absorption equipment that is applied in residential and small commercial applications (3 to 5 tons [10 to18 kW]). Most large commercial (20 to 1,500 tons [70 to 5,300 kW]) water-and-lithium bromide absorption chillers employ water-cooled condensing with cooling towers, because of the higher energy efficiency at design conditions.