Refrigeration system and method using multiple variable capacity devices
View Patent ↗A system and method of controlling a compressor rack having a plurality of variable capacity components is provided. A variable capacity component is selected from the plurality of variable capacity components as a designated variable capacity component. The designated variable capacity component is operated by varying a capacity of the designated variable capacity component. Each variable capacity component of the plurality of variable capacity components, except for the designated variable capacity component, is operated at a fixed capacity corresponding to one of a maximum and a minimum capacity of the variable capacity component.
1. A method of controlling a compressor rack having a plurality of variable capacity components comprising:
selecting a variable capacity component from said plurality of variable capacity components as a designated variable capacity component, a capacity of each variable capacity component being continuously variable within an associated variable capacity range;
operating said designated variable capacity component by varying said capacity of said designated variable capacity component;
operating each variable capacity component of said plurality of variable capacity components, except for said designated variable capacity component, at a fixed capacity corresponding to one of a maximum and a minimum capacity of said each variable capacity component.
2. The method of claim 1 further comprising determining a desired rate of change of a compressor rack operating parameter, wherein said selecting said variable capacity component includes comparing said desired rate of change with said associated variable capacity range for said each variable capacity component and selecting said variable capacity component having a largest variable capacity range, that meets said desired rate of change, as said designated variable capacity component.
3. The method of claim 1 further comprising determining a desired rate of change of a compressor rack operating parameter, wherein said selecting said variable capacity component includes comparing said desired rate of change with said associated variable capacity range for said each variable capacity component, ranking each variable capacity component that meets said desired rate of change, based on a predetermined preference for operating said each variable capacity component, and selecting said variable capacity component as said designated variable capacity component based on said ranking.
4. The method of claim 1 further comprising:
determining a desired rate of change of a compressor rack operating parameter;
varying said capacity of said designated variable capacity component to meet said desired rate of change while said desired rate of change is within said associated variable capacity range of said designated variable capacity component;
cycling an additional component of said compressor rack when said designated variable capacity component is operating at a maximum or a minimum capacity and when said desired rate of change is not met.
5. The method of claim 1 further comprising selecting a different variable capacity component from said plurality of variable capacity components as said designated variable capacity component, when at least two variable capacity components are concurrently operating, based on comparing said associated variable capacity range of each of said at least two variable capacity components such that a larger variable capacity range is preferred over a smaller variable capacity range.
6. The method of claim 1 further comprising selecting a different variable capacity component from said plurality of variable capacity components as said designated variable capacity component, when at least two variable capacity components are concurrently operating, based on a run-time of each of said at least two variable capacity components, such that a shorter component run-time is preferred over a longer component run-time.
7. The method of claim 1 further comprising deactivating said designated variable capacity component after deactivating all other components of said compressor rack.
8. The method of claim 7 wherein said deactivating said designated variable capacity component occurs when a pump-down condition is detected.
9. The method of claim 1 further comprising determining whether a smaller variable capacity component is available and decreasing capacity of said compressor rack by switching said designated variable capacity component to said smaller variable capacity component after deactivating all other components of said compressor rack.
10. A system comprising:
a controller for a compressor rack having a plurality of variable capacity components;
a computer readable medium accessible to said controller and storing a neural network having a plurality of neurons, each neuron being associated with a corresponding variable capacity component and having a neuron output based at least in part on a predetermined preference for operating said corresponding variable capacity component;
said controller being configured to reference said neural network and evaluate said neuron output for each neuron of said neural network, to select a variable capacity component as a designated variable capacity component based on said evaluating, to operate said designated variable capacity component by varying a capacity of said designated variable capacity component, and to operate each variable capacity component of said plurality of variable capacity components, except for said designated variable capacity component, at a fixed capacity corresponding to one of a maximum and a minimum capacity of said each variable capacity component.
11. The system of claim 10 wherein said neuron output is based at least in part on whether a desired rate of change of a compressor rack operating parameter is within a variable capacity range of said corresponding variable capacity component.
12. The system of claim 11 wherein said predetermined preference is determined based on a variable capacity range of said corresponding variable capacity component and said controller is configured to evaluate said neuron output for each neuron to select said variable capacity component having a largest variable capacity range, that meets said desired rate of change, as said designated variable capacity component.
13. The system of claim 10 wherein said controller is configured to determine a desired rate of change of a compressor rack operating parameter, to vary a capacity of said designated variable capacity component to meet said desired rate of change while said desired rate of change is within a variable capacity range of said designated variable capacity component, and to cycle an additional component of said compressor rack when said designated variable capacity component is operating at a maximum or a minimum capacity and when said desired rate of change is not met.
14. The system of claim 10 wherein said computer readable medium stores an additional neural network having a plurality of neurons, each neuron being associated with a corresponding variable capacity component and having a neuron output based at least in part on a run time of said corresponding variable capacity component such that a shorter component run-time is preferred over a longer component run-time, said controller being configured to evaluate said neuron output for each neuron of said additional network when at least two variable capacity components are concurrently operating and to select a different variable capacity component as said designated variable capacity component based on said evaluating.
15. The system of claim 10 wherein said computer readable medium stores an additional neural network having a plurality of neurons, each neuron being associated with a corresponding variable capacity component and having a neuron output based at least in part on a variable capacity range of said corresponding variable capacity component such that a larger variable capacity range is preferred over a smaller variable capacity range, said controller being configured to evaluate said neuron output for each neuron of said additional network when at least two variable capacity components are concurrently operating and to select a different variable capacity component as said designated variable capacity component based on said evaluating.
16. The system of claim 10 wherein said controller is configured to deactivate said designated variable capacity component after deactivating all other components of said compressor rack.
17. The system of claim 16 wherein said controller is configured to deactivate said designated variable capacity component when a pump-down condition is detected.
18. The system of claim 10 wherein said controller is configured to determine whether a smaller variable capacity component is available and to decrease capacity of said compressor rack by switching said designated variable capacity component to said smaller variable capacity component after deactivating all other components of said compressor rack.