Chiller capacity control with variable chilled water flow compensation
AssigneeAmerican Standard International Inc.
InventorLee L. Sibik
Life of this patent
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Abstract
A method of controlling chiller capacity in a chiller system. The method comprises the steps of: measuring entering the fluid temperature of a fluid entering a heat exchanger; measuring the fluid temperature of the fluid leaving the heat exchanger; determining a desired leaving fluid temperature; establishing chiller capacity as a function of the difference between leaving fluid temperature and the desired leaving fluid temperature; and adjusting the determined chiller capacity as a function of the difference between entering fluid temperature and the desired leaving fluid temperature.
Claims19
A chiller system including a chilled fluid loop where the temperature of the fluid is controlled by varying the capacity of a chiller comprising:
- a variable capacity chiller including an evaporator;
- a chilled fluid loop in heat transfer relation with the evaporator;
- a sensor measuring the leaving fluid temperature of the evaporator;
- a sensor measuring the entering fluid temperature of the evaporator;
- a mechanism for providing a desired leaving fluid temperature;
- a pump controlling the rate of fluid flow in the fluid loop;
- and
- a controller operably controlling the chiller capacity and the variable flow rate of the pump, the controller being connected to the setpoint mechanism and the entering and leaving fluid temperature sensors;
- wherein the controller includes a feedback loop controlling chiller capacity in response to leaving fluid temperature and wherein the controller includes a feed forward loop controlling chiller capacity in response to entering fluid temperature.
A chiller system comprising:
- an evaporator having a fluid flow therethrough;
- a chilled fluid loop in heat transfer relation with the evaporator;
- a first sensor positioned to measure a first temperature of fluid leaving the evaporator;
- a second sensor positioned to measure a second temperature of fluid entering the evaporator;
- a mechanism establishing a desired leaving fluid temperature;
- and
- a controller operably connected to the setpoint mechanism and the first and second sensors wherein the controller includes a feedback loop operating in response to the first sensor and wherein the controller includes a feedforward loop operating in response to the second sensor.
A controller for a variable capacity chiller including an evaporator, a chilled fluid loop in heat transfer relationship with the evaporator, a pump controlling the rate of fluid flow in the fluid loop, a first sensor measuring a condition of the fluid in the loop, and a second sensor measuring a second condition in the fluid loop, the controller comprising:
- a controller operably coupled to and controlling the chiller capacity, the controller being operably coupled to and controlling the variable flow rate of a pump and the controller being operably connected to and receiving a first condition measurement from the first sensor and a second condition measurement from the second sensor;
- the controller including a feedback loop controlling the chiller's capacity in response to the first measured condition and the controller further including a feedforward loop controlling the chiller capacity in response to the second measured condition.
A controller for a variable capacity chiller including an evaporator, a chilled fluid loop in heat transfer relationship with the evaporator, a pump controlling the rate of fluid flow in the fluid loop, a first sensor measuring a condition of the fluid in the loop, a second sensor measuring a second condition in the fluid loop, the controller comprising:
- a controller operably coupled to and controlling the chiller capacity, the controller being operably coupled to and controlling the variable flow rate of a pump and the controller being operably connected to and receiving a first condition measurement from the first sensor and a second condition measurement from the second sensor;
- the controller including a feedback loop controlling the chiller's capacity in response to the first measured condition and the controller further including a feedforward loop controlling the chiller capacity in response to the second measured condition;
- and
- wherein the feedback and the feed forward loops each make independent control determinations and the independent control determinations are then combined in a comparitor and used to determine chiller capacity.
Dependencies are inferred from the claim text.