Feedforward control for absorption chiller

A feedforward controller for an absorption chiller system, wherein a control input for said chiller is a heat source controlled by a capacity valve, and a system output is a leaving chilled water temperature, comprising:

• a feedforward loop having a feedforward control transfer function represented by a ratio of a disturbance transfer function to a capacity valve transfer function, wherein said feedforward control transfer function receives a disturbance input as an input;
• a first summer receiving both a set point input and a feedback from a system transfer function as inputs, and sending an output to a capacity control transfer function;
• a second summer receiving an output from said capacity control transfer function and an output from said feedforward control transfer function, and sending an output to said system transfer function;
• said system transfer function receiving said output from said second summer as an input, and also receiving said disturbance input as an input, wherein an output of said system transfer function is said leaving chilled water temperature.

A feedforward control for an absorption chiller system, wherein a control input for said chiller is a heat source controlled by a capacity valve, and wherein said capacity valve is controlled by a feedforward controller, comprising:

• means for determining a disturbance transfer function between a measured disturbance input into said system and a leaving chilled water output;
• means for determining a capacity valve transfer function between said capacity valve and said leaving chilled water output;
• means for measuring an actual disturbance introduced into said system;
• and
• means for controlling said capacity valve based on a feedforward control transfer function in said feedforward controller, wherein said feedforward control transfer function is represented by a ratio of said disturbance transfer function to said capacity valve transfer function.