Filter
Top Products
36 TRG-TRC011-EN
notes
period three
Capacity Control
In more modern absorption chiller designs, adjustable-frequency drives
(AFD), also known as variable-speed drives, are used to vary the speed of the
generator pump motor, thus reducing the flow of solution to the generator.
AFDs have the added benefit of saving pump energy at part-load conditions.
In order to vary the solution concentration, absorption chillers vary the heat
input to the generator. This figure shows a modulating energy valve on a
single-effect, steam absorption chiller. At part load, in response to a changing
leaving-chilled-water temperature, the energy valve begins to close, reducing
the amount of heat input to the generator. Similarly, on a direct-fired absorption
chiller, the amount of heat input to the generator is varied by modulating the
capacity of the burner.
While the solution flow to the generator is varied to maintain the desired
chilled-water temperature, the heat input to the generator is varied to control
the solution concentration. This assures optimal efficiency and keeps the chiller
adjustable
adjustable
-
-
frequency
frequency
drive
drive
generator pump
generator pump
absorber
absorber
spray pump
spray pump
Figure 42
energy valve
energy valve
generator
generator
Figure 43