Refrigeration temperature control system
AssigneesWestinghouse Electric Corp., Honeywell Inc.
InventorsGreg Truckenbrod, Paul C. Wacker
Life of this patent
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Abstract
Apparatus for and method of long-term control of the temperature within a refrigerated space, such as the cargo compartment of a refrigeration truck. The technique employs sensors which monitor both discharge and return air. A control algorithm uses the multiple sensors to control modes of a refrigeration unit capable of supplying cooled or heated air. This causes the temperature within the refrigerated space to remain within a narrow range about a target temperature. The target is chosen to provide maximum safety for the cargo. If the target temperature is too high, the cargo is needlessly exposed to spoilage. If the target temperature is too low, the cargo is subject to the risk of damage from freezing.
Claims12
An apparatus for controlling a system for regulating temperature within a space comprising:
- a. a first sensor for measuring a first parameter of said system;
- b. a second sensor for measuring a second parameter of said system;
- c. means coupled to said first sensor and said second sensor for generating an error signal in response to said first parameter and said second parameter;
- d. means coupled to said generating means for computing an integrated error signal at an integration rate determined by said error signal;
- e. means for algebraically combining said error signal and said integrated error signal to produce a combined error signal;
- and,
- means coupled to said algebraically combining means for adding heat to said space and removing heat from said space in proportion to said combined error signal.
An apparatus according to claim wherein said first sensor further comprises a temperature sensor.
A method of controlling a temperature regulating system comprising:
- a. measuring a first parameter of said system;
- b. measuring a second parameter of said system;
- c. deciding from the value measured of said first parameter and said second parameter whether to control said system by said first parameter or said second parameter;
- d. computing an error signal from said selected parameter;
- e. computing an integrated error signal from said error signal by integrating at a rate determined by said error signal;
- f. algebraically combine said error signal and said integrated error signal to produce a combined error signal;
- and,
- g. controlling said system in response to said combined error signal.
Dependencies are inferred from the claim text.