METHOD AND APPARATUS FOR OPTIMIZING REFRIGERATION SYSTEMS

• US 20130269376A1
• Filed: 06/10/2013
• Published: 10/17/2013
• Est. Priority Date: 12/09/2002
• Status: Active Grant

• Current Assignee: Hudson Technologies, Inc.
• Original Assignee: Hudson Technologies, Inc.
• Inventors: Zugibe, Kevin, Papar, Riyaz
• Granted Patent: US 9,423,165 B2
• Time in Patent Office: Days
• US Class Current: 62/115
• CPC Class Codes: F25B 2500/16 Lubrication
• CPC Class Codes: F25B 2500/19 Calculation of parameters
• CPC Class Codes: F25B 2600/05 Refrigerant levels
• CPC Class Codes: F25B 43/02 for separating lubricants from the refrigerant
• CPC Class Codes: F25B 45/00 Arrangements for charging or discharging refrigerant
• CPC Class Codes: F25B 49/02 for compression type machines, plants or systems
• CPC Class Codes: G01N 25/18 by investigating thermal conductivity by calorimetry G01N25/20; by measuring change of resistance of an electrically-heated body G01N27/18
• CPC Class Codes: G06F 2119/18 Manufacturability analysis or optimisation for manufacturability
• CPC Class Codes: G06F 30/20 Design optimisation, verification or simulation optimisation, verification or simulation of circuit designs G06F30/30
• CPC Class Codes: G06F 30/27 using machine learning, e.g. artificial intelligence, neural networks, support vector machines [SVM] or training a model
• CPC Class Codes: G06F 30/39 Circuit design at the physical level physical level design for reconfigurable circuits G06F30/347
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]

Abstract

A control system for controlling a refrigeration system having an operating point, comprising: a memory configured to store a relationship of at least an evaporator efficiency, an evaporator heat load, a refrigerant amount in the evaporator, and a variable dependent on a non-volatile liquid mixed with refrigerant in the evaporator an input port configured to receive a signal corresponding to at least a measured evaporator heat load during operation; an output port configured to present an output to selectively alter an operating point of the evaporator, by altering the refrigerant amount in the evaporator and thereby changing the variable; and a processor, configured to receive the signal, access the memory; and generate the output to selectively move toward an optimum operating point. A corresponding method and refrigeration system are provided.

Claims

1. An apparatus, comprising:

an input for receiving physical parameters useful for a thermodynamic analysis of refrigeration system performance;

a processor for performing a thermodynamic analysis of the refrigeration system and determining consistency of the thermodynamic analysis; and

an output for presenting an estimate of deviance from an optimal state of the refrigeration system based on said thermodynamic analysis and said consistency analysis.

2. The apparatus according to claim 1, wherein said processor estimates a refrigeration efficiency of the refrigeration system in an operational state, further comprising means for altering a process variable of the refrigeration system during efficiency measurement and calculating a process variable level which achieves an optimum efficiency.

3. The apparatus according to claim 1, further comprising a control for altering physical parameters by altering at least one of an oil concentration in an evaporator and a refrigerant charge of said refrigeration system.

4. A method for determining a deviance from optimum of a refrigeration system, comprising:

obtaining physical parameters for a thermodynamic analysis of refrigeration system performance;

performing a thermodynamic analysis of the refrigeration system;

determining consistency of the thermodynamic analysis with a model of the refrigeration system; and

outputting an estimate of deviance from an optimal state of the refrigeration system based on said thermodynamic analysis and said consistency analysis.

5. The method according to claim 4, wherein said estimate of deviance is used to determine a need for refrigeration system service.

6. The method according to claim 4, wherein said estimate of deviance is used to estimate a refrigeration system capacity.

7. The method according to claim 4, wherein said thermodynamic analysis relates to a state of the refrigeration system, further comprising the step of monitoring refrigeration system performance in real time over a range of operating conditions to determine operating-condition sensitive physical parameters.

8. The method according to claim 4,

wherein said thermodynamic analysis comprises estimating an efficiency of the operating refrigeration system;

further comprising the steps of;

altering a process variable of the refrigeration system;

calculating a refrigeration system characteristic based on an analysis of obtained physical parameters after said alteration; and

optimizing a process variable level in accordance with the determined system characteristic.

9. The method according to claim 8, wherein the process variable is compressor oil dissolved in the refrigerant in the evaporator.

10. The method according to claim 8, wherein the process variable is refrigerant charge condition.

11. The method according to claim 8, wherein the operating point is maintained by closed loop control based on the determined optimum efficiency process variable level.

12. The method according to claim 8, wherein the process variable is compressor oil dissolved in the refrigerant in the evaporator, and wherein the process variable is altered by separating oil from refrigerant in the refrigeration system.

13. The method according to claim 4, further comprising the step of predicting a cost-benefit of a service operation on said refrigeration system to correct at least a portion of the deviance from said optimal state.

14. The method according to claim 4, further comprising the steps of:

determining a sensitivity of the refrigeration system to perturbations of at least one operational parameter;

defining an efficient operating regime for the refrigeration system based on the determined sensitivity; and

performing a service of the refrigeration system to bring the at least one operational parameter within the efficient operating regime when the refrigeration system is operating outside the defined efficient operating regime and a correction thereof is predicted to be cost-efficient.

15. The method according to claim 14, wherein the operating regime has a non-trivial double ended range of values, and continued operation of the refrigeration system follows a consistent trend in change in operating point from a beginning of cycle operating point to an end of cycle operating point, wherein the service alters the at least one operational parameter to within a boundary of the non-trivial double ended range of values near the beginning of cycle operating point.

16. The method according to claim 14, wherein the service comprises a purification of the refrigerant.

17. The method according to claim 4, further comprising the step of predicting a refrigeration capacity of the refrigeration system.

18. The method according to claim 4, further comprising the steps of:

defining cost parameters of operation of the refrigeration system;

determining usage parameters of the refrigeration system;

predicting a thermodynamic effect of a service procedure on a machine with respect to efficiency;

estimating a cost of the service procedure; and

conducting a cost benefit analysis based on the operation cost parameters, usage parameters, predicted thermodynamic effect and estimated cost.

19. A method, comprising the steps of:

thermodynamically modeling a refrigeration system with respect to at least refrigerant purity and superheat level;

predicting a thermodynamic effect of an alteration of a refrigerant purity and compressor power;

altering at a refrigerant purity and a compressor power to achieve a predicted optimum condition under operating conditions.

20. The method according to claim 22, wherein compressor power is modulated by at least one of speed control, duty cycle control, compression ratio, and refrigerant flow restriction.