Refrigeration control using fluctuating superheat

Claim 1

A system for controlling a refrigeration apparatus of the type having a fluid refrigerant that changes state between a liquid phase at a first energy and a vapor phase at a second energy, comprising: a flow control system for regulating the flow of refrigerant; sensor system positioned for detecting a parameter indicative of refrigerant energy; recognition system coupled to said sensor system for discriminating between an energy associated with a predominately liquid phase and an energy associated with a predominately vapor phase; control system coupled to said recognition system and coupled to said flow control system for operating the flow control system such that the energy of said refrigerant at said sensor position fluctuates alternately between an energy associated with the predominately liquid phase and an energy associated with the predominately vapor phase.

Claim 2

A system for controlling a refrigeration apparatus of the type having a fluid refrigerant that changes state between a liquid phase at a first energy and a vapor phase at a second energy, comprising: a flow control system for regulating the flow of refrigerant; sensor system positioned for detecting a parameter indicative of refrigerant energy; recognition system coupled to said sensor system for discriminating between an energy associated with a predominately liquid phase and an energy associated with a predominately vapor phase; control system coupled to said recognition system and coupled to said flow control system for operating the flow control system such that the energy of said refrigerant at said sensor position fluctuates alternately between an energy associated with the predominately liquid phase and an energy associated with the predominately vapor phase.

Claim 3

The system of claim i wherein said refrigeration apparatus employs a heat exchanger having an inlet for introducing fluid refrigerant in the predominately liquid phase and having an outlet for discharging fluid refrigerant in the predominately vapor phase, and wherein said sensor system comprises sensor device positioned adjacent to the outlet of said heat exchanger.

Claim 19

A method for controlling the flow of refrigerant in a refrigeration apparatus of the type at least one refrigerant energy sensor and having a fluid refrigerant that changes state from a liquid state at a first energy to a liquid state at a second energy, with an intermediate chaotic transition state between the liquid state and the vapor state, comprising: ascertaining a first value indicative of the state of the refrigerant at said energy sensor during a first time interval while obtaining a second value indicative of the error between the average energy of the refrigerant at said energy sensor during a first time interval and the average energy of the refrigerant at said energy sensor during a time interval prior to said first time interval; operating a flow control mechanism to control the flow of refrigerant based on a control factor determined from said first and second values, as follows: using said first value to identify the operating regime as being one of the following: a vapor state, an LDOP state and a flood state; using said first and second values to determine a flow rate control factor that causes said flow of refrigerant: (a) to increase at a first rate when operating in the vapor state (b) to decrease at a second rate when operating in the flood state and (c) to fluctuate between increasing and decreasing when operating in said LDOP state, such that refrigerant flow seeks said LDOP state at said energy sensor.

Claim 20

A method for controlling the flow of refrigerant in a refrigeration apparatus of the type at least one refrigerant energy sensor and having a fluid refrigerant that changes state from a liquid state at a first energy to a liquid state at a second energy, with an intermediate chaotic transition state between the liquid state and the vapor state, comprising: ascertaining a first value indicative of the state of the refrigerant at said energy sensor during a first time interval while obtaining a second value indicative of the error between the average energy of the refrigerant at said energy sensor during a first time interval and the average energy of the refrigerant at said energy sensor during a time interval prior to said first time interval; operating a flow control mechanism to control the flow of refrigerant based on a control factor determined from said first and second values, as follows: using said first value to identify the operating regime as being one of the following: a vapor state, an LDOP state and a flood state; using said first and second values to determine a flow rate control factor that causes said flow of refrigerant: (a) to increase at a first rate when operating in the vapor state (b) to decrease at a second rate when operating in the flood state and (c) to fluctuate between increasing and decreasing when operating in said LDOP state, such that refrigerant flow seeks said LDOP state at said energy sensor.