Method and apparatus for optimizing refrigeration systems
First Claim
1. An apparatus, comprising:
- a memory, storing parameters of a model of a refrigeration system derived from a refrigeration system configuration and measurements of actual operational parameters of the refrigeration system in a known state;
at least one input adapted to receive operational physical parameters sufficient for performing a thermodynamic analysis of operation of the refrigeration system;
a processor for estimating a difference in operating cost due to a deviance of the refrigeration system in an operating state from the refrigeration system in the known state by performing a thermodynamic analysis of the refrigeration system in the operating state based on at least the at least one input and the stored parameters in the memory; and
an output for presenting the estimate of the difference in operating cost due to the deviance.
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Accused Products
Abstract
A refrigeration system comprising a compressor for compressing a refrigerant, a condenser for condensing refrigerant to a liquid, an evaporator for evaporating liquid refrigerant from the condenser to a gas, an inner control loop for optimizing a supply of liquid refrigerant to the evaporator, and an outer control loop for optimizing a level of refrigerant in the evaporator, said outer control loop defining a supply rate for said inner control loop based on an optimization including measurement of evaporator performance, and said inner control loop optimizing liquid refrigerant supply based on said defined supply rate. Independent variables, such as proportion of oil in refrigerant, amount of refrigerant, contaminants, non-condensibles, scale and other deposits on heat transfer surfaces, may be estimated or measured. A model of the system and/or a thermodynamic model approximating the system, for example derived from temperature and pressure gages, as well as power computations or measurements, is employed to determine or estimate the effect on efficiency of deviance from an optimal state. Various methods are provided for returning the system to an optimal state, and for calculating a cost-effectiveness of employing such processes.
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Citations
42 Claims
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1. An apparatus, comprising:
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a memory, storing parameters of a model of a refrigeration system derived from a refrigeration system configuration and measurements of actual operational parameters of the refrigeration system in a known state; at least one input adapted to receive operational physical parameters sufficient for performing a thermodynamic analysis of operation of the refrigeration system; a processor for estimating a difference in operating cost due to a deviance of the refrigeration system in an operating state from the refrigeration system in the known state by performing a thermodynamic analysis of the refrigeration system in the operating state based on at least the at least one input and the stored parameters in the memory; and an output for presenting the estimate of the difference in operating cost due to the deviance. - View Dependent Claims (2, 3)
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4. A method for determining a deviance from optimum of a refrigeration system, comprising:
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defining a first thermodynamic model of a refrigeration system in an optimal state based on measurements of actual operating parameters of the refrigeration system an actual costs of operation of the refrigeration system; obtaining physical parameters sufficient for performing a thermodynamic analysis of the refrigeration system at a time when the refrigeration system is not performing optimally; automatically performing a thermodynamic analysis of the refrigeration system based on the obtained physical parameters to define a second thermodynamic model; comparing the first thermodynamic model to the second thermodynamic model of the refrigeration system; and outputting a quantitative estimate of an operating cost of deviance of the state of the refrigeration system at the time when the refrigeration system is not performing optimally from the determined optimal state of the refrigeration system based on said comparing. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21)
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22. A method, comprising the steps of:
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thermodynamically modeling operation of a refrigeration system comprising a refrigerant having a refrigerant purity and a compressor operating at a compressor power, by acquiring actual operating parameters, to generate a thermodynamic model, and a determining a sensitivity of the thermodynamic model of the refrigeration system to perturbations with respect to at least the refrigerant purity and a superheat level; measuring an actual performance of the refrigeration system; predicting a thermodynamic effect of an alteration of the refrigerant purity and the compressor power with respect to the measured actual performance and the determined sensitivity; altering the refrigerant purity and the compressor power to in dependence on the predicted thermodynamic effect on the refrigeration system under operating conditions. - View Dependent Claims (23, 24, 25)
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26. A method, comprising the steps of:
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performing a thermodynamic analysis of a refrigeration system based on actual operational parameters to derive a thermodynamic model of the refrigeration system; determining an efficiency of the refrigeration system based on the thermodynamic model of the refrigeration system; determining a cost-efficient optimum range of operation of the refrigeration system based on the determined efficiency, a cost associated with operation of the refrigeration system in a respective operating state, and a cost associated with an alteration of at least one operating physical parameter of the refrigeration system to a respective different operating state; analyzing the thermodynamic model of the refrigeration system with respect to a set of measured thermodynamic data of the refrigeration system during operation at an operating state; and presenting an estimate of a deviance of the operating state from the optimal range of the refrigeration system, sensitive to at least said analyzing. - View Dependent Claims (27, 28)
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29. A method for analyzing a refrigeration system, comprising measuring physical parameters sufficient for performing a thermodynamic analysis of refrigeration system operation, determining a model of the refrigeration system which defines a refrigeration system configuration based on a thermodynamic analysis of the measured physical parameters;
- determining a sensitivity of an efficiency of the refrigeration system to changes in physical parameters based on measurements of refrigeration system performance under a plurality of different operating conditions, estimating a deviance from the defined system configuration of the refrigeration system, by performing an analysis of the model of the refrigeration system and measured operating parameters of the refrigeration system, and outputting the estimate of the deviance.
- View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
Specification