Adaptable evaporator defrost logic for an aircraft
AssigneeHamilton Sundstrand Corporation
InventorsKodjovi Coussey, Richard Rusich, Tejendra Patel, Anson Stark Coolidge
Life of this patent
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Abstract
Adaptable evaporator defrost logic is employed in a refrigeration system to detect a build-up of ice on the evaporator. In response to the detected build-up of ice, a defrost operation is initiated that includes decreasing the speed of the compressor. At the end of the defrost operation, the adaptable evaporator defrost logic determines whether the defrost operation was a success. If the defrost operation was a success, then normal operation is resumed. If the defrost operation was not a success, then the defrost operation is modified by turning the compressor off and extending a duration of the defrost operation.
Claims15
A method of adaptably defrosting an evaporator in a refrigeration system installed on an aircraft, the method comprising:
- detecting a build-up of ice on the evaporator in the refrigeration system installed on the aircraft;
- initiating in response to detecting the build-up of ice an adaptable defrost operation that includes reducing compressor speed of a compressor to a minimum value greater than zero, wherein the defrost operation includes waiting for a first duration of time after detecting the build-up of ice on the evaporator before initiating the defrost operation, wherein the first duration of time is variable and is based on operating conditions of the refrigeration system that include whether the aircraft is on the ground or in the air;
- and
- determining whether the defrost operation was successful, wherein if the defrost operation was successful then normal operation is resumed at the expiration of the defrost operation, wherein if the defrost operation was not successful, then the defrost operation is modified by turning the compressor off and extending a duration of the defrost operation.
A controller system for a refrigeration system installed on an aircraft, the refrigeration system including at least an evaporator, a compressor and a refrigerant circulated between the evaporator and the compressor, wherein the flow of refrigerant through the evaporator is based, in part, on a speed of the compressor, the controller system comprising:
- a compressor controller that controls the speed of the compressor of the refrigeration system installed on the aircraft;
- and
- a processor unit connected to provide control instructions to the compressor controller to control the operation of the compressor, wherein the processing unit monitors refrigerant pressure provided at an output of the evaporator, and based on the monitored refrigerant pressure detects the presence of ice build-up on the evaporator, wherein in response to detected ice build-up the processor unit implements an adaptable defrost operation that includes reducing the speed of the compressor, wherein the adaptable defrost operation implemented by the processor unit includes waiting for a first duration of time after detecting the build-up of ice on the evaporator before initiating the defrost operation, wherein the first duration of time is variable and is based on operating conditions of the refrigeration system that include whether the aircraft is on the ground or in the air.
A refrigeration and control system installed on an aircraft, the refrigeration and control system comprising:
- an evaporator that receives a refrigerant at an input and provides cooling to an airflow by evaporating the refrigerant;
- a compressor driven by a compressor motor to operate at a determined speed, wherein the speed of the compressor determines a flow rate of refrigerant through the evaporator;
- a condenser connected to condense the refrigerant provided by the compressor;
- an electronic expansion valve (EEV) selectively controlled by an EEV motor to control the flow of refrigerant provided to the evaporator;
- and
- a processing unit that provides control instructions to the compressor motor and the EEV motor to control the operation of the compressor and the EEV, the processing unit further connected to monitor a pressure associated with the refrigerant provided at the output of the evaporator, wherein the processing unit detects a build-up of ice on the evaporator based on the monitored pressure and in response executes an adaptable defrost operation that includes at least one of decreasing the speed of the compressor motor and at least partially closing the EEV value to decrease the flow of refrigerant provided to the evaporator, wherein the adaptable defrost operation includes waiting for a first duration of time after detecting the build-up of ice on the evaporator before initiating the defrost operation, wherein the defrost operation runs for a second duration of time, wherein if the defrost operation is not successful, the defrost operation continues for a third duration of time, and wherein at least one of the first duration of time, the second duration of time, and the third duration of time is variable and depends on operating conditions of the refrigeration system that include whether the aircraft is on the ground or in flight.
Dependencies are inferred from the claim text.