Method and apparatus for determining supercritical pressure in a heat exchanger
First Claim
1. A method of determining the supercritical pressure of a refrigerant in a heat exchanger in a transcritical vapor compression system, said method comprising:
- obtaining a plurality of measurements representative of the temperature of the refrigerant at spaced locations on the heat exchanger;
identifying a first location based upon said plurality of measurements wherein said first location is the approximate location of the minimum temperature gradient of the refrigerant within the heat exchanger; and
determining the pressure of the refrigerant within the heat exchanger based upon the identification of said first location.
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Accused Products
Abstract
A method and apparatus to determine the pressure of a supercritical refrigerant within a heat exchanger of a transcritical vapor compression system. A plurality of measurements, e.g., temperature, are obtained at spaced locations on the heat exchanger and the location of the minimum temperature gradient, i.e., maximum specific heat value of the refrigerant, is determined (“the inflection point”). Obtaining the refrigerant temperature at the inflection point allows the refrigerant pressure to be determined. Alternatively, the temperature of the refrigerant at a second point can be determined together with the change in specific enthalpy between the inflection point and the second point to thereby determine the pressure of the refrigerant. The system can be regulated by controlling the location of the inflection point or by controlling the temperature difference of the refrigerant at the inflection point and a second point, e.g., the outlet of the heat exchanger.
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Citations
26 Claims
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1. A method of determining the supercritical pressure of a refrigerant in a heat exchanger in a transcritical vapor compression system, said method comprising:
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obtaining a plurality of measurements representative of the temperature of the refrigerant at spaced locations on the heat exchanger;
identifying a first location based upon said plurality of measurements wherein said first location is the approximate location of the minimum temperature gradient of the refrigerant within the heat exchanger; and
determining the pressure of the refrigerant within the heat exchanger based upon the identification of said first location. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method of controlling the operation of a transcritical vapor compression system wherein the vapor compression system defines a closed loop circuit through which a refrigerant is circulated and including therein, in serial order, a compressor, a first heat exchanger, an expansion device and a second heat exchanger wherein the refrigerant is at a supercritical pressure within the first heat exchanger;
- said method comprising;
identifying a first location on the first heat exchanger wherein said first location is the approximate location of the minimum temperature gradient of the refrigerant within the heat exchanger;
regulating the operation of the transcritical vapor compression system by controlling at least one characteristic of said first location. - View Dependent Claims (14, 15, 16, 17, 18, 19)
- said method comprising;
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20. A transcritical vapor compression system, said system comprising:
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a closed loop circuit through which a refrigerant is circulated, said circuit including, in serial order, a compressor, a first heat exchanger, an expansion device and a second heat exchanger and wherein the refrigerant is at a supercritical pressure within said first heat exchanger;
a plurality of sensing devices mounted on said first heat exchanger at spaced locations each of said devices generating a signal representative of the temperature of the refrigerant within said first heat exchanger at a respective one of said spaced locations;
means for identifying a first location based upon said signals wherein said first location is the approximate location of the minimum temperature gradient of the refrigerant within said first heat exchanger; and
means for determining the pressure of the refrigerant within said first heat exchanger based upon the identification of said first location. - View Dependent Claims (21, 22, 23, 24, 25, 26)
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Specification